Mercury Flyby 2

The Messenger Probe will make its second pass of Mercury next Monday. The Planetary Society Weblog has a good article summarizing this morning's press conference, laying out the schedule and objectives. There is also a useful map showing the portions of Mercury that were imaged by the first flyby as well as by Mariner in the mid-70's. (click over to see full-size)

I have done a few posts on Mercury (Click on the "Mercury" Label, or here). Here's the thing that engaged me even before new data started coming in: Mercury is pretty small, a bit larger than our moon. Yet it has a proportionally enormous iron core (the moon has no significant core, which is a good topic for another post). Because from Earth, Mercury is always close to the sun, it's very difficult to observe with traditional telescopes- and even when it's at its greatest angular distance from the sun, only a small crescent is illuminated from our perspective. In addition, through the oddities of orbital dynamics, it's much more difficult to get a probe to than one might first assume. So even though it's one of the closer planets, we know very little about Mercury.

And as I've tried to explain numerous times before, stuff we don't know is very, very appealing to me.