Io's Surface Under Construction lake-like feature? (17Aug08)

[pacfandave]

If the picture is of the side of Io that always faces away from Jupiter, and we are looking straight at it, why then does not Jupiter fill the void behind Io?

[neufer]

http://apod.nasa.gov/apod/ap080817.html

If the picture is of the side of Io that always faces away from Jupiter, and we are looking straight at it, why then does not Jupiter fill the void behind Io?

I'm guessing that this is a photomontage of:
http://en.wikipedia.org/wiki/Image:Io_f ... biters.jpg
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When the moon hits you eye like a big pizza pie...That's amore
When the world seems to shine like you've had too much wine...That's amore
Bells will ring ting-a-ling-a-ling, ting-a-ling-a-ling
And you'll sing "Vita bella"
Hearts will play tippy-tippy-tay, tippy-tippy-tay
Like a gay tarantella

When the stars make you drool just like a pasta fazool...That's amore
When you dance down the street with a cloud at your feet...You're in love
When you walk down in a dream but you know you're not
Dreaming signore
Scuzza me, but you see, back in old Napoli
That's amore
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Asterisk Cafe question:

Which moon do you think has the strongest surface gravity?

Asterisk Cafe poll results:

• Io________ [ 1 ] (0.183 g)
  Moon_______ [ 1 ] (0.165 g)
  Ganymede__ [ 1 ] (0.146 g)
  Titan______ [ 3 ] (0.140 g)
  Europa______ [ 0 ] (0.134 g)
  Callisto______ [ 0 ] (0.126 g)
  Triton______ [ 0 ] (0.079 g)

[Case]

Removing distracting background stuff in the process of creating the composite is one possibility. The background wouldn't match anyway with composite images.
Taking the photos at a small angle from precise alignment is another possibility of the blackness in the background.
As the real sizes of the bodies is much smaller, compared to the relative distances, the angle can be much smaller, too.

I tried to confirm this with the Celestia simulation program, as it has paths of various satellites too. Unfortunately, it showed the dark side of Jupiter from the Galileo angle at the photo date. The sun should have been in the opposite direction. So, I don't think the Galileo path in this program is accurate enough for this sort of simulation.

[bailey]

In regard to today's picture (Aug 17, 2008) of Io, at about 11:57 there appears to be a lake or lake-resembling feature. Does anyone know what that feature might be

[Shonkin]

"A likely energy source is the changing gravitational tides caused by Jupiter and the other Galilean moons as Io orbits the massive gas giant planet. "
This is probably true, but let's remember that Io is also moving through a dense part of Jupiter's magnetic field. A very intense electric current associated with the Io flux tube flows between Io and the Jovian atmosphere. Some of the heating has to come from this phenomenon too.

[Chris Peterson]

If the picture is of the side of Io that always faces away from Jupiter, and we are looking straight at it, why then does not Jupiter fill the void behind Io?

The image was constructed mathematically, by taking many small field-of-view images, at different angles and resolutions, and mapping them onto the surface of a sphere. The black in the background is simply where there is no data. It isn't the black of space, so there's no reason to expect Jupiter to be there.

[kovil]

http://apod.nasa.gov/apod/astropix.html

"The notable absence of impact craters suggests that the entire surface is covered with new volcanic deposits much more rapidly than craters are created. What drives this volcanic powerhouse? A likely energy source is the changing gravitational tides caused by Jupiter and the other Galilean moons as Io orbits the massive gas giant planet. Heating Io's interior, the pumping tides would generate the sulfurous volcanic activity. "


I would say that the 1 million ampere electric current flowing between Jupiter and Io would be a much more likely suspect for Io's condition of surface agitation.

"It has been known since March of 1979 (when Voyager 1 flew through the Io-Jupiter electrical connection) that Jupiter and Io are involved in an electrical exchange of approximately 1 million Amperes . A more recent article also attributes a wattage of approximately 2 terawatts (2 trillion watts) to the exchange. A back of the envelope calculation (volts = watts / amps) thus also yields an estimated 2 million volt potential difference between Jupiter and Io (if the estimated amps and watts of the interaction are accurate). "

http://www.thunderbolts.info/thunderblogs/mgmirkin.htm


http://www.lewrockwell.com/orig9/hogan1.html

[neufer]

http://apod.nasa.gov/apod/astropix.html

"The notable absence of impact craters suggests that the entire surface is covered with new volcanic deposits much more rapidly than craters are created. What drives this volcanic powerhouse? A likely energy source is the changing gravitational tides caused by Jupiter and the other Galilean moons as Io orbits the massive gas giant planet. Heating Io's interior, the pumping tides would generate the sulfurous volcanic activity. "


I would say that the 1 million ampere electric current flowing between Jupiter and Io would be a much more likely suspect for Io's condition of surface agitation.

"It has been known since March of 1979 (when Voyager 1 flew through the Io-Jupiter electrical connection) that Jupiter and Io are involved in an electrical exchange of approximately 1 million Amperes . A more recent article also attributes a wattage of approximately 2 terawatts (2 trillion watts) to the exchange. A back of the envelope calculation (volts = watts / amps) thus also yields an estimated 2 million volt potential difference between Jupiter and Io (if the estimated amps and watts of the interaction are accurate). "

http://www.thunderbolts.info/thunderblogs/mgmirkin.htm
http://www.lewrockwell.com/orig9/hogan1.html

I calculate the solar energy flux on Io at ~132 terawatts;
with an albedo of 0.63 this amounts to 49 effective terawatts.

2 terawatts of electrical power might have a 1% [1º K]
effect on the 130º K surface temperature but it is
unlikely to raise Io interior temperatures
by any more than 1º K.

