Hello Io, From Galileo

FortKnox writes: "This afternoon super-durable Galileo will swoop in on the south pole of Io. Scientists hope to learn a little more about the volcanic moon of Jupiter. And it shows some great NASA innovation in the little probe still working great (although low on fuel). Fly-by will happen at 3:23pm EST."

Magnetic field?

[CheshireCatCO]

The article hints at, but doesn't really explain, that the principle goal here is to find out of Io has an intrinsic or induced magnetic field. If the field is induced from Io's moment through Jupiter's whomping-string field (actually, the latter moves over Io more than anything, but whatever), then the south polar pass will show a different field signature than if the field is intrisically due to the internal workings of Io's core (a molten, convecting core ought to be able to create a field).

Last time Galileo tried this, it suffered a glitch just prior to closest approach. The magnetometer was turned out late in the restart sequence (which was probably a poor decision), so we didn't get the data two years ago. (This fly-by has been dubbed the 'cry-by' by several researchers I know.)

Let's just hold the poor, battered warrior survives this one.

How do you tell the difference?

[Yazeran]

I just wonder how the scientists will be able to tell the difference.

As i recall, if a body is magnetic (induced or otherwise) it will look the same from the outside. Perhaps that is why they want a close flyby to be able to monitor small changes near the surface.

If anyone knows how you can distinguish between an intrinsic and an induced magnetic field, please step forward and explain.

Yours Yazeran

Plan: To go to Mars one day with a hammer.

Re:How do you tell the difference?

[JabberWokky]

Plan: To go to Mars one day with a hammer.

So, why the hammer?

--
Evan

Re:How do you tell the difference?

[Yazeran]

I'm a geologist, that's why.. :-)

Yazeran.

Re:How do you tell the difference?

[JabberWokky]

I'm a geologist, that's why.. :-)

Well, now, not if you went to Mars. :) You'd be a... ummm... exogeologist would be too generic. Martian geologist is too wordy. Arieologist? Marteologist? Ariegeologist?

Can you imagine the formations on a low grav, low temp world? Both the immense ones and the formations of microscopic crystals? I'd play photographer... --
Evan "Lunologist? Seleogist?" E.

Re:How do you tell the difference?

[shelflife]

close, but no seegar ..

I think the term would be: areologist.

Re:How do you tell the difference?

[CheshireCatCO]

Actually, it's quite easy to tell the difference with a few good measurments. Jupiter's magnetic field is tilted 10 degrees from the spin axis, so that Io, in the spin equator of Jupiter, is moving not just azimuthally through Jupiter's field as it passes over Io (10 hour period vs a 42 hour period for Io's orbit), but also up and down in the field. This means that the induced field will vary at different times. This is how they detected induced magnetic fields in Europa, Ganymede and Callisto (in these cases, the field strengths and compostions of the bodies point to liquid water).

Hello Io?

[dbolger]

Well it sure puts a whole new spin on the old "Hello World" concept, doesn't it ;)

When NASA gets it right....

[Fenris2001]

I'm still amazed at the successes of our space exploration program - Galileo is still working, even after exposure to Jupiter's radiation belts, Pioneer 10 is still sending signals, and the Viking landers (designed for a six-month mission) functioned for more than two years (four in the case of the second lander)!

I could go on and on about the good things NASA has done - the Deep Space mission, NEAR, etc. But of course these don't get as much press as when a mission goes wrong. The media has created in the mind of the public the irrational desire for perfection - we want it to work 100% the first time. But when pusing the frontiers of science, sometimes things break.

Goodbye, IO

[shelflife]

NASA's Galileo spacecraft successfully completed [nasa.gov] a close flyby to study Jupiter's moon Io at 0123 Universal Time today (6:23 p.m. Oct. 15, Pacific Daylight Time), during the long-lived spacecraft's 32nd orbit around Jupiter.

Galileo passed closer to Io than ever before, within about 181 kilometers (112 miles) of ground level near Io's south pole.