Starship Asterisk*

Curious about today's APOD. Is the infrared Heat indicated in the image a product of solar heating or is it a naturally occuring phenomonon of Saturn?

The image of the dark side almost resembles a Brown Dwarf

http://antwrp.gsfc.nasa.gov/apod/ap070627.html

In the first line of the explanation, there is a link with the words "composite image".

Here are two quotes from that link.

On the night side (right side of image), with no sunlight, Saturn's own thermal radiation lights things up.

At 5.1 microns (shown in red), reflected sunlight is weak and thus light from the planet is dominated by thermal (i.e., heat) radiation that wells up from the planet's deep atmosphere.

BMAONE23 wrote:or is it a naturally occuring phenomonon of Saturn?

Essentially, everything on planets besides nuclear (and perhaps certain chemical) reactions is a product of solar heating.

makc wrote:Essentially, everything on planets besides nuclear (and perhaps certain chemical) reactions is a product of solar heating.

I expect the source of Saturn's radiation is gravitational.

tidal forces from satellites?

I think actually just residual heat of accretion from Saturn's formation. Saturn and Jupiter both are surprisingly strong emitter's of infrared, and if I remember right, this was pegged as the cause.

If it is Exothermic Heating, I would think this could be proven through examination of relative temperature differences remaining stable. The mean temperature of the night side should gradually decrease as the night side extends back toward the day side.
If it is artifact from formation then there should be a gradual cooling from prior years/decades observation.
If it is Endothermic Heating, It should remain indestinguishablly constant since the first recorded observation. (That is unless there is still a gradual cooling process underway)

At the risk of exposing my ignorance, let me ask a question.

I was impressed by the extraordinary detail in the dark side infrared image. If the heating is endothermic, wouldn't there be more uniformity in IR radiation? I am assuming that endothermic heating would originate from the core of the planet.

maybe. Unless the clouds got in the way. I know our clouds and jet stream move the hot areas of the troposphere around. its not uniform by any means. Maybe the other layers of the atmosphere are. There is probably some wondrous mixing going on.

If you look closely at the polar region at the top of the image, you can see the hexagonal shape evident in the infrared signature also.