Thanks to two new spacecraft, we can now see both sides of the Sun, and guess what, the other side looks pretty much the same as this side. – Deskarati
On October 26, 2006, NASA launched two STEREO (Solar Terrestrial Relations Observatory) spacecraft. Using the Moon’s gravity for a gravitational slingshot, the two nearly identical spacecraft, STEREO-A and STEREO-B, split up with one pulling ahead of the Earth and the other gradually falling behind. It’s taken over four years but on February 6, 2011, the two spacecraft finally moved into position on opposite sides of the Sun, each looking down on a different hemisphere. The probes are now sending back images of the star, front and back, allowing scientists for the first time to view the entire Sun in 3D.
Each of the probes captures images of half of the Sun and beams them back to Earth where researchers combine the two opposing views to create a sphere. To track key aspects of solar activity such as flares, tsunamis and magnetic filaments, STEREO’s telescopes are tuned to four wavelengths of extreme ultraviolet radiation.
The resultant 3D images will allow researchers to improve space weather forecasts to provide earlier and more accurate warnings for potentially damaging coronal mass ejections (CMEs) that can impact aircraft navigation systems, power grids and satellites. Previously, an active sunspot could emerge on the far side of the Sun before the Sun’s rotation turned that region toward Earth, spitting flares and clouds of plasma with little warning.