Asteroid Shower (Geminid Meteor Shower December 14th)

NASA ^ | 12.03.2007 | Dr. Tony Phillips

[MarineBrat]

 

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Asteroid Shower	12.03.2007
+ Play Audio | + Download Audio | + Email to a friend | + Join mailing list Dec. 03, 2007: Mark your calendar: The best meteor shower of 2007 peaks on Friday, December 14th. "It's the Geminid meteor shower," says NASA astronomer Bill Cooke of the Marshall Space Flight Center. "Start watching on Thursday evening, Dec. 13th, around 10 pm local time," he advises. "At first you might not see very many meteors—but be patient. The show really heats up after midnight and by dawn on Friday, Dec. 14th, there could be dozens of bright meteors per hour streaking across the sky." Right: A Geminid meteor in 2006 photographed by Christopher Colley of Lombard, Illinois. [Larger image] The Geminids are not ordinary meteors. While most meteor showers come from comets, Geminids come from an asteroid—a near-Earth object named 3200 Phaethon. "It's very strange," says Cooke. How does an asteroid make a meteor shower? Comets do it by evaporating. When a comet flies close to the sun, intense heat vaporizes the comet’s "dirty ice" resulting in high-speed jets of comet dust that spew into interplanetary space. When a speck of this comet dust hits Earth's atmosphere traveling ~100,000 mph, it disintegrates in a bright flash of light—a meteor! Asteroids, on the other hand, don't normally spew dust into space—and therein lies the mystery. Where did Phaethon's meteoroids come from?   Sign up for EXPRESS SCIENCE NEWS delivery One possibility is a collision. Maybe it bumped against another asteroid. A collision could have created a cloud of dust and rock that follows Phaethon around in its orbit. Such collisions, however, are not very likely.   Cooke favors another possibility: "I think 3200 Phaethon used to be a comet." Exhibit #1 in favor of this idea is Phaethon's orbit: it is highly elliptical, like the orbit of a typical comet, and brings Phaethon extremely close to the sun, twice as close as Mercury itself. Every 1.4 years, Phaethon swoops through the inner solar system where repeated blasts of solar heat could easily reduce a flamboyant comet to the rocky skeleton we see today. If this scenario is correct, Phaethon-the-comet may have produced many rich streams of dust that spent hundreds or thousands of years drifting toward Earth until the first Geminid meteors appeared during the US Civil War. Since then, Geminids have been a regular shower peaking every year in mid-December. 3200 Phaethon is now catalogued as a "PHA"—a potentially hazardous asteroid whose path misses Earth's orbit by only 2 million miles. It measures 5 km wide, about half the size of the asteroid or comet that wiped out the dinosaurs 65 million years ago, and can be seen through backyard telescopes—in fact, now is a good time to look: "3200 Phaethon is flying past Earth just a few days before this year’s Geminid meteor shower," notes Cooke. On Dec. 10th, Phaethon will be about 11 million miles away shining like a 14th magnitude star in the constellation Virgo: ephemeris. That's too dim for the naked eye, he says, but a good target for amateur telescopes equipped with CCD cameras. Cooke doesn't expect the flyby to boost the Geminids—"11 million miles is too distant to affect meteor rates"—but the Geminids don't really need boosting. "It's always a great shower," he says. "Don't miss it." SEND THIS STORY TO A FRIEND Author: Dr. Tony Phillips | Production Editor: Dr. Tony Phillips | Credit: Science@NASA More information NASA Meteoroid Environment Office -- home page NASA's Future: The Vision for Space Exploration

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[MarineBrat]

It's gonna be CCCOOLLLLLDDDDD! But I'll be out after midnight!

[blam]

Pray that we don’t get a ‘big one’.

[RightWhale]

We have to do our viewing when it is clear. Last night was clear and there was a meteor out of Gemini. Also, comet Holmes is still visible and Mars is moving retrograde right next to a bright star and you can see the difference in position from day to day.

[RightWhale]

The existing showers don’t have any big ones. They are all busted up long ago. The Geminids are already being seen, which means they are spread out over a relatively large section of space. That’s a sign of age: spreading.

[Domandred]

Tag for reference. Hoping for clear skies. Tonight’s star party went no-go cause we can’t see jack.

[MarineBrat]

Last night was clear and there was a meteor out of Gemini.

It was incredibly clear here last night. The sky was black as coal, even with the waning crescent Moon. Last night I woke up around 2:30am and went outside to take a peek. I was rewarded by a blazing fast meteor out of Gemini, about 40 degrees long. It had nothing of note other than high speed and uniformity.

Orion, Gemini, Taurus, Canis Major/Minor, etc, were incredible. This is my favorite part of the sky. I can rattle off the names of at least a dozen or more bright stars in these early winter constellations. If it hadn't been so darned cold I'd have rolled out the scope to get a peek at Mars and Orion.

[Domandred]

Also, comet Holmes is still visible and fading rapidly. Haven't had clear skies for a few days but on Friday night the core was no longer visible and the ejected material was fading as well.

Maybe Holmes will do another outburst before it leaves us (/crosses fingers)

Mars however on Friday was awesome through my scopes.

[MarineBrat]

Tonight’s star party went no-go cause we can’t see jack.

What part of the country are you in? Our skies were as clear as I've ever seen them last night. (Central-Eastern San Joaquin Valley, California) During the day the mountains look like they're seen through a vacuum.

An undesirable effect of the clear skies around here is bitter cold. I had to run a propane heater on my favorite lemon tree all night. Lord help my avacado trees!

[Dudoight]

Yeah, been watching the Holmes for a few weeks now. It was pretty soft last nite.

[ErnBatavia]

I love watching the Perseids, and will catch this one....we’re in the dark desert and I’m always up a couple of hours before daylight anyhow.

[COBOL2Java]

That’s a sign of age: spreading.

I've noticed that as well, particularly with regards to my waist...

[KarlInOhio]

I can rattle off the names of at least a dozen or more bright stars in these early winter constellations.

You can't be Sirius.

[Domandred]

Idaho. We been catching overcast and mostly cloudy skies for about a week or so. Cleared up real nice on Friday for a few hours then by Sat morning was mucked up again.

[Gabz]

It's gonna be CCCOOLLLLLDDDDD! But I'll be out after midnight!

I will be able to view without being outside in the colld........the door to my upstairs deck faces due west :)

[444Flyer]

Prayer is HIGHLY recommended these days. There are signs in the heavens...Acts 2:17-21 Pay particular attention to verse 19.

[SuziQ]

WooHoo! Our daughter flies home from college that evening, and she and I will attend a concert in Cambridge. We’ll be getting home just in time for this to start. We’ll just have to bundle up and sit outside and chat all night while we’re watching the sky! Might be a good reason to go ahead and get a chiminea!

[SuziQ]

Where, in the sky, is comet Holmes?

[SuziQ]

I’m always up a couple of hours before daylight anyhow.

The only way I'm up before daylight is if I haven't gotten to bed yet! I'm a bad night owl ;o)

[MarineBrat]

You can't be Sirius.

Please, call me Shirley!

[RightWhale]

Comet Holmes is about halfway between Mars and Polaris. It is a fuzzy white patch still easy to see.