[ford prefect]

* i normally do better papers, but this was for college, minimal effort involved and it could only be 1000 words. Very frustrating. i took out the footnotes and works cited.


One of the most fascinating celestial bodies in our solar system is Jupiter’s third largest moon. It has been championed as being the most volcanically active body in our known system. Io was discovered on January 7, 1610 by Galileo, however there is some controversy as to if he was the actual first person to acknowledge it’s existence. One week before Galileo made his announcement, Simon Marius claimed to have made the same discovery. Galileo severely doubted this and claimed it was an act of plagiarism. When researching, all indications show that it was a mutual discovery and both astronomers are credited with the detection. In Roman mythology ‘Jupiter’ is the equivalent of ‘Zeus’. Simon Marius actually suggested the name but it fell into disfavour until the 20th century. Up until then the moons were referred to as Medecian (after the prominent Medici family) and labeled with Roman numerals I, II, III, IV etc. Unfortunately it was realized that this may become too confusing as more and more satellites were being discovered. The name ‘Io’ derives from the Greek myth of a maiden (Io) who angered Hera. Zeus then changed her into a white heifer to hide her from his jealous wife.

Io has a similar bulk composition, the same as the terrestrial planets; composed primarily of silicate rock. Indications show that Io may have an iron core much like the earth’s, with a radius of at least 900km. Also, like the volcanoes here on Earth, Io emits sulfur and sulfur dioxide when erupting. The plumes of the active volcanoes can reach up to 300 km above the surface before falling back to the ground. The largest recorded volcanic activity in the solar system occurred on Io on February 2001,when it was observed by the Keck II telescope on Mauna Kea in Hawaii. Touted as being one of the most important discoveries of the Voyager missions; it was first factual proof that other terrestrial bodies are hot and active. Between the Voyager 1 and Voyager 2 missions, in just 4 months, some of the volcanoes stopped while others started. The power behind these plumes are a result (it has been speculated) of the low gravity of Io (about 1/6th that of Earth’s), and the lack of atmospheric pressure. Also, the actual sulfur itself must be taken into account. “When liquid sulfur dioxide comes into contact with hot material below the surface, the superheated, [sic] boiling liquid rises quickly through fractures in the surface and produces a high-velocity column of gas. Because of the extremely cold conditions, the gas immediately starts condensing into sulfurous snowflakes” (C.Hamilton). The materials around the vents also rapidly change colours as the sulfur cools, giving the area a multi-hued look of yellows, browns and reds.



Io’s geography also includes calderas, non-volcanic mountains, molten sulfur filled lakes, and hundreds of flows kilometers wide and deep. It was once thought that the lava flows were comprised of sulfurous substances, but now it is believed that many of them are molten silicate rock much like here on Earth, with large deposits of sodium. Infrared studies indicate that the surface of Io is much too hot for liquid sulfur with temperatures reaching 2000 K. 1300K higher than the boiling point of sulfur. This suggests that the theory of silicate rock lava flows may be more appropriate.

The reason for the viscous activity may be attributed to the tidal interaction between Io, Jupiter and two of Jupiter’s other moons, Europa and Ganymede. They are locked in Laplace-resonant orbits . And due the fact that one side of Io always faces Jupiter, the gravitational interaction between Jupiter, Ganymede and Europa causes Io to ‘stretch and bend’ as much as 100 meters; comparable to a balloon when squeezed repeatedly. This causes Io internal friction, which raises the temperature. Io also crosses
Jupiter’s magnetic field lines creating an electric current. Though almost irrelevant compared to the tidal heating, this current may carry as much as one trillion watts of power. For a satellite, it is fascinating that Io can impact the planet Jupiter. Due to the electrical current some material is stripped away from Io to form a torus of intense radiation that surrounds Jupiter. “Particles escaping from this torus are partially responsible for Jupiter’s unusually large magnetosphere”(Bill Arnett).

