Researchers have identified 121 giant planets that may have habitable moons

May 31, 2018 by Sarah Nightingale, University of California - Riverside
An artist’s illustration of a potentially habitable exomoon orbiting a giant planet in a distant solar system. Credit: NASA GSFC: JAY FRIEDLANDER AND BRITT GRISWOLD

We've all heard about the search for life on other planets, but what about looking on other moons?

In a paper forthcoming in The Astrophysical Journal, researchers at the University of California, Riverside and the University of Southern Queensland have identified more than 100 giant that potentially host moons capable of supporting life. Their work will guide the design of future telescopes that can detect these potential moons and look for tell-tale signs of life, called biosignatures, in their atmospheres.

Since the 2009 launch of NASA's Kepler telescope, scientists have identified thousands of planets outside our solar system, which are called exoplanets. A primary goal of the Kepler mission is to identify planets that are in the of their stars, meaning it's neither too hot nor too cold for liquid water—and potentially life—to exist.

Terrestrial (rocky) planets are prime targets in the quest to find life because some of them might be geologically and atmospherically similar to Earth. Another place to look is the many gas giants identified during the Kepler mission. While not a candidate for life themselves, Jupiter-like planets in the habitable zone may harbor rocky moons, called exomoons, that could sustain life.

"There are currently 175 known moons orbiting the eight planets in our solar system. While most of these moons orbit Saturn and Jupiter, which are outside the Sun's habitable zone, that may not be the case in other solar systems," said Stephen Kane, an associate professor of planetary astrophysics and a member of the UCR's Alternative Earths Astrobiology Center. "Including rocky exomoons in our search for life in space will greatly expand the places we can look."

The researchers identified 121 giant planets that have orbits within the habitable zones of their stars. At more than three times the radii of the Earth, these gaseous planets are less common than terrestrial planets, but each is expected to host several large moons.

Scientists have speculated that exomoons might provide a favorable environment for life, perhaps even better than Earth. That's because they receive energy not only from their star, but also from radiation reflected from their planet. Until now, no exomoons have been confirmed.

"Now that we have created a database of the known in the habitable zone of their star, observations of the best candidates for hosting potential exomoons will be made to help refine the expected exomoon properties. Our follow-up studies will help inform future telescope design so that we can detect these moons, study their properties, and look for signs of ," said Michelle Hill, an undergraduate student at the University of Southern Queensland who is working with Kane and will join UCR's graduate program in the fall.

The title of the paper is "Exploring Kepler Giant Planets in the Habitable Zone." In addition to Hill, who is the is lead author, and Kane, other contributors are: Eduardo Seperuelo Duarte from Instituto Federal do Rio de Janeiro in Brazil; Ravi K. Kopparapu from the NASA Goddard Flight Center in Maryland; Dawn M. Gelino from the NASA Exoplanet Science Institute at Caltech; and Robert A. Wittenmyer from University of Southern Queensland.

Explore further: Hunting for hidden life on worlds orbiting old, red stars

More information: Exploring Kepler Giant Planets in the Habitable Zone, arXiv:1805.03370 [astro-ph.EP] arxiv.org/abs/1805.03370

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Bill66
3.3 / 5 (3) May 31, 2018
Could explain Fermi's paradox. "Don't bother with that one, Zork. The gas giants are too far out for the moons to be habitable."
rrwillsj
1 / 5 (2) May 31, 2018
I suppose? We need to be careful not to get ahead of the evidence. Our own system's goldilock's zone has four planets. Venus is too hot. Mars is too cold. Luna is too small. Only the Earth is just right!

A Jupiter type gas giant with a stable orbit at one a.u. from a stable star? A moon in a stable orbit, might turn out to be a Living World?

Confirming that data to general acceptance by the scientific community, will be a bitch!

The clickbait headline writers & woo charlatans will be riling up the gullible with lurid claims & merchandise to sell.

