Sara Seager Predicts First Earth Size ExoMoon Discovery in 2015

"Sunrise" on a hypothetical moon of the nearby habitable zone gas giant planet, Upsilon Andromedae d as modeled by me.

Earthlike moons are a big thing in sci-fi. From the green moon of Endor in Star Wars to the equally lush moon Pandora in Avatar, Earthlike moons orbiting gas giant planets in habitable zones or heated tidally may not simply be the stuff of science fiction.

When asked my New Scientist magazine to make a couple of predictions as to what 2015 may hold in terms of planetary science, exoplanet expert and recent Genius Grant recipient, Sara Seager feels one may be hiding in the Kepler or K2 data just waiting for discovery:

At work so ill tag this for later...
But it sounds nice...A sun, a huagass gasplanet
and a green florusiong moon...

Im definatly living in the wrong era....
If i could choose, id be born in 10-20years
from now...

Another wonderful OP JadeStar. I never really considered moons to be habitable for some reason (Yes i have seen the Star Wars movies but it never clicked) so I found this really interesting. It makes sense and even probable in our corner of the Galaxy and the possibility of finding one is very exciting.

Logically if such a gas giant could support one habitable moon could it not support several or even dozens? Imagine the diversity of life that could be in such close proximity to each other yet be so completely/genetically different. What a wonderful concept to ponder.


Boy you really know how to get what's left of my Grey Matter firing off at light speed. Keep up the great work and I always look forward to your contributions. In fact I've probably learnt more from your threads than the total of my formal education.

originally posted by: Kukri
Another wonderful OP JadeStar. I never really considered moons to be habitable for some reason (Yes i have seen the Star Wars movies but it never clicked) so I found this really interesting. It makes sense and even probable in our corner of the Galaxy and the possibility of finding one is very exciting.

It is! It's one of my favorite areas of study.

Logically if such a gas giant could support one habitable moon could it not support several or even dozens?

Several yes. Dozens might be a stretch. We must remember that there would have to be enough material to form large moons which could retain an atmosphere. How many of these large moons would form is down to how much material there was for them to form from.

If we look in our own solar system Jupiter has 4 large moons and dozens smaller ones which could not hold an atmosphere.

Also when we look at Jupiter's moons we find that three of them Europa and Ganymede and probably Callisto have subsurface oceans while IO doesn't.

A lot also would depend on the orbit of the moons. Some may be tidally heated more than others for instance. So a moon in around a gas giant in the habitable zone might be too hot if it were in an orbit where the gas giant plant substantially tidally heated the moon.

Imagine the diversity of life that could be in such close proximity to each other yet be so completely/genetically different. What a wonderful concept to ponder.

Indeed it is. It also would perhaps be the -most- likely scenario for panspermia since one good meteor strike could 'contaminate' all the other moons with life from the moon which was struck.

Boy you really know how to get what's left of my Grey Matter firing off at light speed. Keep up the great work and I always look forward to your contributions. In fact I've probably learnt more from your threads than the total of my formal education.

Thanks!

Here's another video I made of a simulation I did of the same hypothetical habitable moon of Upsilon Andromedae d. You'll see several day/night cycles and you'll notice a few things like during certain times the gas giant would eclipse the star Upsilon Andromedae leading to days with two nights. Also just before the first of these eclipses the shadow of the moon would be cast on the nearby habitable zone giant planet Upsilon Andromedae d. This planet is a prime target for a nearby exomoon hunt.

Also note that most of the night on the side of the moon facing the planet would be fairly brightly lit in a sort of twilight by reflected light from the planet. When night grew darkest, boom, the sun (Upsilon Andromedae) would rise.

One can only imagine the types of myths our ancestors might have come up with if the Earth were a moon orbiting a giant ringed planet like that!

BTW: You'll notice some familiar stars (the Pleiades) rising to the right on the gas giant Upsilon Andromedae d.



So how would we find one using Kepler?

This short video shows how they hope to detect one by analysing the same light curves that allow us to detect planets:



And if all this hasn't quenched your thirst for more exomoon stuff check out this talk at Harvard from David Kipping himself, it's about an hour long and is from the class ""Life as a Planetary Phenomenon" (SPU30):