July 19, 2012
Understanding Lunar Swirls Could Help Protect Astronauts
Lee Rannals for redOrbit.com - Your Universe Online
A study of "lunar swirls" on the moon may eventually lead to new developments in engineering to help protect astronauts in space.
During the Apollo missions, scientists realized that lunar swirls were associated with localized magnetic fields in the lunar crust.
NASA's Lunar Prospector focused on the regions and identified magnetic anomalies that had created fully formed miniature "magnetospheres" similar to what the Earth's planetary-wide magnetic field does.
Now, scientists from RAL Space at the Rutherford Appleton Laboratory have new research that may lead the way to determining if the same mechanism could be artificially manipulated to create safe havens for future space explorers.
The team was able to identify how such small scale magnetic "bubbles" were more efficient in deflecting the solar wind particles bombarding the moon.
“When we first tried the experiment in the Solar Wind Tunnel and it worked, it was very exciting.” lead scientist Dr. Ruth Bamford of the Centre for Fundamental Physics and RAL Space at the Rutherford Appleton Laboratory said recently.
"The active force which deflect the solar wind particles is electric not magnetic. The electric field is created naturally by the edges of the moon's magnetic 'bubbles", Bamford added. "What matters is the "gradient" in the magnetic field, rather than the overall size of the magnetic bubble. So they can be as small as you like - as long as the gradient is steep enough."
Understanding these lunar swirls could lead the way to determining if the same mechanism could be artificially created.
“We still need to determine quite how effective this mechanism would be at deflecting the real hazardous higher energy particles," Bamford said. "The jury is still out on that one, but such an active shield could make the difference between survivable and certain death for astronauts on their way to Mars”.
The lunar soil was originally white, but is believed to have been darkened over time due to exposure to charged particles of "solar wind."
Scientists theorized that the swirls were a result of magnetic shielding of the lunar surface from the solar wind, but no one understood how the relatively weak magnetic fields associated with lunar swirls could sufficiently protect the moon's surface over hundreds of millions of years to prevent surface darkening and produce these patterns.
Bamford said that the strength of the magnetic anomaly near the moon's surface is likely to be very irregular. He said we cannot know the precise arrangement without going to the moon and seeing for ourselves.
Over about 3.8 billion years, these magnetic anomalies would have been deflecting the solar wind particles streaming in from space, helping to create these patterns, Bamford said.
Experiments by the laboratory with the University of York in the U.K. helped confirm the theories by using their "Plasma Wind Tunnel." During the experiments, particles generated were "corralled" by a narrow electrostatic field, protecting areas of the exposed surface.
The interaction of the solar wind with the magnetic field anomalies have been shown to be effective enough to create protected voids above the surface of the moon. Scientists believe this is sufficient enough to stave off against weathering caused by the bombardment of solar particles.