“On Dec. 14, 2006, we observed at least five Geminid meteors hitting the Moon,” reported Bill Cooke of NASA’s Meteoroid Environment Office in Huntsville, AL. Each impact caused an explosion ranging in power from 50 to 125 lbs of TNT and a flash of light as bright as a 7th-to-9th magnitude star.
Lunar impacts since Nov. 2005. Numbers 14-16 and 19-20 are Geminids. Number 18 is a probable Geminid. Credit: NASA Meteoroid Environment Group. |
The explosions occurred while Earth and Moon were passing through a cloud of debris following near-Earth asteroid 3200 Phaethon. This happens every year in mid-December and gives rise to the annual Geminid meteor shower: Streaks of light fly across the sky as rocky chips of Phaethon hit Earth’s atmosphere. It’s a beautiful display.
The same chips hit the Moon, of course, but on the Moon there is no atmosphere to intercept them. Instead, they hit the ground. “We saw about one explosion per hour,” said Cooke.
How does a meteoroid explode? “This isn’t the kind of explosion we experience on Earth,” explained Cooke. The Moon has no oxygen to support fire or combustion, but in this case no oxygen is required: Geminid meteoroids hit the ground traveling 35 km/s (78,000 mph). “At that speed, even a pebble can blast a crater several feet wide,” said Cooke. “The flash of light comes from rocks and soil made so hot by impact that they suddenly glow.”
Cooke’s group has been monitoring the Moon’s nightside (the best place to see flashes of light) since late 2005 and so far they’ve recorded 19 hits: five or six Geminids, three Leonids, one Taurid and a dozen random meteoroids (sporadics). “The amazing thing is,” said Cooke, “we’ve done it using a pair of ordinary backyard telescopes, 14-inch, and off-the-shelf CCD cameras. Amateur astronomers could be recording these explosions, too.”
Indeed, he hopes they will. The NASA team can’t observe 24-7. Daylight, bad weather, equipment malfunctions, vacations—”lots of things get in the way of maximum observing.” Amateur astronomers could fill in the gaps. A worldwide network of amateurs, watching the Moon whenever possible, “would increase the number of explosions we catch,” he said.
To that end, Cooke plans to release data reduction software developed specifically for amateur and professional astronomers wishing to do this type of work. (The release will be announced on Science@NASA in the near future.) The software runs on an ordinary PC equipped with a digital video card. “If you have caught a lunar meteor on tape, this program can find it. It eliminates the need to stare at hours of black and white video, looking for split-second flashes.”
More data will help NASA assess the meteoroid threat as the agency prepares to send astronauts back to the Moon.
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Lunar Impact Monitoring NASA’s Meteoroid Environment Office and Marshall Space Flight Center’s Space Environments Team use Earth-based observations of the dark portion of the moon to establish the rates and sizes of large meteoroids striking the lunar surface. |
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Filed under: Meteors & Meteorites • The Moon
In Polish it's "Ziemia" and "Księżyc" (Earth and Moon respectively)
Meteor Showers and Tons of Space Dust
Facts:
(1) There are nearly a dozen “Meteor Shower” events each year. The QUADRANTID shower is on the night (Monday) of Jan 3rd-4th. When Earth passes through an old comet trail, we see particles of debris that fall into the atmosphere. There is absolutely no reason that other particles could not be simultaneously entrained in a ‘Ring Field’. Gravity works both possibilities simultaneously and shows no known partiality. According to various websites, ‘the USGS says at least 1,000 million grams, or roughly 1,000 tons of material enters the atmosphere every year and makes its way to Earth’s surface.’ This suggests a lot more material in orbit around Earth.
(2) Meteor strikes on the moon blast debris from the surface into space. With the right trajectory and velocity, some particles could be injected into an Earth Ring field. “On Dec. 14, 2006, we observed at least five Geminid meteors hitting the Moon,” reports Bill Cooke of NASA's Meteoroid Environment Office in Huntsville, AL. Each impact caused an explosion ranging in power from 50 to 125 lbs of TNT and a flash of light as bright as a 7th-to-9th magnitude star. The explosions occurred while Earth and Moon were passing through a cloud of debris following near-Earth asteroid 3200 Phaethon. This happens every year in mid-December and gives rise to the annual Geminid meteor shower: Streaks of light fly across the sky as rocky chips of Phaethon hit Earth's atmosphere.
(3) Tektites (from Greek τεκτός tektos, molten) are natural glass rocks up to a few centimeters in size, which most scientists argue were formed by the impact of large meteorites on Earth's surface. Tektites are typically black or olive-green, and their shape varies from rounded to irregular.
Tektites are among the “driest” rocks, with an average water content of 0.005%. This is very unusual, as most if not all of the craters where tektites may have formed were underwater before impact. Also, partially melted zircons have been discovered inside a handful of tektites. This, along with the water content, suggests that the tektites were formed under phenomenal temperature and pressure not normally found on the surface of the Earth.
NASA scientist John A. O'Keefe published numerous papers between the 1950s and 1990s discussing the lunar, rare-earth, isotopic and other chemistries, and how they relate to tektite glass. Thus, some tektite researchers continue to strongly disagree with the popular terrestrial-impact theory; they suggest tektites are more likely … ejecta from the Moon.
(4) The whole Solar System can be compared with a gravitational dust bowl. Earth has a dust tail not because the planet itself is particularly dusty, but rather because the whole solar system is. Interplanetary space is littered with dusty fragments of comets and colliding asteroids. As Earth orbits through this dusty environment, a tail form akin to swaths of fallen leaves swirling up behind a street sweeper. “As Earth orbits the sun, it creates a sort of shell or depression that dust particles fall into, creating a thickening of dust – the tail – that Earth pulls along via gravity,” explains Werner. “In fact, the tail trails our planet all the way around the sun, forming a large dusty ring.”
Comment: In science, the hypothesis that there is ‘nothing-to-look-for’ is generally not acceptable until after a serious search has been done.
November 12, 2010: Did you know that the Earth has a dust tail? The Spitzer Space Telescope sailed right through it a few months ago, giving researchers a clear idea of what it looks like. Spitzer's recent observations have helped astronomers map the structure of Earth's dust tail and figure out what similar “tell-tale tails” attached to alien planets might look like.
If Earth has a ‘dust tail’, there is an increased probability that it has an “O’Keefe Ringâ€.
The fact that it is gradually moving away from the earth suggests that, long ago it may have been part of the earth, before either of them was much more than a loose collection of rocky iron ore and nickel clumped together and being bombarded by all sorts of comets, meteors and asteroids over and over and over all the time for millions of years…. its not much of a stretch to believe that in the beginning, the Earth and Moon were all a big lump that broke up over time. Lucky for us too… the Moon has a stabilizing effect on our rotation. A wobbly Earth would be a rough place to live.
The most favoured theory for the origin of the Moon is that a Mars-sized planet hit the proto-Earth in a glancing collision throwing a large part of the Earth’s surface into orbit in the process. That material then coalesced to form the Moon. It explains why the ratios of elements on the Moon and Earth are so similar. The theory is laid out here: http://www.psi.edu/projects/moon/moon.html