Update for Monday, Jan 7, 2008

Well, the good news is that the high altitude winds are slowly decreasing - throughout the day today, we were in and out for winds, which is a nice change. The bad news is that there was an emergency in Longyearbyen (the town closest to us). The emergency had nothing to do with us, except that an "ambulance plane" needed to be flown in from Tromso on the mainland, which meant that we could not launch - again for safety reasons.

It did turn out, though, that we were not really seeing the ion outflow that we are looking for anyway, so we probably would not have launched.

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Let's get back to some science and, in particular, the sun. Below, I put a picture of the sun taken from the SOHO satellite. You can look at these any time yourself at http://sohowww.nascom.nasa.gov/data/realtime-images.html. As of the time I am posting this picture, it is less than an hour old!!



You can see that a lot is going on here. For us, the important things are the bright spot in the middle, a so-called "active region", and the dark spot just to the right of it, called a "coronal hole". I'll explain why this is what we care about in a minute, but first, I need to make an important point, which is that the sun actually rotates, sort of like the Earth. I say "sort of" because it turns out that at its equator, the sun goes through a complete rotation in about 27 days; nearer its poles, the rotation takes up to 35 days!! This "differential rotation" can only be possible because the sun really is a gas, not a solid.

OK, now go to http://sohowww.nascom.nasa.gov/data/realtime/mpeg/ and watch some movies of the solar rotation (the link is not working right now, though it usually does). The point here is that, as the sun rotates, the coronal hole and active region drift across from left to right. So, when we say that we are watching the sun, we are monitoring these things.

Next step: here is a bit of a curve ball, though. The solar wind that comes from the coronal hole and active region gets sprayed out as the sun rotates, just like water gets sprayed out of a lawn sprinkler. The effect that you get with the lawn sprinkler is a spiral shaped spray of water. Not surprisingly, the same thing happens with the sun - the solar wind is a huge spiral shaped "spray"!! This means that when we look at the sun and see something like a coronal hole, we have to keep the spiral shape in mind and realize that the solar wind from that hole will only hit us a few days later, when the images of the sun show the hole to be about 2/3 of the way across. I hope this is clear.

Another view of the sun can be found at http://stereo-ssc.nascom.nasa.gov/beacon/beacon_secchi.shtml, which shows pictures from the new STEREO satellite (by the way, Toni Galvin at UNH provided one of the "plasma" instruments for STEREO!). The STEREO mission actually consists of two satellites (called Ahead and Behind), separated some distance in order to get 3D images of "coronal mass ejections". To understand where the satellites are located, imagine standing on the north pole of Earth and facing the sun. Then, raise you right arm and you will be pointing to the "Ahead" satellite; it is ahead of where Earth will be in a couple of days. Raise your left arm and you will be pointing to the Behind spacecraft, located where Earth was a couple days ago. With the images from these satellites, you really can use 3D glasses to see features in or near the sun.

Ok, that's the scoop with the sun for now. Let's jump ahead to what the solar wind does to Earth's magnetic field. I already mentioned that the electrically charged particles flow along field lines to carry energy from the solar wind to our upper atmosphere. What maybe was not obvious is how dramatic this effect can be. You can get an idea of the effect by watching a "movie" of a computer simulation at http://artemis.sr.unh.edu/~jraeder/Home/index.php?n=Main.FiguresAndMovies. There are a bunch of movies here, grab some popcorn and poke around. These are from Prof. Jimmy Raeder at UNH.

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We see quite a few reindeer around here. The picture below was taken very near where we are staying; the reindeer didn't mind us being there at all and couldn't be bothered to even lift its head!



This was funny: on our way out to the range this morning, we saw a reindeer eating a Christmas tree that someone had discarded. I guess this reindeer had had enough of Christmas!!