Stargazer Columns 2009

Dec. 26, 2009: Galileo's Moon
Dec. 12, 2009: The Aristotelian World Galileo Dismantled
Nov. 28, 2009: The Rescue of Princess Andromeda
Nov. 14, 2009: The Fox's Swan Song
Oct. 31, 2009: Galileo's New Universe a Book Worth Reading
Oct. 17, 2009: Our Garden of Eden in the Cosmos
Oct. 03, 2009: Stars of the Milky Way Triangle
Sep. 19, 2009: 2009: International Year of Astronomy
Sep. 05, 2009: Contact with Extraterrestrials
Aug. 22, 2009: Planets to Lose Moons and Rings
Aug. 08, 2009: Extraterrestrials
July 25, 2009: Hercules and Ophiuchus: Head-to-Head in the Night Sky
July 11, 2009: Where Were You July 20, 1969?
June 27, 2009: Sorting Out the Greek Gods
June 13, 2009: The World Made Smaller by the Internet
May 30, 2009: Astronomy in the Classroom
May 16, 2009: Cosmic Weight-Loss Plan
May 02, 2009: Arizona's Meteor Crater
Apr. 18, 2009: Saturn's Rings
Apr. 04, 2009: Total Eclipses of the Sun in our Future
Mar. 21, 2009: Astronomy or Astrology?
Mar. 07, 2009: Vernal Equinox
Feb. 21A, 2009: Comet Lulin
Feb. 21B, 2009: Stargazin' and Noticin'
Feb. 07, 2009: International Year of Astronomy
Jan. 24, 2009: That Lucky Old Sun
Jan. 10, 2009: Jupiter's New Moons

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Dceember 26, 2009
Stargazer #521

Galileo's Moon

Four hundred years ago this month, in December 1609, Galileo began his telescopic study of the Moon and almost immediately found evidence that challenged the Aristotelian view that was fundamental to much of the scholarly and ecclesiastical thinking of the day.

The ancient Greek philosopher Aristotle set forth a world view that still influenced Galileo's 17th century world nearly 2,000 years later. According to Aristotle, Earthly things, composed of earth, water, air, and fire, were imperfect, changing, and subject to death and decay, whereas heavenly bodies, composed of aether (quintessence), were of a completely different nature. They were perfect, eternal, and unchanging, thus objects beyond Earth were perfectly round with perfectly smooth surfaces.

Viewed with the naked eye, the Moon appears perfectly round, and even with its obvious darker and lighter areas, it could well have been perfectly smooth, like a multi-shaded marble.

But that's not what Galileo's telescope revealed. He saw what appeared to be mountains and other seemingly uneven terrain. After observing the same areas several nights and giving attention to the changing shadows they cast, it became clear to him that the Moon was not perfectly smooth. Indeed, in many ways, its surface resembled that of Earth's -- the Moon appeared more Earth-like than heavenly.

Being an astute mathematician, Galileo even used shadows and basic geometry to estimate the highest Moon mountains to be some 4 miles high.

He also noted that the Moon's surface was covered with countless roundish areas of widely varying sizes. By studying their shadows, he determined that they were depressions in the Moon, although he never knew what caused them. We now know them to be craters formed from meteor impacts.

When the Moon is in its thin crescent phase, one can easily see its faintly lit night side, even with the naked eye. In Galileo's day many assumed the glow came from the Moon itself, but from his observations, Galileo correctly deduced that earthshine -- sunlight reflecting off Earth -- produced the faint glow, showing that imperfect Earth could have an effect on a heavenly body.

Galileo's lunar discoveries put the first cracks in Aristotle's world view, and there were more to come which we will look at in future columns.

• Next Two Weeks. Avg. sunrise: 7:28 a.m.; avg. sunset: 5:37 p.m. (exact for Waco, TX)
  * Thursday's full Moon, the second of the month, is popularly referred to as a Blue Moon, although it has nothing to do with its color.
  * Jan. 2 the Earth is at perihelion, its nearest point to the Sun in its annual orbit.
  * The Moon is at last quarter Jan. 7.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Evening: Jupiter is the brightest object in the southwest; Mercury is just above the west southwestern horizon at dusk; Mars now rises late in the evening. Morning: Saturn is high in the south with Mars high in the west southwest.

• Astro Milestones. Dec. 25 is the 367th birthday of Isaac Newton (1642-1727), father of modern physics. Dec. 27 is the 438th birthday of Johannes Kepler (1571-1630), discoverer of elliptical orbits.

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December 12, 2009
Stargazer #520

The Aristotelian World Galileo Dismantled

Four hundred years ago, an Italian mathematics professor named Galileo Galilei unwittingly made a dramatic career change when he turned his new telescope skyward and became the world's first telescopic astronomer.

But Galileo didn't merely marvel at the never-before seen sights in the night sky. He gave serious, and often ingenuous thought, to what he saw, and began making discoveries and inferences that profoundly changed our view of the cosmos and our place in it, and in so doing, firmly affixed his lauded place in history.

The 17th century scholarly view of the cosmos was still dominated by the teachings of the Greek philosopher Aristotle (384-322 BCE). And many of his ideas about the nature of things, being more akin to beliefs and conjectures than observation-based science, came to be incorporated into the dogma of Christian religion. Thus, in both academia and the church, Aristotle's world view carried great weight for the better part of two millennia. [Photo: Computeranimated picture of Aristotle by Kolja Mendler (Wikimedia)]

The Aristotelian view saw the Earth and all things earthly as composed of four substances: earth, water, air, and fire. Thus the things of our world -- the realm of imperfect humans -- were imperfect, changing, and subject to death and decay.

All heavenly bodies beyond Earth, were composed of a substance not found on Earth called aether (or quintessence) which was perfect, eternal, and unchanging -- indeed, godly.

Heavenly things were perfectly round with perfectly smooth surfaces; the eternal heavens were fixed and unchanging; and with Earth at the center of the universe, all heavenly objects orbited Earth in perfectly circular orbits.

It was probably not his original intent, yet Galileo and his telescope began to dismantle this world view piece by piece. Each discovery seemed to refute a key element of the Aristotelian view, and in so doing, challenged the official teachings of the Roman Catholic Church, ultimately getting Galileo in big trouble.

In December 1609, Galileo began his study of the heavens, focusing first on the Moon. Next time, we'll see what he found and which part of Aristotle's world view took the first hit.

[Much of the above information is from Stephen P. Maran and Laurence A. Marschall's highly recommended book, Galileo's New Universe, which was recently reviewed in this column. (See below.)]

• Next Two Weeks. Avg. sunrise: 7:23 a.m.; avg. sunset: 5:29 p.m. (exact for Waco, TX)
  * Tomorrow (Sunday) night the Geminid meteor shower peaks with no Moon interference.
  * The Moon is new Wednesday.
  * The crescent Moon is below Jupiter the evening of Dec. 20, and above the planet the next evening.
  * Dec. 21 is the Northern Hemisphere's winter solstice, the first day of winter and shortest day of year after, which days begin growing longer.
  * The Ursid meteor shower peaks the night of Dec. 22 with the best viewing after the Moon sets around 11 p.m.
  * The Moon is at 1st quarter Dec. 24.
  

• Naked-eye Planets.
  Evening: Jupiter is the brightest object in the southwest; Mercury is near the west southwestern horizon at dusk.
  Morning: Saturn is high in the southeast with Mars even higher in the southwest. Venus is all but lost in the glare of the rising Sun.
  

• Star Party. The Central Texas Astronomical Society's free monthly star party is tonight at the Lake Waco Wetlands beginning at 7 p.m., weather permitting. For directions see my Web site.

• Astro Milestones. Dec. 14 is the 463rd birthday of Danish astronomer Tycho Brahe (1546-1601) whose meticulous observations and records of Mars' movement over many years enabled Johannes Kepler to discover elliptical orbits.

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November 28, 2009
Stargazer #519

The Rescue of Princess Andromeda

It's the time of year for Hero Perseus' annual rescue of Princess Andromeda, the damsel in the sort of distress only the ancients could have dreamed up.

It all started with Andromeda's brash mother, Queen Cassiopeia, who lacked the good graces -- and good sense -- to keep her bragging under control. Always raving about her daughter's beauty, she once went too far, claiming that Andromeda was more beautiful than the sea nymphs.

Big mistake. Neptune, the powerful god of seas swore revenge. He kidnapped Andromeda, chained her to a small island, and left her to be devoured by Cetus the Sea Monster.

Enter Perseus the Hero. Hearing of Andromeda's plight, he appealed for help from another of the gods, and was told to go to the cave of Medusa and cut off her head. Medusa, who had snakes rather than hair growing from her head, was so hideously and frightfully ugly that anyone who looked upon her was petrified with terror and turned into stone. All Perseus had to do was take Medusa's head out to sea, show it to Cetus who would be turned to stone, and then rescue Andromeda.

Simple enough, yet there were a couple of problems. How could he cut off Medusa's head if he dared not look at her, and how could he quickly get to the island where Andromeda was soon to become a sea monster's snack.

More help from the gods. They gave him a shiny shield with which he could dimly, but not clearly, see Medusa enough to sever her head and put it in a sack. Then upon accomplishing that feat, from Medusa's headless body emerged Pegasus, a flying horse.

So, as adeptly as my childhood hero cowboy Gene Autry mounted Champion every Saturday afternoon, our hero mounted Pegasus. With Medusa's head stashed in the sack, he took to the skies and headed to sea, hoping he wasn't too late to make his rescue.

He arrived just in time to find Cetus licking his chops as he approached the poor hapless Andromeda. Perseus uncovered Medusa's hideous head -- without looking at it, of course -- and showed it to Cetus who shrieked in terror, turned to stone, and sank to the bottom of the sea. After tossing the head into the sea, Perseus steered Pegasus down to the island whereupon he freed the grateful Andromeda, and returned her to her home.

Perseus was so taken with Andromeda's charm and beauty -- all princesses are beautiful, right? -- and she was so overcome by his bravery and good looks -- all heroes are handsome, right? -- that they married and lived happily ever after.

This Greek myth is played out each evening in the fall sky. The diagram of the Andromeda's Rescue region shows the constellations of these characters. Facing south, the great Square of Pegasus is high over head.

