Pragyan rover reveals signs of magma ocean on ancient moon

Vikram’s
landing spot is about 300 km from the solar system’s largest impact crater, the
South Pole-Aitken Basin, which is around 8 km deep; scientists theorise that a
powerful meteor strike created the depression, excavating material from deep
inside the moon and splashing it around the surface. The consensus among
scientists is that these anorthosite rocks could be the
remains of an ancient ocean of magma that blanketed the moon’s surface some
four billion years ago.

·    Overview: The
Pragyan rover on the moon bids farewell to operators at the Indian Space
Research Organisation (ISRO) one last time. The sub-zero temperatures proved
too low for the suitcase-sized rover. Fourteen days after landing on the moon
as part of India’s historic Chandrayaan-3 mission, the rover went to sleep
forever.

·      
Discoveries: It had
spent two weeks studying the lunar soil and relayed valuable scientific data
back to the earth in anticipation of a slew of discoveries — from recording the
presence of sulphur to confirming the presence of certain small rock fragments
around crater rims near Shiv Shakti point, the place where the Chandrayaan-3
lander descended.

·      
Origins of
the moon: As the consensus goes, the moon was born from the remains of
a headlong collision between the early earth and some rogue planetary body
aeons ago. The moon’s rocky surface was initially molten. The minerals in there
slowly crystallised as the lava cooled to form rocks of various kinds,
including ferroan anorthosite, which is why ferroan anothorise rocks
are very common on earth.

·      
Surface of
the moon: Meteorites raining down on the moon beat these rocks down to
fine dust over many centuries. Similar weathering phenomena occur on the earth
but the moon has a very thin atmosphere and lacks volcanic activity, so all
meteors reach the surface and the surface is not replenished with new rocks
over time.

·      
The overall
journey: During its journey, the rover occasionally stopped to
observe moon dust with its instruments — from some 23 locations around Statio Shiv
Shakti. Its APXS instrument, mounted close to the rover’s navigation cameras,
affirmed the dust’s chemical and mineral composition by firing X-rays and alpha
particles at it produced from a radioactive mass of curium. Pragyan also
stopped for a few minutes to around two hours to scan the soil. This is because
the dust particles often deflected the alpha particles in some direction away
from the APXS detector. Its stops allowed the detector to collect enough
readings.

·      
Deciphering
the moon dust: Subsequent meteor strikes on the moon created a
pretty uniform mixture of this magnesium-rich content and the anorthosite
dust.