Astronomers Capture Rare Lunar Meteor Strike

Dec 23, 2005
Astronomers Capture Rare Lunar Meteor Strike
This artist´s rendering of a small but powerful meteor strike on the surface of the moon demonstrates a key concern for future lunar explorers -- mitigating potential risks from impact "ejecta," or the spray of debris that follows an impact, unimpeded by gravity or atmosphere. NASA astronomers are studying lunar impacts to help safeguard future missions to Earth´s nearest celestial neighbor. (NASA/MSFC)

Astronomers at NASA's Marshall Space Flight Center, Huntsville, Ala., have recorded a small but powerful meteoroid strike in the night on the moon’s surface. On Nov. 7, using a 10-inch-diameter telescope, astronomers recorded a tiny blip northwest of Mare Imbrium, the moon's "Sea of Showers." Such impacts are not uncommon, but it was only in 1999 that scientists first recorded a lunar strike as it happened.

"People just do not look at the moon anymore," said Dr. Robert Suggs, Space Environment team lead in the Natural Environments Branch of the Marshall Center's Engineering Directorate. "We tend to think of it as a known quantity. But there is knowledge still to be gained here."

As NASA plans to return to the moon, the agency has a need to understand what happens after lunar impacts in order to protect lunar explorers. On Earth, the atmosphere vaporizes most small meteoroids, leaving nothing behind but a brief streak of light. The vacuum environment on the moon, however, means there is nothing to slow incoming meteoroids before they strike.

"The likelihood of being struck by a meteoroid on the lunar surface is very, very small," said Bill Cooke, an astronomer in Marshall's Meteoroid Environment Office. "The challenge is learning what happens to high-velocity ejecta, the debris kicked up by a meteoroid strike, which is not hindered by atmospheric friction or Earth gravity. What threat does that debris pose to humans or equipment?"

Suggs, who heads the impact study, used commercial software tools to study the video frame by frame, and spotted a very bright flash. The burst of light diminished gradually over the course of five video frames, each 1/30th of a second in duration. Suggs called in Cooke, and both scientists agreed that the bright light was an impact flash, captured by video from some 248,000 miles away.

Immediately, the team began ruling out other possible causes. Two telling characteristics won out – the gradual diminishment of the flash rather than an on-off "winking" effect, and its motionlessness. A flicker of light from a moving satellite, Cooke noted, would have appeared to shift perceptibly, even in five brief frames of video.

Suggs and Cooke next consulted star charts and lunar imaging software and determined the meteoroid was likely a Taurid, part of an annual meteor shower active at the time of the strike. Based on the amount of light produced the object was roughly five inches in diameter, traveling more than 60,000 mph, and may have gouged a crater nearly 10 feet in diameter out of the moon's surface.

The Taurids, which approach Earth from the direction of the Taurus constellation, are believed to be ancient remnants of comet Encke, which orbits the Sun every 3.3 years.

NASA scientists previously studied lunar meteor strikes during the Apollo moon program, but lacked the sophisticated video cameras and high-powered image processors to capture the tiny, telling flashes. Now, however, as NASA readies its next-generation spaceship to carry explorers back to the moon for potential long-term stays, Suggs and Cooke say lunar impact research is more vital than ever.

"Large-scale lunar facilities are sure to be well-protected, using impact-resistant technologies much like those developed to shield the space shuttle and the International Space Station," Suggs said. "We want to support additional measures that safeguard personnel working in the lunar field – early-alert systems, emergency protective measures and new technologies that will mitigate risks from flying impact debris."

Source: NASA

Explore further: SDO captures images of two mid-level flares

add to favorites email to friend print save as pdf

Related Stories

Bright explosion on the Moon

May 17, 2013

For the past 8 years, NASA astronomers have been monitoring the Moon for signs of explosions caused by meteoroids hitting the lunar surface. "Lunar meteor showers" have turned out to be more common than anyone ...

100 Explosions on the Moon

May 21, 2008

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.

Recommended for you

SDO captures images of two mid-level flares

Dec 19, 2014

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Why is Venus so horrible?

Dec 19, 2014

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

Image: Christmas wrapping the Sentinel-3A antenna

Dec 19, 2014

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

Dec 19, 2014

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.