Real Deal on Mars

Real Deal on Mars
by Dave Adalian

If you were hoping to see Mars appear the size of a full moon last August, as a widely circulated hoax email suggested it would, no doubt you were very much disappointed.

Some prankster decided for reasons known only to himself to twist information about the close pass of Mars back in 2003 to make it sound as though the Red Planet would make an impossibly close pass by Earth this summer.

Thankfully, it didn’t happen. Had Mars come close as that hoax email described, the resulting disruption to Earth would have spelled disaster.

The real facts are these: Back in August 2003, Mars came closer to Earth than it has during recorded human history, about 34.6 million miles. For those lucky enough to get a look at the God of War through a telescope at 100X magnification during that close approach, its disk appeared the same relative size as a full moon does when viewed with the naked eye.

As I said in this space during summer of 2003, in a scope Mars looked like a pea in a Petri dish, although a beautiful one with reddish planes, dark surface features and clouds obscuring the southern pole -- in other words, like an alien planet that we still cannot be sure doesn’t harbor life of some kind.

If you missed it during summer 2003, it won’t be as close again until 2287. It really was a once-in-a-lifetime experience and a spectacular one at that.

But life is as full of second chances as it is once-in-a-lifetime opportunities.

Mars is coming in for another close pass this month, one of 40.3 million miles, a mere 4.3 million miles further away than in 2003. Bumping up the magnification to about 125X will give that full-moon effect once more. And, yes, it will be a breathtaking sight to behold.

Opposition, when Mars rises at sunset, will happen on Nov. 7, but the closest pass will come two nights before Halloween, when a pumpkin-colored Mars will rise about 6:30 to fly high in the east and come closest at about 8:25 p.m. It will be shining high and bright still when trick-o’-treaters take to the streets on Halloween.

Tonight, Mars is in the east over the trees by about 9 o’clock. If you watch night by night, you’ll see it rise earlier and double in brightness by October’s end as autumn’s warmth fails.

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Join the Tulare Astronomical Association Friday, Oct. 21, 8-10 p.m., for a close-up look at the Angry Red Planet at the Arthur L. Purcell Observatory, 9242 Ave. 184, 2.1 miles west of Highway 99. Information and directions: http://starry-starry-nights.blogspot.com/.

Clouds Win Again

Sorry, folks, but the satellite images show that this cloud cover over Central California is probably going to last most of the night, so there goes the star party. We'll try again on Friday, Oct. 21. See you then!

Return of the Long Nights

Return of the Long Nights
by Dave Adalian

Summer is taking an early departure this year, folding away her brown mantle and allowing the cool days and chill nights of autumn to come quickly as the leaves begin to fall.

This is fitting as (on Sept. 22, 2005) at 2:23 p.m. PDT the Sun crosses south of the celestial equator, reaching equinox and marking the moment when autumn begins and the days shorten while nights grow long and cold.

When the Sun sets this evening, it will fall directly west and rise again tomorrow due east, silhouetting the crags of the Sierra Nevada. Though the periods of light and dark won’t be perfectly equal as the Latin term equinox implies, the time between sunset tonight when half the Sun’s disk is below the horizon and sunrise tomorrow when half the disk is above the horizon will be just eight minutes shy of 12 hours.

The equinox is the moment when the Sun crosses the dividing line that splits the sky into two equal northern and southern halves, creating some special effects here on Earth.

At the equator on the days of the March and September equinoxes, the Sun not only rises and sets at the points of true east and west, it also passes directly overhead when it reaches its highest point in the sky, something it never does at more northern or southern latitudes.

At the poles, the effect is far more dramatic.

At the North Pole, the September equinox signals a plunge into six months of darkness, with the Sun dropping below the horizon not to be seen again until the end of March.

On the bottom of the planet, the effect is reversed, with the Sun finally returning to the sky for six uninterrupted months of daylight. Instead of rising and falling as it does elsewhere, during the months-long period of day the Sun skims along the icy horizon, climbing higher in the sky as the solstice approaches.

