Cool Solar Flare

This has been making the rounds and its pretty cool so I figure I would mention it as well. On June 7th the Sun let off a rather impressive solar flare which was observed by the satellites which observe the Sun, the Solar Dynamics Observatory (SDO), Solar and Heliospheric Observatory (SOHO), and Solar Terrestrial Relations Observatory (STEREO) to name a few. While this explosion wasn't out of the ordinary in terms of size or power, it was interesting because a lot of the material that was originally ejected fell back onto the surface of the Sun. This made for a rather spectacular movie by the SDO of material being shot up by the flare and then falling back to burn up on the surface.

So what is going on in the movie? Well a solar flare occurs because of magnetic fields on the Sun. Normally the magnetic fields on the Sun allow for material to flow off the Sun and form the Solar Wind. However if the fields get tangled that can stop that material from leaving the Sun and pressure begins to build up. Think of the Sun as a pot of boiling water and the Solar Wind as the steam rising off of the water to release energy. Tangled magnetic fields act like a very tight lid, which turns the Sun into a pressure cooker. The pressure builds and builds and builds until something gives way. In the case of the Sun, the magnetic field lines end up breaking in an event called reconnection. The reconnection event triggers the release of energy and material. This release is seen as a solar flare

In the case of this particular case the flare material didn't have enough energy to escape the Sun's gravity so it fell back on to the Sun. The material looks dark because it is cooler than the surface of the Sun. You will also notices that the material doesn't fall the way one expects. Rather it falls more slowly and is twisted around as it goes. This is the magnetic fields of the Sun at work again. The fields a strong enough to counter the force of gravity and channel the flow of material on the Sun.

The material from the flare that escaped was directed towards the Earth but only delivered a glancing blow to the Earth's magnetosphere. This caused a boost in auroral displays. We will be seeing more of these types of events from the Sun in the years to come as solar activity increases to its projected peak in 2013.