Friday, March 9, 2012

Is Asteroid 2011 AG5 A Threat To Planet Earth

There have been internet and media reports that an asteroid whose orbit crosses Earth's orbit will be a threat to our planet in the year 2040. Like several previous stories about death-dealing asteroids, this one exaggerates the threat tremendously for its shock value. (More and more it seems, competition among the many media channels forces everyone to exaggerate the importance of all kinds of news stories!)

We only have very limited observations of this relatively small and dim piece of cosmic rock. With those limited observations, experts have put its chances of hitting us at 1 chance in 625. Already, that number doesn't make me rush out and take out extra insurance on my home. But the key here is that we will know the asteroid's orbit much better after September 2013, when it will be well placed for observing. At that time, with more of its orbit clear to us, we will be able to say far better what its chances of hitting us are. Most likely, the chances will become even slimmer, as they have for most such objects in the recent past.

That's not to say that some asteroid will not hit us again sometime in the future. We have good evidence that Earth-crossing asteroids have blasted craters on our planet in the past. But we have to examine each candidate carefully and not rush to judgment as some web sites did in the present case. Luckily we have time between now and 2040 to gather more information.

For a responsible report on Asteroid 2011AG5, see:
http://www.universetoday.com/93877/will-asteroid-2011-ag5-hit-earth-in-2040/

Asteroids that threaten Earth are rare but real.  To find out more about this intriguing topic, here are some responsible general web sites:

http://impact.arc.nasa.gov/ (Organized by astronomer David Morrison, of NASA)

http://neo.jpl.nasa.gov/  (From the Jet Propulsion Laboratories)