Exomoon Detection Technique Could Greatly Expand Potential Habitable Systems

Luminary Crush (109477) writes Most of the detected exoplanets thus far have been gas giants which aren't great candidates for life as we know it. However, many of those planets are in fact in the star's habitable zone and could have moons with conditions more favorable. Until now, methods to detect the moons of such gas giants have been elusive, but researchers at the University of Texas, Arlington have discovered a way to detect the interaction of a moon's ionosphere with the parent gas giant from studies of Jupiter's moon Io. The search for 'Pandora' has begun.

Comments

We need telescopes

[NotInHere]

We need telescopes, on and around earth. lots of them. Kepler has only scanned a small region of the sky.

That's no exomoon...

[Anonymous Coward]

Sorry, just had to do it.

Re:That's no exomoon...

[Anonymous Coward]

It's an Exxon Mobil space station!

Intense radiation bands

[Anonymous Coward]

The intense radiation bands that likely surround any of these planets would quickly sterilize any moons down to a depth of hundreds of feet.

Re:Intense radiation bands

[Anonymous Coward]

Not only that, but the tidal effects of a gas giant would make the surface of the moon so unstable as to preclude anything more than bacterial life being able to survive.

Re:Intense radiation bands

[Luminary Crush]

From TFA:

Io’s ionosphere interacts with Jupiter’s magnetosphere, a layer of charged plasma that protects the planet from radiation, to create a frictional current that causes radio wave emissions.

Much like our magnetosphere on Earth protects us from radiation so too can that of a moon with an atmosphere and molten core. Mars doesn't have one and thus is hard-hit by solar radiation.

Your statement is accurate if you are talking about Earth's moon, but not correct in other cases.

Re:Intense radiation bands

[Luminary Crush]

Tidal effects are relative to the nearness of the orbit. Such a grandoise statement is not accurate.

We need faster-than-light travel

[mi]

We need telescopes, on and around earth. lots of them.

What for? We've already determined, a vast variety of planets exist — including those, which can be human-habitable. What good is known, that there is a billion rather than a mere million of them "nearby", if we can't get to even the nearest star anyway?

Re:We need faster-than-light travel

[Sowelu]

We need cloning bays, and extremely hardened ships. Don't send a person, send a blueprint and some way to raise and teach a first generation. We don't have to get there ourselves as long as our "children" can.

Re:We need faster-than-light travel

[ArcherB]

OK, so we build a ship that can take us anywhere in a reasonable amount of time. Then what? What's the point without a destination?

Right now, our technical ability allows us to detect planets that may be capable of harboring life. Why don't we go ahead and do what we can do rather than sulking over the fact that we can't do more? Once the day comes when we can actually go there, we'll do that. Until then, let's do what we can, which is detection.

Re:We need faster-than-light travel

[tysonedwards]

It's also worth noting that even ignoring the hard radiation concerns, we as a species have had a really hard time simply leaving our Solar System, let alone considering the undertaking that would be involved with reaching a planet in another System, with living, breathing humans! The emphasis on putting more Kepler class satellites in orbit before we're willing to as a species commit to designing a launch vehicle that would allow us to return a human to the surface of the Moon, let alone commit to long term habitation there, then there isn't much point considering the billions of dollars of effort required today on the intellectual jerk-off session of "are there 4,781 habitable exoplanets or 3,781,574 habitable exoplanets *AND* exomoons?" Getting us as a species back to the moon, let alone another planet in our Solar System is a requirement before we consider the several orders of magnitude differences in engineering effort, understanding, skill and expertise of getting a person to another star system. And once we start to tackle those sorts of problems, the problems like getting a more complete view of the night sky, or better satellites with more up-to-date satellites solves itself.

Re:We need faster-than-light travel

[mi]

Then what? What's the point without a destination?

The point of my posting was that we already have — using the old imperfect methods — compiled a list of destinations. We can continue looking for them, but studding the entire globe with uber-telescopes, as NotingHere insisted, seems pointless until we can (or, at least, come close to being able to) reach any of them in reasonable time.

Re:We need faster-than-light travel

[Anonymous Coward]

But *I* want to go you insensitve clod!

Re:We need faster-than-light travel

[NotInHere]

We don't know which of them is the closest one, or has an atmosphere that can be terraformed easily. Even if we had FTL travel or at least > .1c capable ships, we probably wanted to choose the most suitable candidate before investing trillions of dollars.