• Next Two Weeks. Avg. sunrise: 7:13 a.m.; avg. sunset: 5:25 p.m. (exact for Waco, TX)
  * Wednesday's full Moon is called the Moon Before Yule and the Long Night Moon.
  * The Moon is at 3rd quarter Dec. 8.
  * The morning of Dec. 10 the crescent Moon is to the lower right of Saturn in the southeast, and the next morning is to the right of the Virgo's brightest star Spica.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Jupiter is the brightest object in the south.
  Morning: Saturn is midway up in the southeast with Mars high in the southwest. Venus doesn't appear until well into dawn, rising only 45 minutes before the Sun.

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November 14, 2009
Stargazer #518

The Fox's Swan Song

High in the west in the early evening are the three bright stars forming the Milky Way Triangle, also called the Summer Triangle. Each is the brightest star of its respective constellation.

The brightest by far is Vega in Lyra the Lyre (harp). Next brightest is Altair in Aquila the Eagle, and the least bright of the three is Deneb in Cygnus the Swan.

Finding them isn't too difficult. Facing west, Vega is mid way a bit to the right (north) with Altair mid way up to the left (south). Deneb is higher above Vega.

Within the triangle are two other constellations: Vulpecula the Fox and Sagitta the Arrow. Both are smaller, consist only of faint stars, and are difficult to see. But Vulpecula, a cunning and stealthy hunter, likes it that way.

Most foxes are content with a diet of small animals, insects, and fruits -- but not Vulpecula. Although sly, he has a foolish streak that's about to do him in. While out looking for a meal, he has spotted huge Cygnus flying in his direction. Prudence would warn other foxes against taking on such a large prey, but not Vulpecula. Thinking only of what a tasty meal the big bird would be, his mouth is watering as he throws caution to the wind.

Off in the distance he failed to note Sagittarius the Archer also out hunting; the archer barely missed the fox as Sagitta the Arrow whizzes just beneath his belly. But the archer won't have time for a second shot for Aquila, the large eagle, is swooping down, about to turn the careless Vulpecula from predator to prey.

Not far away, Lyra is watching the drama unfold with its harp strings softly strumming the fox's swan song.

The moral of the story? There's nothing wrong with thinking big -- just don't become blinded by greedy ambition.

• Next Two Weeks. Avg. sunrise: 7:02 a.m.; avg. sunset: 5:27 p.m. (Exact for Waco, TX)
  * Tomorrow morning a thin crescent Moon is to the right of Venus near the eastern horizon at dawn.
  * The Moon is new Monday.
  * Tuesday morning (midnight to dawn) the Leonid meteor shower peaks with no Moon interference and possibly enhanced rates.
  * The evening of Nov. 23 Jupiter is to the lower left of the Moon. The Moon is at 1st quarter Nov. 24.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Evening: Jupiter is the brightest object in the south. Morning: Venus, near the eastern horizon at dawn, is fast approaching the rising Sun. Saturn is well up in the east with Mars high in the south.

• Astro Milestones. Nov. 20 is the 120th birthday of Edwin Hubble (1889-1953), American astronomer for whom the Hubble Space Telescope is named. While not as well known as Galileo and others who revolutionized our cosmic understandings, Hubble's contributions were no less profound. In 1924 the then-35-year old astronomer discovered that what was considered to be the Andromeda "nebula" was, in fact, another far-away galaxy. Up to that time, astronomers thought our Milky Way galaxy was the entire universe. But thanks in large part to Hubble, we now realize the universe is far more vast than was ever imagined, and that it contains countless billions of galaxies besides our own.

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October 31, 2009
Stargazer #517

Galileo's New Universe a Book Worth Reading

Being the 400th anniversary of Galileo's first astronomical use of the telescope, 2009 is being celebrated as the International Year of Astronomy. As such, it's not surprising to see new books and articles on the subject. One book that has come to my attention is Galileo's New Universe: The Revolution in Our Understanding of the Cosmos by astronomers Stephen P. Maran and Laurence A. Marschall (Benbella Books, Dallas, 2009). At 174 pages and $14.95, it's an easy and inexpensive read which I highly recommend.

Having already read many accounts of Galileo's story, I was tempted to pass on the book, but I'm glad I didn't. While it contains much I already knew, there's plenty of new material to make it well worth my while. And beyond that, the literary device used by the authors is engaging.

After a brief but informative account of Galileo's story, they devote a chapter each to telescopes, the Moon, the Sun, Jupiter, Saturn, Venus, comets, the Milky Way, and cosmology. With each, they present the 17th century view followed by the contemporary, dramatically illustrating the progress of the past 400 years.

For example, they describe the telescopes Galileo made and used for his Earth-shaking discoveries in the early 1600s, telescopes that were inferior even to today's inexpensive department store scopes. They then describe today's huge observatory telescopes, and the mammoth scopes currently under development -- instruments Galileo couldn't have imagined in his wildest dreams.

With each of the other topics, they relate what was known to Galileo and his contemporaries, and then contrast that with what we now know 400 years later. It is sobering to realize that even many of the school children with whom I work could teach the brilliant Galileo things about the solar system and the cosmos that would leave him dumbfounded.

In future columns, drawing from this book, we'll look at the Moon, Sun, and planets as they were understood then and now. In the meantime, just for fun, imagine traveling into the future and reading a comparable book that contrasts what we know today with what our descendants will know in 2409.

Time Change. Tonight (Saturday) before retiring, set your clocks back one hour ("fall back") to Standard Time.

• Next Two Weeks. Avg. sunrise: 6:49 a.m.; avg. sunset: 5:35 p.m. (exact for Waco, TX)
  * Today (Saturday) is Halloween, a traditional cross-quarter day celebrating the middle of fall.
  * The mornings of Oct. 30 - Nov. 2, Mars passes through the Beehive star cluster high in the southeast; binoculars will help.
  * The Nov. 2 full Moon is called the Hunter's Moon, Frosty Moon, and Beaver Moon.
  * The morning of Nov. 9, the Moon is at 3rd quarter with Mars above it.
  * The morning of Nov. 12 Saturn is to the left of the crescent Moon low in the east southeast at dawn.

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Evening: Jupiter is the brilliant object in the south. Morning: "Morning star" Venus is near the eastern horizon at dawn with creamy-colored Saturn higher in the east and reddish Mars high overhead.

• Star Party. The Central Texas Astronomical Society's free monthly star party is Saturday, Nov. 7, at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this Web site.

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October 17, 2009
Stargazer #516

Our Garden of Eden in the Cosmos

There are many things I like about stargazing, not the least of which is the unfathomable beauty and wonder found in the night sky. I especially appreciate how this can be enjoyed at many levels.

Peering naked-eye into the richness of the Milky Way under a dark moonless sky, observing unimaginably distant objects through binoculars and telescopes, seeing images from the incredible Hubble Space Telescope -- things I've done so many times one might suspect by now a 69-year old stargeezer like me would be jaded by it all. But one would be wrong. The beauty and wonder of the cosmos can still take my breath away and leave me without words. I doubt I'll ever tire of it.

That being said, after recently watching all six episodes of Ken Burns' "The National Parks: America's Best Idea" on PBS, I've had to refocus my perspective just a bit. I've not been unaware of beauty and wonder of nature right here on Earth. For years our family has traveled, visited and camped in numerous parks in many states and even other countries, and I've had a special love affair with Big Bend and the Davis Mountains since my first visit in 1970.

So how could the program expand my view? A comment by a narrator about Earth being a Garden of Eden got me thinking. According to the Hebrew creation story, Earth was a Garden of Eden until our long-ago ancestors messed up and got thrown out.

But when I behold the beauty, magnificence and bounteousness our planet still has to offer, I wonder if the ancients really got the story right. Maybe we're still in the garden, and it remains to be seen whether we will preserve or destroy it.

Yes, the beauty of the Milky Way, the full Moon, and Venus as the "evening star" are hard to beat. Views of Saturn and its rings never fail to awe. And what artist could match some of nature's exquisite colors and shapes captured by Hubble?

Yet, within our solar system, Earth is the only place we can survive, much less find hospitable. We would burn to ashes on Mercury and Venus, and freeze solid on the outer planets and their moons, and even on our Moon. And even if we didn't burn or freeze, we would be hard pressed to find food to eat, air to breathe, and water to drink.

Some day our species will surely colonize the Moon, Mars and beyond, living in biospheres that provide food, air, water and comfortable temperatures. But will they have mountains to climb, rivers to raft, glaciers to hike, oceans to swim in, beaches for building sand castles, fields and forests to romp through? Will they have Old Faithful, Niagara Falls, giant sequoia and redwood trees, whales, and crying seagulls chasing after fishing boats?

The first line of a marvelous "Sesame Street" song comes to mind: "I'd like to visit the Moon, but I don't think I'd like to live there."

To be sure, I'll never cease marveling at the beauty and wonder of the distant cosmos, but I'll make sure I also look around and fully appreciate the Garden of Eden in my own back yard.

• Next Two Weeks. Avg. sunrise: 7:38 a.m.; avg. sunset: 6:47 p.m. Tomorrow the Moon is new. This could be a good year for the Orionid meteor shower which peaks Tues. night with no Moon interference virtually all night. The Moon is at 1st quarter Oct. 25, and the next evening, bright Jupiter is to the Moon's left.

• Naked-eye Planets. Evening: Jupiter is the brightest object in the south. Morning: At dawn Venus is low in the east with Saturn above and Mercury below near the horizon; Mars is high in the east.

• Astro Milestones. Oct. 29 is the 353rd birthday of Edmund Halley (1656-1742), English astronomer of Halley's Comet fame.

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October 3, 2009
Stargazer #515

Stars of the Milky Way Triangle

The Milky Way Triangle, also called the Summer Triangle, is currently high overhead in the early evening. Formed by three of the night sky's bright stars -- Vega, Altair, and Deneb -- the triangle is easy to identify.

Vega, the brightest overhead star, is a little to the northwest of the sky's straight-up point, called the zenith. Then with your hand held at arm's length, Deneb, the faintest of the triangle stars, is two fist-widths to the northeast of Vega. Altair, to the south, is four fist-widths from Deneb and three from Vega.

Although easily recognizable, the Milky Way Triangle is not an official constellation but rather is an asterism -- an informal pattern of stars. Each star of the triangle is the brightest star of its own constellation.

Vega, the night sky's fifth brightest star, is part of Lyra, the Musical Lyre, one of the smallest constellations. It's most distinctive feature is a small parallelogram hanging from Vega.

Deneb is the tail of Cygnus, the Swan. Under dark skies, Cygnus is seen flying generally southward down the middle of the Milky Way with its wings spanning the width of the Milky Way. The swan's head, a fainter star, is two fist-widths from its tail.

