One week ago astronomers Gennady Borisov and Timur Kryachko discovered an asteroid (a space rock) using an 8-inch astrograph (a sophisticated telescope camera) at the Crimean Astrophysical Observatory. Named 2013 TV135, it turned out to be a near-Earth asteroid that had swung by Earth on September 16th at a distance of 4.2 million miles. Many asteroids come closer than that to our planet including some that come closer to us than the Moon.
However, when the preliminary orbit was calculated for 2013 TV135, it was noticed that it was going to swing by Earth again in August 2032, and on the 26th it was going to be very, very close to us. So close in fact that there would be a 1-in-63,000 chance that it could impact Earth.
Media outlets around the world latched on to the announcement and some headlines were “doomsday - end of the world” in nature. At an estimated size of 1,300 feet 2013 TV135 is not capable of the global wide destruction that scientists believe caused the demise of the dinosaurs 65 million years ago. The estimated size of that asteroid or comet was 6 MILES across.
An asteroid the size of 2013 TV 135 would cause destruction on the scale of a large metropolitan area and according to one unofficial estimate - http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=100&diam=400&pdens=3000&pdens_select=0&vel=30&theta=90&tdens=2500&tdens_select=0 -may make a crater 6-miles across and release 10,000 megatons of energy, very powerful indeed but not a global size event.
The impactor that created Chesapeake Bay Crater, centered on Cape Charles, Virginia, and estimated to be 50-plus miles across, was about 2 miles in size and hit 35 million years ago. Its damage was wide spread affecting most if not all of the east coast http://www.virginiaplaces.org/geology/bolide.html.
NASA responded immediately - http://neo.jpl.nasa.gov/news/news180.html - now that its employees and websites are back after the government shutdown, that there was a less than 1% chance of impact - 99.998% to be exact. This percentage of impact probability is based on only a few observations of the asteroid.
Further observations over the coming months are almost certainly going to increase the odds against an impact if not altogether eliminate the possibility. 2013 TV135 swings by Earth about every four years and the more observations we obtain the better the upcoming orbital passes can be determined, including 2032. Astronomers are gathering these observations now and will be doing so for the next several months while 2013 TV135 is visible.
To me the most important part of this story, besides some of the sensational media hype, is that this space rock was discovered AFTER it had passed by us. Earthlings are finally getting it that space rocks (and comets) do matter to us and are not just figments of science fiction and Hollywood. Remember Armageddon and Deep Impact?
Just ask the residents of Chelyabinsk, Russia, if space rocks are real and I am sure they would respond with a resounding “YES!” as the events of February 15th are still very fresh in their minds - http://www.foxnews.com/science/2013/10/17/russians-pull-huge-meteorite-from-lake-and-promptly-break-it/?intcmp=obinsite. Chelyabinsk’s impactor was estimated to be about 50-feet across and was not known before it entered our atmosphere.
Astronomers have discovered as of October 17, 2013, 10,037 Near Earth Objects (NEO’s) http://neo.jpl.nasa.gov. That’s the good news as many of these are large in size and could cause significant damage if they impacted our planet. The bad news is that NASA says there are at least ten times more NEO’s “out there” http://www.jpl.nasa.gov/news/news.php?release=2013-207.
Simply put, we have a lot more looking to do to find more NEO’s. And what if one is found that truly has our planet’s name on it? What then? That would depend on its size, how far away the NEO is and what the predicted impact area would be http://neo.jpl.nasa.gov/neo/target.html. President Obama has made it a priority for NASA to send astronauts to the asteroids and NASA is preparing for an asteroid redirect mission http://www.nasa.gov/larc/nasa-develops-additional-concept-for-asteroid-redirect-mission/#.UmKsoBYbRSU
The bottom line is that we have to keep looking for these NEOs so that we can find the Chelyabinsks and 2013 TV135s that are out there. We also need a vibrant space program to travel to and study NEOs and defend ourselves against them if need be.
Sky Guy in VA