Last week we talked about Jupiter and we could sense right away it would be too much to handle. This week, we'll talk about Jupiter's moons - how many are there? What makes them so interesting? Is it true that the most likely place in the solar system to find life (other than Earth) is actually on one of Jupiter's moons? Hang on tight. We're going to cover a lot.

<strong><a href="http://media.libsyn.com/media/astronomycast/AstroCast-071010.mp3">Episode 57: Jupiter's Moons (15.5MB)</a></strong><br />&nbsp;<br />

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Cool episode. But, thought this might be brought up. Gan De, (Chinese astronomer), in 362BC. http://en.wikipedia.org/wiki/Galilean_moon#_note-0. But I guess it can be considered controversial.

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Thanks,
Marasama (^_^)

I am hoping that you will do an episode about the Centaurs after Saturn and its moons. Talk about the Trojans, too, would be nice.

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Keeper of the Jabberwock

Should have mentioned one very cool feature of the Jovian moons that amateur astronomers can view, i.e. shadow transits and eclipses.

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“Life is not measured by the number of breaths we take, but by the moments that take our breath away”

Pamela mentioned it briefly, something about the challenge of exploring Europa and Ganymede (for possible life forms), without 'contaminating' them with Earth microbes.

After reading this post on Universe Today, I just realized how very real this danger is:
http://www.universetoday.com/2007/09...ome-from-mars/

Sorry to arrive so late to the party.

Found this site after listening to Fraser and Pamela guest on the skeptic's guide and have been working my way up through these fascinating podcasts.

I have a question about the nature of the radiation in Jupiter's magnetosphere.
Pamela mentioned that there would be alpha radiation and photons (would that be microwaves?), but it seemed to me that the electrons moving at reletavistic speeds would qualify as beta radiation.

Noting that Jupiter's radiation belts were similar Earth's Van Allen belts, a little research (from http://www.clavius.org/envrad.html, primarily) indicated that a key hazard there are protons.

Thus, I can summarize my inquiry by asking what kind of radiation would one expect near Jupiter (say, near Io) and what you could do to shield a potential traveler from it?

Thanks!

Electron emission is, by definition, beta radiation. Alpha radiation is helium nuclei and gamma radiation is photons at that specific wavelength.

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Keeper of the Jabberwock

So there are alpha, beta, gamma and protons and a whole zoo of rare radiation types, each of which are significantly different. My guess is an inch of lead would shield you from 99% of Jupiters radiation, but thire are some galaxtic cosmic rays which require much more shielding. A lifetime of exposure to galaxtic cosmic rays likely means death a few years sooner and perhaps sinility or Alzheimers a decade sooner. We don't know for sure. Neil