Scientists spot a coronal hole on the Sun's South Pole, which is hundreds of times bigger than the size of the Earth.
The U.S. National Aeronautics and Space Administration (NASA) has recently released an image of the Sun that was taken on Jan. 1 by the Atmospheric Imaging Assembly (AIA) instrument on the agency's Solar Dynamics Observatory (SDO). The image shows a dark region at the south pole of the sun, which is the coronal hole.
"Coronal holes are regions of the corona where the magnetic field reaches out into space rather than looping back down onto the surface. Particles moving along those magnetic fields can leave the sun rather than being trapped near the surface," explained NASA.
The trapped particles glow when they heat up. The coronal hole appears to be dark in parts where the trapped particles leave the sun.
NASA said that, in 1973 and 1974, astronauts on the space agency's Skylab station were the first to take the images of coronal holes. The coronal holes are usually seen over a long period of time; however, the shape of the coronal hole may change from time to time. Polar hole may last and be visible even for five years at a stretch.
Astronomers revealed that the coronal hole is about 400,000 km, or about 250,000 miles, wide.
Dr. C. Alex Young, associate director for science for the heliophysics division at NASA's Goddard facility in Greenbelt, Md., said that the total surface area of the coronal hole is around 410 times the size of the Earth.
This is not the first time that NASA's SDO has captured images of the coronal holes. In 2013, NASA released a few images of the sun taken on June 18, 2013, which showed a huge coronal hole that appeared near the North Pole of the sun. The coronal hole that was observed in 2013 was at least 400,000 miles across, which is more than 50 Earths put side by side.