Were it not for the killing cold of the arctic winter, the North Pole would be a Moon-lover’s delight. During the six-month darkness, the Moon rises above the horizon not to set again for two weeks. The Moon moves through its cycle in unashamed plain sight before dipping again below the horizon for a fortnight’s absence.

Late Sept. 21 and 22 here at home, the Moon will put on a beautiful display in the east, joining the Seven Sisters of the Pleiades, the V-shape of the Hyades and a bright and ruddy Mars.

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Join the Tulare Astronomical Association for a public star party this Friday, Sept. 23, 8:30-10:30 p.m. at the Arthur L. Purcell Observatory, 9242 Ave. 184, south of Tulare and 2.1 miles west of Highway 198.

Deep Impact Reveals Comet's Secrets

The first findings from the Deep Impact collision with Comet Tempel 1 back in early July have been announced and the mission's results are going to change the way astronomers think about comets in a lot of ways. We've assumed comets were dirty snowballs, but it's looking more like they're icy dirt balls made mostly of powder and have the consistency of a soufflé, so don't slam the oven door or your comet may collapse.

Here's a great article on the findings from Science News.

Soak In Some Earthshine

When a very slim crescent moon joins Jupiter, Venus and Spica on the western horizon tonight just after sunset, be sure to look for the Earthshine, too.

The Sun is the only source of bright light in our solar system. All the light coming from the planets and their moons is just a reflection of our home star. When the Moon is only a couple of days past its new phase it presents a large dark limb, and the light that makes that dark limb visible is Earthshine, light from the Sun that strikes the Earth, reflects back to the dark portion of the Moon and then shines back on the Earth.

Venus and the Virgin

The sky show continues tonight on the western horizon after sunset with Spica, the alpha star of Virgo the Virgin, shining less than two degrees southwest (down and to the left) of Venus. Jupiter is about four degrees to the right. For those with a clear view to the west, a very young new moon is just above the horizon and will set by about a quarter after 8 o'clock local time. The Moon will be right in the midst of this grouping tomorrow night 30-45 minutes after the Sun goes down.

One Hundred Billion Failed Stars

For every star shining in our galaxy there's another one that didn't make it. Astronomers at Arizona State University working from Hubble Space Telescope infrared data have discovered the Milky Way has as many brown dwarf bodies as it does stars -- 100,000,000,000 of them and every one without enough mass to begin nuclear fusion, the process that makes the stars shine. These dark bodies weigh anywhere between 13 to 75 times as much as Jupiter, so their combined mass isn't enough to account for all of the galaxy's so-called missing matter by a long shot.

Here's Astronomy.com's article announcing the discovery.

Look to the West

Don't forget the meeting of Jupiter and Venus. Look due west 30 minutes after sundown to see these bright planets converge. They'll come closest to one another Thursday, Sept. 1, when they'll be about 1.2 degrees apart, just more than twice the width of a full moon or about the width of your pinkie finger when held at arm's length.

Click here for my earlier, more detailed post about this conjunction.

CalStar Party at Lake San Antonio

Lake San Antonio is a great dark-sky location and CalStar is a well-attended party attracting observers from all over the state. The 2005 CalStar, hosted by the San Jose Astronomical Association, will be held Sept. 29-Oct. 1 at Lake San Antonio, 25 miles east of Paso Robles.

Details are here:

http://www.sjaa.net/calstar2005.html

Mars NOT Looming Large

If you expect to see Mars swelled to the size of a full moon on Saturday, Aug. 27, 2005, you've probably been the victim of a cruel hoax. Someone, for reasons known only to himself, decided to pull a prank on all the would-be planet-gazers out there by sending around an email describing a closer-than-ever pass of Earth by the Red Planet.

It's not going to happen, at least not again.

Most of the information in this fatuous email is very near the truth about the close approach of Mars back in summer 2003. Mars did come closer to Earth than it has in 60,000 years and it did appear the size of a full moon, but only if you viewed it magnified by 100 times in a quality telescope. I wrote a column about it at the time, which you can read here.

The good news for those who'd like a gander at the God of War is he'll be making a bright appearance at the end of October and beginning of November. Watch this space as details will come as the date approaches. In the meantime, Mars is coming up in the east about 11 p.m. your local time, and over the month of September it will double its brightness, which is a great reason to start watching now.

