Coronal rain and a solar storm

Two stories popped through twitter today to demonstrate just how important NASA’s Solar Dynamics Observatory is likely to be.

The first is a science result. We’re probably by now all familiar with images of activity on the Sun (if not, there’s some pictures and video at the original article here). Loops of magnetic field extend from beneath the surface to huge outward distances and plasma travels along these field lines. Huge amount of plasma can be launched along the loops and then shoot away from the surface of the Sun, but sometimes bits seem to be pulled back, break off and these blobs then fall back down to the solar surface and cause a brightening when they impact. These blobs, each of which dwarf the Earth in size, are referred to as “Coronal Rain”. One enduring mystery about coronal rain is the time taken for the blobs to fall down to the surface of the Sun. Even accounting for the totured magnetic field they have to negotiate, the blobs seem to drift a little too slowly given the gravitational pull of the star. The reason, SDO has seen through its sensitive filters, is that there’s a lot of background plasma that other observations have just missed. It is thin, but it is hot and constantly rising. This buffets the blobs and they float on it a little, causing them to slow before impact.

Meanwhile, the geomagnetic activity at the beginning of April managed to claim at least one victim. Galaxy 15, a telecommunications satellite found itself blasted with radiation and killed off. It became what is known in the industry as a Zombiesat – an uncontrolled, dead satellite that will now slowly find its own way to a fiery end. But this one has a sting in its tail, for Galaxy 15 took the name Zombiesat and took it one step further than usual. Its brain may be dead and unresponsive to external stimuli, but its functions – relaying signals and the like – are still ongoing. This might sound like good news, but if the satellite isn’t in the right place, it won’t be relaying the signals correctly, and worse, if it’s too close to another satellite, it will try and steal its bandwidth, interfering with things like GPS satellites that share parts of its orbit. Since April 5th, different things have been tried including an unusually powerful signal being blasted at it, but nothing so far has staked the heart of this undead satellite. If we’re to prevent a contagion of these things, then we must look to the Sun to save us and make sure those observations are detailed and well studied.

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