Hi!
Darren Garrison wrote:
> I'm still wondering over this line:
>
> "Bush said it is common to see meteorites, pieces of a meteor, hitting the
> Moon's surface, however,
> but it was a rare occurrence to catch a meteor strike."
Both statements are ridiculous, of course. It would be an incredibly rare
event to see or photograph.
As I recall, there is only one good candidate for a photo of a meteor strike on
the Moon. It was, I think,
back in the late 1950's (1957?). I read about it (and the arguments that
insued from the claim) in Sky &
Telescope magazine and I'm sure the article is there in my 52 year deep stack
of Sky & Telescope's. But I
ain't gonna search for it.
The interesting thing is, at that time, most geologists (especially British
and Australian ones) were
absolutely convinced that the Moon was geologically active and that ALL the
craters were volcanoes.
Impacts? Tut, tut, they said, unlikely. So the arguments were about whether
what had been photographed
was an impact event or a volcanic eruption!
So powerful was the hold of the volcanic model on some geologists that I
have a marvelous 1976
Australian text (which I bought for the section on Australian tektites) that
resolutely affirms that the
lunar landscape was all formed by volcanic action. This was years after we had
already been to the Moon
and seen a small planet's worth of evidence that it WASN'T volcanic. The
author dismissed the Apollo
observations by remarking that those fine fellows were, after all, aviators,
not geologists!
As for impacts, no problem. The seismometers left behind on the Moon
recorded not only "moonquakes,"
but a number of impacts, including a series of five of what were almost
certainly beta Taurid meteor stream
objects. Each one was estimated at a weight of 2-5 tons and with a terminal
velocity of about 24 km/sec,
all five of them on one day! But no photographs...
On the other hand, the Moon has been mapped with some accuracy for over two
centuries and no one has
come up a crater big enough to have been seen that just wasn't there in the
past, which puts a limit on the
frequency of large impacts. In fact, after two centuries, there have been no
verifable instances of any
lunar feature changing in appearance, at least that can't be plausibly
explained by observer limitations
and errors.
Most of us here on the List are familiar with NASA's Astronomy Photo of the
Day webside:
<http://antwrp.gsfc.nasa.gov/apod/astropix.html>
But did you know there's a Lunar Photo Of The Day website (since Jan. 1,
2004) for us "loonies"?
<http://www.lpod.org/>
And of course the Malin Space Science Systems (Mars Observer Camera) web
site has a Mars Photo Of The
Day (along with its archive of 187,000 Mars images):
<http://www.msss.com/>
And just so the Earthlings don't feel left out, an Earth Photo Of The Day
web site:
<http://epod.usra.edu/>
Can't forget the Earthlings...
Sterling K. Webb
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