India to focus on solving 'Solar Mystery'

Chennai: In an effort to solve one of the great mysteries of science, India’s focus will be on the Sun’s corona experiment (ADITYA-1), which will study why the sun’s corona is hotter than the actual surface of the sun.

For some reason the corona’s temperature is 1 to 2 million degrees celsius while the Sun’s surface temperature is only 5,700 degrees celsius. The largest layer of the Sun’s atmosphere (corona) is hotter than the surface below it and no one is able to know why; which is why it is called the great Solar Mystery.

“The space advisory committee is studying various aspects of the Sun corona experiment. Along with the Chandrayaan-2 and the next interplanetary mission, we are also focusing on this corona experiment,” says U.R. Rao, former Isro chairman and the head of the advisory committee for space sciences. 

“Understanding the Sun is very important as it may help to know the evolution of the stars. These types of observations are not being done and planned by any other payloads,” he said.  The experiment mission is expected to be realised in three to four years.  

“Knowing the reasons for this phenomenon is very important as the high particles emitted from the Sun can affect the Earth’s atmosphere, climate and can also disturb the satellites,” says Jagdev Singh, Principal Investigator, VELC mission, Indian Institute of Astrophysics, Bengaluru.

Visible Emission Line Coronagraph (VELC), an important payload of ADITYA-1, is being built and is undergoing various tests.

The experiment will be placed in the Lagrangian point (L1). It is about 1.5 million kilometers from Earth where the gravitational force due to the Earth and the Sun works in opposite directions and the payload put at that point can see the Sun all the time without any eclipse, he added.  This is also one percent of the total distance between the Sun and Earth. 

The coronagraph can also predict the weather in space. High-resolution Spectrographic observations in 5 lines simultaneously can provide unique and very important information about understanding the heating, dynamics and temperature structure of the solar corona. “Though nations like Japan tried to understand the reason, but they don't have all the payloads to study it. We want to make this a multiple purpose mission, so other payloads to study the Sun is also equally important,” UR Rao said.