Two views of a Halo CME as seen by SOHO's LASCO C2 instrument on June 20, 2015.
Two views of the CME on June 20, 2015 from the Solar and Heliospheric Observatory, or SOHO. Earth-directed CMEs like this one are often called halo CMEs, because the material shooting off from the sun looks like a ring around the disk of the sun. This halo can be seen more clearly in the right-hand image called a difference image, which is created by subtracting two consecutive frames to see how the image has changed. Credit: ESA&NASA/SOHO