[Boner]

If the surface is constantly changing due to volcanic activity and the throwing up of lava. Does this mean that the moon is getting larger in circumference and more hollow under the surface?

[Chris Peterson]

I would say that the 1 million ampere electric current flowing between Jupiter and Io would be a much more likely suspect for Io's condition of surface agitation... A more recent article also attributes a wattage of approximately 2 terawatts (2 trillion watts) to the exchange.

That's a trivial amount of energy compared with the dissipation caused by tidal distortion. Additionally, the currents aren't flowing from within Io, but involve a cloud around the moon.

Million amp currents are seen under aurora conditions on Earth, and generate no detectable rise in temperature at the surface (let alone enough to melt sulphur), and only tiny heating of the atmosphere.

[Chris Peterson]

If the surface is constantly changing due to volcanic activity and the throwing up of lava. Does this mean that the moon is getting larger in circumference and more hollow under the surface?

A body as massive as Io can't contain much hollow space, as gravity will cause it to collapse. Because this moon is in hydrostatic equilibrium, it's just going through some kind of surface recycling, extending perhaps a few kilometers (or more) deep.

[neufer]

I would say that the 1 million ampere electric current flowing between Jupiter and Io would be a much more likely suspect for Io's condition of surface agitation... A more recent article also attributes a wattage of approximately 2 terawatts (2 trillion watts) to the exchange.

That's a trivial amount of energy compared with the dissipation caused by tidal distortion. Additionally, the currents aren't flowing from within Io, but involve a cloud around the moon.

Million amp currents are seen under aurora conditions on Earth, and generate no detectable rise in temperature at the surface (let alone enough to melt sulphur), and only tiny heating of the atmosphere.

• Aurora Versus Power Lines
  Article #506 by T. Neil Davis
  http://www.gi.alaska.edu/ScienceForum/ASF5/506.html
  
  <<The northern lights are pretty to look at, but we all know that every silver cloud has a cruddy lining. At least it does for the electrical engineer.
  
  One problem is that intense electrical currents in the ionosphere accompany large auroral displays. Sometimes currents as large as a few hundred thousand amperes flow along the aurora, 60 miles above the earth's surface. As these currents wax and wane from minute to minute, they induce voltages in the conducting surface of the earth. The induced voltage can be as large as one volt per kilometer, about six-tenths of a volt per mile.
  
  This voltage also appears in wires such as telegraph or electrical transmission lines which are grounded to earth at each end. The voltage appearing is proportional to the length of the line, hence a long line can acquire a large voltage. A thousand volts will sometimes appear in a line a thousand kilometers long if there are strong auroras overhead.
  
  In the olden days of overland telegraph lines, the key operators sometimes were in for nasty surprises during auroral displays. Unwanted sparks erupted around their telegraph terminals, and the telegraph systems became unusable. Had the Alaska-Siberia Telegraph not been abandoned in 1867 before being completed, the system surely would have had much trouble with the aurora.
  
  More important now is the current induced in long electrical transmission lines. The aurorally induced current is small compared to the 60 hertz current intentionally placed in a power transmission line, but even so, the auroral current surges have characteristics that do cause problems. The current finds it way into protective relays in the line and can cause them to trip off, stopping the power transmission. Power grids in eastern Canada and northeastern United States have undergone blackouts for this reason. Similarly, extensive auroral storms tripped off the power line between Winnipeg and Minneapolis during October 1980 and again in April 1981.
  
  Still another problem with the auroral currents in power lines is that they create undesirable noise in the lines. The noise bothers people living near the power transmission lines and it may indicate undesirable mechanical and thermal stresses which reduce the useful lifetime of transformers; the damaging effects are thought to be cumulative.
  
  Also, the induced currents can cause catastrophic failure of transformers during an auroral storm. An expensive 735 thousand volt transformer at St. James Bay, Canada, had to be replaced after the December 19, 1980 great red aurora, but it blew again during another display in April 1981.
  
  The great red aurora seen by many Alaskans and Canadians on the early morning of December 19, 1980 fed current into the protective relays at the Gold Hill substation on the power line between Healy and Fairbanks, Alaska, but did not trip the relays. This line is comparatively short, so the induced current was not large.>>

[Chris Peterson]

Aurora Versus Power Lines
Article #506 by T. Neil Davis
http://www.gi.alaska.edu/ScienceForum/ASF5/506.html

Yeah, these currents are plenty large enough to cause problems. I live in ranching country, and know of anecdotal stories about people getting shocked off of fence lines during active solar periods. And we have any number of high tech devices (including the power grid) that are susceptible to damage from auroral currents. Still, that's a far sight from melting the ground!

[pacfandave]

Thanx to all for your responses.

[Nereid]

In regard to today's picture (Aug 17, 2008) of Io, at about 11:57 there appears to be a lake or lake-resembling feature. Does anyone know what that feature might be

I'm not sure just what feature you're referring to, but I don't think there are any lakes in this image.

However, there are (frozen, lava) lakes on Io, for example in this APOD.

[neufer]

In regard to today's picture (Aug 17, 2008) of Io, at about 11:57 there appears to be a lake or lake-resembling feature. Does anyone know what that feature might be

I'm not sure just what feature you're referring to, but I don't think there are any lakes in this image.

However, there are (frozen, lava) lakes on Io, for example in this APOD.

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<<Io's volcanism is responsible for many of that satellite's unique features. Its volcanic plumes and lava flows produce large surface changes and paint the surface in various shades of red, yellow, white, black, and green, largely due to the sulfurous compounds.>>

http://en.wikipedia.org/wiki/Io_(moon)
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