What is bigger than Apophis and will arrive on November 8, 2011?

Asteroid 2005 YU55.

And no one is talking much about it.

This asteroid, first discovered in December of 2005, remains mostly a mystery.  Even its size is a guess.  What’s not a guess is when it will arrive again in the vicinity of earth.

The object was monitored a total of 42 times between December 28th 2005 and January 23rd of 2006.  Since then, this object has been speeding along its orbit around the sun, out of sight.  The next opportunity to view this asteroid will come in less than a year, on April 19th of 2010.  It will pass, according to estimates somewhere between the earth and the moon.  The distance for the April, 2010 encounter is estimated at around 150,000 miles.

The estimate for the November 8, 2011 visit is guessed at around 95,000 miles.  That close, but it doesn’t sound too close, it will probably just fly right by, no problem for us.  But wait a minute, before you get too comfortable, these estimates are based on a very short observation period and in fact, these numbers are just estimates, educated guesses at best.

2005 YU55 Orbit

Apophis was big news a few years ago when it was predicted to hit in 2029.  Much more is known about Apophis than 2005 YU55 and now it is said that Apophis will miss in 2029.  The size of Apophis is estimated to be about 270 meters across, about 885 feet.  2005 YU55 is estimated to be as large as 280 meters or 918 feet.

Certainly not big enough to be a planet killer.  Worst-case scenario, using the given estimates of size, the most thing could do would be to wipe out an area around 900 square miles.  It’s certainly enough to take out any city along with all of the suburbs.  It would leave a crater about four times the size of the meteor crater in Arizona.

 Meteor Crater, Arizona

The problem with 2005 YU55 is that so much is up in the air.  The actual size estimate given by astronomers is between 120 and 280 meters, that’s more than a 100% difference between the upper and lower estimate.  Even if the estimates on its orbit are correct, this thing has been left unattended in space for over three years.  It will have been out of sight for over 4 years when it returns in April of next year.  How would its orbit change if it were to have a collision with some small object during this time?

We will certainly learn more about this asteroid in April 2010 when it returns.  Chances are nothing will happen at all.  With any luck this will just pass us by like so many that have come before.  Everyday on earth we take part in a cosmic lottery of sorts.  Problem is, no one wants to collect the grand prize.  Some day though, we will collect that prize.  Let just hope it’s not in out lifetime.

NeoDys Information On 2005 YU55

 2005 YU55 Orbit Diagram

2005 YU55 on the impact risk table

Asteroid Impact Calculator

This entry was posted on Wednesday, September 30th, 2009 at 6:42 am and is filed under Space & Science. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.