Category Archives: planetary science

Evolutionary Earth

Hawai’i Style

Last summer Mark and I and a group of science writers took an exciting hike across newly deposited lava flows on the Big Island of Hawai’i. To get to our hiking spot, we drove across flows that had been laid down over the past decade; fields of lava not 30 minutes from downtown Hilo. After gearing up (including plenty of water and food and safe clothing), we hiked out to live flows that originate at the Pu’u’ O’o vent on the flanks of Kileaua volcano. Our guide was noted volcano photographer and amateur astronomer Stephen J. O’Meara (in the image with me below).

That vent is still active, still pumping out lava each day, and recently it has been finishing the paving job it began when it first begain to engulf Kalapana Gardens subdivision more than a decade ago. If you take a look over at the USGS Hawaii Volcano observatory web page, you can see the latest action on the flanks of the volcano.

While we were hiking, we stepped across very live flows (like the one above) and took time to watch as slower flows moved leisurely across the already rocky and desolate fields. It’s hard to believe that this region was once a beautiful rainforest, dotted with homes. Not far from where we stood, there used to be a Park Service building and the site of an old heiau, a sacred site for the native Hawaiians.

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This recent picture (taken March 5, 2008) caught my eye because it shows the same road we drove over to get to our hike last summer with SteveO. As you can see, it doesn’ t matter to the lava whether it’s covering a road, a house, a forest, or dribbling into the ocean. It just keeps on flowing, a splendid example of the ongoing creation of new surface rock that planet Earth does with its volcanic eruptions.

If you ever visit the Big Island and take on the volcano, be warned that it’s not for the faint of heart. Earth-building processes aren’t delicate. The rock is hot, its action is incessant, and its a smelly and hazardous. But, it’s worth your while to confront the volcano. You can walk away from it knowing that you’ve experienced one of the most important surface-altering processes in the solar system. As one of the hiking cohort said last summer, what you’re seeing here are the most recent steps in the death of a massive star. If you think about it, that’s correct; and we were watching the NEWEST steps in the creation of our planet. You can see more of our pictures from last summer here.

An Evolutionary Ring

Prometheus Bound to the F Ring at Saturn

F-ring at  Saturn

What happens when you put a small world orbiting through an ethereal pair of dust and ice particle rings, all encircling the planet Saturn? You get intricate whirled and kinked structure in the rings, as seen in this image from the Cassini Mission’s imaging subsystem.

It’s all in the gravity of the situation. Prometheus (which is a natural satellite (moon) of Saturn off to the right of the F ring (center)) does a little dance with the F ring, getting closer and farther away over a period of just under 15 hours. As this little oddly-shaped moon gets close to the ring particles, its gravitational interaction draws out a stream of material. The stream then gets more misshapen as it orbits around Saturn, forming the graceful loops and curves we see in this image. The Cassini Mission pages have many more images of this phenomenon, which is yet another good reason to study a planetary system over long periods of time. Snapshots give us a frozen moment in time; long-term observations tell us a more detailed and exacting story of just how things change on both large and small scales in the solar system.

For more fascinating images from the Cassini Mission, visit the Cassini-Huygens mission web pages and do a little browsing. You’ll learn more about Saturn, its moons (particularly fascinating Titan), and those glittery, wonderful rings that have so captivated planetary scientists.