Category Archives: planetary science

Mars, planetary science, planets

It’s Not Dead, Jim

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It’s Alive!!!! (In the Geological Sense, That Is…)

For those of you who thought Mars was a dead planet, this just in: there are avalanches out there, Captain!

The ongoing in situ exploration of Mars, which includes two rovers, and three orbiters (plus another spacecraft headed out to Mars by May of this year) is showing us a lot of Mars for our money. Just about every day, and more than once a day, you can log into the Mars missions web pages and see the latest from the Red Planet. And that doesn’t even count the great  images that Hubble Space Telescope gets every once in a while.

If you have been checking out Mars images pretty frequently, you’ll know that the place is far from being a dead planet. Sure, it has no biological life (that we know of , so far), but in every other way that counts, it is an evolving planet. The atmosphere changes with the seasons, its surface is constantly sculpted by winds and possibly the action of tectonic forces, and its polar caps grow and shrink throughout the year. If it had some liquid water on the surface, we’d probably see that change as the years go by. As it is, we are limited to watching what happens with ice and dust and rocks, but Mars hasn’t let us down. The Red Planet is giving us quite a show for our exploration money. And that’s the beauty of sending long-term missions to other planets: we get to see them change over time, which lets us understand them far better than if we only had snapshots to work from.

The latest in planetary surface modification at Mars comes to us from the High Resolution Imaging Science Experiment on the Mars Reconnaisance Orbiter. It caught a sequence of events on near the Martian north pole that are clearly action shots of an avalanche in progress. Dust and ice are tumbling down a 700-meter (2,300-foot) tall cliff and settling out on a gentler slope below. It’s pretty dramatic-looking, isn’t it?

Mars avalanche

astronomy education, planetary science

Object Lesson: How Science Works

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Learn What’s a Planet… and What’s Not.. and Why

graphic of solar system

A couple of years ago you might recall there was a huge uproar about the supposed “demotion” of Pluto from its status as a planet and its re-characterization as a “dwarf planet.” The International Astronomical Union adopted a definition of the term “planet” that continues to be batted around in science and public debates about the meaning of “planet.”

In the wake of that decision, and because it’s one that captured public attention, NASA, The Planetary Science Institute, and the Johns Hopkins University Applied Physics Laboratory have teamed up to offer a special two-day science conference and educator workshop August 14-16, 2008, called the Great Planet Debate: Science As Process.

Its purpose is to discuss science as a process, and use the ongoing debate about what should or should not be a planet as a framework for discussion. It looks like an excellent way for science teachers to get an inside look at the working processes of science that don’t always get enough attention in the classroom. If you’re interested, check out the web page and contact information. As an added bonus, there will be continuing education credit offered for teachers who attend.