Altair is the head of Aquila, the Eagle, which is flying along the eastern edge of the Milky Way in the opposition direction of Cygnus.

As with many things in nature, appearances can be deceiving. Our Sun is blindingly bright to us, yet it is much fainter than any of the triangle stars. It seems so bright because it is so close, a mere 8 light minutes (93 million miles) away.

While Deneb appears as the faintest star in the triangle, its true brightness is greater than that of Vega, Altair, and our Sun combined. A white supergiant star, Deneb only seems fainter because it is so much further away. Whereas Altair and Vega are virtual neighbors at 16 and 25 light years, respectively, Deneb is a whopping 1,500 light years away making it one of the most distant bright stars we can see with our naked eyes.

In a future column we'll tell the story of Vulpecula, a sly but foolish fox lurking in the Milky Way Triangle.

• Next Two Weeks. Avg. sunrise: 7:28 a.m.; avg. sunset: 7:02 p.m. (exact for Waco, TX)
  * Tomorrow (Sunday) night's full Moon is this year's Harvest Moon, the full Moon nearest the fall equinox.
  * Thurs. (Oct. 8) morning, Saturn is within a moonwidth of brighter Mercury low in the east; rising at dawn, they are below brilliant Venus.
  * Oct. 11 the Moon is at 3rd quarter.
  * The morning of Oct. 12, Mars is above the bright Moon high in the east before dawn.
  * The morning of Oct. 13, Saturn is a moonwidth to the left of much brighter Venus low in the east as they rise shortly before dawn.
  * The morning of Oct. 14, Leo's brightest stat Regulus is to the upper left of the crescent Moon in the east before dawn.
  * The morning of Oct 16, the crescent Moon is to the right of Venus with Saturn just above and Mercury further below the brilliant "morning star."

• Naked-eye Planets. Evening: Jupiter dominates in the south southeast. Morning: Saturn and Mercury are near the eastern horizon at dawn, below brilliant Venus with much fainter Mars high in the east.

• Astro Milestones. Oct. 4, 1957, Russia launched Sputnik I, beginning the Space Age and the Cold War space race.

• Star Party. The Central Texas Astronomical Society's monthly public star party is Sat., Oct. 10, 7 p.m., at the Waco Wetlands, weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this Web site.

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September 19, 2009
Stargazer #514

2009: International Year of Astronomy

This year marks the 400th anniversary of the birth of telescopic astronomy, so the International Astronomical Union and UNICESCO have designated 2009 the International Year of Astronomy "to foster a global appreciation of the role and value of science and astronomy as a unifying activity for humanity."

It could also be the symbolic 400th anniversary of the Copernican Revolution in which a scientific theory--that the Sun, not the Earth, was at the center of the universe--shook the foundations of western civilization. The international nature of IYA2009 is fitting as each of the major revolutionaries was from a different country.

The revolution began in earnest with the death of its namesake, the Polish Nicolaus Copernicus (1473-1543). In 1533 he set forth his theory in a book, On the Revolutions of the Celestial Orbs. But knowing his Sun-centered theory was at odds with the church-government's view of things--and to disagree could be deadly--he arranged to have his book published upon his death, thus the first shot was fired in 1543. While many thought Copernicus' view made sense, he offered no observational data to support his theory, so it simply circulated underground for several decades.

In the latter 1500s, the Dane Tycho Brahe (1546-1601), blessed with exceptionally keen eyesight and a penchant for meticulous record-keeping, amassed a wealth of observational data, including the precise movements of Mars over many years. Having little idea what to do with his data, he had the good sense to hook up with the German Johannes Kepler (1571-1630).

A brilliant mathematician, Kepler made good use of Tycho's data. In 1609, he published Astronomia Nova in which he set forth the elliptical (rather than circular) nature of orbits. Thus he contributed important theoretical support for Copernicus' theory--but firmer observational verification was still needed.

Enter the Italian Galileo Galilei (1564-1642). Upon hearing of the newly-invented telescopes made by the Dutch lens-grinder Hans Lippershey, Galileo in 1609 made his first telescope and began using it to study the night sky. His discoveries--such as the moons of Jupiter, the phases of Venus, and the mountains and craters of our Moon--finally began providing observational data to support Copernicus' theory.

The final shot was fired decades later in 1687 by the Englishman Isaac Newton (1642-1727). "Standing on the shoulders of giants," as he put it, Newton published Principia in which he set forth our modern understanding of gravity.

Thus, with two critically important turning points occurring in 1609, it seems fitting to celebrate 2009 as the symbolic 400th anniversary of the 144-year long Copernican Revolution.

• Next Two Weeks. Avg. sunrise: 7:19 a.m.; avg. sunset: 7:20 p.m. (exact for Waco, TX)
  * Tomorrow (Sunday) morning Leo's brightest star Regulus is one moonwidth to the right of brilliant Venus low in the east at dawn.
  * Tues. is the autumn equinox, the beginning of fall when day and night are of equal length.
  * The Moon at 1st quarter Sep. 26.
  * The evening of Sep. 29 the big gibbous Moon is above Jupiter in the southeast.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Jupiter is the brightest "star" in the southeast.
  Morning: Venus rises shortly before dawn while much fainter Mars is well above it high in the east.
  

• Astro Milestones. Using the calculated predictions of Urbain Jean Joseph Leverrier of France, Johann Galle & Heimrich d'Arrest discovered the planet Neptune from Germany's Berlin Observatory Sept. 23, 1846.

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September 5, 2009
Stargazer #513

Contact with Extraterrestrials

In their short but fascinating book, Extraterrestrials: A Field Guide for Earthlings, science writer Terence Dickinson and artist Adolf Schaller offer some educated conjectures about living beings elsewhere in the cosmos. Dickinson starts off with the reminder that as yet there is no evidence of any life beyond Earth, yet with the enormity of the cosmos, he thinks it is almost inconceivable that we are alone. If only one star in a billion had a planet with life, the universe would still contain a trillion or more homes for ETs, a hundred or so of which could be in our own Milky Way galaxy.

After presenting some popular conceptions of aliens in science fiction, he identifies the kinds of environments that might support life as we understand it, and where such places might be found. Then with Schaller's marvelous depictions, they pose some ideas of how alien beings might appear.

Finally, Dickinson offers some plausible responses to questions begged by the rest of the book, like "Where are they?" and "If they're out there, why haven't we been contacted?"

Perhaps we are the most advanced life form in our sector, and we'll have to find our less-advanced neighbors. Then again, maybe highly advanced beings are trying to contact us right now, but we're not advanced enough to receive their signals.

Possibly other intelligent beings know we exist but we're so primitive they have no interest in contacting us, or they have chosen only to monitor us and not intervene in our life. And, of course, there remains the unlikely prospect that we are alone.

Assuming extraterrestrials exist, Dickinson suggests four ways contact could occur. Aliens might visit us as they did in Steven Spielberg's 1977 movie Close Encounters of the Third Kind.

Or maybe we'll receive a signal from afar such as the Message received from the star Vega and discovered by radio astronomer Dr. Ellie Arroway in Carl Sagan's 1985 novel Contact, later made into a movie starring Jody Foster as Ellie.

Perhaps we'll discover something left behind by intelligent beings like the signaling device left on one of Jupiter's moons in Arthur C. Clarke's and Stanley Kubrick's classic 1968 movie 2001: A Space Odyssey.

Or we may just have to wait until we have the resolve and sophistication to venture out and discover other life as did Captain Kirk, Mr. Spock, and their intrepid crew of explorers in Star Trek, the highly popular 1960s television series -- and countless other science fiction books and movies.

If it's not in your local bookstore, Extraterrestrials is available via the Internet.

• Next Two Weeks. Avg. sunrise: 7:11 a.m.; avg. sunset: 7:38 p.m. (exact for Waco, TX)
  * The Moon is at 3rd quarter Friday.
  * The morning of Sep. 13, the Moon is above Mars.
  * The morning of Sep. 15 the crescent Moon is to the right of the Beehive star cluster low in the east before dawn; binoculars will help see the cluster.
  * The Moon is new Sep. 18.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Evening: Saturn and Mercury are all but lost in the setting Sun as Jupiter dominates in the southeast. Morning: Venus is low in the east with much fainter Mars well above it.

• Star Party. The Central Texas Astronomical Society's free monthly star party is Sep. 12 at the Waco Wetlands beginning at 7:30 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this Web site.

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August 21, 2009
Stargazer #512

Planets to Lose Moons and Rings

Twenty years ago when I first set up my new 8-inch Schmidt-Cassegrain telescope for a public star party, I thought folks would be most interested in seeing far-away objects like star clusters, galaxies, star-birthing nebulae and dead-star remnants.

But I was wrong. A common reaction was, "That's interesting, but can we look at the Moon?" It was the Moon that got comments like, "Wow, that's really cool! I can even see craters."

It didn't take me long to learn that three nearby neighbors -- the Moon, Saturn, and Jupiter -- are the public's favorites. Far-away objects can still be interesting, but most are faint, fuzzy and ill-defined. But with the Moon we see craters, mountain ranges and other intriguing features. Saturn, of course, has its beautiful rings, and Jupiter proudly displays its four large Galilean moons, named in honor of Galileo who discovered them in 1610.

Regarding two of these public favorites, we're about to witness the relatively rare occurrences of Saturn "losing" its rings and Jupiter "losing" its moons, with both events happening at nearly the same time.

Saturn's rings, composed of billions of small chunks of ice, are thousands of miles wide but less than a mile thick. When seen at an angle, the reflective ice makes the rings a dazzling view. But every 14-15 years, owing to the tilt of Saturn on its axis and the slight tilts of the orbits of Earth and Saturn, we see the thin rings edge-on with no tilt, making them seem to disappear.

Over the past few months, the rings have been growing noticeably thinner as their angle of tilt decreases. This will continue until the evening of Sept. 3 when the rings become exactly edge-on and invisible from Earth. Unfortunately, this is happening as Saturn is sinking into the setting Sun, making it difficult to see in the twilight.

Jupiter, however, loses its moons in the dead of night Sept. 2. You'll want to view this through a telescope--even a small one will do. In the early evening, Jupiter is the brilliant object in the east. At first, three of its four Galilean moons will be visible with two on one side, one on the other. As the night progresses, all three gradually move toward the planet. At 10:43 p.m. (all times CDT), one moon disappears followed by a second 15 minutes later, and the third one vanishes at 11:43 p.m. From then until 1:30 a.m., you'll see Jupiter with no moons visible. Seen only a few times each century, this won't happen again until 2019, so don't miss it.

