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."
ANN's Daily Aero-Term (11.29.25): Waypoint
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