On Nov. 8, 2011, asteroid 2005 YU55 will fly by the earth. It will pass closer than the moon is to us, which is kind of scary for some people who think it might hit us. But really, the experts know whether any planetoid out there will be a danger to earth for as long as they've had ample time to study them. Since asteroid YU55 has been known for quite some time, the people on earth really have nothing to fear. According to JPL Goldstone scientist, Marina Brozovic, "We know exactly where it is going to be, and we don't have any chance of impact for the following hundred years." So alright, that's good to know. So it's our grandchildren that will have something to worry about in the future.
But asteroid YU55 isn't really about the end of the world. It's by far the greatest opportunity for astronomers, amateur and professional to be able to get their telescopes set up and see what an asteroid looks like in person and up close. Sure some of you reading this may have already observed a few famous asteroids like Vesta and Ceres, but how they appear in a small telescope would be nothing compared to YU55 as it passes by the earth. At 201,700 miles close and at 1,300 feet wide (about 4 football fields) and seemingly round (which is kind of uncommon for a small asteroid), and black, like charcoal - so it is taunting us in a way, like it's saying, "Come on now, this is a once in a lifetime chance to see a strange asteroid up close, so watch me!"
More details about the path and other things about asteroid YU55 are in The Watchers, and of course, Wikipedia.
Christopher Go is an amateur astronomer in the Philippines. He's know for taking pictures of Jupiter and observing the change in color of a spot on Jupiter called Red Spot Jr. He alerted astronomy authorities about it. Now, he's known worldwide. That was back in February of 2006. Ten years later, on June 3, 2010, it seems his religious observation of Jupiter had paid off again when he documented the impact of a large object on Jupiter on video. The event, which he confirmed with the footage, was actually observed by his friend, Australian astronomer, Anthony Wesley.
The object that hit Jupiter was unknown, but it hit in these coordinates: Jovian latitude minus 16.1°, and central meridian longitudes CM1: 300°, CM2: 33.8° and CM3: 210.4°."The impact produced a flash that was likely the result of the object exploding in the Jovian atmosphere. It is likely an asteroid. The photo and cropped detail shown here is from a still of the video made by Go of the event.
Wesley and Go (left) are now well-known Jupiter observers. Their success proves that it pays to keep an eye on Jupiter with your telescope. If you have the equipment to take photos and video, then you can capture events that professional astronomers may be too busy to notice. Jupiter presents a nice disk where anything can happen. Cloud patterns change and you never know if another object hits it. If you watch the video, you will see a faint flash (impact) first followed by a larger one (explosion). Here is the link to the video of Christopher Go of the Jupiter-impact event. It was posted on YouTube by kurtjmac: http://www.youtube.com/watch?v=0AXSA9rZzrU.
You've probably heard of that asteroid tracked to it's explosive demise over the Sudan desert in 2008 (fragment shown at left). Only a few meters across, it didn't survive intact and shattered before it hit the ground, sending hundreds of debris strewn on the desert sand. Eventually, fragments of the doomed asteroid were recovered. It was easy because astronomers knew where it went and it also left fireball dust like in the following picture left behind by the Almahata Sitta fireball.
A lot of meteorite collectors would have scrambled to get a piece of Asteroid 2008 TC3 if they also knew where to look. But the fact is that meteorites are quite difficult to find. Usually, scientists look for them on ice fields, where they stand out starkly against the white ice. Others prefer vast stretches of sandy desert, where they also stand out like sore thumbs. But of course, not everyone has the means to travel to the North Pole or the Empty Quarter of Saudi Arabia just to hunt to meteorites.
The next best thing to collecting such souvenir rocks from space is to simply collect tektites (top pic from http://www.tektites.co.uk/). Tektites, of course, are rocks that are the result of asteroids that have impacted Earth in the past. thrown high above the atmosphere as molten globs that solidified, they form strange shapes upon reentry into the atmosphere since they are melted again. They drop to the ground, on what are called strewn fields, as odd rocks that do not match others on the ground.
Here is a table of major tektite strewn fields in the world:
Australia, Tasmania, Indonesia, Philippines, and most of Southeast Asia
0.75
Czechoslovakian
Czech Republic
14.8
North American
Texas, Georgia, Martha's Vineyard, Cuba
35
Ivory Coast
Ivory Coast of Africa
~ 1.0
Libyan
Libyan Desert
28.5
Irgiz
North of the Aral Sea
1.07
Aouelloul
Mauritania (West Africa)
3.5
If you live in a country or in a specific area that's part of a major strewn field, then you're lucky, because the chances of you finding tektites is high. In the Philippines, for instance, tektites are regularly collected and sold as amulets in Manila. People simply go and walk by the side of rivers and over fields to look for them. They are simply visually sorted out and picked up by hand from the other rocks on the ground. Most are small - an inch or two, but some can be as big as five inches in diameter or even more, although these big tektites are rare. Dr. Henry Otley Beyer (left), the renowned American anthropologist who lived with the Ifugaos, did most of the collecting of Philippinites. His collection now forms part of the National Museum displays, including those at the Planetarium at the Luneta park.
Of course, you have to know what tektites look like in order for you to find them. Most are dark and grooved, but others, like Libyan desert glass (left), are translucent and appear shattered. You can see samples of how tektites look here in this entry in Wikipedia. There you'll also see how some rocks like sandstone can have the shape, but not the texture and color of a tektite.
FACT: In the Philippines, tektites were once collected in Ortigas in Metro Manila. Today, there are the Tektite towers that stand along Exchange road to remind us of the richness of the area for tektites! You can check out one of the abstracts of the research papers where a find in the Ortigas site is mentioned, here at the SAO/NASA Astrophysics Data System. Just type the words "tektites" and "ortigas" together and you'll find it.
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