Next Two Weeks. Avg. sunrise: 7:02 a.m.; avg. sunset: 7:56 p.m. (exact for Waco, TX)
* This evening (Aug. 22), the crescent Moon is to the left of Mercury which is to the left of Saturn, all near the western horizon at dusk.
* The Moon is at 1st quarter Thurs. (Aug. 27, my 69th birthday!}
* The morning of Sept. 1, Venus is just to the right of the Beehive star cluster low in the east before dawn; binoculars will help see the cluster.
* The evening of Sept. 2, Jupiter is to the right of the Moon.
* The Sept. 4 full Moon is called the Fruit Moon.

Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
Evening: Saturn and Mercury are very low in the west at dusk with Jupiter rising in the east.
Morning: Jupiter is the bright object in the southwest as "morning star" Venus is in the east and much fainter Mars well above it.

Star Party. Tonight (Saturday, Aug. 22) I'll be presenting a free public slide program ("Constellations of the Season") followed by a star party at Reynolds Creek Park near Waco beginning at 8 p.m. For directions, see MAPS & DIRECTIONS elsewhere in this website.

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August 8, 2009
Stargazer #511

Extraterrestrials

Are we alone, or are "they" out there somewhere? While we can only guess how long humans have wondered about life beyond Earth, such curiosity surely predates recorded history.

In 1994 Terence Dickinson and Adolph Schaller published Extraterrestrials: A Field Guide for Earthlings. Amateur astronomer and author Dickinson's text is fascinating and artist Schaller's illustrations are dazzling. (Copies are available via the Internet.)

After showing a sampling of Hollywood-created extraterrestrials -- like Mr. Spock, ET, and others -- they conjecture about what real aliens might be like. Right off, Dickinson acknowledges that, paraphrasing earlier writers, extraterrestrials -- if they exist -- are apt to be not just stranger than we anticipated, but stranger than we could have anticipated. Still, he and Schaller make some intriguing speculations about such beings based on things we do know, like some basic laws of nature.

It is almost certain beings from other places would not resemble us. Just as we have been shaped by conditions on Earth, conditions where they live -- temperature, gravity, atmospheric pressure and composition, amount and form of water, and the like -- would have shaped their evolution.

Dickinson first looks at the kinds of places, in our solar system and beyond, where conditions might support life as we know and understand it. He discusses the evolution of brains and emergence of intelligence, and how smarter species are likely to out-survive the less smart ones.

He then examines, and Schaller visually portrays, the kinds of sensory organs aliens might use to gather information about their environment. Like humans, other life forms are likely to have mechanisms for sight, hearing, taste, smell, and touch.

They might have other sensory capabilities such as sonar (like bats and dolphins) or magnetic-field detection (like some birds, insects, and fish). Aliens might have "sight" in parts of the electromagnetic spectrum invisible to humans, enabling them to "see" ultraviolet, infrared, microwave, radio waves, x-ray, or gamma rays.

The authors pose one final mind-boggler. On Earth the chemical foundation of all life is carbon-based, but this might not be universal. Some life elsewhere might be silicon-based where crystalline critters nibble on rocks rather than bananas.

In a future column, we'll see what Dickinson has to say about how we might discover other life, and why we haven't already.

Next Two Weeks. Avg. sunrise: 6:54 a.m.; avg. sunset: 8:12 p.m. (exact for Waco, TX)
* The Moon is at 3rd quarter Thurs.
* Fri. morning the Moon passes through the Pleiades star cluster but moon glow will make binoculars necessary for seeing the cluster.
* Fri. Jupiter is at opposition -- its best for the year being nearest, appearing largest and brightest, and up all night.
* The morning of Aug. 16, the crescent Moon is to Mars' lower left.
* The evening of Aug. 17, Saturn is to the upper right of brighter Mercury near the western horizon at dusk.
* The Moon is new Aug. 20.

Perseid Meteor Shower. Most are predicting the best time for seeing Perseid meteors is Wed. evening (Aug. 12) until the Moon rises at midnight, although some think Tues. night could be better. So maybe we should just keep an eye out both nights! The constellation Perseus rises in the northeast, but it's generally best to watch mostly overhead where the sky is darkest.

Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
Evening: Saturn and Mercury are low in the west at dusk as Jupiter rises in the east.
Morning: Jupiter is the brightest object in the southwest with "morning star" Venus in the east and much fainter Mars well above it.

Star Party. The Central Texas Astronomical Society's free monthly star party is Aug. 15 at the Waco Wetlands beginning at 8 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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July 25, 2009
Stargazer #510

Hercules and Ophiuchus: Head-to-Head in the Night Sky

It's the time of year when two giants, Hercules the Strong Man and Ophiuchus the Serpent Bearer, butt heads in the night sky. As with many constellations, their stories come from ancient Greek religion.

Hercules (aka Heracles) was one of many offspring of Zeus (Jupiter), king of the gods. Zeus was married to his sister Hera, yet he had many mistresses, some immortal goddesses, some mortal women. Hercules' mother, Alcmene, was a mortal making Hercules a part god, part human demigod.

Not only did he feel haunted by his half-god status, the powerful goddess Hera hated him and made his life miserable. Known for his strength and courage, Hercules is famous for accomplishing the Twelve Labors of Heracles--incredibly hard tasks no mere mortal could perform. His reward was immortality.

While the origins of the lesser-known constellation Ophiuchus are uncertain, he seems to represents Asclepius, a healer. By observing a serpent using a herb to heal another serpent, he discovered that the powerful herb, when administered to humans, enabled them to avoid death or even come back to life.

When Zeus saw that Asclepius had the power to make humans immortal--and thus like gods--he couldn't allow that, so he killed Asclepius with a bolt of lightening. But to ease his guilt, Zeus gave Asclepius a place in the night sky. Now bearing the name Ophiuchus, the serpent bearer carries the serpent from whom he learned of the healing herb.

Among Asclepius' daughters are Hygieia, Meditrina, and Panacea, goddesses of cleanliness, medicine, and healing.

The Rod of Asclepius, a snake-entwined staff, is a symbol used in the medical world to this day. It is often mistakenly used interchangeably with the caduceus, a staff with two serpents, although Asclepius' Rod and the caduceus come from different Greek stories and gods.

Hercules and Ophiuchus are large constellations, neither of which contains notably bright stars, thus they are a challenge to make out. But here's how you can at least find where they are. Facing south at 10 p.m. Scorpius the Scorpion, looking like a giant fishhook, is a little above the southern horizon. Directly above the scorpion, Ophiuchus is mid way up. Above him, Hercules is high overhead, between the two brightest overhead stars, reddish Arcturus to the right (west), and white Vega to the left (east).

• Next Two Weeks. Avg. sunrise: 6:45 a.m.; avg. sunset: 8:25 p.m. (exact for Waco, TX)
  * This evening the crescent Moon is to the left of Saturn low in the west.
  * Tomorrow morning reddish Mars is to the upper left of the equally bright reddish star Aldebaran in east as Orion rises below them.
  * Tuesday morning the Delta Aquarid meteor shower peaks with Aquarius in the southwest.
  * The Moon is at 1st quarter Tuesday.
  * Aug. 1 is Lammas, a cross-quarter day celebrating the middle of summer.
  * The Aug. 5 full Moon, called Grain Moon and Green Corn Moon, is to the upper right of Jupiter in the evening and to the planet's lower right the next morning.
  

• Naked-eye Planets.
  Evening: Saturn, low in the west, sets by 11 p.m. as Jupiter is rising in the east.
  Morning: Jupiter is the brightest object in the southwest with brilliant "morning star" Venus in the east and much fainter Mars above it.

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July 11, 2009
Stargazer #509

Where Were You July 20, 1969?

Wednesday, July 16, 1969, we watched with keen interest as Apollo 11 blasted off from Kennedy Space Center on what we hoped would be a historic mission to the Moon. We already had a Sunday night party planned to watch the lunar landing with friends.

Just 15 years before, my scout troop camped at the old West Ranch near Clear Lake, the future home of Johnson Space Center's Mission Control. Then space exploration existed only in science fiction. But the Russians abruptly changed all that Oct. 4, 1957, when they shocked the world with the launch of Sputnik 1, the world's first human-made satellite. They simultaneously launched the Space Age and began the Cold War space race with the U.S.

The early years saw the U.S. frantically playing catch-up. Apr. 12, 1961, Russian cosmonaut Yuri Gagarin became the first human to orbit Earth in a space ship.

Then six weeks later, on May 25, 1961, the newly-elected President John Kennedy made his now-famous bold declaration: "I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to Earth." And indeed, the race was on.

First came the Mercury flights, each carrying one astronaut. Alan Shephard's 1961 suborbital flight made him the first American in space. Then Feb. 20, 1962, Mercury Friendship 7 took John Glenn into orbit, making him an American hero. But the Russians were still comfortably ahead.

Next came the two-person Gemini flights in which Gemini 3 took Gus Grisson and John Young into orbit in March 1965. The next several Gemini flights saw increasingly sophisticated maneuvers, like the orbital rendezvous and docking of two space craft.

The three-person Apollo series got off to a tragic start when Jan. 27, 1967, Gus Grisson, Edward White, and Roger Chaffee were killed in a flash fire inside Apollo 1 during a launch pad training exercise. The Russians also had tragedies and cosmonaut deaths in what was clearly a dangerous space race.

In 1968 the Apollo 7 crew orbited Earth, and the Apollo 8 crew were the first humans to orbit the Moon in Dec. 1968. May 1969, Apollo 10 conducted a "dress rehearsal" by going to the Moon and doing all but landing.

Then came the main show Sunday night, July 20, 1969. Our family and friends were huddled around our small black & white tv, set up in our side yard so we could also see the real Moon low in the west. Although we were pretty confident of success, it was still a nail-biter as we knew it could end in failure, or worse. But when it became apparent that Neil Armstrong and Buzz Aldrin had landed safely, we were ecstatic. To this day, I still get goose bumps at Armstrong's first words from the surface of the Moon, directed at my old campsite: "Houston, Tranquility Base here. The Eagle has landed."

