Earthquakes

In case you haven't heard, a spate of earthquakes have hit the Sumatra region of Indonesia in the last 24 hours - more than 60 of them according to CNN. For the scientifically/geographically minded, here's a map of the region from the USGS in which color indicates how recent the quake was (red is most recent), and size of the box indicates magnitude. It's a little nuts how many of the >7 boxes there are.

FWIW, the biggest nuclear bomb ever exploded had as much energy as a 7th magnitude quake, and ever additional magnitude is more than 30 times more energy.

No significant tsunami as of yet thankfully - a 0.6m (2ft) one was confirmed yesterday, and there's rumors of a 1-3m (3-9ft) one but unconfirmed.

N-body problem

Next time you need some entertainment, check out this Planet simulation game. Although "solving" the three-body problem is not possible, simulations are trivial. For a couple goals, try to get a "Mercury" type planet - closer to the Sun than the Earth, highly elliptical orbit. When you get it, it will precess naturally due to Earth's gravitation (rather than due to general relativity as Einstein proved). And a harder goal is getting a Moon to orbit the Earth (I haven't managed yet).

Happy Earth Day!

It's our Earth.



Please take care of it.



It's the only one we've got.



We live on a thin skin of livable air and water. When we destroy that, it's gone.



And take care of each other. We're what makes this lifeless rock livable.

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.