Io has a very thin atmosphere composed of 90% sulfur dioxide because of the volcanic activity. And due to it’s low gravitational pull, the atmosphere does not remain for very long. Researchers have found evidence that there may be chlorine in the atmosphere. There seems to be proportionally, a million times more chlorine in Io’s atmosphere than in Earth’s. And with sodium (also present), when these two chemicals mix together they form sodium chloride (common table salt). It is speculated that there may be underground rivers producing the salt or it may happen in the actual atmosphere. The first atmospheric measurement was made in 1971. The researchers waited for a star to pass behind Io. Measuring the time it took the star to occult Io, they were able to discern Io’s diameter as well as check for an atmosphere. If Io had any distinguishable atmosphere of more than one microbar, the star’s light would have dimmed as it passed behind; however it extinguished completely. When in 1973 Pioneer10 passed behind Io it was discovered that Io had a high concentration of electrons close to its surface (by monitoring radio signals), proving that Io has an ionosphere. “This implied that there must be atmospheric gases to provide the source of electrons and ions. What gases were present was unknown at the time. Later telescopic observations discovered that a neutral cloud of Sodium and Potassium was associated with Io's orbit and ionized sulfur in the Jovian magnetosphere”(C.Hamilton). Because of the conflicting data it is difficult to
guess at the exact composition. Only by having a specific journey to Io, will the question of atmosphere be answered.


Io is an enigma; conflicting data means that no one will know anything specific until directed studies and a voyage there are done. But what is known is startling: the fact that a moon can have the same composition and geologic symptoms as a terrestrial planet; that a moon so tiny could affect such a large planet as Jupiter in major ways. Perhaps when more is known about the atmosphere and the chemical compounds of the terrain, we can begin to understand more about our own planet.

[Mathsorcerer]

Most college papers don't require work worthy of publishing in Scientific American (or other field-specific journals).

Excellent research on Io.

[The_Heroic_Loser]

Thanks for giving me an idea of what I'm gonna have to deal with when I go to college.

[Tadgie]

If you're worried, just go business. Those lucky bastards never had to do anything. Four year all day club it was. Five years for the slow ones.
But all the sciences are pretty much the same.

[ford prefect]

I am replying to Six Flags comment over here as Micahs power thread is being over run by astronomy nuts.

Oh, most definitely if a star is 25 solar masses it will turn into a black hole (Supernova) BUT!!!!
Not always the case. Sometimes the buggers just fizzle out and turn into a red dwarf. They are not quite sure why this happens either, except they think it has somethign to do with the internal rotation.

Stars are tricky. They can go nova, supernova, planetary nova (misnomer), those are the prettiest. They can fizzle out.
If they are a binary system they can just poof if the other star is sucking all the matter away. Very neat-o illustrations of this in Astronomy today mags.

They can go white dwarf, red dwarf, pulsar, magnetar, black hole, super massive black hole.......

normally depends on the mass. But there are always exceptions :P

Betelgeuse which is disgustingly huge, is going to go supernova. BOY WILL IT!
-427 light years away (thats ~10 trillon km x 427)
-super redgiant (nearing the end of its life cycle)
-diameter 650 times that of our sun (its as big as the ORBIT of jupiter!!)

when this bugger goes supernova, it will either turn into a oxygen-neon white dwarf or a balck hole. Either way, it will screw with our ozone layer and be as bright as our moon and seen in the day.

[supergroovymama]

You are AMAZING fordy! :wink:

[tobnameless]

very non ford like whole new dimension.....makes me randy....grrrrr

[sixflags11804]

Man that was a great research paper! It was very informative and interesting. How long have you been in college for astrophysics?

[Dargan]

Originally Posted by sixflags11804

Man that was a great research paper! It was very informative and interesting. How long have you been in college for astrophysics?

I concur

[ford prefect]

went to college for a pre physics prep course, and to brush up on the math.
I am in first year astrophysics at university.
But i have been a huge nerd forever. I have a gazillion books on it (love the pics) and have my own telescope. Its a newtonian reflector with a dobsonian mount. 4mm reflector. Not great but still cost $600.

I can see the US flag on the moon clear as a bell.

Fairly good at any nebula, cluster within a 10 light year radius.

Of course, any planet!

* I am not just a quick wit and pretty face you know!!

I wish other guys got as turned on with this as you do Toby! Most guys are intimidated or call me a bitch or smartass.