The Chandrayaan-2 Orbiter has for the first time mapped the level of presence of the element sodium on the moon’s surface, the Indian Space Research Organisation said on Friday.

The findings of the Chandrayaan-1 X-ray Fluorescence Spectrometer, or CLASS, could be helpful in figuring out the amount of sodium present on the moon’s surface, the space research body said.

The findings of the spectrometer were published in The Astrophysical Journal Letters in the last week of September.

What is the significance of sodium on moon?

The ISRO on Friday said that the rock and soil samples brought by Neil Armstrong and two other astronauts on the Apollo-11 mission in 1969 showed that the moon surface has remnants of an ancient lunar crust, mainly composed of silicate, or rock-forming minerals.

Such minerals are common on earth but the samples from the moon contained more calcium than sodium, which marked a “general trend in compositional differences between earth and moon”, according to ISRO.

Establishing the fact that there has been a loss of sodium and potassium from the moon’s surface could be helpful in tracing back to the time “when earth and moon formed together in a solar system that was young and fiery,” the ISRO said in its press release on Friday.

What has Chandrayaan found about sodium on moon?

The CLASS spectrometer of the Chandrayaan has found that there are two types of sodium on the moon – those which are loosely bound on its surface and the other which are part of its mineral composition.

External agents such as solar radiation make the loosely bound sodium atoms leave the the moon’s surface. These atoms act as a source of continuous supply of sodium to the moon’s exosphere which causes it to have a faint glow, “which is just the colour of light emitted by a sodium vapour lamp”, the ISRO said.

Presence of sodium on moon as mapped by ISRO

What next?

The new findings will be helpful in the study of surface-exosphere interaction on the moon, “which would aid development of similar models for Mercury and other airless bodies” in our solar system and beyond, according to the ISRO.

The co-relation between sodium on moon’s surface and its exosphere had been elusive so far, the ISRO had said in September last year, according to The Indian Express.