Wednesday, April 24, 2013

SDO - Three years in 3 mins.

The NASA satellite Solar Dynamic Observatory (SDO) has put together a great movie showing the dynamics on the sun over a three year period - in three minutes.

There is an article at NPR accompanying this movie. I found a lot of the comments interesting. A common question that can up was does the sun spin or is the spinning due to the Earth? Yes, the Sun spins around it's own axis and is made up of hot ionised gas which we call plasma. Plasma acts kind of like a liquid, so different parts of the sun will rotate at different rates. Near the Sun's equator it rotates once ever 25 days or so while at the Sun's poles it's closer to 30 days. This is pretty impressive if you consider that it takes the Earth ~1/27 = 0.037 of a Sun's rotation to rotate and the Sun is ~109 Earth's across!

Although the sunspots, flares, brightenings on the Sun all appear to be in two belts, They actually go through what we call the Butterfly pattern. At the beginning of a solar cycle (11 year period) These regions are found closer to the poles. As time goes on they move towards the equator. This solar cycle is where the Sun's magnetic field reverses, so the south pole becomes the north and the north pole becomes the south. Our magnetic field also does this, but on a much longer time scale.

The Sun is incredibly interesting and so important to life here on Earth. There are quiet a few great missions which focus on studying the Sun. If you want to check out more wonderful photos and videos search for SOHO and STEREO. STEREO is actually two satellites looking at the Sun in stereo allowing us to get some amazing 3-D images of the Sun! One of the Satellites is trailing us in our orbit while the other is running ahead of us. At the moment they are situated so that we can actually see what is going on behind the Sun as well for the first time!