APOD: Io's Surface: Under Construction (2013 Aug 04)

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APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by APOD Robot » Sun Aug 04, 2013 4:09 am

Image Io's Surface: Under Construction

Explanation: Like the downtown area of your favorite city and any self-respecting web site ... Io's surface is constantly under construction. This moon of Jupiter holds the distinction of being the Solar System's most volcanically active body -- its bizarre looking surface continuously formed and reformed by lava flows. Generated using 1996 data from NASA's Galileo spacecraft, this high resolution composite image is centered on the side of Io that always faces away from Jupiter. It has been enhanced to emphasize Io's surface brightness and color variations, revealing features as small as 1.5 miles across. 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.

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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by Beyond » Sun Aug 04, 2013 5:08 am

Ah, the moon pizza has returned. YUM :!: Image
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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by Boomer12k » Sun Aug 04, 2013 6:30 am

Reminds me of a bad peach....
But it is very interesting place...all those elements brought to the surface and a painting so beautiful...that no man made.


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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by garyj » Sun Aug 04, 2013 12:03 pm

I've read that scientists have been able to ascribe only about 10% of Io's heating (which causes volcanism and infrared surface radiation) to tidal effects. They are still looking for the source of the other 90%.

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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by neufer » Sun Aug 04, 2013 12:30 pm

garyj wrote:
I've read that scientists have been able to ascribe only about 10% of Io's heating (which causes volcanism and infrared surface radiation) to tidal effects. They are still looking for the source of the other 90%.
https://en.wikipedia.org/wiki/Io_%28moon%29#Tidal_heating wrote:
<<Unlike the Earth and the Moon, Io's main source of internal heat comes from tidal dissipation rather than radioactive isotope decay, the result of Io's orbital resonance with Europa and Ganymede. Such heating is dependent on Io's distance from Jupiter (= 421,700 km vs. 384,399 km for our Moon), its orbital eccentricity (= 0.004 v. 0.055 for our Moon), [its orbital period (= 1.77 d vs. 27.32 for our Moon)] the composition of its interior, and its physical state. Its Laplace resonance with Europa and Ganymede maintains Io's eccentricity and prevents tidal dissipation within Io from circularizing its orbit. The resonant orbit also helps to maintain Io's distance from Jupiter; otherwise tides raised on Jupiter would cause Io to slowly spiral outward from its parent planet. The vertical differences in Io's tidal bulge, between the times Io is at periapsis and apoapsis in its orbit, could be as much as 100 m. The friction or tidal dissipation produced in Io's interior due to this varying tidal pull, which, without the resonant orbit, would have gone into circularizing Io's orbit instead, creates significant tidal heating within Io's interior, melting a significant amount of the moon's mantle and core. The amount of energy produced is up to 200 times greater than that produced solely from radioactive decay. This heat is released in the form of volcanic activity, generating its observed high heat flow (global total: 0.6 to 1.6×1014 W). Models of its orbit suggest that the amount of tidal heating within Io changes with time, however the current amount of tidal dissipation is consistent with the observed heat flow. Models of tidal heating and convection have not found consistent planetary viscosity profiles which simultaneously match tidal energy dissipation and mantle convection of heat to the surface.>>
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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by Lordcat Darkstar » Sun Aug 04, 2013 1:59 pm

Just read question number 13 on the apod FAQ. Lol. Great pic today. 8-)

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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by MichelleEH » Sun Aug 04, 2013 2:01 pm

I am surprised that the photo seems to have been scrubbed of its coronal atmosphere. The photo shows numerous plumes of volcanic smoke but no ring around the moon to show the atmosphere that has to be there. We all know of the photographic evidence of plumes that seem to eject miles above the surface but are drawn back by Io's gravity.

Any thoughts?

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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by Chris Peterson » Sun Aug 04, 2013 2:31 pm

MichelleEH wrote:I am surprised that the photo seems to have been scrubbed of its coronal atmosphere. The photo shows numerous plumes of volcanic smoke but no ring around the moon to show the atmosphere that has to be there. We all know of the photographic evidence of plumes that seem to eject miles above the surface but are drawn back by Io's gravity.

