From UPSC perspective, the following things are important :
Prelims level : Geotail, Chandrayaan 2
Mains level : Accomplishments of Chandrayaan2 mission
- Recently on board with Chandrayaan-2 mission, an instrument called CLASS, designed to detect signatures of elements in the Moon’s soil, had detected charged particles during the mission.
- This happened in September, during the orbiter’s passage through the “geotail”.
- The geotail is a region in space that allows the best observations.
- The region exists as a result of the interactions between the Sun and Earth.
- The Sun emits the solar wind, which is a continuous stream of charged particles. These particles are embedded in the extended magnetic field of the Sun.
- Since the Earth has a magnetic field, it obstructs the solar wind plasma.
- This interaction results in the formation of a magnetic envelope around Earth.
- On the Earth side facing the Sun, the envelope is compressed into a region that is approximately three to four times the Earth radius.
- On the opposite side, the envelope is stretched into a long tail, which extends beyond the orbit of the Moon. It is this tail that is called the geotail.
- CLASS stands for Chandrayaan 2 Large Area Soft X-ray Spectrometer.
- For the CLASS instrument seeking to detect element signatures, the lunar soil can be best observed when a solar flare provides a rich source of X-rays to illuminate the surface.
- Secondary X-ray emission resulting from this can be detected by CLASS to directly detect the presence of key elements like Na, Ca, Al, Si, Ti and Fe.