Nasa team sees explosion on Moon

In article , rk
wrote:

Nasa team sees explosion on Moon

Nasa scientists have witnessed a rare explosion on the Moon, caused by a
meteoroid slamming into it.


These have been seen before. (e.g. by me.)

http://aio.arc.nasa.gov/~leonid/leonidnews35.html
http://science.nasa.gov/headlines/y2001/ast30nov_1.htm

--
David M. Palmer (formerly @clark.net, @ematic.com)

David M. Palmer wrote:


These have been seen before. (e.g. by me.)

http://aio.arc.nasa.gov/~leonid/leonidnews35.html
http://science.nasa.gov/headlines/y2001/ast30nov_1.htm



Did you ever get a size and velocity estimate on the impactor?

Pat

In article , Pat Flannery
wrote:

David M. Palmer wrote:


These have been seen before. (e.g. by me.)

http://aio.arc.nasa.gov/~leonid/leonidnews35.html
http://science.nasa.gov/headlines/y2001/ast30nov_1.htm



Did you ever get a size and velocity estimate on the impactor?

The ones I recorded were from the Leonid meteor shower. These
meteoroids come from a comet in a retrograde orbit that (when combined
with Earth's 30 km/s prograde orbital speed around the Sun) gives an
impact speed of about 70 km/s.

Combining that with the brightness of the impacts (3rd-7th magnitude
for a ~1/60 of a second) and the estimate (meaning guess) that the
production of visible light is about 0.1%-1% efficient gives a mass in
the few kg range.

The Leonids were good for this because they
a) were stormy in those years
b) have a high relative velocity and correspondingly-squared high
kinetic energy

--
David M. Palmer (formerly @clark.net, @ematic.com)

David M. Palmer,
Apparently these impacts from just one of the Apollo archives haven't
been seen before, or at least they haven't been openly shared before.

How about a topic; NASA/Apollo team sees explosion on Moon

With regard to such impact explosions upon our moon, I believe here's
something that I'd consider as offering us a good look at whatever's a
whole lot bigger than a bread box worth of an impact and subsequent
explosion on the moon. Try out these interesting Apollo-14 views from
orbit:
http://www.lpi.usra.edu/resources/ap.../?AS14-70-9835
http://www.lpi.usra.edu/resources/ap.../?AS14-70-9836
http://www.lpi.usra.edu/resources/ap.../?AS14-70-9837
Personally, I'm thinking it's either suggesting a substantial volcanic
or geothermal/gas vent release, as having produced a horrific cloud of
lunar debris and/or possibly the likes of a sal****er expansion/sublime
explosive like event, as otherwise there's always the impact and
subsequent debris cloud of their fly-by-rocket lander to consider, as
imaged shortly after having bit the dust.

Not that many other Apollo mission images as having been obtained from
orbit (robotic or supposedly manned) are not every bit if not more so
close up and interesting, I'm just sharing for the moment of what this
one archive has to offer from their Apollo-14 group. I'll suppose,
because the A-14 mission was limited to just 34 orbits is why there's
not a great many more of such images as having been obtained from orbit
for us to review. Whereas 66.5 hours worth of 34 orbits might have
limited their solar illuminated picture taking to perhaps as few as
1,000 frames. Don't bother asking where the heck all the other frames
are.

Perhaps folks simply do not realize there's a less publicized but
otherwise rather serious bunch of these nifty close-up look-see images
of our lunar surface to being had?
Wouldn't you like to see a few of those better examples?
http://www.lpi.usra.edu/resources/apollo/catalog/70mm/

BTW; here's another one of their pesky oops blue-screen frames:
http://www.lpi.usra.edu/resources/ap...m/magazine/?73
http://www.lpi.usra.edu/resources/ap...?AS14-73-10182

A couple more of those mid-flim role of pesky blue-screens to share and
share alike:
http://www.lpi.usra.edu/resources/ap...m/magazine/?72

Here's a few geological zig-zags that are quite believably interesting:
http://www.lpi.usra.edu/resources/ap.../?AS14-72-9954
http://www.lpi.usra.edu/resources/ap.../?AS14-72-9955

Another serious bunch of A-14 frames that actually looks as though
we've landed and walked upon the moon, that is if you pay absolutely no
attention whatsoever to the laws of physics, or even appreciate the
total lack of any composite soil/mineral color as their xenon lamp
spectrum worth of terrestrial like photons relates to having
illuminated such natural substances (meaning side by side having
recorded identical color saturation and contrast as to what's
xenon/terrestrial), of photographic moments that at least
scientifically suck and blow, especially since those were essentially
full spectrum, as in unfiltered Kodak moments supposedly obtained upon
a dark and nasty (we're talking dark mineral composites plus basalt, if
not nearly coal like due to all of the carbon/soot) as a 12% albedo
moon that was supposedly receiving the fullest benefit of the raw solar
worth of illumination influx that had to have included a rather great
amount of UV energy/m2, which should have noticeably skewed all such
frames towards being bluish if not sharing a fair degree of
secondary/recoil worth of near-blue.
http://www.lpi.usra.edu/resources/ap...m/magazine/?66
Unfortunately, there's all sorts of nifty Apollo's stuff that's within
frame after frame, as color and albedo checks, thereby proving that the
moon upon which they'd landed was extensively 55~65% albedo worthy, and
otherwise looking exactly as though covered in a thin layer of 50/50
portland cement and cornmeal, though without ever so much as a
meteorite nor secondary impact shard to spare.
-
Brad Guth