• Next Two Weeks. Avg. sunrise: 6:36 a.m.; avg. sunset: 8:33 p.m. (exact for Waco, TX)
  * Tue. morning brilliant Venus is to the upper left of Taurus' reddish star Aldebaran.
  * The Moon is a 3rd quarter Wed.
  * The morning of July 18, the crescent Moon, Pleiades star cluster, Aldebaran, Mars, and Venus are grouped low in the east before dawn, with Venus and Aldebaran at the bottom and the Pleiades at the top.
  * The July 21 new Moon produces a total solar eclipse over India, China, and the Pacific, but not here.
  * The evening of July 24, the crescent Moon is below Saturn low in the west at dusk.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn is low in the west and Jupiter is up in the east by 11 p.m.
  Morning: Jupiter is the brightest object in the south with "morning star" Venus low in the east and much fainter Mars above it.

• Star Party. The Central Texas Astronomical Society's free monthly star party is tonight at the Waco Wetlands beginning at 8:30 p.m., weather permitting. For directions see my Website.

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June 27, 2009
Stargazer #508

Sorting Out the Greek Gods

The planets along with several constellations and other night sky objects are named for gods of ancient Greece, although most are now known by their counterpart in later Roman religion.

Sorting out the relationship among the gods is complicated as most religious stories from antiquity have multiple versions, yet we'll introduce some of the better-known members of this family of Greek gods (with their Roman names in parentheses).

It all began in a void of nothingness called Chaos, out of which arose the first goddess Gaia (Earth). Without need of a male, she gave birth to Uranus, the god of the sky and the first ruler of the universe. He became Gaia's mate and together they produced many children, some of whom were the Titans

One of the Titans was Cronus (Saturn) who married his sister Rhea; they had six children: Zeus, Poseidon, Hades, Demeter, Hestia, and Hera.

Uranus, fearing his children would rebel against him, had them imprisoned, but with help from Gaia, Cronus and the Titans escaped and defeated Uranus. But he too fell victim to his own children who defeated him and the Titans.

His three sons divided the universe among themselves. Zeus (Jupiter) became god of the heavens and earth, and king of the gods. Poseidon (Neptune) became god of the seas and earthquakes. Hades (Pluto) became god of the underworld (later incorporated into other religions as "hell").

Zeus, the most important of the gods, married his sister Hera, and fathered several children with her, one of whom was Ares (Mars). He fathered many more children by other women, some of whom were immortal goddesses and some mortal humans.

Some of his other well-known offspring were Aphrodite (Venus), goddess of love and beauty; Apollo, god of youth; Artemis (Diana), the huntress goddess; Hermes (Mercury), messenger of the gods; Perseus, a Greek hero; Heracles (Hercules), god of strength and courage and Greek hero; Helen of Troy, and the Muses, gods of creativity.

Among his famous grandchildren were Eros (Cupid), son of Ares and Aphrodite; Pan, son of Hermes; and Asclepius (Ophiuchus), son of Apollo and god of healing.

Now with this introduction to some of the Greek gods and goddesses, maybe you'll feel more at home under the night sky.

• Next Two Weeks. Avg. sunrise: 6:28 a.m.; avg. sunset: 8:37 p.m. (exact for Waco, TX)
  * Tonight Saturn is to the upper right of the Moon.
  * The Moon is at 1st quarter Mon.
  * The midpoint of the year comes Thur. at noon.
  * Fri. Earth is at aphelion when it is farthest from the Sun in its elliptical orbit.
  * The evening of July 4 the star Antares is just to the left of the bright gibbous Moon.
  * The morning of July 5, Venus (bottom), Mars (upper right) and the Pleiades (upper left) form a nearly equilateral triangle low in the east before dawn.
  * The July 7 full Moon, called Hay Moon and Thunder Moon, produces a barely noticeable penumbral eclipse.
  * For binocular and telescope viewers, the morning of July 9 faint Neptune is just above vastly brighter Jupiter.
  * The next morning the bright Moon is to their right.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn, low in the west, sets just after midnight, and Jupiter rises in the east just before midnight.
  Morning: Jupiter is the brightest object in the south while "morning star" Venus is low in the east with much fainter Mars just above it.

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June 13, 2009
Stargazer #507

The World Made Smaller by the Internet

The Internet is amazing, not that I'm telling you anything you don't already know. It's just that I'm constantly reminded of it.

By posting a website -- something that requires minimal resources and expertise -- one is stepping onto a world stage and becoming available to anyone with access to the Internet. The "www" prefix says it all -- truly a world wide web spanning our entire planet.

When I created and posted my Stargazer website in 2002, I knew, yet didn't fully grasp, the scope of what I was doing. But in the past 7 years, I've heard from people all over the world.

Just within the past week, I received emails from people in two far away places -- Eric and Tristan, a father and his teenage son who live in Johannesburg, South Africa, and Renas, a Kurdish Iraqi. They found my website and email address from Internet searches. And at their request, they now receive the free email version of this column along with others around the U.S. and the world.

Eric and Tristan first emailed me last year with a question about colliding galaxies -- an inquiry that inspired a Stargazer column. They're now asking about looking for communications from other life in the cosmos, and I see another column in their query. (I get many column ideas from readers' so don't hesitate to write.)

This father and teenage son exemplify another thing I love about amateur astronomy -- it cuts across the generations, being an interest that can be shared by all ages.

Renas first contacted me in 2006, inquiring about my Learning the Night Sky book. A 22-year old just completing a degree in geology, he and some friends had recently organized the Amateur Astronomers Association of Kurdistan. In one email he sent a photo of the Iraqi National Observatory showing damage done, according to Renas, by Iranian and U.S. air strikes in earlier times -- a sad reminder of the longstanding and tragic conflicts in Iraq.

In last week's email Renas said he is coming to the U.S. -- and specifically to Texas -- for graduate study in geology. After spending the summer in Houston improving his English, he hopes to enter the University of Texas at Austin in the fall. So I may get to meet him and even take him out to our local astronomy club's observatory. A small world indeed, and all thanks to the Internet.

• Next Two Weeks. Avg. sunrise: 6:24 a.m.; avg. sunset: 8:36 p.m. (exact for Waco, TX)
  * This morning Jupiter is to the lower left of the Moon.
  * The Moon is at 3rd quarter Mon.
  * Fri. morning Mars is the upper left of much brighter Venus with the crescent Moon further to their upper left, all low in the east before dawn.
  * The summer solstice comes June 21 this year.
  * The Moon is new June 22.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn, high in the west, sets after midnight.
  Morning: Jupiter is the brightest object in the south; "morning star" Venus and much fainter Mars are low in the east; Mercury, lower in the east at dawn, is at its best June 13-18.

• Star Party: The Central Texas Astronomical Society's free monthly star party is tonight at the Waco Wetlands beginning at 8:30 p.m. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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May 30, 2009
Stargazer #506

Astronomy in the Classroom

Many respected experts point to an alarming trend among our youth which is likely to have dire consequences for our society. They're not referring to drugs, sex and the usual litany of things we hear and read about. Rather, their concern is a declining interest and proficiency in science and mathematics.

They warn that if this trend isn't reversed, and soon, we could quickly find ourselves in the backwater of knowledge-building and technological development--important components of the foundation of our societal and economic well-being. So what, you may wonder, does this have to do with amateur astronomy and stargazing?

As members of the Central Texas Astronomical Society, I and others conduct dozens of free classes, programs and star parties for schools each year. Part of our motivation, of course, is a desire to share our passion for the night sky with anyone willing listen. For many of us, the stargazing spark was ignited long ago by an interested adult; maybe we can pass that spark along to the next generation.

But we have another motive which relates to the issue mentioned above. Astronomy is an excellent vehicle for getting kids' attention. We show images of beautiful and exotic objects in the cosmos. We talk about black holes, space-travel and other mind-bending topics. We even conjecture about life beyond Earth and discuss the many things we still don't know.

And after we get them wondering about things, we suggest that just maybe some of them will go into careers where they can help find answers to some of the intriguing questions and make discoveries to further our knowledge about the world, and indeed, the cosmos around us. Someone has to, so why not some of them?

Our aim is not to encourage youngsters to become professional astronomers. We don't even expect that a high percentage of them will pursue careers in science or math.

But maybe we can increase the number who will at least consider science or math. And hopefully those who don't will become more enlightened citizens with greater respect and appreciation for science and math, and who will support it more vigorously.

If you're a teacher (or parent) perhaps you'd like to have an amateur astronomer speak to your students. Contact me and maybe we can come up with some ideas to make it happen.

• Mars Hoax. Each year since Mars' August 2003 close approach to Earth, the same emails have circulated, misleading folks into believing it's about to happen again this August. Sorry, but it isn't.

• Next Two Weeks. Avg. sunrise: 6:23 a.m.; avg. sunset: 8:31 p.m. (exact for Waco, TX)
  * Tonight's 1st quarter Moon is below Saturn.
  * The June 7 full Moon is called Flower Moon, Rose Moon, and Strawberry Moon.
  

• June 6 Occultation. The evening of June 6, the nearly full Moon occults (passes in front of and temporarily hides) the star Antares. The star passes behind the bottom left of the Moon about 8:50 p.m. in the twilight when the Moon is still low in the east, and emerges from the Moon's upper right about 10:05 p.m. Antares is a bright star, but due to the Moon's glare, you'll want to use at least binoculars to see the star.

• Naked-eye Planets.
  Evening: Saturn is high in the southwest.
  Morning: Jupiter is the brightest object in the southeast with "morning star" Venus low in the east and much fainter Mars to Venus' lower left just before dawn; Mercury is emerging low in the east at dawn.
  

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May 16, 2009
Stargazer #505

Cosmic Weight-Loss Plan

Want to lose a few pounds? No problem, just go to Mars. And if you want to lose even more, go to the Moon. It's true, you'll really weigh less on Mars, and even less on the Moon.

If your bathroom scales show 200 pounds, on Mars you'll weigh a mere 76 pounds, and on the Moon, those same scales will register a minuscule 34 pounds. Now that's serious weigh-loss.

Unfortunately though, traveling to distant worlds won't slim you down or make you look better because your body's mass won't change. Mass is a measure of the amount of matter in an object and this isn't affected by where the object happens to be.

Weight, however, is a measure of the amount of gravitation force on an object, and mass is but one factor affecting weight. The other is gravitational attraction, thus location does affect an object's weight. Every object, from the smallest atomic particle to the largest galaxy, exerts at least some gravitational attraction, the amount depending on the object's mass. The more massive, the greater the gravitational attraction.

We've all heard that Earth's gravity keeps us from flying off into space, and that's essentially true, but it's not the whole story. Earth and our bodies exert mutual attraction on each other, but since Earth is vastly more massive, it does most of the attracting.

