Coronal mass ejections and magnetic reconnections

Did you think you would read about coronal mass ejections today? Well, Stephanie Osborn is a rocket scientist who has a wonderful ability to explain space, solar, and geomagnetic weather over at According to Hoyt.

The end result is that a whole bunch of energy gets transferred from the field into kinetic energy. This heats up the plasma AND accelerates it, and, at least on the surface of a star like our Sun, a titanic explosion is the result. A great big blob of plasma goes flying out into space, and that blob is a “coronal mass ejection,” because a big mass of the corona just got ejected from the Sun. (Imaginative name, huh?)



So you can think of the reconnection event as being like a titanic nuclear bomb, and the CME is the mushroom cloud moving up…and out, into interplanetary space. (How big a bomb? Well, solar flares vary in size and power. But NASA solar scientists estimate they’re “the equivalent of millions of 100-megaton hydrogen bombs exploding at the same time.” Keep in mind that the biggest nuke ever detonated on Earth was Tsar Bomba, at only 50 megatons.)

The vast majority of them aren’t THAT big, and aren’t even Earth-directed. The chances of one smacking Earth aren’t that great. But because there are a lot of them, especially at Solar Max, it happens fairly often. Sometimes it’s just the edge of the expanding bubble, but sometimes it whacks Earth upside the head. And when they come in, they’re coming fast.

If you’re talking how massive, well, on average they’re about 3,520,000,000 lb (1,600,000,000,000 kg). That’s over three and a half billion pounds of plasma. On average, their speed is about 304 mi/s or 1.1 million mph (490km/s). IF, however, one follows close on the heels of another, so that the first one has swept most of the interplanetary medium out of the way (decreasing drag), the speed can increase to 2,000 mi/s or 7.2 million mph (3,200 km/s). And with the Sun 93 million miles away, that means a really fast CME can reach Earth in just under 13 hours.

Read more here.