How do volcanoes in space greet one another?

Io (an answer to the joke and a greeting to readers of this post)

I seem to remember reading that Io (one of Jupiter's Moons) was the only other celestial body in our solar systam to have active volcanoes. My good friend Alice reminded me of this yesterday when she woke me with a text telling the next The Sky at Night episode will be about volcanoes in space. Soon after realising that I hadn't actually been stirred by the fall of another wicket, I remembered this fact about Io, Alice needs confirmation from Sir Patrick, I now think I do too and maybe Io just has the most volcanism. Whatever the case, it has some which is cool so here are some facts about it.

Io has high orbital eccentricity, which means it is an elliptical shape, this means it has large gravitational pull, resulting in large tidal heating and this causes it's volcanism. Earth's volcanoes are due to magma movement from the geothermal activity or something like that (I really hope no physicists read the blog, actually I don't think anyone really reads it, so I should definitely make more stuff up).  There are three types of eruptions that occur on Io; intra-patera eruptions, flow-dominated eruptions and explosion dominated eruptions. Intra-patera eruptions occur in pateras which are caldera-like depressions on the moons surface, these can eruptions can be divided into those that with lava flows and those with lava lakes (a pool connected to a magma reservoir). Flow dominated eruptions seem to be similar to earth's Hawaiian eruption in that they continue for long periods of time and are often from lava tubes and fissures. Like Plinian eruptions, Explosion dominated eruptions are spectacular and violent, they occur when a magma body reaches a fissure and often produce lava fountains.

Hopefully there will more on this in next weeks The Sky at Night so I will be able to fill in all those gaps in my extraterrestrial volcano knowledge and pass on some wisdom. Issue Three will be out for in time for Christmas and I'm pretty sure that everyone you know would want a copy of the magazine so get ordering.
Finally here is another blog with a volcano of the week feature- definitely a copy of mine! http://www.gishbartimes.org/2010_08_01_archive.html