[meteorite-list] Moon/Earth impact rates

[Chris Peterson]

Nobody has a good idea about ELE scale events, because they are so rare 
as to make statistics useless. But we have a very good idea about the 
local meteoroid environment, including good estimates for lunar impacts, 
which are regularly observed. Reasonable estimates now exist for 
material distribution, including size, velocity, and orbits, from dust 
through tens of meters. These estimates are backed up by observational 
evidence from space-borne test surfaces, the previously mentioned lunar 
impact data, hundreds of thousands of optically recorded meteors, and 
tens of millions of radar meteors. The Earth environment models are 
presumed to describe quite well both the shadowing and focusing effects 
of the Earth and Moon on each other.

The folks at NASA who are working on this are extremely competent, and 
are in close association with meteoritics research groups at 
universities and observatories around the world. To suggest that these 
people are incompetent says more about you than it does them.

Chris

*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On 7/3/2011 5:55 PM, E.P. Grondine wrote:
> Hi Sterling -
>
> Usually, you are spot on, but in this case...
>
> In fact, no one knows if the Earth sweeps stuff up for the Moon, or the Moon pulls in more stuff that hits the Earth.  NASA's garbage estimates for ELEs are a perfect example of how bad their "modeled" impact estimates are; NASA's estimated human ELE rates are even worse - they appear to be off by two orders of magnitude.
>
> Earth impact rates need to be determined from Earth data. Then a more general model may be worked out, using accretion data from all bodies in our solar system.
>
> All the theories in the world added together do not amount to one fact.
>
> As far as the effects of hyper-velocity dust goes, I seem to recall parts of Surveyor being examined after lunar surface exposure.
>
> all the best,
> E.P. Grondine