[meteorite-list] Small Asteroid 2010 AL30 Will Fly Past TheEarth

From: geozay at aol.com <geozay_at_meteoritecentral.com>
Date: Wed, 13 Jan 2010 10:39:05 EST
Message-ID: <25ebb.52fc448e.387f4319_at_aol.com>

>>The only objects I know of that are moving
faster than the local escape velocity of the
solar system (and hence must be from outside
our solar system) are a small percentage of
the "meteoroids" detected by AMOR radar
systems. But they're so small they're usually
referred to as "dust" or "micrometeoroids,"
although the largest particles are at about
100 microns and might be called small
meteoroids by some.<<

I'm not sure where all my original sources were from. Below is what I
wrote down in my notes about 12 years ago.
>> The fastest geocentric velocity a meteor can have while in solar orbit
is 72 km/s (45 mps). Visually a meteor at this speed appears to be a very
fast streak. From a 1948 - 1950 Canadian Radio survey, it has been learned
that less than 1 percent of all meteors were traveling faster than the
established 72 km/s solar speed limit. Of these that were traveling at apparent
hyperbolic speeds, none were traveling faster than 80 km/s. As the survey
noted, this excessive solar speed is within the realms of being measurement
errors. But in recent years, additional research has been done that
indicates the Canadian survey was relatively accurate. The Christchurch (New
Zealand) meteor radar AMOR(Advanced Meteor Orbit Radar) has also yielded about
1% of meteoroids having an atmospheric speed in excess of 100 km/s. In
addition, the Ulysses space probe dust detector has in 1994, discovered
interstellar grains in the outer solar system at about 5 AU, having hyperbolic
trajectories. This mean it?s traveling too fast to stay in orbit around the
sun.<<

GeoZay
Received on Wed 13 Jan 2010 10:39:05 AM PST