Galileo's Flyby of Almathea

An anonymous reader writes "The spectacular Galileo flybys of Jupiter, Europa and Io are largely credited with the discovery of frozen water ice and some of the earliest examples of non-solar (tidal) heating anywhere in our solar system. For the next 10 days, Galileo scientists are preparing for their next target: probing one of Jupiter's moons, Almathea, at the close-up range of 100 miles. Almathea is one of the most unusual moons in the solar system, because it gives off more heat than it receives from the Sun."

Comments

Nice rendered pictures

[Dark Lord Seth]

For those of us who aren't very much at home in astronomy and it's terms and who just want to see (relatively) pretty pictures; Celestia also has Almathea available for your viewing pleasure, along with allot of different stuff in our solar system and even beyond there. Besides, it's a pretty proggy... :)

AmaLthea, not ALmathea

[Anonymous Coward]

Hell, has nobody noticed that the real name is Amalthea?
Where are your classics!?
She was the goat that nurtured baby Zeus = Jupiter!

Re:Gives out more heat that it recieves.

[verag]

The planet itself does this as well... "...Jupiter radiates nearly twice as much heat as it receives from the Sun." Found here

Jupiter is by far the most interesting planet (with it's moons) to me, other than the Earth. More information as well as pictures can be found on NASA's site for the planet itself.

Amalthea

[Blackneto]

The Correct spelling is Amalthea.
It says so on the JPL's website.
Also Amalthea was a nymph that nursed Jupiter in mythology. This fits in with the naming of the other moons.
It looks like it was only misspelled once on the astrobio site which may be the cause of the confusion.

Jupiter's mass is the cause of the heating

[Big Mark]

Jupiter is so heavy that it's inner reigions are incredibly hot - some think it's actually a star that just wasn't big enough to have it's own mass crush it's innards to the point where nuclear fusion occurs and the star is born. It's big enough, though, that the innards are squished to to superheat. It's this heat from the inside that makes Jupiter warm up.

The moon's heating is accounted for by tidal forces - Jupiter is just so flippin' MASSIVE that it's gravity stretches and squeezes the moon, and these tidal forces make it heat up.

The surface of Amalthea (sp.?) will be interesting to look at. I think it will have pronounced cracks on the surface where aeons of tidal forces have had their way.

Re:Jupiter's mass is the cause of the heating

[LMCBoy]

It's this heat from the inside that makes Jupiter warm up.

This parses to "Jupiter is hot because it is hot."

You're correct that Jupiter's core is not hot enough for nuclear reactions (core temperature is about 20,000 K).

Just to clarify, Jupiter gives off more heat than it receives because it is still collapsing! Sounds incredible, but the "heavier" elements are still slowly settling out toward its core. As they do, they release gravitational potential energy in the form of heat. This settling process must be incredibly slow, since it's presumably been happening steadily for the past 4.6 Gyr; the fact that it still produces a significant amount of heat demonstrates how damn BIG Jupiter is.

See SEDS.org for more information (about halfway down the page, right after the section on the Great Red Spot).

Re:For those looking for Earth like planets...

[overunderunderdone]

This really bugs me, when I see people say "life can't exist there, that planet is twice Earth's distance from its star..." and rubbish like that. Aarrgghh !

If you are ranting about the "rare earth hypothesis" you should remember that the authors believe that life is MUCH more common than was previously believed. However they believe that advanced life and advanced civilizations are MUCH rarer than previously believed and do require conditions substantially similar to earths. Even you own post basically makes some of the same assumptions - you see the heat from this moon as promising because that heat is one of the prerequisites for life, the rare earth hypothesis adds additional prerequisites which must be present for *advanced* life. There are those that simply assume without thinking that life must evolve on a planet substantially similar to earth. The rare earth hypothesis arrived at pretty much the same conclusion through serious thought on the subject. They may be wrong (we simply don't have enough data) but their reasoning is sound and not based on simple prejudice or ignorance.

Mr. Armchair Science butts in.

[erik_fredricks]

Almathea is one of the most unusual moons in the solar system, because it gives off more heat than it receives from the Sun."

Actually, Triton (Neptune's largest) does, too, IIRC. All the gas giants do as well.

In Amalthea's case (as well as Europa and Io), the moon is constantly being contracted and stretched by Jupiter's gravity, and those tidal forces generate heat in the moon's core. You can duplicate this effect by squeezing a piece of styrofoam in your hand and feeling it heat up.

Of course, all the gas giants have internal heat sources due to the immense gravity in their highly contracted solid cores. Neptune gives off way more heat and light than it receives from the Sun.

A sneak peak at Almathea

[mraymer]

Celestia is a 3D space simulator much like OpenUniverse. It's avaible for both Windows and *nix OSes. In it, you can view all the planets, some moons, asteroids, and a fair number of stars. Here's a shot of Almathea. They release add-ons every now and then-- you can even download the recently discovered Quaoar!