Any thoughts?
What passes for an atmosphere on Io is actually an extremely hard vacuum. With a pressure less than a billionth of Earth's (and as little as a trillionth outside some special conditions very close to the surface), it is not optically detectable by simple scattered light, as you'd see in an image like this. Detection of the atmosphere requires very sensitive instrumentation.
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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by BDanielMayfield » Sun Aug 04, 2013 2:38 pm

It’s easy to imagine some not completely dry exoplanet looking much like Io. The non-polar white areas could be lowland salt flats, while the widespread light green areas could be grassy or lichen covered plains. The medium green areas could be forested, while the darkest areas could be alga covered bodies of water. The polar regions are brown also because of plants, but one pole is experiencing die back and frosts of fall after a dry summer while the other enjoys a flowering springtime watered by melting frost and snow. 8-)

But nah, most exoplanets that look like this are probably lands of fire and brimstone, just like Io, only much hotter. :evil:

(I did not make this comment because of any belief on my part in any hellfire myths, just to be clear.)
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Re: APOD: Ios Surface: Under Construction (2013 Aug 04)

Post by gmPhil » Sun Aug 04, 2013 5:47 pm

<sings>
When moon hits your eye-O
Like a big pizza pie-O
It's an Io.....
</sings>

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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Beyond » Sun Aug 04, 2013 8:19 pm

If Io hit your eye-o, your eye-o would look worse than Io. You'd then have an Io-eye-o :!: :lol2:
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by DavidGovett » Sun Aug 04, 2013 11:46 pm

Does anyone else see a semi-uniform distribution of volcanoes on Io?
The distribution does not seem random.

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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Chris Peterson » Mon Aug 05, 2013 12:02 am

DavidGovett wrote:Does anyone else see a semi-uniform distribution of volcanoes on Io?
The distribution does not seem random.
There isn't much that does a poorer job of distinguishing random structure from actual pattern than the human eye and brain.
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by neufer » Mon Aug 05, 2013 1:44 am

DavidGovett wrote:
Does anyone else see a semi-uniform distribution of volcanoes on Io?
The distribution does not seem random.
  • Why would you expect the volcano distribution to be random :?:
http://www.nasa.gov/topics/solarsystem/features/io-volcanoes-displaced.html wrote: <<As Io gets closer to Jupiter, the giant planet's powerful gravity deforms the moon toward it and then, as Io moves farther away, the gravitational pull decreases and the moon relaxes. The flexing from gravity causes tidal heating -- in the same way that you can heat up a spot on a wire coat hanger by repeatedly bending it, the flexing creates friction in Io's interior, which generates the tremendous heat that powers the moon's extreme volcanism.

"Our analysis supports the prevailing view that most of the heat is generated in the asthenosphere, but we found that volcanic activity is located 30 to 60 degrees East from where we expect it to be," said Christopher Hamilton of the University of Maryland, College Park.

Hamilton and his team performed the spatial analysis using the a new, global geologic map of Io, produced by David Williams of Arizona State University, Tempe, Ariz., and his colleagues using data from NASA spacecraft. The map provides the most comprehensive inventory of Io's volcanoes to date, thereby enabling patterns of volcanism to be explored in unprecedented detail.

Assuming that the volcanoes are located above where the most internal heating occurs, the team tested a range of interior models by comparing observed locations of volcanic activity to predicted tidal heating patterns.

"We performed the first rigorous statistical analysis of the distribution of volcanoes in the new global geologic map of Io," says Hamilton. "We found a systematic eastward offset between observed and predicted volcano locations that can't be reconciled with any existing solid body tidal heating models."

Possibilities to explain the offset include a faster than expected rotation for Io, an interior structure that permits magma to travel significant distances from where the most heating occurs to the points where it is able erupt on the surface, or a missing component in existing tidal heating models, like fluid tides from an underground magma ocean, according to the team.>>
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Anthony Barreiro » Mon Aug 05, 2013 7:55 pm

neufer wrote:
DavidGovett wrote:
Does anyone else see a semi-uniform distribution of volcanoes on Io?
The distribution does not seem random.
  • Why would you expect the volcano distribution to be random :?:
http://www.nasa.gov/topics/solarsystem/features/io-volcanoes-displaced.html wrote:
<<As Io gets closer to Jupiter, the giant planet's powerful gravity deforms the moon toward it and then, as Io moves farther away, the gravitational pull decreases and the moon relaxes. The flexing from gravity causes tidal heating -- in the same way that you can heat up a spot on a wire coat hanger by repeatedly bending it, the flexing creates friction in Io's interior, which generates the tremendous heat that powers the moon's extreme volcanism.

