Sun’s Corona

  Aug 05, 2020

Sun’s Corona

Q. Why is this in news?

A. Scientists have recently discovered tiny flashes of radio light emanating from all over the Sun, which they say could help in explaining the long-pending coronal heating problem. The data was collected with the help of the Murchison Widefield Array (MWA) radio telescope.

Q. What is it?

A. The radio lights or signals under study result from beams of electrons accelerated in the aftermath of a magnetic explosion on the Sun. These observations are the strongest evidence till date that the tiny magnetic explosions, originally referred to as ‘nano-flares’ by eminent American solar astrophysicist Eugene Parker. Researchers believe that these explosions could indeed be heating up the corona.

Q. What Is the Sun's Corona?

A. The Sun’s corona is the outermost part of the Sun’s atmosphere. The corona is usually hidden by the bright light of the Sun's surface. That makes it difficult to see without using special instruments. However, the corona can be viewed during a total solar eclipse.

Q. What are its features?

A. The corona is about 10 million times less dense than the Sun’s surface. This low density makes the corona much less bright than the surface of the Sun.

Q. Why is the corona so hot?

A. The corona’s high temperatures are a bit of a mystery. Astronomers have been trying to solve this mystery for a long time. The corona is in the outer layer of the Sun’s atmosphere far from its surface. Yet the corona is hundreds of times hotter than the Sun’s surface.

Q. How does the corona cause solar winds?

A. The corona extends far out into space. From it comes the solar wind that travels through our solar system. The corona's temperature causes its particles to move at very high speeds. These speeds are so high that the particles can escape the Sun's gravity.

Q. What is Widefield Array (MWA) radio telescope?

• It is a joint project between an international consortium of organisations to construct and operate a low-frequency radio array.

• Operating in the frequency range 70–300 MHz, the main scientific goals of the MWA are to detect neutral atomic Hydrogen emission from the cosmological Epoch of Reionization (EoR), to study the sun, the heliosphere, the Earth's ionosphere, and radio transient phenomena, as well as map the extragalactic radio sky.