This is the image of solar prominence compared to that of the earth.
They are pockets of hydrogen and helium plasma stretched and curved by the sun’s magnetic fields.
Prominences are connected to the sun’s surface on the photosphere and extend out from there to a really big distance.
The longest prominence ever recorded extend it to 800,000 km, more than the radius of the sun itself (695,508 according to NASA). It takes about a day or two to form a prominence and the stable ones can last up to a month.And when they break apart, they erupt ejecting billions of tons of plasma with great speed and release lots of radiation. This is called ‘ coronal mass ejection ’. Observations and studies of prominences have been going on for quite a lot of years but the reasons for their formation and eruptions are yet to be known.