These coronal holes were later confirmed by the Skylab mission.

It has long been thought to originate from open magnetic fields, called coronal holes.

They were first observed in the two 1970 rocket flights which also detected coronal holes.

Coronal holes are linked to unipolar concentrations of open magnetic field lines.

An active region or coronal hole may persist for some 27 days resulting in a second aurora when the Sun has rotated.

More probably, the Alfvén waves are responsible for the acceleration of the solar wind in coronal holes.

The fast-moving component of the solar wind is known to travel along open magnetic field lines that pass through coronal holes.

Skylab's experiments confirmed coronal holes and were able to photograph eight solar flares.

Coronal holes are the polar regions which look dark in the X-rays since they do not emit much radiation.

So what's a coronal hole.

For example, coronal holes allow fast-moving plasma to escape from the photosphere, which can effect a local increase in the solar wind speed.

Coronal holes are areas where the Sun's corona is darker, and colder, and has lower-density plasma than average.

The solar regions which are not part of active regions and coronal holes are commonly identified as the quiet Sun.

The fast solar wind is thought to originate from coronal holes, which are funnel-like regions of open field lines in the Sun's magnetic field.

During periods of quiet, the corona is more or less confined to the equatorial regions, with coronal holes covering the polar regions.

During solar minimum, coronal holes are mainly found at the Sun's polar regions, but they can be located anywhere on the sun during solar maximum.

During the declining phase of the solar cycle, however, longer-lived solar structures, coronal holes, are important sources of geomagnetic activity.

In contrast, formations with open magnetic field lines are called coronal holes, and these are darker and are a source of the fast solar wind.

Numerous scientific experiments were conducted aboard Skylab during its operational life, and crews were able to confirm the existence of coronal holes in the Sun.

Coronal holes are open field lines located predominantly in the polar regions of the Sun and are known to be the source of the fast solar wind.

These loops are the closed-magnetic flux cousins of the open-magnetic flux that can be found in coronal hole (polar) regions and the solar wind.

In the UV images of the coronal holes, some small structures, similar to elongated bubbles, are often seen as they were suspended in the solar wind.

At the beginning of January a coronal hole opened up on the surface of the Sun and a stream of deadly radioactive particles blasted towards Earth.

The barrage of solar wind is 24/7 but when a coronal hole opens up this allows a more intense solar wind to escape and shoot towards earth.

This barrage is 24/7 but sometimes a hole opens up in the suns surface, a coronal hole, triggering the release of a really intense stream of solar wind.