Re:We need faster-than-light travel

[mi]

And until we figure out, how to travel with even the .1c speed, we don't even need to know, which one can be terraformed — easily or otherwise. Sure, the pursuit of abstract knowledge is valuable in itself, but more than that is needed to justify extending the effort and the resources needed for "telescopes, on and around earth".

Heck, we haven't even colonized Antarctica yet — which can already be reached in a few hours and is known to have breathable air and plenty of water...

Re:We need faster-than-light travel

[Anonymous Coward]

Why does this borderline tripe always get modded up?

Re:We need faster-than-light travel

[Type44Q]

I see you read The Songs of Distant Earth. FYI, you probably don't want to consider that a how-to guide; we need to work on our FTL capabilities before we start expending our [oh-so-precious] resources trying to colonize the galaxy on a ten-million-year timetable. :)

Re:We need faster-than-light travel

[Anonymous Coward]

That turns out to be much, much harder than it sounds. Charlie Stross's Saturn's Children discusses the problem a bit. Humans need an entire ecosystem of plants, animals, and bacteria to survive. Even a single human has lots of bacteria living within them that are not in their DNA that are essential to their survival. There's also likely plenty of details of exactly what is passed from mother to child that we simply don't even know about yet. The DNA-as-blueprint analogy turns out to be vastly oversimplified.

Re:We need faster-than-light travel

[Intrepid imaginaut]

To be honest the best way for us to colonise the universe will be through space stations. We can control the gravity, the atmosphere, the environment completely, and the raw materials are just floating around in insane abundance. Socially it's not even that much different to the way most people live today anyway, with most of their lives spent in urban environments commuting from home to work or class and back again, peppered with occasional vacations to other habitats or planetside.

No need to plot centuries-long pilgrimages strapped to the top of an antimatter skyscraper for a while yet. The first step is to build great city states in the sky.

Re:We need faster-than-light travel

[Anonymous Coward]

Two Words: Event Horizon. We don't need candidates where we are going..

Re:We need faster-than-light travel

[luis_a_espinal]

We need telescopes, on and around earth. lots of them.

What for? We've already determined, a vast variety of planets exist — including those, which can be human-habitable. What good is known, that there is a billion rather than a mere million of them "nearby", if we can't get to even the nearest star anyway?

Before we spend resources trying to build FTL tech, don't we want to know a bit more in detail what is out there using relatively cheaper tech (telescopes and probes)? In fact, I don't see how these two are mutually exclusive. Doing both, or the cheaper first is good, sound science.

Re:We need faster-than-light travel

[luis_a_espinal]

I see you read The Songs of Distant Earth. FYI, you probably don't want to consider that a how-to guide; we need to work on our FTL capabilities before we start expending our [oh-so-precious] resources trying to colonize the galaxy on a ten-million-year timetable. :)

And we need to scout what is out there with telescopes and probes before/while we work on our FTL capabilities.

Re: We need faster-than-light travel

[caveqat101]

Boy, have we unlearned history. How about tang? Like it? We have been outside of earth, and business wants some reason to go back. Mining the asteroids anyone, low orbit hotels maybe next year for the uberfolks. We keep revisiting the same argument from the 60's, it costs too damn much to send humans to space. But to expand a robots knowledge to some experimental bad designed place with limited programmed powers is okay, then to design another experiment many further years in the future done by a select few, I think you get the point. And we don't learn a thing, and argue over the results of poorly designed questions...

Re:We need faster-than-light travel

[ultranova]

Don't send a person, send a blueprint and some way to raise and teach a first generation. We don't have to get there ourselves as long as our "children" can.

And that "some way" would be?...

In all likelihood it would take a fully sapient AI with a humanlike body puppet to raise a human being. At that point, what would be the point? Just accept these sapient spaceships are as good as our "children" as meatbags would be. And of course, since we're talking about sci-fi tropes here, there's always brain uploading.

Also, you're not considering the moral implications of sending a bunch of babies to live or die in an alien planet, in what are likely to be extremely limiting and harsh conditions. Whether you personally care for such things or not, a society that can simply ignore them is unlikely to send anyone anywhere, for the simple reason that this entire project requires a lot of people putting other objectives before their personal interests for a long period of time.

