Tuesday, September 07, 2010

Close Call With Asteroid in 2015

Looking at the latest info from the Near Earth Object survey that NASA and several other groups have in progress, I found this little guy.  2004 JC is the asteroid depicted in this computer simulation.  Crosses earth orbit regularly, but in 2015 it looks pretty durned close.  Of course this is still many many miles away, but this demonstrates the need for the survey.  Being able to plot these objects and model their courses could help us spot a potential danger far enough in advance to do something about it.
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1 comment:

Anonymous said...

Very interesting. I noticed that you could play with the controls of the JAVA display, and in theory find its closest point in 2015, and on which date and time almost exactly. I found that the big day will be on September 16, 2015 with the distance will be 0.160AU.

Had to look up what "AU" was since I'd forgotten my high school astronomy class subject material. One AU is an astronomical distance of about 92,955,807 miles. This is approximately the average distance of the Earth to the Sun. The "AU" is defined here:
http://en.wikipedia.org/wiki/Astronomical_unit

So, if the closest distance of 2004JC will be on September 16, 2015 is 0.160AU, then a simple multiply of 0.160AU * 92,955,807 miles per AU is 14,872,929 miles.

Note that the average distance from Earth to Moon is 238,857 miles. The closest that 2004JC will get to the Earth will be about 62 times the distance the Moon is from the Earth. Not much of a chance that it will hit anything.

But each time a large astronomical object comes close to another large or larger object, that orbit will be slightly modified. It may be modified closer together, or farther away.

I also noticed you could run the Orbit Simulation backwards in time. On June 5, 2004, the 2004JC object was only 0.148AU from us. That's 0.012AU less, making the 2004JC object closer in 2004 than in will be in 2015. Seems the orbit is getting further away. Even my playing with the controls never brought it closer than 0.182AU on a far far future date, August 11, 2115!

Unless someone or something pushes this object around (reminds me of an old Stargate SG1 episode), it will always be two ships that pass in the night... And that's a good thing!

richard h.
fort worth, texas, usa

11:07 PM

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