The bodies revolving around the sun are continuously being bombarded by the particles that are released away from the sun, these particles are known as solar wind particles.  These solar wind particles do not have any effect on the earth, but on the moon or mercury, the uppermost layer of rocks is gradually eroded by its impact. New results published in the planetology journal Icarus reveal that the effects of solar wind bombardment are more drastic than they were earlier thought to be.  

An exosphere of shattered rock

The solar wind consists of charged particles comprising hydrogen and helium ions.  These particles hit the rocks on the surface at high speed of 400 to 800 km per second which leads to the ejection of numerous other particles from the surface which rise high before they fall back onto the surface- creating a fragile atmosphere of atoms released from the surface – known as an exosphere.  The composition of the exosphere helps to analyze the chemical composition of the rock surface.

Charge matters

On investigating the effect of ion bombardment on wollastonite, a typical moon rock it was found that the high electrical charge of the particles plays a decisive role which was unseen till now instead it was assumed that the kinetic energy of the fast particles was primarily responsible for the atomization of the rock surface. When particles of solar wind carry multiple charges, they carry a significant amount of energy which is released in a flash on impact. So there must also be considered. Protons make up the most significant part of the solar wind, so earlier it was thought that they affected the rock, but now it is clear that helium plays the main role.  

The contribution of heavy ions having greater electrical charge should also be considered. Cooperation of different research groups was necessary for these findings: high precision measurements were carried out with a specially developed microbalance at the Institute of Applied Physics. Computer simulations with codes developed for nuclear fusion research were carried out to interpret the results correctly. The Analytical Instrumentation Centre and the Institution for Chemical Technologies and Analytics also made essential contributions.