Re:We need faster-than-light travel

[ultranova]

We can continue looking for them, but studding the entire globe with uber-telescopes, as NotingHere insisted, seems pointless until we can (or, at least, come close to being able to) reach any of them in reasonable time.

Putting telescopes in orbit is a good way of pumping money to the emerging spaceflight industry.

Re: We need faster-than-light travel

[tysonedwards]

We completely agree on the subject that robotic exploration is extremely important and can be done in a far more effective fashion than human exploration at this time. However at a certain point we also need to accept that prior to reaching out to targets beyond our star system (let alone specifically for inhabitable worlds that we as a species could one day hope to colonize!) we should also consider looking at some of our celestial neighbors. Very comprehensive studies can be conducted on our own Solar System and places that can be exploited within our lifetimes in comparison to the ice age that it would take to travel the 40,680,272,100,000 km (4.3 light years) to get to the nearest star, which *may* house a planet 0.04 AU from it's star with a surface temperature of 1200 C, but more likely we'd need to venture the leap ice age or two to reach the 144,651,479,000,000 km (15.29 light years) bringing us to the closest known planet. Even if we could somehow find some way, somehow of accelerating to just 1% the speed of light and let robot probes explore and relay back the data, we're still talking about 153 years to reach there. And the level of effort to accomplish that engineering feet is frankly well beyond us as a species considering the "success rate" that we have at having probes successfully reach other planets in our Solar System. We need to take smaller steps. Goals are great, I love goals, I love lofty goals in fact, but there needs to be specific actionable steps to be able to execute upon those goals and at present there haven't been any. Just layers upon layers of political spin.

Re:We need faster-than-light travel

[mi]

In fact, I don't see how these two are mutually exclusive.

They are not mutually exclusive, but undertakings as substantial as building a network of telescopes would certainly be, will always be at the expense of something else. And there are plenty of those "somethings", that should have a higher priority, in my not so humble opinion.

Doing both, or the cheaper first is good, sound science.

No. Because the two fields — hunting for exo-planets and developing the theory of very fast space-travel — are not much related, there is no synergy in doing both at once. Various scientists may choose to pursue either (or both) as they please, but no coordinated effort needs to be extended to further increase the list of destinations before we even know, we'll ever be able to reach any of them.

Re:We need faster-than-light travel

[flyingsquid]

We need cloning bays, and extremely hardened ships. Don't send a person, send a blueprint and some way to raise and teach a first generation. We don't have to get there ourselves as long as our "children" can.

Minor detail- who's going to raise the children in this sci-fi scenario? You're going to have a whole generation of children brought along as frozen embryos, brought to term in artificial womb tanks, then fed and cared for as infants by robots, raised by robots, taught language by robots, getting the "where do babies come from" talk delivered by robots (in this case, they get a really freaky explanation), going through a rebellious teen phase ("What are you talking about? I do not dress like a little slut! All the cool girls dress like this! God! You're so lame! I just want to hang out with my friends at the supply depot! You never let me do anything fun! I hate you Matriarch-371B! You're a terrible parental simulacrum!")... most humans do a terrible job at this, do you really think an AI could handle this kind of stuff? Any AI capable of raising an infant to an adult and doing a good job would find interstellar exploration trivial by comparison.

Re:We need faster-than-light travel

[Vitriol Angst]

That's a really bad idea.

You start sending out clones to live on other planets, and what happens 200 years later when they come back and try and blow up our planet?
"You suck dad! Fricken' planet never had a dry day, there's no beach, and our Froyo' cloning vat broke down so we can't grow any hot chicks."

Re:We need faster-than-light travel

[Vitriol Angst]

We should definitely tag our comments with;
SOLUTION FOR: "Optimist, Realist, Progressive, Libertarian, Tee-Hugger, Authoritarian, Goth, Unmitigated-As$hole"

Re:We need faster-than-light travel

[Anonymous Coward]

Why do you need a destination? Space is large.

Who Cares?

[Anonymous Coward]

I have been following these discoveries with great interest, being a bit of an amateur astronomer myself. But once we get beyond the point of 'hey, there really are other planets out there...' it becomes more or less useless until we have a way of going there. And not a generation ship...

Re: Who Cares?

[joh]

Why is it so important to go there? When we find a planet or a moon with habitable conditions and signs of life (like free oxygen in the atmosphere) there's a LOT to study, just spend enough money on space-based telescopes. And at some point we may be curious enough then to put real effort into going there.

