Saturday, April 9, 2011

Asteroid Apophis a threat in 2029? 03.14.11

Astronomers have been tracking a 900-foot wide rock that is hurtling towards earth. Will it strike us? Only the math can tell.

Image credit:
Photographed on January 31, astronomers said on March 9 that this was the first clear shot they have been able to take of the approaching asteroid in at least 3 years. The photo was taken from atop one of Hawai’i’s dormant volcanoes, Mauna Kea, using a telescope. It was originally thought that the rock had a 1-in-37 chance of hitting earth, but new calculations made the number grow substantially; it now has a 1-in-250,000 chance of dashing earth to bits. Oh, joy!

All of the calculations are made by doing some careful comparisons with the “known” distances of stars near the asteroid. As stars move very slowly, they can be fairly reliable space-scale distance markers, but the passage of time still has to be taken into consideration upon each new measurement. 

If it does not smash into earth in 2029, it should pass by again in 2036 and 2068. The pass in 2029 will likely alter its path, too, making it slide ever so much closer to earth. The pass in 2029, in fact, will most definitely be closer to earth than a lot of communications satellites are! You can expect to see Apophis without the aid of a telescope or even binoculars, weather permitting. Until then, all we can do is sit, measure, and crunch some more numbers.


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