Planet Earth is taking a hit today from back-to-back solar eruptions. No need to brace for impact: At worst this combined eruption will mess up radio and GPS signals for a few hours on the planet's sunny side. At best, people on the earth's darkened half might see the aurora as far south (or north) as the 39th parallel.
The eruptions, called coronal mass ejections (CME), happened in the early morning on Tuesday, June 10. They came from an active young sun spot called AR2087 in the mid latitudes of the sun's lower hemisphere, less than an hour apart. They were so close, in fact, that the second CME "cannibalized" the first, creating a double ejection. The solar ejecta is set to hit Earth in the early morning hours in North America.
This three-part graphic (courtesy of NASA's Space Weather Research Center) shows a CME that erupted last week, on June 4. The leftmost animation shows a top-down view of the CME erupting out of the sun like a cosmic Hadouken and ripping across the inner solar system. The middle animation shows the CME's up/down extent with a sidelong view from the Earth's orbital plane. The final graph is a wraparound view of our planet's orbital path, showing the CME's width and height as it licks the Earth. The view is from the inside the orbit, and can be a little confusing, since the east/west axis is turned sideways.
Currently, the sun is at solar maximum: the peak energy level of its 11-year cycle. This means it has more activity like sun spots, solar flares, and CMEs. While CMEs average about three per day during solar maximum, today's CMEs are special because they came from "X-class" solar flares, the most powerful type of solar ejection.
CMEs are not always tied to solar flares. Flares are bright outbursts of radiation and energy, while CMEs are charged particles that get flung out into the solar system. And while one often accompanies the other, they have been known to happen in isolation. Scientists believe CMEs are caused when the sun's magnetic field lines reorganize themselves, exciting the plasma in the corona and causing it to violently erupt.
Here is an animation of the June 10th CMEs.
