For the first time in human history, we can see what’s going on on both sides of the Sun at once, thanks to NASA. In 2006, the space agency launched two probes into space, jointly called STEREO (Solar TErrestrial RElations Observatory), to monitor the Sun; now that both are in position, we can see the front and back of the Sun simultaneously, and will be able to do so for the next eight years.
Unlike the Moon, which has a so-called “dark side” never visible from Earth, we see the Sun’s entire surface over the course of a month. But being able to see front and back at the same time is a big help; not only does it mean we won’t be surprised by a damaging solar flare, but it gives us more data for understanding how the big ol’ ball of stellar nucleosynthesis works. Phil Plait explains:
Events that happen anywhere on the Sun can have a ripple effect everywhere else… literally. A solar flare is a vast explosion on the Sun’s surface, releasing as much energy in a few minutes as millions or even billions of nuclear bombs. This sends gigantic seismic waves, ripples, across the Sun’s surface, affecting other regions. Gigantic coronal mass ejections (CMEs) are like hurricanes over the Sun, and the region causing one can extend onto the far side of the Sun where we can’t see it. Solar prominences and other features can be huge, stretching across the face of the Sun, again hiding part from view.
And, of course, in astronomy more is better. Having a better view, a better vantage point, just plain ol’ more data, is a big help.
Nifty video below: