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Space volcanoes July 31, 2006

Posted by dr. gonzo in Science, Space.

I haven’t written much about space or astronomy lately. Since I wrote about volcanoes and other natural disasters here I will continue that discussion on a system-wide scale.

Volcanism is not limited to Earth. In fact, Earth isn’t even our system’s most active volcanic body.

A journey to the solar system’s other rocky planets, Mercury, Venus and Mars (Pluto is purposely left out due to the current semantics debate surrounding our most distant “planet”) reveals that both Venus and Mars have had very active geologic pasts.

Mars is home to Olympus Mons, the solar system’s largest volcano. Also the solar system’s largest known mountain. It is absolutely massive, its peak towering over twice the height of Mount Everest. Standing at over 88,000 feet from its base the volcano is so massive that its profile could not be viewed by an astronaut standing on the Martian surface, the planet’s curvature would obscure the view. It covers a land area about the size of the state of Arizona. But Mars, while home to volcanoes, has no active volcanic bodies, they are all extinct so far as we know.

Venus is home to more volcanoes and volcanic features than any other body in the solar system. The planet remains an enigma, however, and scientists still debate whether Venus is an active volcanic body.

As we travel further out into our star system we begin to find wonders that ancient astronomers could only have dreamed might exist.

First we encounter Jupiter, the king of planets, a massive gas giant with a toxic atmosphere made up mostly of hydrogen and helium. The King Planet is nearly a star sytem by itself, almost a miniature solar system in the cold depths of our celestial neighborhood.

Orbiting Jupiter are scores of natural satellites, at least 63. Of those satellites the four known as Galilean satellites (for their famous discoverer) are probably the most intriguing. There is Europa, possible home to a sub-surface ocean and a great hope for astrobiologists searching for extraterrestrial life. Then Callisto and Ganymede. Callisto is another body which is likely home to a sub-surface ocean of some sort. Ganymede is the solar system’s largest satellite (nearly half the diameter of Earth (.413 Earth)) and also likely to have a layer of liquid water somewhere beneath its surface as well.

But it’s Io that attracts the attention of what I am going to call “astrovolcanologists.” Voyager‘s 1 and 2 observed nine and eight active volcanoes on Io, respectively. These volcanoes are likely powered by tidal interactions with Jupiter and its largest satellites.

In 1995, after six long years of traveling through the depths of the solar system, the Galileo probe arrived at Jupiter.

What Galileo found was that Io was indeed the solar system’s most active volcanic body. Huge plumes were photographed by the probe erupting into space. Spewing sulfur and sulfur dioxide into space, some plumes ejected up to 300 km above the surface of the moon. Just check out the image below.

Volcanoes on Io.

Truly amazing. But our journey doesn’t end there. The solar system is quite geologically active and volcanoes are just the tip of the iceberg, no pun intended, as you will see.

Beyond Jupiter, Saturn, a ringed wonder. Starkly beautiful, even through simple backyard telescopes Saturn is the kind of planet that can inspire a life long awe with the cosmos. It is indeed a stunning sight to behold.

And it too, is large and home to a wide variety of natural satellites, another mini-solar system of at least 47 moons.

The joint ESA/NASA mission to Saturn, Cassini-Huygens, has produced a windfall of hitherto unknown scientific information about the Saturnian system. Aside from landing the Huygens probe on the mysterious moon of Titan (a sort of primordial Earth) the Cassini orbiter has continued to produce loads of science and discoveries.

The biggest of these discoveries is arguably that of active geologic processes on the tiny moon of Enceladus. Cassini discovered a cryo-volcanic process similar to geysers on Earth on the small moon. Huge plumes of water ice spray far into space above the surface of the moon and are likely fueled by resevoirs of liquid water beneath the surface. The water is heated by the tidal forces of the huge planet that looms forever in the sky of Enceladus.

Behold, the fountains of Enceladus

The reason this discovery is so important is because on Earth, where there is water there is life. Enceladus may prove to be the best hope for life in our solar system outside of our biosphere.

As we leave the potentially life-giving geysers of Enceladus behind our race through space heads to distant Neptune, the outer most of the gas giant planets.

In 1989 Voyager 2 made the first close observations of Neptune and its moons. While the Neptunian system isn’t nearly as large as the mini-solar systems surrounding Jupiter and Saturn it does have 13 known moons.

The only large known moon is Triton. Triton orbits Neptune in a retrograde orbit (a direction opposite the planet’s rotation). This orbit is not the result of the moon forming in the same region as Neptune. Retrograde orbits result from either a) collisions or b) being captured. The latter scenario is likely in Triton’s case and many scientist believe it may be a captured Kuiper Belt object, much like Pluto or 2003 UB313.

Voyager 2 revealed a surprisingly young surface on Triton and conclusive evidence of cryovolcanism as well.

The fringes of the solar system are much more active than once thought. Every time we make assumptions about our surrounding science comes through to find evidence of a new view. Amazing. In science there is no one truth only highly plausible circumstances which appear to be correct but are often found to be wrong or at least a little bit off.



1. bloglily - August 5, 2006

Good heavens! I had no idea you KNEW so much stuff. This is a wonderful essay. You’re going to need some lovely file folders to put this sort of thing in. Watch your mail….

2. alicia - September 9, 2007

volcanose and spce both interest me a lot. i live in montana so the nearest volcano is yellow stone. i am doing a science fair either this year or the next. i am in 7th grade. if you have any more picctures or suggestions for reserch on volcanose on other planets please let me know. i aprciate it. :)

3. alicia - September 9, 2007


4. Stinky Wilson - October 19, 2007

Wow! That euption is stunning isn’t it! The upper end is still in space! amaginme how massive it would be standing right next to it (well… you would be dead because you would be burnt and 500000 years is a long time to hold your breath in a spaceship).

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