Posted on 02/21/2003 1:47:27 PM PST by cogitator
Clementine image of the moon showing the fresh crater believed to be the impact site for the event photographed on November 15, 1953 by amateur astronomer Dr. Leon Stuart.
Full press release:
NASA Solves Half-Century Old Moon Mystery
(click link for additional pictures, including the "Stuart Event" picture of the Moon)
In the early morning hours of Nov. 15, 1953, an amateur astronomer in Oklahoma photographed what he believed to be a massive, white-hot fireball of vaporized rock rising from the center of the Moon's face. If his theory was right, Dr. Leon Stuart would be the first and only human in history to witness and document the impact of an asteroid-sized body impacting the Moon's scarred exterior.
Almost a half-century, numerous space probes and six manned lunar landings later, what had become known in astronomy circles as "Stuart's Event" was still an unproven, controversial theory. Skeptics dismissed Stuart's data as inconclusive and claimed the flash was a result of a meteorite entering Earth's atmosphere. That is, until Dr. Bonnie J. Buratti, a scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Lane Johnson of Pomona College, Claremont, Calif., took a fresh look at the 50-year-old lunar mystery.
"Stuart's remarkable photograph of the collision gave us an excellent starting point in our search," said Buratti. "We were able to estimate the energy produced by the collision. But we calculated that any crater resulting from the collision would have been too small to be seen by even the best Earth-based telescopes, so we looked elsewhere for proof."
Buratti and Johnson's reconnaissance of the 35-kilometer (21.75-mile) wide region where the impact likely occurred led them to observations made by spacecraft orbiting the Moon. First, they dusted off photographs taken from the Lunar Orbiter spacecraft back in 1967, but none of the craters appeared a likely candidate. Then they consulted the more detailed imagery taken from the Clementine spacecraft in 1994.
"Using Stuart's photograph of the lunar flash, we estimated the object that hit the Moon was approximately 20 meters (65.6 feet) across, and the resulting crater would be in the range of one to two kilometers (.62 to 1.24 miles) across. We were looking for fresh craters with a non-eroded appearance," Buratti said.
Part of what makes a Moon crater look "fresh" is the appearance of a bluish tinge to the surface. This bluish tinge indicates lunar soil that is relatively untouched by a process called "space weathering," which reddens the soil. Another indicator of a fresh crater is that it reflects distinctly more light than the surrounding area.
Buratti and Johnson's search of images from the Clementine mission revealed a 1.5-kilometer (0.93 mile) wide crater. It had a bright blue, fresh-appearing layer of material surrounding the impact site, and it was located in the middle of Stuart's photograph of the 1953 flash. The crater's size is consistent with the energy produced by the observed flash; it has the right color and reflectance, and it is the right shape.
Having the vital statistics of Stuart's crater, Buratti and Johnson calculated the energy released at impact was about .5 megatons (35 times more powerful than the Hiroshima atomic bomb). They estimate such events occur on the lunar surface once every half-century.
"To me this is the celestial equivalent of observing a once-in-a-century hurricane," said Buratti. "We're taught the Moon is geologically dead, but this proves that it is not. Here we can actually see weather on the Moon," she said.
While Dr. Stuart passed on in 1969, his son Jerry Stuart offered some thoughts about Buratti and Lane's findings. "Astronomy is all about investigation and discovery. It was my father's passion, and I know he would be quite pleased," he said.
Buratti and Johnson's study appears in the latest issue of the space journal, Icarus.
The newest branch of the science of geology is known as "exogeology." Exogeology is the study of planetary bodies outside of the earth. I first heard the term several years ago from a firnd who worked at the JPL in Pasadena, CA. He was working on the exogeoglogy of the moons of Jupiter. I thought that was pretty neat.
About every five years. Most detonate in the atmosphere rather than reach the ground.
They do. I wrote a FR editorial proposing that NASA should take up the SpaceGuard mission proposed by Arthur C. Clarke in Rendesvous with Rama, to become an international space organization with the capability to protect the Earth from asteroid impacts.
On June 30, 1908, the Tunguska impact caused a major event in Siberia.
The Tunguska Event (with pictures of the aftermath)
On August 10, 1972, a large asteroid or comet fragment passed over Wyoming and other western states before "skipping" back out of the Earth's atmosphere. Below is a picture of the fireball over the Tetons.
There was also a large fireball and possible impact on the Greenland ice sheet in the 1990s.
I should be able to find my editorial with a FR search; I'll post the link in a subsequent reply if I do.
Main Entry: sel·e·nol·o·gy
Pronunciation: "se-l&-'nä-l&-jE
Function: noun
Date: 1821
: a branch of astronomy that deals with the moon
- se·le·no·log·i·cal /"se-l&-nO-'lä-ji-k&l, s&-"lE-n&l-'ä-/ adjective
- sel·e·nol·o·gist /"se-l&-'nä-l&-jist/ noun
Ummmm, didn't a few monks in England report an impact on the moon's top "horn", the resulting shower of sparks, and the appearance (illusion) of the moon shuddering in the 1200's? IIRC this tracks with the location and estimated age/youth of the Tico crater...
The Moon is plaid??
Actually, from the root of the word, Geo, it does - this is lunology :^
I think the actual term is "Selenology"...
Yes on the monk's observations (1178), but I don't think it was Tycho. One Web article says this might be the crater "Bruno".
What in the Dickens do you use a a key word for the search?
I used Google with "monks moon impact observation".
Here's the article with the reference I mentioned:
Here's another article about it, that throws doubt on the impact theory for the 1178 event and Bruno crater:
The Mysterious Case of Crater Giordano Bruno
Same article topic, better picture:
Lunar Impact or Heavenly Coincedence
This article also refers to the Stuart impact photograph.
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