Thursday, October 21, 2010
And you can tell from the name that it's bigger than a lot of the others that have been whizzing by the Earth recently, since it was discovered seven years ago. On the list of near-Earth flybys in the near future the closest approach that we know of will be 2010 TG19 in just two days from now (22 October) at a distance 1.1 times that from the Earth to the Moon (400,000 km or so), but more interesting from the point of view of potential human exploration are the asteroids in the hundreds of metres in diameter, and on the 30th one of these will pass by the Earth at a distance 5 times that from the Earth to the Moon, which isn't bad considering its relatively large diameter of 600 m or so (370 - 820 m). You can see its orbit here, and a thread on a forum here (cloudynights.com) gives a lot more information on the flyby from one astronomer who is getting ready for the flyby. The flyby trajectory will look like this:
The asteroid will get fairly close to the Earth again in 2017 at a distance of 0.05 AU (7 million km), and though distancewise this is about the kind of asteroid we can expect to send a human mission to this one isn't a good candidate at that time, as the proposed mission to an asteroid would take a number of months (six weeks there, two weeks at the asteroid, six weeks back) and after passing by the Earth then it heads directly in towards the Sun, getting as close as Mercury. 2021 is a fairly close approach but still too far.
Dimensions: assuming a diameter of 600 metres we get a surface area of about 1.3 km2, or a third that of Central Park in New York. This massive image shows Central Park from above:
Circumference is almost 2 km so at a walking speed (if you could walk on it) that's about 20 minutes to walk around it once. At average density it would have a mass of 450 million tons, surface gravity is 0.003% that of Earth, and escape velocity is just 1.6 kph.
Finally, sometimes these asteroids turn out to be binary or trinary asteroids so we may find out that this is the case for 2003 UV11 as well. One (or more?) recent study has shown that these asteroids should be fairly common, as the Sun's energy has a tendency to spin these asteroids like a top, and this often results in one or more asteroids breaking off and becoming a tiny moon. If this asteroid turns out to be a binary or trinary system we should see it get some coverage in the news as was the case with 1994 CC as it flew by us last year.