This picture was taken by a NASA solar observatory yesterday, and it shows one of the biggest explosions we've ever seen on the sun. For perspective, look at the upper left corner. There's a little circle the size of Earth.
The explosion dwarfs our planet by many times. So what does this explosion mean for Earth?
The image above was prepared by Universe Today's Jason Major, who added the circle to show Earth's size.
Bad Astronomy's Phil Plait posted this video today, with an explanation. Given that Plait wrote an entire book called Death from the Skies, about threats to Earth from space, the guy knows what he's talking about. Here's what he says:
What you're seeing here is a solar flare (an enormous explosion of pent-up magnetic energy) coupled with a prominence (a physical eruption of gas from the surface). This event blasted something like a billion tons of material away from the Sun. Note the size of it, too: while it started from a small region on the Sun's surface, it quickly expanded into a plume easily as big as the Sun itself! I'd estimate its size at well over a million kilometers across. It looks like most of the material fell back down to the Sun's surface; that's common, though sometimes such an event manages to blast the material completely away into space . . . The energy of the event was colossal. A good flare can release up to 10% of the Sun's total energy, the equivalent of billions of nuclear bombs exploding. What's funny to me is that this wasn't all that big a flare; it was rated as a class M2.5, far lower in energy than the vast explosions from the Sun back in February.
Plait says we're not in any danger from the event, though space weather watchers are issuing an advisory that's the solar storm equivalent of "we may get some sprinkles."
Here you can see the explosion from a number of angles, via NASA's Solar Dynamics Observatory. The Space Weather Prediction Center notes that the storm will deal our planet a "glancing blow," meaning we aren't in the main firing line for all those particles zooming out into space. In fact, according to the group:
As it is expected to make but a glancing blow on the Earth's magnetic field, the timing of the impact is difficult (much more straightforward for a direct hit). Look for G1 (minor) Geomagnetic Storm conditions from 1200 UTC tomorrow (June 9) through June 10. The possibility remains for heightened Radiation Storm levels with the passage of the CME shock, but nothing greater than S2 (moderate) is forecast.
A G1 storm, according to the space weather experts, is extremely minor. Here's what you can expect: Weak power grid fluctuations, possible minor impacts on satellite operations, and possibly an aurora at high latitudes. Also, migratory animals are sometimes confused by impacts to the magnetosphere. And an S2 storm can put people flying planes at high latitudes at risk for increased radiation exposure. The Space Weather Prediction Center has a helpful guide to geomagnetic and solar storm effects here.