View Full Version : Detecting Tidally heated ExoMoons

2012-Oct-15, 08:24 PM
Now, scientists are coming to believe that what happens in our solar system may be happening all over the galaxy. A new study just submitted for publication by a pair of astrophysicists at Princeton University suggests that as investigators discover more and more exoplanets — worlds orbiting other stars — they might also discover tidally heated exomoons. This not only dramatically expands the scope of exoplanet research, it also represents a big step forward toward the field’s ultimate goal: finding worlds like our own — mirror Earths — that just might be home to life.

Read more (http://science.time.com/2012/10/15/never-mind-life-on-distant-planets-what-about-distant-moons/#ixzz29OwMXhtO)...

2012-Oct-15, 08:57 PM
Whilst new detection capabilities may lead to an expansion of our knowledge about the diversity of our galactic environment, how exactly does that necessarily imply that they might also be home to life?

Why wouldn't knowledge of such diversity, also be said to equally lead in the opposite direction?

2012-Oct-15, 09:35 PM
The interesting thing to me is that this heating mechanism does not require a host star at all. Microlensing studies indicate that gas giant sized rogue planets are about as common as gas giant sized planets with host stars. But with rogue planets, a warm tide heated exomoon wouldn't compete with the glare of a host star at all!

Perhaps WISE has already detected a warm exomoon, in orbit around a rogue planet?

2012-Oct-15, 10:19 PM
A little reminder: please make sure you indicate clearly what is quoted text from a source, just a link to show that it came from somewhere isn't enough.


2012-Nov-12, 05:40 AM
How stable a mechanism is tidal heating? The energy source that produces the heat is the kinetic energy of the bodies' rotation and revolution and the gravitational potential energy. It's not an infinite source, nor a perpetual motion machine, and I don't see how the mechanism could produce a more or less steady flow of energy for hundreds of millions or billions of years.

Of course, we have empirical evidence in the moons of Jupiter and Saturn, but I've not seen anything about the stability of presumed oceans under the ice. Maybe the sub-surface oceans of rogue planets would be very stable, not being subject to impacts and star activity. It's a set of interesting speculations.

2012-Nov-12, 11:23 PM
I've read a few papers on tide heating of planets or moons. It seems to be a very smooth source of energy, and can provide relatively steady heating for billions of years. The exact curve depends on the situation, but IIRC it rises up to a hump relatively quickly, levels off, and then gradually declinces as the planet/moon gently circularizes.

I'd have to hunt around to find specific references.