For the millions of people across North America who will be treated to a total solar eclipse on April 8, it will be spectacular show — a chance to see the moon fully obscure the sun’s face.
But for scientists, it is a rare opportunity to study Earth, the moon and the sun “in entirely different ways than we usually do,” said Pam Melroy, NASA’s deputy administrator.
One of the agency’s main priorities will be to observe the sun’s outer atmosphere, or the corona, which normally can’t be seen because the star is too bright. During a total solar eclipse, the corona comes into view as faint wisps around a glowing halo when the moon blocks light from the sun’s surface.
“Things are happening with the corona that we don’t fully understand, and the eclipse gives us a unique opportunity to collect data that may give insights into the future of our star,” Melroy said in a news briefing last week.
Scientists are interested in the corona because it plays a key role in transferring heat and energy into the solar wind, the constant stream of charged particles released from the sun’s outer atmosphere. The solar wind ebbs and flows, occasionally shooting high-powered solar flares into space. These can hit Earth with electromagnetic radiation, which can cause radio blackouts and knock out power grids.
Amir Caspi, a solar astrophysicist at the Southwest Research Institute in Boulder, Colorado, has an instrument installed in the nose of a WB-57 aircraft that will study the sun’s atmosphere as the plane chases the eclipse.
It’s a golden opportunity, he said, since even the special telescopes that can block out a star’s light, known as coronagraphs, have limitations.
“A total solar eclipse is like nature’s perfect coronagraph,” he said. “The moon comes between us and the sun, and it’s exactly the right size in the sky to block out the disc of the sun but not too much more.”
Caspi will focus on trying to understand the origin of the solar wind. He…
Read the full article here
