Monday, January 2, 2012

The Stars Fell on Abe and Frederick

The 1833 Leonids (Source: Wikipedia)
Word on the street is there's a meteor shower set for late Tuesday night, peaking at 2 am EST on January 4th [1].  The meteors in question are the Quadrantids, which often go unnoticed for two good reasons.  Reason the first:  apparently [2], they are usually pretty awful.  Unlike the "good" meteor showers, the Quadrantids are bright and pretty for only a few hours (instead of a few days). This means that a lot of the time, we just miss them.  Reason the second: they have a lame name [3]. But this year, they should be pretty good if the weather is right.

Now, there's lots of neat physics to talk about with meteors, but that's not why I bring it up. This has all just been flimsy pretext so I could share a historical anecdote about a meteor shower. Trickery, indeed.  Those who feel cheated are free to leave now with heads held high.

Those still around (Hi, Mom!) will hear about the night in 1833 when the stars fell on Alabama (and the rest of the country, too).

Sunday, January 1, 2012

How Long Will a Bootprint Last on the Moon?

Buzz Aldrin's bootprint (source: Wikipedia)
A couple of months ago, I stumbled across a bunch of pictures of Apollo landing sites taken by one of the cameras onboard the Lunar Reconnaissance Orbiter. The images have a resolution high enough that you can resolve features on the surface down to about a meter. Looking at the Apollo 17 landing site, you can see the trails of both astronauts and a moon buggy. It's pretty cool.

It also got me thinking about how long the landing sites would be preserved. More specifically, I want to know how long Buzz Aldrin's right bootprint (shown, incidentally, to the left) will last on the Moon.  Since the Moon has no atmosphere, the wind and rain that would weather away a similar bootprint here on Earth are not present and it seems as though the print would last a really long time. But how long? Let's try to quantify it [1].