Hubble Scanning Moon for Base Sites

I know this is meant to be an astronomy blog, but I find this so cool I have to post it. The Hubble Space Telescope is being used to look for lunar base locations. I'll be packing my bags! Here's the story as told in New Scientist magazine.

Wanna See Something Beautiful?

Go out and look west tonight just after sunset and you'll see two extremely bright "stars" down near the horizon. These are really Jupiter, king of the gods, and his daughter Venus, goddess of love. Venus is the one on the lower right and Jupiter is up to the left.

Over the next two weeks they are going grow closer until they reach their closest on the nights of Wednesday, Aug. 31 and Thursday, Sept. 1. Keep watching as they part ways because on Tuesday, Sept. 6, they're going to be joined by a very slender sliver of a moon. Make sure to look for earthshine in the Moon's darkened limb that night.

Venus and Jupiter will be easiest to find about 30-45 minutes after sunset. If you have trouble finding planets, here's a Quicktime video of this conjunction from skyandtelescope.com that may help.

Full Green Corn Moon

The Moon is full today, Friday, Aug. 19. Because this is the month before harvest begins in many areas, this full moon is sometimes known as the Green Corn Moon or the Grain Moon. It's also the Full Sturgeon Moon, this being the season when that fish is most easily caught. (But don't ask me why--damn it, Jim, I'm an astronomer not a ichthyologist!) You'll find the names of each month's full moon here:

http://www.space.com/spacewatch/full_moon_names_2005.html

The Strolling Astronomer

The Strolling Astronomer
by Dave Adalian

During summer I take my walks after the Sun is down, when my family's gone to bed and the heat of the day has faded. I stroll among the stars, hoping for the thrill of a meteor and making sure those points of light are still fixed to their places.

My front door faces east, and as August fades the Great Square of Pegasus, part of the winged horse’s constellation, hovers above my neighbor’s rooftop. Later the Square will rise high into the night sky, trailing Pisces the Fish behind, but early on it sits on its eastern point, a huge diamond-shape of stars.

Right of Pegasus’ Square are the dim, indistinct zodiacal constellations of Aquarius the Water Bearer and Capricornus the Sea Goat. This seemingly empty ocean of sky has a single bright star, lonely Fomalhaut in Pisces Austrinus, the southern fish, hanging over the southeast horizon, bobbing above the houses as I lope along.

Beyond this barren portion of the night is Sagittarius the Archer with his famous Teapot asterism and to his right the long, barbed hook of Scorpius the Scorpion, home of the red supergiant star Antares. Despite the city lights, I can still sometimes see the Milky Way rising like steam from the Teapot’s spout to trail beside huge Ophiuchus, the snake-handler, whose healing power defied death itself until Zeus immortalized him in the sky.

Walking west, I see the orange star Arcturus shimmering in the heavy air marking Boötes the Plowman, and above it is a half-circle of stars, Corona Borealis, the Northern Crown. Higher still is brave Hercules, club at the ready.

As I march along, I catch glimpses of the Big Dipper in Ursa Major among the trees and housetops northwest, and due north is always faithful Polaris, the North Star, in the Little Dipper in Ursa Minor. When I finally turn back toward home again there is the W-shape of Cassiopeia the Queen standing on edge in the northeast, and below her the hero Perseus defending Andromeda, the Chained Lady, who lends her brightest star to Pegasus as the northernmost corner of his Square.

I arrive back at my doorstep and crane my neck to look straight overhead for the Summer Triangle: Altair in Aquila the Eagle, white Vega in Lyra the Lyre and Deneb marking the tail of Cygnus the Swan. Then I quietly steal inside, careful not to awake those who lie sleeping.

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This column appeared originally in the Visalia (Calif.) Times-Delta on Aug. 25, 2005.

And Still More Perseids

I woke up at a quarter past three and came back outside where I stayed until about a quarter after four, lying under a blanket on the diving board at the north end of the yard where the light is least. I spotted another 25 Perseids and three more meteors from other sources, including two that seemed to come from the direction of Aquarius, home to a minor shower or two this month. What a beautiful night of viewing, especially considering I was able to do it from my own backyard.

