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

From: Richard Kowalski <kowalski_at_meteoritecentral.com>
Date: Wed, 28 Jul 2010 15:51:58 -0700
Message-ID: <4C50B48E.8070300_at_lpl.arizona.edu>

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
 >

Received on Wed 28 Jul 2010 06:51:58 PM PDT