--MESSENGER--

~Hi everyone, and welcome to my new blog. In case you missed it, my last blog, David Does Japan, ended when I returned to America in April 2007 after a year of teaching in Japan. You can read all about it (and see many of the pictures I took), on the blog, which will no longer be updated.

But fear not, oh soon-to-be-loyal-again readers! This blog, Debonair David, will now host my witty thoughts, caustic commentary, and whatever else I feel like posting. The postings on this blog, however, will be somewhat different from David Does Japan. That was mainly a photo and commentary blog about living and working in a foreign county. Debonair David will be less photo-oriented, although I may post an interesting photo or graphic every so often.

Instead, it will be composed of things I find interesting: news reports, book and film reviews, philosophical observations, and my ever-popular public service announcements. Since I'm now a busy graduate student, I will be posting less frequently, but I'll try to post at least week (though I make no promises).

To kick off, I bring news of MESSENGER, a space probe sent by NASA to Mercury, the closest major planet to our Sun. MESSENGER, an acronym for MErcury Surface, Space ENvironment, GEochemistry and Ranging, was launched in 2004 and took pictures of Venus in June 2007 before making its first pass by Mercury just a few days ago, taking pictures of previously unknown parts of Mercury's surface (some of which you can see at left).

Why, you may ask, did it take three years for MESSENGER to get to Mercury? The answer is that Mercury is a very difficult planet to get to. Being so close to the sun, it's period of revolution is very short; a year on Mercury lasts about 88 Earth days. For a slow-moving, weakly-propelled space probe to reach such a fast-moving object presents significant navigational challenges.

Compounding the travel problem is the Sun itself, the heat of which becomes more and more intense as you get closer to it. In fact, MESSENGER must travel so that its heat shield is always facing the Sun, otherwise its delicate scientific instruments would fry in minutes. To ensure correct orientation, the probe carries a series of gyroscopes, star-tracking cameras, and accelerometers, with small thrusters to adjust course as needed.

So why send a mission to Mercury, anyway? The answer is that Mercury is the least explored of all the major planets. The only other space probe to visit was Mariner 10 in 1974, which was only able to map about 45% of the planet's surface...a surface which is the oldest of the four major rocky planets. A careful analysis of Mercury will help us better understand how Earth formed, and how planets form in general (which will be valuable in locating Earth-sized exoplanets).

The instruments carried by MESSENGER are designed to help solve six puzzling questions about Mercury's surface. For example, we know that Mercury and Earth have magnetic fields, but Mars and Venus do not...but why? Also, Earth-based observations have shown areas of high reflectivity near the poles of Mercury, which may be areas of ice!

MESSENGER will make one additional pass by Mercury before finally settling into orbit in March 2011. I'll be looking forward to hearing what secrets NASA scientists are able unearth about our oldest, smallest neighbor down the solar street.