Lunar "UFO"s May Be Volcanic Belches
Mysterious lunar flashes match up geographically with puffs of radon gas
By JR Minkel for Scientific American on-line
Reprinted by permission
June 26, 2007
Strange, bright flashes observed on the Moon for centuries and often dismissed as the lunar equivalent of UFOs may in fact be emissions of volcanic gas. A researcher says he has reviewed the evidence for so-called lunar transients and found them to occur only in areas of the moon that belch radon gas, suggesting that the flashes could be the result of dust stirred up by such emissionspossibly volcanic in origin.
"A lot of people think that this is just crazinessthis is up there with UFOs," says astrophysicist Arlin Crotts of Columbia University. "But no, this is real science. And it's something people should have done 30 years ago." Other experts, although intrigued, are not yet convinced of transients or Crotts's proposed explanation.
Moon watchers since at least 1540 have reported seeing bright spots or other pinpoint distortions on the moon's surface that faded anywhere from a minute to a few hours later. Interest in these transients exploded in the late 1950s and 1960s among amateur astronomers, who cranked out many a spurious-looking report of lunar lights, Crotts says; even the Apollo astronauts claimed to see a few. "People have been wondering about this for hundreds of years, to the point where they've given up on it," he says.
To determine which, if any, sightings were legit, Crotts statistically analyzed the hundreds of documented transients"a hair ball of a data set," he saysand found 450 sightings, most pre-1960s, that were similar in description despite occurring in different centuries or on different continents. "However you split them up, historically or by the geography of observers
, everybody sees the same [kind of] thing," he says. "It makes it easier to believe they're real."
The crater Aristarchus was the site of the most transients, followed by Plato, Grimaldi, Kepler, Copernicus and Tycho, Crotts reports in a paper submitted to the journal Icarus. These areas, which account for about 10 percent of the lunar surface, also encompass four sites where lunar missions have pinpointed emissions of radioactive radon 222 gas, a by-product of uranium 238, and the more diffuse radon by-product, polonium 210. Crotts says the odds of such overlapping are less than 1,000 to one.
One possible explanation for transients, he says, is volcanic gas escaping from the moon's interior to the surface, where it might build up under the fine lunar soil until it erupts, puffing up a visible cloud of dust. Researchers believe that Aristarchus was the most volcanically active part of the moon, leaving behind solidified lava called basalt riddled with gas pockets.
Crotts' analysis goes further than prior work in proving that transients are real, but the gas explanation is "mostly 'correlations equals causation,'" says astrophysicist Paul Spudis of the Johns Hopkins University Applied Physics Laboratory. Transients are considered fringe, he adds, because observations are hard to confirm or replicate. Hoping to address that problem, Crotts is currently setting up a robotic imaging system in Chile to begin a systematic search for transients.
Astronomers Observe Leonid Impacts on the Moon
December 2, 1999
In June of 1178, monks in Canterbury, England, wrote that they had observed an impact on the Moon. In a1953 photo of the Moon by Dr. Leon Stuart, an unusual bright spot near the lunar terminator can be seen and has been interpreted by some as the flash from a meteor impact. But now, amateur astronomersin the US and Mexico have observed several Leonid meteors striking the Moon. These are the first confirmed lunar impact observations of any kind.
The first lunar impact was observed during the Leonid meteor storm by Brian Cudnik in Houston, Texas, who saw a flash on the dark side of the lunar disk at10:46 pm CST on November 17, 1999 (0446 UT November 18). The flash was also observed by David Dunham in Maryland, who saw the flash in two frames of a video recording. Dunham estimates that the flash reached a peak brightness of at least 3rd magnitude.
Since that initial report, Pedro Valdes Sada, an observer located near Monterrey, Mexico, reported seeing two similar flashes in his video of the Moon at around 0514 and 0515 UT. It was later found that these flashes appeared in Dunham's video as well.
The peak of the Leonid storm on Earth was at 0200 UT on November 18. The Moon was at the same solar longitude as Earth, and thus passed through the peak of the storm about three hours after Earth did.
These observations were part of a concerted effort by many amateur astronomers to witness lunar impacts during a Leonid meteor storm, which occurs each year. Several astronomers had predicted that flashes created if Leonid meteors impacted with the Moon would be faint but visible from Earth with even modest amateur telescopes.
In 1998, astronomers saw indirect evidence for Leonid impacts on the Moon. Boston University astronomers noticed the Moon generated a short-lived tail of sodium atoms that were kicked up by Leonid impacts and then swept back away from the Moon by the solar wind. The tail was noticed by astronomers when the Earth passed through it a few days after the peak of the Leonids.
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Andrew Chaikin's A Man on the Moon is the definitive guide to the Apollo program. Click above to order from Amazon.com.
Robert A. Heinlein's classic, The Moon is a Harsh Mistress, is a must read for all Lunar enthusiasts.