what scientists hope to observe from the “Black Sun”

The Sun meets the moon on Monday, a rare and spectacular phenomenon that will only be visible in North America. The opportunity for scientists to collect data on our star and its influence on the Earth.

A total eclipse will occur Monday, April 8 late in the afternoon. This “Black Sun” will only be visible on the other side of the Atlantic, from Mexico to northern Canada to Saint-Pierre-et-Miquelon, but NASA will broadcast it from 7 p.m. French time on his YouTube page.

The last total eclipse observed in mainland France was that of 1999. What a specialist looks at when the Moon hides the Sun is first of all this thin edge of light which persists, this solar corona which has not been observed for a long time. was possible only at these precise moments, recalls astrophysicist Miguel Montargès, of the Paris-PSL Observatory.

“For several centuries, astronomers traveled to the ends of the earth to study the solar corona.”

Miguel Montargès, astrophysicist

at franceinfo

“It was the only way to do it ! Now, we can generate artificial eclipses using this instrument called the coronagraph, which was invented at the Paris observatory in 1930 by Bernard Lyotexplains the scientist. There, it’s true that with the , we really only have the surface of the Sun which is hidden and we see the entire corona closest to the Sun.

The natural eclipse therefore remains of great interest for studying this periphery with its astonishing properties. “At the heart of the Sun, there will be millions of degrees and one of the great enigmas is that, when we move away from the Sun obviously, we expect the temperature of the gas to decrease. Whereas No, explains Miguel Montargès. When we move away from the Sun, we cross the chronosphere and the corona which are at higher temperatures than the surface of the Sun.

“Collect data on the effect of solar rays on the Earth’s ionosphere”

NASA will also take advantage of this “Black Sun” to carry out other studies, this time on the Earth side, in the upper layer of the atmosphere subject to the light of our star and through which GPS or telecommunications data constantly pass. coming from our satellites. Increasing our knowledge of the functioning of this ionosphere and its disturbances is therefore a major challenge, explains Pam Melroy, former astronaut now deputy director of the American space agency.“By observing the decrease in light which, thanks to the eclipse, will be much faster than during a classic sunrise or sunset, we will be able to collect more precise data on the effect of these solar rays on the earth’s ionosphere.

NASA will use three small sounding rockets sent before, during and just after this great hide-and-seek between the Sun and the Moon which will not occur in mainland France until September 2081.