Perseids Watch

I did a short Perseid meteor watch from my backyard tonight starting at about 12:40 and going until just before 2 a.m. I saw 22 Perseids, some of them very bright and beautiful, and about five sporadic meteors. I'm going to get some sleep now, but I may come back for another look in about 90 minutes.

Astronomy TV Online

Here are a couple of astronomy-oriented television programs available via the web:

First, here's Jack Horkheimer's Star Gazer, a series of one- and five-minute programs on the week's astronomical highlights. And, second, the venerable The Sky at Night hosted by Sir Patrick Moore.

Getting to the Purcell Observatory

Getting to the Arthur L. Purcell Observatory is very simple in broad daylight, but can be a bit tricky in the dark.

Take Highway 99 south past Tulare to the Avenue 184 exit. Turn left onto Avenue 184 and drive west approximately 2.1 miles. To do this you'll have to go through the intersection of 184 and Road 96; the observatory is about half a mile past the intersection on the right-hand (north) side of the road, so keep an eye on your odometer.

We have a sign for the observatory at end of the driveway, but it sits slightly off the road and is not lighted. The driveway leads to our parking lot, and the observing is done in our courtyard just beyond.

If you're not comfortable walking in darkness, a flashlight with a red filter will help, but please do not use unshielded lighting once you have left the parking lot.

This interactive Google map can provide driving directions from any location in Tulare County.

Welcome to Starry Nights!

Welcome!

This is the new online home of my astronomy column, Starry Nights, published monthly in the Visalia (Calif.) Times-Delta. Besides posting my columns both old and new, I'll be including interesting astronomy-related news and links, as well as announcements of the Tulare Astronomical Association's monthly star parties.

Comet Dust Drives Summer Shower

Comet Dust Drives Summer Shower
by Dave Adalian

(July 28, 2005) Anyone who attempted to observe Comet Tempel 1 earlier this month when NASA’s Deep Impact probe slammed it with an 814-pound copper bullet moving at 6.3 miles a second knows first-hand comets are an unpredictable lot.

Hopes were high this visitor from the outer reaches of the Solar System would brighten from an almost undetectable smudge in small telescopes to a naked-eye delight. The mission succeeded, but the brightening didn’t happen.

Fortunately, next month holds good promise of a sort for would-be comet observers.

August, as seasoned meteor observers know, is time for the year’s most reliable meteor sky show. The Perseids began lighting the night sky early this week and continue until late August with the peak expected to produce between 40-80 meteors an hour on the night of Aug. 11-12 and perhaps again on Aug. 12-13. Meteors from other minor showers will add 15-20 an hour.

Perseus, the constellation from which the Perseids stream, rises in the northeast around 10 o’clock. The best meteor viewing is after moonset--around 11 the first night and nearer midnight the next--until dawn. The darker sky you find yourself under, the better the viewing will be.

What does this have to do with comets? The Perseids are tiny pieces of Comet Swift-Tuttle.

Meteors aren’t really stars falling from the sky. Instead, they are bits that have broken off of other bodies--usually ice and dust the consistency of ash or more rarely solid rock--colliding with Earth’s atmosphere at several thousand miles an hour, ionizing the air and producing that magical glow.

Comet Swift-Tuttle is a periodic comet, returning again and again to swing around the Sun before heading off to the dark and frozen outskirts of our star system on a 135-year circuit. While Swift-Tuttle was first discovered in 1862, the shower it produces is known throughout history. During the 11th century, astronomers in China recorded an intense display, and Perseids are sometimes called St. Lawrence’s Tears to honor his martyrdom in coincidence with the shower of 258.

Swift-Tuttle returned most recently in 1992, freshening its trail of debris significantly as the Sun’s gravity drew the comet in, warming its surface and causing it to shed potential meteors. Therein lies this comet’s uncertainty. This year Earth enters the 1992 debris stream for the first time, and the usual rates of 40-80 meteors an hour on nights near the shower’s peak could be far higher than normal.

Or maybe not... We’ll just have to see.

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This column originally appeared in the Visalia (Calif.) Times-Delta on July 28, 2005.