- the planet Mercury. We knew Mercury was dense (not 'dense' in that writerly way! but dense the way a golf ball is more substantial than a ping-pong ball). I always thought that was because Mercury had a really big core of iron, but Jim said today new measurements show it might be because Merury is really 'compressed' - like it got put into one of those squeezes in the junk yard.
- The Moon! Like what could be new about our own moon when there are so many cool (ha ha) moons out there around Jupiter and Saturn? Jim showed us a nifty geologic map of the back-side of the Moon. We usually don't get to see that side, because the Moon spins just fast enough to keep the same side facing us every night.
- Mars and water. It really has it, it really can be found not to far below the surface. There are even glacier-sized regions under the surface at mid-latitudes (the equivalent of where we live in California). I knew about the little dots of surface ice they'd seen come and go in selected images, but didn't realize so much of it had been found. What a cool result from those miraculous rovers! How this opens up our ways of thinking about the planet Mars!
- Mars and the methane-thing. methane is a gas that is produced in both biological ways (think cows and pigs and horses, Oh My!), and naturally in abiotic processes. So they've begun to map methane on Mars (who'd have thought), and see now a seasonal variation. It is by no means a statement that cows and pigs and horses are responsible. If anything it would be some sort of bacteria. But just the fact that this is up for discussion is one of the wonders of the science of this decade. I agree with Jim there.
- Jupiter's moon Europa. This is an old story. We heard more about the potential for the Europa Jupiter System Mission (EJSM) - to be joint between NASA and ESA - at the meeting this week. Nonetheless, it seems appropriate that Europa is still on a list of the seven wonders, with its sub-surface ocean! (discovered in the last decade by the Galileo mission).
- Saturn's moon Titan and the lakes of methane. For decades after the Voyager mission to Saturn, where we really ddi't understand what we were looking at when we got that little fuzzy orange dot of Titan (one of the largest moons - larger than the planet Mercury), we speculated and speculated about what the surface was like. Pictures are still a mystery with lots of unexplained features. But we now understand that some of what we are looking at are lakes and lakes and lakes.
- Saturn's moon Titan and the rain of methane in the southern hemisphere - so reminiscent of Earth, and perhaps early Earth. Titan doesn't have many clouds, and certainly doesn't have weather like we know it on Earth. Nonetheless, rain is something that happens rarely in the solar system. And Titan, with its 'reducing' egosystem (abiotic), gives us so much to think about in terms of chemical cycling, and what the earliest Earth might have been like (earliest Earth was 'reducing' too, not oxidizing like it is now).
Wednesday, October 6, 2010
science: NASA's Seven Wonders!
I was privileged to hear Dr. Jim Green of NASA headquarters speak today at the AAS Division of Planetary Sciences meeting. He's the guy in charge of the planetary program at NASA. He talked about the wonders of the solar system, in the same vein as the standard 'Wonders of the Ancient World ...' Here's Jim's Magnificent Seven:
thanks Jim for sharing these insights with us! Jim also said that next year there will be three (3!) NASA launches of new planetary missions. As I say all the time, it is an exciting time to be a scientist!