Double Whammy

Every now and then, an event occurs which surprises even the people that are accustomed to unusual events.

The Solar and Heliospheric Observatory (SOHO) was launched December 2, 1995, and has been continuously observing the Sun ever since. Designed to observe the surface and atmosphere of the Sun, it can also observe any object in the sky within a few degrees of our closest star. On June 2, 1998, it spotted not one but two comets very near the solar surface. Perhaps this will surprise you, but comets graze the Sun quite often, and even commonly impact the solar surface. SOHO has actually seen dozens of them. However, seeing two at once took everyone by surprise.

The image above is a small version of a single frame from a movie you can download yourself from the SOHO web page. In the small image, you can see a dark disk which is a mask used by SOHO to cover the disk of the Sun (the white circle inside the dark mask is where the Sun actually is in the image). You can clearly see one of the comets below and to the right of the Sun, and the other is to the right of the Sun, with its tail sticking out from under a bright part of the Sun's corona. A few minutes after this image was taken, both comets impacted the surface, never to be seen again.

Or were they? One thing SOHO studies are huge eruptions from the Sun called "Coronal Mass Ejections". These happen rather often, but they also seem to happen just after comets hit the Sun. Is there a connection? No one knows. It might just be a coincidence!