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Post Info TOPIC: Lunar impact


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RE: Lunar impact
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Title: The Flux of Kilogram-Sized Meteoroids from Lunar Impact Monitoring
Author: Robert Suggs, Danielle Moser, William Cooke, Ronnie Suggs

The flashes from meteoroid impacts on the Moon are useful in determining the flux of impactors with masses as low as a few tens of grams. A routine monitoring program at NASA's Marshall Space Flight Center has recorded over 300 impacts since 2006. A selection of 126 flashes recorded during periods of photometric skies was analyzed, creating the largest and most homogeneous dataset of lunar impact flashes to date. Standard CCD photometric techniques were applied to the video and the luminous energy, kinetic energy, and mass are estimated for each impactor. Shower associations were determined for most of the impactors and a range of luminous efficiencies was considered. The flux to a limiting energy of 2.5E-6 kT TNT or 1.05E7 J is 1.03E^-7 km^-2 hr^-1 and the flux to a limiting mass of 30 g is 6.14E-10 m^-2 yr^-1 at the Moon. Comparisons made with measurements and models of the meteoroid population indicate that the flux of objects in this size range is slightly lower (but within error bars) than flux at this size from the near Earth object and fireball population by Brown et al. 2002. Size estimates for the crater detected by Lunar Reconnaissance Orbiter from a large impact observed on March 17, 2013 are also briefly discussed.

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Lunar impacts 2006 - 2013

impacts.jpg



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ScienceCasts: Bright Explosion on the Moon

NASA researchers who monitor the Moon for meteoroid impacts have detected the brightest explosion in the history of their program on March 17th 2013.



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On this day in 1178...

"Just after sunset, according to the English monk and chronicler Gervase of Canterbury, five monks watch the moon explode into flames."

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Not so long ago, anyone claiming to see flashes of light on the Moon would be viewed with deep suspicion by professional astronomers. Such reports were filed under "L" for lunatic.
Not anymore. Over the past two and a half years, NASA astronomers have observed the Moon flashing at them not just once but one hundred times.

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Lunar Impact Monitoring
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Mission statement: Use Earth-based observations of the dark portion of the moon to establish the rates and sizes of large meteoroids (greater than 500 grams or 1 pound in mass) striking the lunar surface.

When we observe: Observations are taken between New and 1st Quarter Moon and between Last Quarter and New Moon, when the solar illumination is between 10 and 55 percent. These conditions yield 10-12 observing nights per month.

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RE: Lunar impact
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NASA scientists are proving that you can go home again if you bring a telescope with you. "Home" is north Georgia's Walker County, where astronomers Bill Cooke and Rob Suggs have just set up a research-grade observatory for their old school system.

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Image3
A meteorite hits the Moon--recorded from the MSFC's lunar observatory in Huntsville, Alabama, in May 2006. The Walker County Observatory will soon be detecting similar flashes.

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"Every day, more than a metric ton of meteoroids hits the Moon" - Bill Cooke, Marshall Space Flight Centre's Meteoroid Environment Office.

Meteorites literally fall out of the sky, in all shapes and sizes, from specks of comet dust to full-blown asteroids, travelling up to a hundred thousand mph. And when they hit, they do not disintegrate harmlessly in the atmosphere as most would on Earth. On the airless Moon, meteoroids hit the ground.

Clues to how often and how hard the Moon is hit lie in data from four seismometers placed on the Moon by the Apollo 12, 14, 15, and 16 missions during 1969-72. They operated until NASA turned them off in 1977.
For years, the seismometers recorded all manner of tremors and jolts, including almost 3000 moonquakes, 1700 meteoroid strikes, and 9 spacecraft deliberately crashed into the Moon. All these data were transmitted to Earth for analysis.

"Here's what's interesting. Of some 12,000 events recorded by the seismometers, less than half have been explained by known phenomena. There are thousands of tremors caused by ... no one knows what. Many of them may be meteoroid impacts."- Bill Cooke.

According to the Standard Model, such meteoroids hit the Moon approximately 400 times a year—more than once a day.

Source

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Observers also saw optical flashes on the lunar surface - likely the fleeting result of impacting meteoroids during the 1999 Leonid meteor shower. Orchestrated by David Dunham, president of the International Occultation Timing Association (IOTA), video recordings made with modest equipment and visual telescopic observations detected and confirmed a total of six flashes on the Moon's dark side.
The flashes, some initially as bright as a third magnitude star, were all seen within hours of Leonid meteor shower peak.


Credit: David Palmer (LHEA/ GSFC)

Their locations are indicated by the red Xs on this projection of the Moon as it appeared on the night of November 18. Similar flashes would have been difficult to see if viewed against the Moon's brightly lit portion. It has been estimated that the brightest flashes were made by meteoroids weighing around a tenth of a kilogram, resulting in lunar craters about one meter across.

-- Edited by Blobrana at 17:57, 2005-12-25

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The light curve of the flash observed by Suggs and Swift on November 7, 2005.
Credit: NASA/MSFC

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