Sparking, melting soil on Moon due to solar storms, says NASA

New Delhi: As per NASA, solar storms trigger sparks and also melt soil on Moon's surface. The NASA study says that these storms possibly produce sparks that vaporise and melt the lunar soil on the surface.

This alteration may become evident when analysing future samples from these regions that could hold the key to understanding the history of the Moon and solar system.

The Moon has almost no atmosphere, so its surface is exposed to the harsh space environment.
Impacts from small meteoroids constantly churn or "garden" the top layer of the dust and rock, called regolith, on the Moon.

"About 10 per cent of this gardened layer has been melted or vaporised by meteoroid impacts," said Andrew Jordan of the University of New Hampshire in the US.

"We found that in the Moon's permanently shadowed regions, sparks from solar storms could melt or vaporise a similar percentage," said Jordan.

Explosive solar activity, like flares and coronal mass ejections, blasts highly energetic, electrically charged particles into space.

Earth's atmosphere shields us from most of this radiation, but on the Moon, these particles - ions and electrons - slam directly into the surface.

They accumulate in two layers beneath the surface; the bulky ions can not penetrate deeply because they are more likely to hit atoms in the regolith, so they form a layer closer to the surface while the tiny electrons slip through and form a deeper layer.

The ions have positive charge while the electrons carry negative charge. Since opposite charges attract, normally these charges flow towards each other and balance out.

In August 2014, however, researchers showed that strong solar storms would cause the regolith in the Moon's permanently shadowed regions (PSRs) to accumulate charge in these two layers until explosively released, like a miniature lightning strike.

The PSRs are so frigid that regolith becomes an extremely poor conductor of electricity.

Therefore, during intense solar storms, the regolith is expected to dissipate the build-up of charge too slowly to avoid the destructive effects of a sudden electric discharge, called dielectric breakdown.

(With PTI inputs)