Aurorae

This weekend, if you live in more Northern climes, keep your eyes peeled for the Northern lights (or Southern if you live more southerly). As we come more into solar maximum, they should become more common. Aurorae are caused by charged particles from the Sun interacting with the Earth's magnetic field, much like a current in a fluorescent bulb interacts with the ionized gas inside. As we approach solar maximum, the Sun is more likely to throw off loops of material in a solar flare, like in the below picture.



If there is enough material, and it's sent in the right direction (towards Earth), then in a few days it'll get to us and we'll have a chance of Northern lights! Because of how the Earth's magnetic field is shaped, they tend to happen towards the poles, so if you live in Canada chances are you've seen them, and if you live in Florida chances are you never will.

Lunar Eclipse Saturday!

Saturday is a total lunar eclipse (pointed out to me by Sclerotic_Rings as usual).

Man, I just love these things! Notice how Saturday's lunar eclipse is followed in two weeks by a partial solar eclipse. Also note how that happens again later this year (six months later) in August/September. The reason? When the Earth-Moon-Sun are aligned just right for a part of the year (line of nodes, eclipse season), they may cross each others paths for a couple weeks before and after - this means that whenever there's a solar eclipse (at a New Moon), there's a good chance of a lunar one two weeks before or after (at the Full Moon). And if there's one set on a certain date, there's a good chance six months before or after, halfway around the Sun, that it might happen again.

More info on Wikipedia.