So how much would a 200-pound person weigh in other parts of the solar system? Going to Venus wouldn't help much as she or he would still weight in at 182 pounds. But on tiny Pluto, his or her weight would be an unbelievably light 10 pounds.

There's another side to this little weight-game -- like places you can go to gain weight, such as to the larger gas planets. Their outer layers are mostly gas, so it wouldn't actually be possible to stand on them, but if one could, a 200-pounder would weight a manageable 231 pounds on Neptune and a whopping 505 pounds on Jupiter.

And to really put on some extra pounds, try standing on the Sun. Assuming the Sun had a solid surface and you wouldn't burn to a crisp, you would tip the scales at over 5,000 pounds.

If you're just tired of dealing with weight altogether, move to the International Space Station. There, in the weightlessness of outer space, you'll weight virtually nothing. Now that's a weight-loss plan that's hard to beat.

• Next Two Weeks. Avg. sunrise: 6:28 a.m.; avg. sunset: 8:23 p.m. (for Waco, TX)
  * Tomorrow morning the 3rd quarter Moon is to the left of Jupiter.
  * Tues. morning the crescent Moon is to the left of Venus and above much fainter Mars low in the east at dawn.
  * The Moon is new May 24.
  * The evening of May 28 the crescent Moon is to the left of the Beehive star cluster low in the west.

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn is high in the south.
  Morning: Jupiter is the brightest object in the southeast with "morning star" Venus low in the east and much fainter Mars to Venus' lower left just before dawn.

• Star Party: The Central Texas Astronomical Society's free monthly star party is tonight at the Waco Wetlands beginning at 8:30 p.m. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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May 2, 2009
Stargazer #504

Arizona's Meteor Crater

Arizona is known as "the Grand Canyon state" and with good reason. The awe-inspiring beauty of the famous Grand Canyon is matched only by its unbelievable enormity. For millions of years the Colorado River has been carving the mile-deep canyon, and it's not finished yet.

But the state has another huge hole in the ground which, while not as large and well-known, is impressive in its own right -- and it was blasted out in a matter of seconds. Some 50,000 years ago Earth was impacted by a large piece of solar system debris, resulting in what is popularly called Meteor Crater.

A 150-foot in diameter chunk of iron, probably from the asteroid belt, weighing several hundred thousand tons and traveling 27,000-40,000 mph (estimates vary) struck the northern Arizona desert with the explosive force of 20 million tons of TNT. In less than 10 seconds, 175 million tons of earth -- rock, soil, and sand -- were excavated, leaving a gaping crater more than 700 feet deep, 4,000 feet across, and 2 1/2 miles around.

Over the years, erosion has partially filled the crater -- also called Barringer Crater and Canyon Diablo Crater -- so that it is now only 550 feet deep. Still, that's deep enough that if a 55-story building, or the Washington Monument, was placed on the crater's floor, the building's or monument's top would be at ground-level.

Geologist Gene Shoemaker estimated that an event comparable to the Meteor Crater impact can be expected, on average, every 50,000 years, so we are due. What if one were to hit now? Being much smaller than the comet or asteroid impact 65 million years ago believed to have caused the extinction of many species, including the dinosaurs, it would not mean the end of our species or any other.

But such an impact in or near a populated area would almost certainly produce staggering destruction and death to many thousands if not millions. Or imagine the tsunami resulting from an ocean impact. In my view, government programs to identify and track near-Earth objects and formulate plans for averting such impacts should not be regarded as futuristic science fiction or "wasteful government spending." Indeed, only an ignorant or foolish species would ignore such a threat.

• Next Two Weeks. Avg. sunrise: 6:36 a.m.; avg. sunset: 8:14 p.m. (exact for Waco, TX)
  * Tonight Mercury is to the left of the Pleiades star cluster very near the west northwestern horizon at dusk.
  * Tomorrow evening Saturn is to the upper left of the large gibbous Moon.
  * Wed. morning the Eta Aquarid meteor shower peaks but the Moon doesn't set until 2 hours before sunrise.
  * Friday's full Moon is called Milk Moon and Planting Moon.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn is high in the south with Mercury low in the west northwest at dusk.
  Morning: Jupiter is the brightest object in the southeast with "morning star" Venus low in the east and much fainter Mars to Venus' lower right at dawn.

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April 18, 2009
Stargazer #503

Saturn's Rings

Don't look now but Saturn is losing its rings. Actually, do look as the famed ringed planet is still a beauty, and its rings really aren't going anywhere--it just looks that way.

In 1610, the year Galileo discovered Jupiter's four largest moons with his new telescope, he also viewed Saturn and saw that something was different. But with his crude telescope--inferior even to today's department store scopes--he misinterpreted what he saw as he wrote, "the planet Saturn is not one alone, but is composed of three, which almost touch one another...the middle one is about three times the size of the lateral ones."

Two years later, he was perplexed when Saturn's companions disappeared: "Have they vanished or suddenly fled? Has Saturn, perhaps, devoured his own children? Or were the appearances indeed illusion or fraud?" Later, when the secondary bodies reappeared, he was even more dumbfounded. Sadly, he died never knowing what he had discovered and having no clue about the mysterious disappearance and reappearance of his discovery.

The quality of telescopes rapidly improved, and the mystery was solved in the decade following Galileo's death. Christiaan Huygens determined that surrounding Saturn is a "flat ring which nowhere touches the body of the planet." He referred to the rings in the singular as he thought they were one solid body; we now know there are dozens of flat rings, each composed of millions of small icy particles.

In 1659, Huygens explained the rings' periodic disappearance. Like Earth, Saturn is tilted on its axis, so at different points in its orbit around the Sun, we see its rings at different angles. About every 14 3/4 years (twice during each Saturn-year of 29 1/2 Earth-years) we see the rings edge-on. Being only a mile or so thick, from our distance of 800 million miles, they seem to vanish for a few weeks.

Huygens' diagram helps visualize this. The inner views of Saturn show the planet as it orbits the Sun; the outer views show how the planet and rings appear to us at each corresponding point.

Saturn's rings, now slightly tilted, are still visible, but the tilt gradually decreases over the next few months until early September when we cross the ring plane. At that point, the rings will seem to disappear once more--showing us the sight that so mystified Galileo nearly 400 years ago. Unfortunately, by September Saturn will be close to the setting Sun and difficult to see in the twilight. So find a telescope and take look now as this won't happen again until 2024.

• Next Two Weeks. Avg. sunrise: 6:49 a.m.; avg. sunset: 8:04 p.m. (exact for Waco, TX)
  * Tomorrow (Apr. 19) morning Jupiter is just below the crescent Moon.
  * Wed. morning the Lyrid meteor shower peaks about 5 a.m. with Venus is just below the crescent Moon.
  * The Moon is new Fri.
  * The evening of Apr. 26, Mercury is below the crescent Moon at dusk low in the west with the Pleiades star cluster between them.
  * Venus is at its brightest the morning of Apr. 29.
  * May 1 is May Day and Beltane, the cross-quarter day celebrating the middle of spring, and the Moon is at 1st quarter.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn is high in the southeast with Mercury low in the west northwest at dusk.
  Morning: Jupiter is the brightest object in the east southeast as "morning star" Venus and much fainter Mars (to Venus' lower right) are just above the eastern horizon before dawn.

• Star Party. The Central Texas Astronomical Society's free monthly star party is tonight, Apr. 18, at the Waco Wetlands beginning at 8 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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April 04, 2009
Stargazer #502

Total Eclipses of the Sun in our Future

Of all astronomical phenomena, probably none are as captivating as total eclipses of the Sun, and with good reason. What could be more dramatic than having the Sun briefly disappear during a clear, cloudless day, or more alarming?

Until they figured out what was going on, our ancestors came up with many different explanations, and most didn't view eclipses as good things. Some thought an animal was eating the Sun and had to be frightened off with noise. Others saw eclipses as portends of bad events to come.

We now know total solar eclipses result when the Moon passes exactly between the Earth and Sun, blocking the Sun from view for up to several minutes.

While many have seen total eclipses of the Moon, most (including myself) have never seen a total solar eclipse. Lunar eclipses are more easily seen because, when the Moon passes through Earth's shadow in a lunar eclipse, the darkened Moon can be seen by everyone on the side of Earth facing the Moon.

But when the Moon passes in front of the Sun, it casts a narrow--on average 100-mile wide--shadow across Earth called the path of totality. The total eclipse is visible only from that narrow path, beyond which only a partial eclipse can be seen. Thus, the occurrence of a total solar eclipse over any given location on Earth is rare, explaining why most of us have never seen one.

On average less than one per decade occurs over the lower 48 states, the last three being in 1979, 1970 and 1963. And none of these passed over our southwestern quadrant of the U.S.

Between now and the end of the century, there will be 8 total solar eclipses where the path of totality passes over the lower 48 states: 2017, 2024, 2044, 2045, 2052, 2078, 2079, and 2099. That's not a lot, but the next two should be well worth the wait.

August 21, 2017, an eclipse enters the U.S. in Oregon, moves southeasterly across the heartland, and exits in South Carolina, with it's point of maximum duration of 2 minutes and 40 seconds being in western Kentucky. That's just 8 years away and during vacation season, so start making your plans.

Then, the one I'm anxiously awaiting is occurs Apr. 8, 2024. The eclipse reaches it's point of maximum duration of 4 minutes and 28 seconds in central Mexico, then enters the U.S. near Eagle Pass, Texas. It moves northeasterly, exiting the U.S. in Maine. My excitement comes from the fact that it will pass directly over my home in Central Texas, so I won't have to go anywhere. Since it will be here in only 15 years, the rest of you can start calling me to book our guest room or a camping spot in our side yard--for free, of course. We'll have a grand party.

For an enhanced version of this column with more photos and diagrams, go to Solar Eclipses in this website.

• Next Two Weeks. Avg. sunrise: 7:05 a.m.; avg. sunset: 7:55 p.m. (exact for Waco, TX)
  * Mon. evening Saturn is to the left of the waxing gibbous Moon.
  * Thursday's full Moon is called Egg Moon, Grass Moon, and Easter Moon.
  * The morning of Apr. 13, the star Antares is to the left of the waning gibbous Moon.
  * The Moon is at 3rd quarter Apr. 17.

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Saturn is well up in the east southeast.
  Morning: At the first crack of dawn Jupiter is the brightest object in the east southeast with "morning star" Venus and much fainter Mars (to Venus' right) rising in the east.

