[meteorite-list] Asteroid Gets Initial Elevated Risk Rating, But Impact Unlikely (Asteroid 2004 MN4)

From: Herbert Raab <herbert.raab_at_meteoritecentral.com>
Date: Thu Dec 23 18:26:37 2004
Message-ID: <41CB620D.18857.15FC306_at_localhost>

Charles Viau wrote:

> Are our orbital calculating capabilities really good enough to
> project out 25 years on such a small object?

Yes and no. The calculating capabilities are certainly not the
limiting factor, but rather the limited amount of observations
(35) on a limited number of nights (5), each with small (but
a-priori unknown) error limits the accuarcy.

A number of possible orbits for such an asteroid can be found
that agrees with the available observations. On some of these
orbits, the asteroid will have a close encounter with Earth in
2029, on others (on 1 in 300 or so) the object will collide with
our home planet. There is no way to tell which of these orbits
is the "true" path along which the asteroid moves, unless more
data is collected.

When additional observations are added (the object is observable
until May 2005), the number of orbits compatible with the available
observations will be narrowed, the uncertainty in the predicted
position for 2029 will decrease, and in all likelyhood, the impact
solutions will be removed.

Happy holiday to all!

  Herbert Raab
Received on Thu 23 Dec 2004 06:25:49 PM PST