The biggest problem is visible in Jupiter's own system of satellites. Jupiter is very energetic & only Callisto is outside the powerful radiation belts. As we can see, the Mar's size moon has only the thinnest of atmosphere and no visible water. Perhaps because of the distance from our Sun?

At an a.u. from it's sun? The gas giant will be energized by proximity to it's sun. Flooding it's moons with radiation.
TrollBane
5 / 5 (1) May 31, 2018
rr, you cherry-pick the case of Jupiter and its powerful radiation, but ignore the possibility of more quiescent giant planets like Saturn, Uranus and Neptune, which are large enough to possess both large and numerous satellites.
rrwillsj
1 / 5 (2) Jun 01, 2018
Okay TB I can see your point. However the article first mentioned Jupiter-like gas giants, then included Saturn. If the Father of the Olympians is so quiescent? Why all the debris orbiting it?

It is not relevant what the gas giants in our solar system are doing. The issue is how any of their facsimiles would react to the energies received from their primary star while orbiting at an approximate radius of one a. u. +/-?

Won't hurt my feelings if anyone eventually proves me wrong with confirmed and verified evidence for any of the observed systems.

Though I suspect that other factors would prove that it is an outlier. Some reason for such a lucky oddball. Just as the Earth is.
antialias_physorg
4 / 5 (4) Jun 01, 2018
Our own system's goldilock's zone has four planets.

The idea of goldilock's zones is bunk (and science is increasingly coming around to that view)
https://phys.org/...lem.html

The prerequisite for liquid water (which in itself is a questionable exclusive sine-qua-non) doesn't require closeness to a star. It requires enough energy within a given volume. That energy can come from any source, be it a star, radioactive elements, tidal heating, ... you name it.

The idea that life can only arise on the surface is also dubious at best. We've found life miles down mineshafts that feeds on radiation, and who's to say that that wasn't the first life that then migrated up (and if not here, then that may very well have happened elsewhere)? Life underground eliminates all limitations due to external radiation felds (like around Jupiter or close to a star)
rrwillsj
1 / 5 (2) Jun 02, 2018
q_p good points but not the whole picture. The extremophiles of Earth are slime. Surviving in environments precluding more complex organisms. Including the Hadal Zone. Where the hydothermal vents nourish colonies of extremophile micro-organisms. That in turn are fed on, second-hand, by a variety of more advanced sea creatures.

As for the possibility of life on ice covered moons such as Enceladus? Observers remark on how clean the surface ice is. Those geysers would be spewing crap all over that shiny orb if there was any exolife down underneath the ice.

It is my opinion we will discover that those oceans are sterile. At least until we get there to contaminate it with cigarette butts and candy-wrappers.

I wouldn't mind being proven wrong. But you are going to have to bring some mighty rigorous proofs to the table to satisfy me. Announcements and pronouncements won't cut it! Being able to falsify data to justify speculative claims, is a scientific aphorism.
TheGhostofOtto1923
5 / 5 (1) Jun 02, 2018
observers remark on how clean the surface is
So at 10 meters per pixel just what kind of schmutz do you think 'observers' would be expecting to see? 800ft tall glassy-headed alien bodies strewn about?
In my opinion
You keep on demonstrating that your opinion is garbage. But the act of opinionating is all that concerns the garden variety of psychopath isnt it?
antialias_physorg
1 / 5 (1) Jun 03, 2018
Those geysers would be spewing crap all over that shiny orb if there was any exolife down underneath the ice

I don't think it's a given that any species is as heedless of their environment as us. While I don't think we'll see any kind of advanced life on Enceladus this is another one of those things I'm not on board with when looking for extraterrestrial civilizations by their atmospheric signatures. I think advanced civilizations will not have any such signatures (or even anything in the way of structures - much less megastructures)

Whether we'll find life on Enceladus I don't know (neither does anyone else). Though I think we should take a look ASAP.
rrwillsj
1 / 5 (2) Jun 03, 2018
Wow! Okay You guys actually expect archean-type exo-slime to obey your expectations?

