Bad Astronomy

First HD Moon video!

The Japanese probe Kaguya has returned a series of very high-resolution images from the Moon. The Japanese space agency JAXA is claiming they make up the first high-def video ever returned from the Moon.

The video is very cool. They have it set up in a way that I cannot figure out how to embed it (grrrr), and it’s a flash file, so you have to go to the page and click the link they have there. I imagine it’ll be on YouTube pretty quickly though. :-)

Here is a still from the movie (click to embiggen):

The images are very nice, that’s for sure! This one is of the crater Repsold, which is about 100 km across. The long crack going across is it actually a rille, a gully carved by flowing lava when the Moon was still geologically active billions of years ago. Usually rilles are smooth and sinuous, and this one is a bit jagged. Evidently Repsold has been pummeled a bit since it was created; the rim has collapsed somewhat.

Repsold is located at a lunar latitude of about 50 degrees north, so it’s easily visible from Earth… but not at high resolution. Even though the Moon is close by, even the biggest telescopes on Earth can’t see objects smaller than about 50 or so meters across – it’s just a matter of physics. Even Hubble can’t see objects smaller than 100 meters across. We need to send probes to the Moon to see anything smaller, and it looks like Kaguya will be able to do just that.*

Here’s another shot from the video, this time of the north pole region:

Yikes, what a mess. The Moon has undergone extensive battering from impacts over the past 4.5 billion years. I’ve been waiting for images like this for a long, long time. And these are just the first! Just wait until next year, when NASA sends the Lunar Reconnaissance Orbiter to the Moon. It will have 50 cm (18 inch) resolution!

*OK, fine: to be honest, we can do better than that using a technique called adaptive optics However, that only allows us to map a small area of the sky at a time. We need probes to do real large-scale cartographic measurements.