"Our analysis supports the prevailing view that most of the heat is generated in the asthenosphere, but we found that volcanic activity is located 30 to 60 degrees East from where we expect it to be," said Christopher Hamilton of the University of Maryland, College Park.

[...]

Possibilities to explain the offset include a faster than expected rotation for Io, an interior structure that permits magma to travel significant distances from where the most heating occurs to the points where it is able erupt on the surface, or a missing component in existing tidal heating models, like fluid tides from an underground magma ocean, according to the team.>>
The first of these possibilities, that Io's rotation is faster than currently believed, should be fairly easy to test. Does anybody know if the Juno probe will be able to take her eyes off Jupiter long enough to measure Io's rotation? If the Juno probe were carrying a smaller probe to send to Io's surface, would the smaller probe be called Asilus?
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Chris Peterson » Mon Aug 05, 2013 8:08 pm

Anthony Barreiro wrote:The first of these possibilities, that Io's rotation is faster than currently believed, should be fairly easy to test.
I think something got lost in translation in preparing the report you are referencing. The suggestion, as given, makes no sense. The rotational speed of Io is known with complete accuracy, because the moon is tidally locked to Jupiter. Its rotational period is exactly the same as its orbital period.

I don't know if they were referring to some sort of internal rotation of a fluid layer, or something to do with libration. But referring to the rotation of Io itself (as referenced to its surface) doesn't make sense.
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Anthony Barreiro » Mon Aug 05, 2013 8:57 pm

Chris Peterson wrote:
Anthony Barreiro wrote:The first of these possibilities, that Io's rotation is faster than currently believed, should be fairly easy to test.
I think something got lost in translation in preparing the report you are referencing. The suggestion, as given, makes no sense. The rotational speed of Io is known with complete accuracy, because the moon is tidally locked to Jupiter. Its rotational period is exactly the same as its orbital period.

I don't know if they were referring to some sort of internal rotation of a fluid layer, or something to do with libration. But referring to the rotation of Io itself (as referenced to its surface) doesn't make sense.
That makes sense, that it doesn't make sense. :)

I still hope that Juno will look at Io, if only for mythological reasons.
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EVERy little BRIZE seems to whisper Disease

Post by neufer » Mon Aug 05, 2013 9:38 pm

Anthony Barreiro wrote:
I still hope that Juno will look at Io, if only for mythological reasons.
-----------------------------------------------------
*BRIZE* - Juno's gadfly: Large as a sparrow with a sting the size of a dagger, BRIZE was sent by Hera/Juno to torment Io (transformed into a cow by Zeus, her lover, so that Hera couldn't find her, but to no avail). When Hermes rescued Io he killed BRIZE, too.
-------------------------------------------------------------
  • Antony and Cleopatra (Folio) Act 3, Scene 10
Scarus: On our side, like the Token'd Pestilence,
. Where death is sure. Yon ribaudred Nagge of Egypt,
. (Whom Leprosie o're-take) i'th' midst o'th' fight,
. When vantage like a payre of Twinnes appear'd
. Both as the same, or rather ours the elder;
. (The BREEZE vpon her) like a Cow in Inne,
. Hoists Sailes, and flyes.

-----------------------------------------------------
Click to play embedded YouTube video.
. Shakespeare p. 18 by Michael Wood.

<<Shakespeare would use 'BREEZE' in a memorable
image when describing the Egyptian queen's flight
from the battle of Actium in Antony & Cleopatra

The BREEZE upon her like a Cow in Iune,
Hoists Sail, and flies.


'BREEZE' here is an Anglo-Saxon word
that was still used in Midlands dialect in Tudor times.
It refers to the gadflies that, in summer, trouble cows.

That's the kind of knowledge you don't get
at Oxbridge, or in a rich man's house.
>>
----------------------------------------------------------
Perhaps, AESCHYLUS was a Warwickshire farmer, too:
-----------------------------------------------------------
_PROMETHEUS BOUND_ ( Trans. Anna Swanwick.)
http://www.monologuearchive.com/a/aeschylus_009.html

IO: Forthwith my shape and mind distorted were,
. And horned, as ye behold me, goaded on
. By GAD-FLY, keen of fang, with frenzied bounds
. I to Kerchneias' limpid current rush'd,
. And found of Lerna. Then the earth-born herdsman,
. Hot-tempered Argos, ever dogged my steps,
. Gazing upon me with his myriad eyes.
. But him a sudden and unlooked-for fate
. Did reave of life; but I, *BRIZE-tortured* , still
. Before the scorge divine am driven on
. From land to land; the past thou hearest; now
. If thou canst tell my future toils, say on,
. Nor, pity-moved, soothe me with LYING TALES,
. For GARBLED WORDS, I hold, are basest ills.