David M. Palmer wrote:

Combining that with the brightness of the impacts (3rd-7th magnitude
for a ~1/60 of a second) and the estimate (meaning guess) that the
production of visible light is about 0.1%-1% efficient gives a mass in
the few kg range.


Interesting! That sounds like something that could make it to the ground
if it had hit Earth instead of the Moon.

Pat

In article , Pat Flannery
wrote:

David M. Palmer wrote:

Combining that with the brightness of the impacts (3rd-7th magnitude
for a ~1/60 of a second) and the estimate (meaning guess) that the
production of visible light is about 0.1%-1% efficient gives a mass in
the few kg range.


Interesting! That sounds like something that could make it to the ground
if it had hit Earth instead of the Moon.

I have heard that there has never been a meteorite recovered from a
shower. Cometary material is weak and fluffy, and at 70 km/s, a piece
that size probably wouldn't survive entry into the atmosphere.

--
David M. Palmer (formerly @clark.net, @ematic.com)

David M. Palmer wrote:

I have heard that there has never been a meteorite recovered from a
shower. Cometary material is weak and fluffy, and at 70 km/s, a piece
that size probably wouldn't survive entry into the atmosphere.



Which leaves the question of just how large a piece of that weight would be.
As far as impacts on earth, the Tunguska event coincided with the peak
of the Beta Taurid shower, although the connection between the event and
comet Encke which is responsible for that shower is controversial.

Pat

In article , Pat Flannery
wrote:

David M. Palmer wrote:

I have heard that there has never been a meteorite recovered from a
shower. Cometary material is weak and fluffy, and at 70 km/s, a piece
that size probably wouldn't survive entry into the atmosphere.



Which leaves the question of just how large a piece of that weight would be.
As far as impacts on earth, the Tunguska event coincided with the peak
of the Beta Taurid shower, although the connection between the event and
comet Encke which is responsible for that shower is controversial.

The International Meteor Organization page on this subject
http://www.imo.net/fireball/meteorites
says that the cometary meteor material in showers ranges from 0.2-0.9
g/cm^3. So a few kg would be in the size range of a head to a torso.

Tunguska was somewhat larger. Is the Beta Taurid coincidence
consistent with observations (i.e. was the radian above the horizon and
to consistent with the direction that people saw the fireball coming in
from?) But there wasn't a crater at Tunguska, so it is consistent with
an air-burst which adds to the likelihood of it being cometary.

--
David M. Palmer (formerly @clark.net, @ematic.com)

David M. Palmer wrote:

The International Meteor Organization page on this subject
http://www.imo.net/fireball/meteorites
says that the cometary meteor material in showers ranges from 0.2-0.9
g/cm^3. So a few kg would be in the size range of a head to a torso.


That's a fairly unusual comparison to use... do they have some fixation
on the loss of the Columbia over at that organization? :-)

Tunguska was somewhat larger. Is the Beta Taurid coincidence
consistent with observations (i.e. was the radian above the horizon and
to consistent with the direction that people saw the fireball coming in
from?) But there wasn't a crater at Tunguska, so it is consistent with
an air-burst which adds to the likelihood of it being cometary.



That's debated also; some say the direction of flight favors a asteroid
rather than a Beta Taurid, and given that some new evidence suggests
that some asteroids may be conglomerations of loose material only weakly
held together by gravity, who knows? With an asteroid one would expect
at least some of its components to be large enough to reach the surface
though.
If it was a very small asteroid or a large stray meteor, the leading
candidate type is a Carbonaceous Chondrite, as they are know to explode
in midair.
I still personally favor the small dead comet theory myself, due to the
apparent complete lack of surface impacts from it, although given the
swampiness of the Tunguska area, any fragments might well be submerged.

Pat

That's odd. Talk about something of a massive lunar impact as having
been photographed via NASA/Apollo, whereas instead of Usenet folks
sharing, it seems all of the topic lights go out. It's almost as though
NASA's E-MIB are just about everywhere these days.

You can't even share and share alike as to a few of the NASA/Apollo
blue-screen imaging process methods that so kindly eliminated all
possible other items that could rather easily nail down exactly where
and when a given Kodak moment was taken.
-
Brad Guth