Context: Recently, a group of India scientists have discovered tiny flashes of radio light emanating from all over the Sun could which help in explaining the long-pending coronal heating problem. The data was collected with the help of the Murchison Widefield Array (MWA) radio telescope.
Issue and Challenges

• For more than a half-century, astronomers have tried to figure out what causes the corona to be so hot.  It is one of the most vexing problems in astrophysics.
• One of the big questions of coronal heating has been: Is the corona heated everywhere at once, or is heat delivered in discrete, bomb-like events?

Key Observation:

• The researchers state that these radio lights or signals result from beams of electrons accelerated in the aftermath of a magnetic explosion on the sun.
• They state that these weak radio flashes that they have discovered are ‘smoking guns’ or the evidence for magnetic explosions and hence bring us closer to explaining the coronal heating problem.
• Corona is the aura of plasma that surrounds the sun and other stars.
• These observations are the strongest evidence till date that the tiny magnetic explosions, originally referred to as ‘nanoflares’ by eminent American solar astrophysicist Eugene Parker, can indeed be heating up the corona.
• While the phenomenon of coronal heating has been known for the last 70 years, the availability of cutting-edge data from the Murchison Widefield Array (MWA) radio telescope proved to be a game-changer.

About Sun’s Corona

• The corona is the outermost part of the Sun’s atmosphere. It is the aura of plasma that surrounds the Sun and other stars.
• The Sun’s corona extends millions of kilometres into outer space and is most easily seen during a total solar eclipse, but it is also observable with a coronagraph.
• Spectroscopy measurements indicate strong ionization in the corona and a plasma temperature in excess of 1000000 Kelvin much hotter than the surface of the Sun.

How does the corona cause solar winds?

• 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

Radio lights observed

• These radio lights or signals result from beams of electrons accelerated in the aftermath of a magnetic explosion on the Sun.
• While the magnetic explosions are not yet observable, these weak radio flashes are ‘smoking guns’ or the evidence for the same.
• Hence it brought the researchers closer to explaining the coronal heating problem.

About 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.