This picture shows a huge solar prominence. A prominence is a loop of gas and plasma in the Sun's atmosphere. The loop is held in place by powerful magnetic fields. The prominence in this picture is on the right side of the Sun. The right side of this picture shows a close-up of the prominence. It also shows Earth - see how huge the prominence is! Of course, Earth isn't really right next to the Sun like this. This picture was taken by a spacecraft called SOHO.
Original artwork by Windows to the Universe staff (Randy Russell) using images courtesy SOHO (ESA & NASA).