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March 21, 2009
Stargazer #501

Astronomy or Astrology?

[A version of this Stargazer classic first appeared in January 1991.]

"Hey, Dr. Derrick," said a young woman, "I saw your picture in the paper. I didn't know you were into astrology."

Trying not to grimace, I replied, "I'm into astronomy," to which she quickly corrected herself, "Sorry, astronomy."

When confused with astrologers, most astronomers bristle as if they've been insulted, even if unintentionally. While both study the stars and other heavenly bodies, the purposes and methods of study are quite dissimilar and lead to very different outcomes.

Astronomy is the scientific study of the universe, and as such adheres to the rules of scientific inquiry. Science formulates testable theories to explain, predict and increase our control over nature. As theories are supported by observations, they gain validation and credibility. When not supported by the evidence, they are modified or discarded. By this time-honored method, our knowledge advances even if tediously and imperfectly.

The well-known big bang theory illustrates the scientific method. Around 1927 based on then current knowledge, Georges Lemaitre suggested a theory--later dubbed the big bang theory--to help explain the origin of the universe. For many years, new data supported his theory, however in recent years some new data suggest the theory needs to be modified, or maybe even replaced. Contrary to the insinuations of anti-science types, this does not reflect negatively on science or scientists. Indeed, this is how science works. It is science at its best.

Astrology is a false- or pseudo-science which studies heavenly bodies in the belief that they have direct influence on the course of human affairs. But credible evidence to justify such beliefs is totally lacking as statistical studies fail to find any convincing correlations between the motions of stars or planets and human affairs. Yet astrology has a wide following, as indicated by the fact that more papers carry horoscopes than astronomy or science columns.

Pseudo-sciences like astrology may entertain, they may provide solace or the illusion of control when humans feel weak and vulnerable. But pseudo-sciences, superstition, and other forms of magical thinking didn't develop vaccines, grow more wheat and put humans on the Moon. They didn't give us autos, TVs, computers, air conditioning, and the other devices which make possible life as we know it. Nor will they solve the myriad problems still confronting humanity.

In the advancement of human knowledge, pseudo-sciences like astrology are pacifiers devoid of nourishment. Science is Mother Nature's milk by which we survive, grow and progress.

• Next Two Weeks. Avg. sunrise: 7:22 a.m.; avg. sunset: 7:45 p.m. (exact for Waco, TX)
  * Tomorrow morning (Mar. 22) the crescent Moon is to the upper right of Jupiter low in the east at dawn.
  * The Moon is new Thurs. (Mar. 26).
  * The evening of Mar. 29 the crescent Moon is below the Pleiades star cluster low in the west at dark, and above the cluster next evening.
  * The Moon is at 1st quarter Apr. 2.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Venus, now setting soon after sunset, passes between Sun and Earth Mar. 27 and emerges in the morning sky in early April. Saturn is now at its best all night--in the east in the evening and in the west in the morning. Jupiter rises before dawn while Mars rises as dawn is breaking.

• Star Party. The Central Texas Astronomical Society's free monthly star party is tonight, Mar. 21, at the Waco Wetlands beginning at 8 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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March 7, 2009
Stargazer #500

Vernal Equinox

In the earliest years of the TV western "Gunsmoke," do you recall the name of Marshall Dillon's deputy? Nope, Festus came later. It was Chester (played by Dennis Weaver), and perhaps you'll remember that Chester walked with a limp, the origin of which I never learned.

Now let's go much further back to when our 5 billion year-old solar system was young--perhaps no more than several hundred million years old. It's a good thing we weren't around yet as the yet as the planet that would eventually become our home was whacked by a smaller planet producing a cataclysmic collision that destroyed the other planet and left Earth, like old Chester, with a limp.

Ever since, as Earth orbits the Sun, its North and South Poles aren't straight up and down but rather are tilted at a 23 1/2 degree angle. And as a result, each hemisphere spends half a year tilted toward the Sun and the other half tilted away. When tilted toward the Sun, its days are longer than its nights, and when tilted away, its nights are longer than its days.

Twice each year Earth reaches a point in its orbit when the hemispheres reverse positions, and one of those times comes Mar. 20, the first day of spring in the Northern Hemisphere (and fall south of the equator). Called the vernal equinox--Latin for "spring equal night"--it's the day when for an instant neither pole is tiled toward or away from the Sun, and the day and night are of equal length...at least theoretically.

But a look at sunrise and sunset times shows it's not so. For my home in Waco, Texas, Mar. 20 sunrise is at 7:32 a.m. and sunset at 7:40 p.m., thus on this day of the "equal night," day is 8 minutes longer than night. So what's going on here? Well, actually two things account for this apparent discrepancy--one a human factor, the other natural.

The first has to do with how we the define day and night. Since the Sun has a discernible diameter, in theory day should start when half the Sun has risen and end when half has set. However, by definition, day officially begins the instant the first part of the Sun peaks over the eastern horizon and doesn't end until the entire Sun sinks below the western horizon, and this adds about 2 minutes to each day.

The second factor, which lengthens day even more, comes from the bending of light called refraction. As the Sun nears the horizon, its light rays are bent upward as they pass through Earth's atmosphere. Acting like a strategically placed mirror, the atmosphere lets us see a little below the horizon--enough that we can actually see the Sun some 2-3 minutes before it physically rises above the horizon, and we see it 2-3 minutes after it sets.

So just as in George Orwell's Animal Farm, where "some animals are more equal than others," days are "more equal" than nights, even at the equinox.

• Daylight Time. Tonight before retiring tonight, set your clocks forward ("spring forward") to Daylight Saving Time.

• Next Two Weeks. Avg. sunrise: 7:40 a.m.; avg. sunset: 7:36 p.m. (exact for Waco, TX)
  * Tomorrow night Saturn is at opposition--opposite the Sun as seen from Earth--when it rises at sunset and is up all night.
  * Wednesday's full Moon is called Lenten Moon, Sap Moon, Crow Moon, and Worm Moon.
  * The Moon is at 3rd quarter Mar. 18.

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Venus, ending its run as the "evening star" in the west, is lost in Sun by month's end, but Saturn, in the east in the evening, is now at its best all night.
  Morning: Jupiter and Mars are low in the east at dawn with Saturn the brightest object in the west.
  

• Comet Lulin Postscript. My apologies to those of you who looked unsuccessfully for Comet Lulin. It simply didn't get as bright as I hoped. Under dark skies it did approach naked-eye visibility, but for those of us who live with light pollution, it remained quite difficult. Maybe we'll have better luck next time.

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February 21, 2009      [Two Stargazers for the price of one this time!]

Stargazer #499A

Comet Lulin

In this column we usually call attention only to night sky objects that can be seen without optical aids, but we're making an exception this time. There's a new comet passing by that is worth a look.

Comet Lulin, discovered in July 2007 in China, is best seen in binoculars although it might barely reach naked-eye brightness away from city lights. Now visible in the evenings, it looks like a faint fuzz-ball with a bright center. Traveling east-to-west along the ecliptic (the path of the Sun, Moon and planets) and is rising earlier each night, Lulin passes several interesting objects.

For the next few nights it approaches and passes Saturn, the brightest starlike object in the east. Tonight about 9:30 p.m. Saturn is 25 degrees above the eastern horizon. (The width of your fist held at arm's length is 10 degrees.) Comet Lulin is 10 degrees below Saturn. If you keep watching an hour or so, the comet gets easier to see as it rises further above the horizon.

Tomorrow night it is 5 degrees below the planet, both being within the same field of view of most binoculars. Monday evening should be spectacular when the comet passes 2 degrees to Saturn's right. By Tuesday evening, it is 6 degrees above the planet, and is expected to be nearest Earth and at its brightest.

By Wednesday, it is up by 8 p.m. and mid way between Saturn and Leo's brightest star Regulus which is 25 degrees above Saturn. Then for three nights the comet and star will be within the same field of view with Lulin 5 degrees below the star Thursday, 2 degrees to its right Friday, and 5 degrees above it Saturday.

Then moonlight becomes a problem in the evening as the waxing crescent Moon, setting an hour later each evening, grows more illuminated and brighter and washes out the comet.

Diehards, however, can continue following the comet by staying up later each evening (or rising very early) until the comet sets around 5 a.m. And it might be worth the effort when Comet Lulin passes near the beautiful Beehive star cluster the mornings of Mar. 5 and 6. The moon sets at 2:40 a.m. Mar. 5 and 3:40 a.m. Mar. 6 when the comet and cluster are at their closest.

After that viewing Comet Lulin will probably be over for most of us as the Moon gets in the way and the comet will likely have dimmed notably. So let's hope for clear skies so we can catch this surprise visitor before it returns to its home in the deep freeze of the outer solar system.

Stargazer #499B

Stargazin' and Noticin'

[A version of this Stargazer classic first appeared in April 1991.]

Several years ago I got a letter from a young prison inmate, Beatrice, telling of her newfound interest in stargazing. She said, "Looking up into the heavens gives me a sense of freedom...I plan to enjoy this beautiful universe for the rest of my life."

Her letter reminded me of a story someone once shared with me. During an extended visit in the country, a city fellow came upon a local farmer named Elijah who was standing stock still in the field staring into the darkening twilight sky. With a touch of ridicule, the urbanite said, "Whatcha doin', Elijah?" to which Elijah witheringly replied, "Noticin'."

Indeed, it's hard to imagine the beauty and wonder of the heavens failing to elicit deep feelings and thoughts in those who, like Elijah and Beatrice, notice.

People stargaze for different reasons. Some pursue it like a second vocation. For others it is an enjoyable hobby, or maybe a respite from life's hassles and stresses. But stargazing, like bird-watching and other nature-noticing activities, can be more than mere diversion.

In replying to Beatrice, I acknowledged that while stargazing is certainly enjoyable, I also find it a philosophical activity, both humbling and affirming. Contemplating the unfathomable size of the universe and the probability of countless other beings and civilizations "out there" takes me beyond myself, and can leave me feeling small and insignificant. Yet at the same time, stargazing takes me deep within myself to the very core of my being when I realize that I, too, am a part of this magnificent whole, no less so than any other being.

Roy Bedichek, in his 1947 classic book, Adventures with a Texas Naturalist, wrote, "What a large percentage of urbanized populations miss beginning the day under the spell of the silent, pervasive, leisurely preparations of the heavens to receive the Sun!" That man also knew how to notice.