-----------------------------------------------------
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Chappy » Mon Aug 05, 2013 10:38 pm

The green patches on Io are intriguing, any info on what chemical process creates such hues of green?

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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Chris Peterson » Mon Aug 05, 2013 10:49 pm

Chappy wrote:The green patches on Io are intriguing, any info on what chemical process creates such hues of green?
This is a false-color image. It consists of frames collected through infrared, green, and violet filters, which are then mapped in some unspecified way to red, green, and blue display channels. You'd need to go back to the original data to try and estimate the actual color of what is being displayed here as green, and probably use the multichannel data in a clever way to deduce the possible mineralogical possibilities for the regions displayed as green.
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by BDanielMayfield » Mon Aug 05, 2013 11:27 pm

Chappy wrote:The green patches on Io are intriguing, any info on what chemical process creates such hues of green?
Chlorophyll? (See my first post in this thread.) :lol2:

However, there’s also this less prosaic, conventional reasoning:
Wikipedia wrote:Io's volcanism is responsible for many of the satellite's unique features. Its volcanic plumes and lava flows produce large surface changes and paint the surface in various shades of yellow, red, white, black, and green, largely due to allotropes and compounds of sulfur.
But I'm confident that Chris is also correct and the colors are not completely as our eyes would see this moon. I'm more used to seeing this object as yellow or even orange, so I was supprised by how green it was, which led me to my vegitative mussings.
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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Chappy » Tue Aug 06, 2013 2:38 am

BDanielMayfield wrote: Chlorophyll? (See my first post in this thread.) :lol2:
LOL...I was thinking the same thing :wink:
Chris Peterson wrote: This is a false-color image. It consists of frames collected through infrared, green, and violet filters, which are then mapped in some unspecified way to red, green, and blue display channels. You'd need to go back to the original data to try and estimate the actual color of what is being displayed here as green, and probably use the multichannel data in a clever way to deduce the possible mineralogical possibilities for the regions displayed as green.
I thought when they said "It has been enhanced to emphasize Io's surface brightness and color variations" that it meant they simply enhanced the original tint for better contrast. Still, an amazing Moon in all respects
Thanx Chris!

Dave

Roland

Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by Roland » Tue Aug 06, 2013 1:33 pm

It is possible that the location of the volcanoes is caused by buster impacts. a relatively thin crust would help account for the small number of more classical appearing impact craters.?!

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Re: APOD: Io's Surface: Under Construction (2013 Aug 04)

Post by neufer » Tue Aug 06, 2013 2:38 pm

Roland wrote:
It is possible that the location of the volcanoes is caused by buster impacts.

a relatively thin crust would help account for the small number of more classical appearing impact craters.?!
Volcanic activity is taking place on a much shorter time scale than meteor cratering.

Io has a much younger surface than even neighboring Europa:
http://en.wikipedia.org/wiki/Europa_%28moon%29 wrote: <<Europa is one of the smoothest objects in the Solar System. The prominent markings crisscrossing the moon seem to be mainly albedo features, which emphasize low topography. There are few craters on Europa because its surface is tectonically active and young. Europa's icy crust gives it an albedo (light reflectivity) of 0.64, one of the highest of all moons. This would seem to indicate a young and active surface; based on estimates of the frequency of cometary bombardment that Europa probably endures, the surface is about 20 to 180 million years old. There is currently no full scientific consensus among the sometimes contradictory explanations for the surface features of Europa.

Slightly smaller than Earth's Moon, Europa is primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. Its surface is composed of water ice and is one of the smoothest in the Solar System. This surface is striated by cracks and streaks, while cratering is relatively infrequent. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life. This hypothesis proposes that heat energy from tidal flexing causes the ocean to remain liquid and drives geological activity similar to plate tectonics. The radiation level at the surface of Europa is equivalent to a dose of about 5400mSv (540 rem) per day, an amount of radiation that would cause severe illness or death in human beings exposed for a single day.>>
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