And PUHLEEZE! Let us NOT rush into a possibly alien environment we do not understand. Make some sort of effort to avoid damaging what we discover. Into a situation where we have not prepared a way to escape from without having to retreat in a stampeding panic!

Unless a previously unobserved rogue moonlet suddenly appears to smash into Enceladus? It ain't going nowhere. And will still be there when we have collected a lot more information about it and prepared ourselves accordingly.

For a major series of planned expeditions? We need Callisto to base automated facilities and supply depots for any serious effort to explore the Outer System.

We are talking entire planets and planetoids here, boys and girls. And we need to be methodical and economic in how we go about it.

One or two "shoot-the-moon" publicity stunt manned voyages will afterwards be considered expensive disappointments.
TheGhostofOtto1923
5 / 5 (1) Jun 03, 2018
Wow! Okay You guys actually expect archean-type exo-slime to obey your expectations?
Well YOU seem to be expecting them to be leaving huge turd piles on the surface. Why IS that willis?

And just who are the 'Observers' who 'remark on how clean the surface ice is' -? Got a ref to support that particular pattie?
TheGhostofOtto1923
5 / 5 (1) Jun 03, 2018
But you are going to have to bring some mighty rigorous proofs to the table to satisfy me
-Not because you are an uncommon skeptic but because you are just a big eater as I suspect. Besides you don't seem to feel obligated to supply the same sort of rigorous proofs for the bullshit you make up.

I cry foul.
savvys84
not rated yet Jun 04, 2018
Only time will tell if there is really life out there
rrwillsj
1.5 / 5 (2) Jun 04, 2018
Yes oddo, you are pretty foul with your constant crying of-poor-little-me. One could feel sorry for you but you are such a creepy little stalker. Perhaps you should take up the moniker of 'Gimli" online? Since you imbue the personality.

https://en.wikipe...nceladus

TheGhostofOtto1923
3 / 5 (2) Jun 05, 2018
Your link contains nothing about clean surfaces willis. Perhaps your corroberation is here
https://en.wikipe...disorder
antialias_physorg
1 / 5 (1) Jun 05, 2018
Yes oddo, you are pretty foul with your constant crying of-poor-little-me. One could feel sorry for you but you are such a creepy little stalker.

Just put him on ignore. He tries to latch on to one after another poster here trying to brown-nose and get some sort of validation for his craziness. It's always the same story (and has been through the past umpteen incarnations of his nick for the past umpteen years). Just google around for his past nicks on physorg (variations on the Otto theme)
rrwillsj
2.3 / 5 (3) Jun 05, 2018
a_p, undoubtedly good advice however I enjoy sadistically mistreating the pathetic masochist.

otto, beg your nurse to find where you, for the umpteenth time, left your glasses.

https://en.wikipe...nceladus
first paragraph ".... Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. ...."

TheGhostofOtto1923
3 / 5 (2) Jun 05, 2018
Just put him on ignore. He tries to latch on to one after another poster here trying to brown-nose and get some sort of validation for his craziness
Yeah, and aa likes to tolerate liars and fact-fabricators who nevertheless agree with his/her twisted POVs, which often have little to do with truth or facts.

Which of the 2 of us has the proper respect for science and for the integrity of this site?
undoubtedly good advice however I enjoy sadistically mistreating the pathetic masochist
Man. You do sound exactly like the other resident psychopath on this site.

You sure youre not the same slimy troll?
TheGhostofOtto1923
3 / 5 (2) Jun 05, 2018
".... Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. ...."
-and so what does that have to do with your claim that
Observers remark on how clean the surface ice is. Those geysers would be spewing crap all over that shiny orb if there was any exolife down underneath the ice
-???

BTW poor aa could never win any arguments with otto because facts always does trump opinion, which obviously annoyed the hell out of him/her... so sad.

Eurodisney is mostly fiberglas you know? Easier to remove gum und Hochwerfenstoff.

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