That point is that we will NEVER do that without a destination. Finding one is the first step and even without going it's worthwhile.

Re:Who Cares?

[Anonymous Coward]

Radical life extension therapies will hit the market over the coming 50 years. In 200 years, space travel will be cheap. The warp drive would be great to have, but you can still go and you don't even need to be frozen to do it.

Re:Who Cares?

[HiThere]

Why not a generation ship? We are probably on 50-60 years from being able to build a generation ship, if we can handle the sociology. Perhaps up to a century. It's not clear that we'll *EVER* be able to do it in any other way.

If you're in a hurry, you were already born too soon.

Re:Who Cares?

[Anonymous Coward]

I would prefer a TARDIS myself..

Re:Who Cares?

[Anonymous Coward]

Mostly because if you can build generation ships you render planets obsolete. And no we're nowhere near being able to build one.

habitable moons are the way to go

[Anonymous Coward]

That's a significant aid in finding habitable worlds. There are probably more habitable moons around those gas giants than all the other kinds of planets put together.
A gas giant in the habitable zone of a red dwarf system can protect its moons from the star's solar wind making them great places for life to develop.

Re:habitable moons are the way to go

[ShanghaiBill]

Indeed. In our solar system, liquid water is known, or believed, to exist in four places: Earth, Europa, Ganymede, and Callisto. 75% of those are moons.

Reasonably, how long would a solar eclipse last?

[mark-t]

I can easily envisiion a situation where an entire moon is plunged into shadow as it orbits a gas giant. This would, I presume, cause temperatures to fall for the duration of the eclipse, and if it lasted too long, I can imagine that such a regular occurrence would likely make the moon inhospitable to life as we know it, even if it is the right distance from the sun to support liquid water, and even if it had an appropriate gravitational pull and atmosphere.

Base on the moon

[Anonymous Coward]

Put a permanent base on the moon first.

Re:Base on the moon

[Anonymous Coward]

I'm trying, but as my video card just quit (or my mainboard's slots stopped working, I'm not sure which) my Kerbal's Munbase is just a dream for the time being.

Re:Reasonably, how long would a solar eclipse last

[pushing-robot]

Probably between one and several hours. Half the moon might have an extra long night every month, but the planet would retain enough heat that it shouldn't threaten the biosphere.

Well, except for the hordes of flying monsters thirsty for blood that emerge every eclipse...

Reasonably, how long would a solar eclipse last?

[Anonymous Coward]

The eclipse wouldn't last for more than a few hours. That is to say, too short a time for drastic temperature changes to take place, at least under an atmosphere of any reasonable thickness. Here on Earth we are eclipsed by the Earth itself for a few hours every day, and while temperatures do drop during that time (commonly known as 'night'), ecosystems are perfectly capable of handling it.

Wouldn't vivacious moons inoculate the gas giants?

[Anonymous Coward]

If a moon can develop life then it stands to reason that an impact event on the moon could result in life travelling into the upper atmosphere of the gas giant where it may survive even if it could not have evolved there and if it could survive it could then evolve to utilise as much of the giant as possible while altering the composition of the giant's atmosphere in a way that could be detected.

But is anyone looking for that sort of signature yet?

d@3-e.net

Re:Reasonably, how long would a solar eclipse last

[mark-t]

I imagined the eclipse lasting several days each revolution... it would be orbiting a gas-giant, which is substantially larger than the moon itself, and close enough to the gas giant that it may possibly even tidally locked to it.

Rampaging across the galaxy

[Anonymous Coward]

OK, so we build a ship that can take us anywhere in a reasonable amount of time. Then what? What's the point without a destination?

Cross your fingers that we'll find good destinations before long.

This planet's biosphere is dying. We'll soon need another one to begin killing off.

Lies

[TrollstonButterbeans]

" There are probably more habitable moons around those gas giants than all the other kinds of planets put together."

Gas giants have massive radiation belts caused by their magnetosphere. Moons around a gas giant can't have life as we know it. Even going anywhere near Jupiter's space would expose an astronaut to an intense dose of radiation.

Quote: "If astronauts were able to approach the planet as close as the Voyager 1 spacecraft did, they would receive a dose of 400,000 rads, or roughly 1,000 times the lethal dose for humans." https://solarsystem.nasa.gov/s...

