[meteorite-list] 1999 RQ36 V.I.

From: Matson, Robert D. <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Wed, 28 Jul 2010 16:17:27 -0700
Message-ID: <7C640E28081AEE4B952F008D1E913F1703FABF40_at_0461-its-exmb04.us.saic.com>

Hi Richard/List,

I just added three more positions for this V.I. taken from Haleakala
on September 12, 2005. The observations are bracketed by a pair of
positions from Pulkovo taken on 9/10 and four more on 9/13 from
Catalina Sky Survey, so I don't expect the impact probabilities to
be altered much by my new positions.

I note that there is a triplet of images from 2/7/2006 taken by
Spacewatch
that ought to be sensitive enough to see 1999 RQ36. It would be very
close to the bottom center of the frame (and quite possibly just off
the frame in some or all of the images). The other Spacewatch triplet
to check is from 12/27/2005 -- the NEA is definitely in the field of
view of the camera; the only question is whether it's bright enough
at magnitude 21.4 to be detectable.

--Rob

-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
Richard Kowalski
Sent: Wednesday, July 28, 2010 3:52 PM
To: Meteorite List
Subject: Re: [meteorite-list] Scientist Warns Massive Asteroid Could Hit
Earth in 2182

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-war
n-scientists/?test=faces

Received on Wed 28 Jul 2010 07:17:27 PM PDT