Prelim Bits 09-10-2019

The science behind Physics Nobel Prize

This year’s Nobel Prize for Physics recognises research that helps us understand our place in the universe.
It was awarded to,Canadian-American cosmologist James Peebles.
He won one-half of the Prize for his theoretical work to understand how the universe evolved after the Big Bang.
The other half went to Swiss astronomers Michel Mayor and Didier Queloz.
It is for their discovery of an exoplanet that challenged preconceived ideas about planets.

James Peebles Work on Evolution of Universe

Modern cosmology assumes that the universe formed as a result of the Big Bang.
Peebles used theoretical physics and calculations to interpret what happened after.
His work is focused largely on ‘Cosmic Microwave Background’ (CMB) radiation.
CMB is electromagnetic radiation left over from the early universe once it had cooled sufficiently following the Big Bang.
Peebles has correlated the temperature of this radiation with the amount of matter created in Big Bang.
This was a key step towards understanding how this matter would later form the galaxies and galaxy clusters.
From his work derives our knowledge of how mysterious the universe is,

Michel Mayor and Didier Queloz Work on Exoplanets

The two scientists detected the first planet orbiting an alien star.
Exoplanets are being discovered very frequently, today over 4,000 are known.
The planet discovered by Mayor and Queloz in 1995 is 50 light years away.
It is orbiting the star ‘51 Pegasus’ that is similar to our Sun.
ELODIE a spectrograph, built by Mayor, predicted the planet.
It was, by observing the “Doppler effect” when the star wobbles as an effect of a planet’s gravity on its observed light.
It is a gas giant comparable to Jupiter, yet it is very hot, unlike icy cold Jupiter;
51 Pegagsus b is even closer to its star than Mercury to our Sun.
Until then, gas giants were presumed to be cold, formed a great distance from their stars.
Today, it is accepted that these hot gas giants represent what Jupiter would look like if it were suddenly transported closer to the Sun.
The discovery of the planet started a revolution in astronomy and since then many exoplanets have been found in our galaxy.

Geotail and its impact on Chandrayaan-2

Recently, ISRO tweeted that an instrument on Chandrayaan-2, CLASS, had detected charged particles during the mission.
This happened 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 3 to 4 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.
Once every 29 days, the Moon traverses the geotail for about six days.
When Chandrayaan-2, which is orbiting the Moon, crosses the geotail, its instruments can study the properties of the geotail.
It can helps to detect the presence of key elements like Na, Ca, Al, Si, Ti and Fe the lunar soil.

Source: PIB, The Indian Express