'Hole' 20 times larger than Earth appeared on the Sun

The giant "hole" in the Sun's surface could launch solar winds at speeds of 2.9 million km/h towards Earth this weekend.

A coronal hole with a diameter of 18-20 times that of Earth appears on the Sun. Photo: NASA/Solar Dynamics Observatory

The new hole comes after another coronal hole 30 times the size of Earth. As this first hole began to rotate away from Earth, a new coronal hole appeared, about 18-20 times the diameter of Earth, Business Insider reported on March 27.

In soft X-ray and ultra-violet (EUV) images, coronal holes appear as dark regions in the corona (the outermost layer of the Sun's atmosphere). They appear dark because they are cooler and less dense than the surrounding plasma, and have an open, unipolar magnetic field. This open-field structure allows the solar wind to escape into space more easily, creating rapid solar winds, often called high-velocity flows, when analyzing structures in interplanetary space.

Coronal holes launch solar winds into space, which can damage satellites and trigger beautiful auroras if they reach Earth. Scientists aren't worried about the new vulnerability damaging infrastructure, but it could help create aurora borealis in some parts of the world.

Coronal holes are relatively common, but they usually occur near the Sun's poles. According to Mathew Owens, a professor of astrophysics at the University of Reading, as the Sun is about to reach its peak in its 11-year cycle, these holes are more likely to appear closer to the Sun's equator.

"This hole is at the equator, which means we will almost certainly see some high-velocity winds heading towards Earth a few days after the hole rotates through the central meridian," Owens said.

The solar wind can blow very fast, more than 800 km/s or 2.9 million km/h, according to Daniel Verscharen, associate professor of climate and space physics at University College London.

"The shape of this coronal hole is not very special. However, its location makes it very interesting. I predict some fast winds from that coronal hole will hit the Earth around the dark. Friday to Saturday morning this week," Verscharen said.