Re:Lies

[Gavagai80]

Nobody said you have to go to an inner moon. Radiation levels on Titan, for example, are fine.

Re:Lies

[tragedy]

Europa is probably a non-starter due to the high radiation, but Callisto gets two orders of magnitude less and Ganymede about three orders of magnitude less than that.

Re:Lies

[Anonymous Coward]

Too bad about the rest of the conditions. But yeah, "fine".

Are you a Space Nutter?

Moon?

[Anonymous Coward]

Why isn't our moon so habitable ... it is in the almost right distance ... everything right... except no life?

Re:Moon?

[Anonymous Coward]

Most importantly, because of the lack of sufficient gravity to hold an atmosphere. If the moon orbiting the gas giant has sufficient mass to have enough gravity to hold an atmosphere, then that wouldn't apply.

Re:Reasonably, how long would a solar eclipse last

[Anonymous Coward]

I was wondering why everything on Pandora in Avatar glows in the dark. It's for the long periods of darkness when Pandora is behind it's planet for a week or more at a time and there is no sunlight.

I wonder: How about detecting planets?

[Ungrounded Lightning]

This mechanism makes me wonder whether another mechanism, involving the solar wind / magnetic field and a planetary magnetic field or ionosphere, might also produce a detectable radio signature.

Re:Reasonably, how long would a solar eclipse last

[Gavagai80]

I hear there's a planet called Earth that has 12 hours of darkness every day at the equator, and months of it at the poles! Clearly uninhabitable.

Re:Reasonably, how long would a solar eclipse last

[mark-t]

In both of those situations, only *part* of the planet is in darkness for that period... what if the entire planet was?

Re:Reasonably, how long would a solar eclipse last

[Gavagai80]

If you completely turned off the sun, http://www.popsci.com/node/117... says it'd take a week for the temperature to hit 0 F, a temperature at which Canadians survive.

Re:Reasonably, how long would a solar eclipse last

[Neil Boekend]

In our winters most plants do not need sunlight at all. They hibernate. Why wouldn't an alien plant be able to do such a thing?
Creatures do not really need sunlight all that much. Only to see and there are other solutions for that (IR sensors, sound or electric signals for example).
It'll get cold. True. But not 0K cold. The freezing of stuff gives off warmth, temporarily pausing the dropping of the temperature.

Al in all it doesn't have to be so different from our planet, assuming the average temp is similar and the radiation belt of a massive planet doesn't fry anything that tries to live and a million other things aren't all that different.

Re:Reasonably, how long would a solar eclipse last

[Anonymous Coward]

Orbital mechanics makes long eclipses unlikely. If the moon is very close to the planet, such that a significant fraction of its orbit is in the shadow, it'll orbit so fast, the eclipse will last hours, not days at best. If it is further out, on one hand its orbital plane must be perfectly aligned to spend any time at all in the shadow, and on the other hand, the fraction of the entire orbit spent in the shadow should be insignificant.

Re:Reasonably, how long would a solar eclipse last

[Anonymous Coward]

Maybe life there only comes out at night, and to survive such an eclipse one would need an escaped ex-convict who has surgically altered his eyes to be able to see in the dark on your side.. I see where this is going.. Stay in the light!

Re:Wouldn't vivacious moons inoculate the gas gian

[Anonymous Coward]

Someone has read "The Cassini Division" by Ken McCloud. Good book! It was human beings who had used nanotechnology to become sentient swarms of nanites. Not exactly life.. as we know it captain, but similar to what you are talking about.

Re:Reasonably, how long would a solar eclipse last

[ultranova]

You do realize this scenario happens beyond the Arctic and Antarctic circles on Earth every winter, right? Both of which have life.

Re:Reasonably, how long would a solar eclipse last

[mark-t]

Thank you... that's exactly the sort of statistics I was wondering about. So it's survivable, but probably regularly quite chilly. Basically, you'd get short period of winter like weather at least once every orbit, regardless of the actual season based on its orientation to the sun.

Re:Reasonably, how long would a solar eclipse last

[mark-t]

And you realize that the arctic and antarctic circles do not account individually account for a very large percentage of the earth's surface that continues to receive sunlight while they are in darkness, right? The planet, as a whole, still receives heat from the sun.

Pandora

[roc97007]

> The search for 'Pandora' has begun.

Well done. As long as I don't have to sit through the movie again...