• Next Two Weeks. Avg. sunrise: 6:57 a.m.; avg. sunset: 6:26 p.m. (exact for Waco, TX)
  * Tomorrow (Sunday) morning the crescent Moon (upper right), Mercury, Jupiter, and Mars (lower left) are aligned near the east southeastern horizon 45 minutes before sunrise; binoculars will help.
  * Tues. morning Mercury is just below bright Jupiter, and the Moon is new.
  * Fri. evening a crescent Moon is just to the left of Venus low in the west at dark.
  * The Moon is at 1st quarter Mar. 4.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: Brilliant "evening star" Venus, looking like a tiny crescent Moon in telescopes, is low in the southwest and Saturn rises before 8 p.m.
  Morning: Jupiter, Mercury, and Mars are very low in the east at dawn with Saturn the brightest object in the west.

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February 7, 2009
Stargazer #498

International Year of Astronomy

This is a special year for astronomers throughout the world, professional and amateur alike--not for any unusual events in the night sky, but for what will be happening here on Earth.

The International Astronomical Union and UNESCO have designated 2009 the International Year of Astronomy "to foster a global appreciation of the role and value of science and astronomy as a unifying activity for humanity."

With such objectives as "Increase scientific awareness..." and "Support...science education," IYA2009 relates as much to science in general as to the field of astronomy.

And given the attacks on science in recent years (and attacks still occurring in Texas), it couldn't come any too soon. With the theme, The Universe, Yours to Discover, this joint emphasis on science and astronomy is fitting. Astronomy is widely held to be the oldest science, and the fascination so many hold for the cosmos makes it is an excellent vehicle for promoting science.

Consider the Hubble Space Telescope. Not only is it a remarkable scientific tool, but as perhaps the most popular scientific instrument ever built, it is one of astronomy's and science's best ambassadors to the public. In two decades it has dazzled us with hundreds of thousands of images ranging from nearby solar system neighbors to distant galaxies, quasars and other cosmic exotics in the most remote corners of the universe.

Astronomy is one of the few sciences where amateurs still contribute and make discoveries. An example is the partnering of the Central Texas Astronomical Society, an organization of amateurs, with McDonald Observatory and the University of Texas-Austin's Department of Astronomy. Using CTAS's 24-inch research-quality telescope at its observatory outside of Waco, TX, amateurs collect data on white dwarfs which UT astronomers then use in their study of these dying stars.

Why 2009? This year marks the 400th anniversary of the birth of modern observational astronomy when, in 1609, Galileo first used a telescope to study the heavens. It is also the 40th anniversary of the first Moon landing by Apollo 11 astronauts Neil Armstrong and Buzz Aldrin.

To learn about IYA2009 national and global activities, see www.astronomy2009.org. The IYA2009 page in this website lists places and events in central Texas. For those living in other areas, perhaps your town has an observatory, planetarium or astronomy club hosting events. See see www.skyandtelescope.com/community/organizations for a listing. If you would like to arrange a free public program or star party in your community, contact me (paulderrickwaco@aol.com) and maybe we can work something out.

• Next Two Weeks. Avg. sunrise: 7:11 a.m.; avg. sunset: 6:15 p.m. (exact for Waco, TX)
  * Monday's full Moon is the Wolf Moon, Snow Moon, and Hunger Moon.
  * Wed. morning the big gibbous Moon is below Saturn, and that evening is to the planet's lower right as they rise around 9 p.m.
  * The Moon is at 3rd quarter Feb. 16.
  * The morning of Feb. 17 an hour before sunrise Mars is a moonwidth to the right of much brighter Jupiter low in the east with Mercury further to their upper right; also note the Moon to the upper right of Scorpius' brightest star Antares in the south.
  

• Naked-eye Planets. (The Sun, Moon, and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.)
  Evening: "Evening star" Venus, appearing as a tiny crescent in small telescopes, is at its brightest in the west, and Saturn rises by 9 p.m.
  Morning: Mercury is at its best low in the east at dawn Feb. 7-13 with Saturn the brightest object in the west.

• Comet Lulin. Newly discovered Comet Lulin, now rising in the east before midnight, appears as a subtle fuzz ball in binoculars. Traveling east-to-west along the ecliptic (the path of the Sun, Moon and planets) and rising earlier each night, it passes near Virgo's brightest star Spica Feb. 15 and 16, Saturn Feb. 23, Leo's brightest star Regulus Feb. 27, and the Beehive star cluster Mar. 4 and 5. Under dark skies, it might become naked-eye visible the last week of Feb.

• Star Party. The Central Texas Astronomical Society's free monthly star party is Feb. 14 at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

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January 24, 2009
Stargazer #497

That Lucky Old Sun

In a 1949 #1 hit song, Frankie Laine crooned "that lucky old sun has nothin' to do but roll around heaven all day." I like the song, but with all due respects to Frankie, it just ain't so.

In fact, the Sun is an incredible workhorse that's on duty 24 hours a day, 365 days a year, doing the job it's been doing for 5 billion years and will continue doing another 5 billion, give or take a few hundred million years. And we can thank our lucky stars that it is for without the Sun we wouldn't be. Should the Sun suddenly go out--which it won't any time soon--we would go out with it, and very quickly.

It's easy to take the Sun for granted, and during hot summer days we might even find ourselves having bad thoughts about it. Yet all we have to do is imagine a frozen, dark Earth, and we promptly become Sun-appreciators. But providing warmth and light to see by is just part of the Sun's job.

Animal life depends upon plant life for survival. Chlorophyll-containing green plants--which include virtually all the plants we eat--require light for photosynthesis, the process by which they live and grow--and that light directly or indirectly comes from the Sun. Photosynthesis also converts the carbon dioxide we breath out into the oxygen we need to breathe in. So, no Sun, no plants. And no plants, no plant-eating, oxygen-breathing animals--and thus, no us.

The Sun is also the mother of all energy generators. According to Wikipedia, the amount of solar energy reaching Earth in an hour is more energy than the world uses in a year. And the solar energy reaching Earth in a year is twice the total amount of energy we could ever obtain from all of Earth's non-renewable resources--coal, oil, natural gas, and uranium--combined.

So it turns out that our "lucky" old Sun really has a lot more to do than just roll around heaven. But as essential as it is, it also has its darker side, so to speak.

The radiation that provides all the life-giving benefits also has destructive powers. Sun burns, skin cancers, cataracts, and heat strokes are but some of the ways the Sun is harmful to us. And that same radiation--mostly ultraviolet--that damages us also breaks down and destroys many products we rely on daily, like paint, rubber, plastic, and roofing.

And if that's not enough, our star of life and energy will eventually become a death star of destruction. In the last stages of its life, the Sun will expand, becoming so huge that Mercury, Venus, and Earth will be vaporized and consumed. All Earth-bound life that still exists in 5 billion years will be extinguished by the very star that made life possible.

So that hardworking "lucky" old Sun is a mixed bag, deserving both our gratitude and our wary respect.

• Next Two Weeks. Avg. sunrise: 7:22 a.m.; avg. sunset: 6:02 p.m. (exact for Waco, TX)
  * Monday's new Moon produces an annular solar eclipse not visible from our hemisphere.
  * Friday evening a crescent Moon is above Venus.
  * Feb. 2 is Groundhog Day and Candlemas, a cross-quarter day celebrating the middle of winter, and the Moon is at 1st quarter.
  

• Naked-eye Planets. [The Sun, Moon, and planets rise in the east and set in the west because of Earth's west-to-east rotation on its axis.]
  Evening: Brilliant "evening star" Venus is now at its highest in the southwest at dark, and Saturn is up by 9 p.m.
  Morning: Saturn is high in the west southwest, and by early February Mercury begins appearing very low in the east southeast at dawn.
  

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January 10, 2009
Stargazer #496

Jupiter's New Moons

According to popular lore, scientists, upon making a discovery, are supposed to exclaim, "Eureka!" However, it's said that, in reality, they are more apt to muse to themselves, or comment to a colleague, "That's funny!" And judging by his notes, that was Galileo's reaction nearly 400 years ago when, using his new telescope, he made the earthshaking discovery that Jupiter has moons.

The night of Jan. 7, 1610, upon seeing a magnified Jupiter for the first time, he noticed "three little stars" which he assumed to be ordinary background stars. "Yet," as he wrote, "they made me somewhat wonder because they seemed to be arranged exactly in a straight line, parallel to the ecliptic."

The next night, he "found a very different state of things, for there were three little stars all west of Jupiter." Curious, he "waited for the next night with the most intense longing, but was disappointed for the sky was covered with clouds."

Over the next several nights, he was able to make observations and each time saw the "stars" in a different pattern. At this point his brilliance and ability to think outside the box came into play, enabling him to infer what he was seeing--and it flew in the face of what was believed about the heavens at that time.

He wrote, "I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, which was established as clear as daylight by numerous other subsequent observations." He even determined "that there are not only three, but four, erratic sidereal bodies performing their revolutions around Jupiter."

His discovery was earthshaking because the prevailing scientific and theological world view held that all heavenly objects orbited Earth which was at the center of the cosmos. Galileo's discovery of bodies orbiting Jupiter provided visual evidence in support of the heretical Copernican theory that the Sun was at the center.

Galileo's four new "stars," which he called Medicean planets, are now named Io, Europa, Ganymede, and Callisto, and are called Jupiter's Galilean moons in his honor.

There's an irony related to Galileo's discovery. As he focused his attention on Jupiter, the planet Uranus, which would not be discovered for another 171 years, was less than 3 degrees away. However, with his crude telescopes, and given Uranus' distance, faintness, and slow movement against the background stars, it is unlikely he would have recognized it as a planet. But if he had, perhaps he would have shouted, "Eureka!"

• Next Two Weeks. Avg. sunrise: 7:28 a.m.; avg. sunset: 5:50 p.m. (exact for Waco, TX)
  * Tonight's full Moon is called Moon After Yule and Old Moon.
  * Thursday morning, the gibbous Moon is to the lower left of Saturn.
  * The morning of Jan. 17 the 3rd quarter Moon is to the right of the star Spica.
  * The crescent Moon is just to the lower right of the star Antares the morning of Jan. 21.
  

• Naked-eye Planets. Evening: "Evening star" Venus is brilliant in the southwest with Mercury the brightest object low in the west southwest at dark. Morning: Saturn is the brightest object high in the southwest before dawn.

• Star Party. The Central Texas Astronomical Society's free monthly star party is Jan. 17 at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.