[meteorite-list] Scientist Warns Massive Asteroid Could Hit Earth in 2182

[Richard Kowalski]

Wow what a sham(e).

A friend asked me about this earlier today but he cited a British rag. I told 
him that the British tabloids still report this sensationalistic crap every so 
often but the media in the US has figured out to ignore it. Well at least most 
of them have.

A quick explanation:

When we observe an asteroid, there is some uncertainty in our observations so 
while we get a good handle on the orbit, the orbit isn't exactly known to a 
precise amount. As such, there are often a number of similar orbits that satisfy 
the set of observations of the object we have on hand.

There are scientists at JPL and elsewhere who's job it is to determine which 
NEOs will come close to the Earth. During their calculations they run all the 
possible orbits that satisfy the observations and determine which objects have 
possible orbits that intersect the Earth, when the Earth is at that 
intersection. These objects that have such a possible orbit are then referred to 
as "Virtual Impactors" or VI for short. The way we reduce this uncertainty of 
the orbits for a given object is to re-observe it over time. As we continue to 
obtain additional observations the number of possible orbits that satisfy all of 
the observations gets smaller until we come to an orbital solution that is most 
likely the one that the object actually is in.

When an object has been determined to be a VI that alerts observatories around 
the world to obtain additional observations of this object.

NASA & JPL have a page on the NEO Program website ( http://neo.jpl.nasa.gov/ ) 
that is updated daily as new observations come in and get folded into the 
dataset. It is the Impact Risk page at: http://neo.jpl.nasa.gov/risk/

If you visit the page you'll see information on the object in question, but 
you'll also note that there are other objects that are also of interest, Watch 
it every day and you'll see "impact probabilities" for any given object rise and 
fall, with new ones appearing as they are discovered and others dropping off the 
list entirely as more observations come in and the orbits become more refined.

My advice is unless you hear of a 100% chance of impact, ignore the story. The 
media is just wasting your time by making a story out of something that is not 
news... But then again that does seem to be the business they are actually in 
now, isn't it?



-- 
Richard Kowalski
Catalina Sky Survey
Lunar and Planetary Laboratory
University of Arizona
http://www.lpl.arizona.edu/css/


--- On Wed, 7/28/10, Thunder Stone <stanleygregr at hotmail.com> wrote:

 > From: Thunder Stone <stanleygregr at hotmail.com>
 > Subject: [meteorite-list] Scientist Warns Massive Asteroid Could Hit Earth in 
2182
 > To: meteorite-list at meteoritecentral.com
 > Date: Wednesday, July 28, 2010, 3:23 PM
 >
 > Wow - that's only 72 years from now... Don't think I'll be
 > around
 >
 > Greg S.
 >
 >
 > 
http://www.foxnews.com/scitech/2010/07/28/massive-asteroid-hit-earth-warn-scientists/?test=faces
 >