Help find an alien moon

By Phil Plait | March 10, 2012 7:00 am

David Kipping is an astronomer at the Harvard-Smithsonian Center for Astrophysics, one of the most prestigious astronomical research institutions on Earth. He studies exoplanets: planets orbiting other stars. Specifically, he’s interested if they have moons. Why? Because big, massive planets are the easiest to find, but even if they orbit their parent star at the right distance to have liquid water, they’re too big to harbor life as we know it. But it’s possible some of these giants might have moons that could! After all, both Saturn and Jupiter have moons we know are made of water (mostly ice, but also some have liquid water).

The problem is detecting them. It’s a difficult, complicated problem given the data we have, but Dr. Kipping thinks he may have a way to tease them out of the observations. The problem is simply computational time, and that means a fast, dedicated computer. Getting funds for that is hard, so he’s set up a campaign to raise money on petridish.org — which is like KickStarter but for science — called Help Us Find the First Exomoon. He’s hoping to raise $10,000 to get the computer he needs.

Here’s his pitch:

Not bad. This is a worthy project, and one I think is very cool as well. I know some folks who study exoplanets, and they’re very excited about looking for moons. It pushes our technology to the limit, but it certainly can be done. And you can help make it happen!

And I have to chuckle; he used images by my friend Dan Durda, whose artwork has graced my blog many times (the painting at the top is one of Dan’s) and some time lapse footage from TimeScapes, which I’ve featured here before as well. Small world. Or worlds.

Tip o’ the Doppler wobble to geologist Matthias M. M. Meier.

CATEGORIZED UNDER: Astronomy, Cool stuff, Science

Comments (31)

  1. andy

    Taking a look at the Kepler candidates list and running them through various models of the habitable zone, it seems that there are already several potential transiting habitable zone gas giants in the list which may be good targets for an exomoon survey.

  2. SLC

    Bad analogy to Jupiter and Saturn. Jupiter and Saturn arenot themselves in the habitable zone of the Sun. However, Jupiter’s moon Europa may be habitable because the gravitational field of the former sets up frictional forces in the latter that warm it sufficiently to produce a liquid water ocean under the thick layer of ice the covers it. Thus I fail to see why the search should be limited to giant gas planets that are themselves in the habitable zone of the stars around which they revolve.

  3. L Ron Hubbub

    We could call the first one Pandora.

  4. Satan Claws

    Since in the 2-minute clip Kipping claims the bottleneck is computational power, would it be feasible to design the hard part of the work to be done by smaller worker units to be deployed under the BOINC platform? That way, people could volunteer their personal computers’ spare computing cycles to such a program.

  5. Mike

    Sounds like a cool project, but it makes me slightly suspicious that he is directly begging the general public for funding. Surely if this project had scientific potential, the NSF or NASA would fund it… And he’d get a lot more than $10k.

  6. VinceRN

    Wouldn’t this be a perfect project for distributed computing? I’ve had machines working on “Einstein at Home” for year and been watching the BOINC plated finder project not come out for just as long.

    Also, that $10k number is a little odd. That is not a supercomputer, or even all that much time on one. It is about the price of a top of the line gaming machine though…

    I could probably muster the computing power he would get for ten grand in my two desk tops and five notebooks.

  7. andy

    It is about the price of a top of the line gaming machine though…

    High-end graphics cards have interesting uses these days, you can do general-purpose computing with CUDA or OpenCL to take advantage of these.

  8. Dave

    @SCL (#2):
    Not sure what you think is bad. The point is that Jupiter and Saturn have moons that have stuff (water) that’s crucial for life as we know it. The moons happen to be too cool to have liquid surface water (at least usually) but it’s not crazy to think that planets that are similar to Jupiter and Saturn but are closer to their stars might have moons with liquid surface water.

    @Mike (#5):
    Federal funding is hard to come by. Grant succes rates for astrophysics are in the range of 10-15% these days. Lots of excellent ideas end up not being funded. Also, isn’t what he’s doing sort of the conservative ideal of how science should be funded? Instead of “big government” deciding how to spend money, individuals decide on their own what projects they want to support. I don’t think science has to operate this way, but if it sometimes does I see nothing wrong with it, and the fact that a scientist is making a direct appeal to the public doesn’t (in my view) lessen the apparent value of the science he is pitching.

    Also, no one ever applies for $10K in grant funding. It would look like a suspiciously tiny amount to a grant awarding committee. But if that’s the amount he actually needs, isn’t it better for him to actually get that amount than to come up with ways to bump the price tag up to $100K just to improve the chances of success?

  9. Mike Saunders

    @5 Mike
    A hahaha. Yeah, getting grants from NSF and NASA is HARD. First, your idea has to be really good. You are competing against hundreds to thousands of other projects. Second, your idea has to fall in line with the road map that NSF or NASA is currently pursuing. What that road map is, isn’t always so clear.

    @6 Vince
    $10k can give you a lot of computing power. There are a lot of components that aren’t so great at gaming but are good at parallel processing. GPU CUDA has been mentioned already, also you can get a server blade for computing with a lot more than 8 processors on it. I don’t know all the cool stuff around, the last time I had to make a computer purchase was 5 years ago. We bought a couple of workstations at $20k each, and we are still using them heavily and they do their job well.

    Just wanted to add that the hardware cost these days is cheap. The software is an enormous cost. To enable GPU computing on the suite we have it is $150k per annum. It sucks, but what can you do?

  10. Kappy

    @L Ron Hubub: we already have a real moon named Pandora: http://en.wikipedia.org/wiki/Pandora_(moon)

  11. Chris

    Is this considered a charitable donation for tax purposes?

  12. Radwaste

    Aside from BOINC, there are the folks at distributed.net. See that page. They’ve had as many as 260,000 PCs working on decryption and Golomb Ruler calculations.

  13. Brett

    Is it really likely that gas giants will have a moon large enough to have habitable surfaces in the habitable zone of a star?

    I think we under-estimate how big and massive the Earth is by comparison to any of the gas giant moons in our solar system. All of the four Galilean moons combined only add up to about 7% of the Earth’s mass. Even a Mars-copy moon is about 50% more massive than that. I’m wondering if the gas giant would suck up most of the matter in its vicinity, leaving its moons too little material to form in large size like that.

    I suppose you could have a captured moon really early on (when the gas giant is migrating inwards), but that’s very gravitationally tricky.

  14. In linguistics many people are asking for small grants, in some areas moneys have been specifically set aside for smaller projects so they don’t have to compete with the big boys. Why don’t the federal agencies do the same???

  15. SLC

    Re Dave @ #8

    I think Mr. Dave is missing my point. I am in agreement that a moon revolving around a gas giant in the habitable zone of a star is certainly a candidate for life. My point is that life might also exist on a Jupiter/Europa situation so that limiting the search for gas giants in a star’s habitable zone is too restricting. I might also add that rogue planets unaffiliated with stars, which have recently been discovered, are also possible candidates for a Jupiter/Europa situation.

  16. Dave

    Hi SLC, I did miss your point.

    It’s true that Europa-like moons MIGHT be potential abodes for life. But we wouldn’t know anything about potential subsurface life on an object out of our Solar System (Europa’s much closer and we still have no idea whether there’s life there). If we hope to actually find life, it’s important to be able to get a spectrum of the object and see if the life has altered atmospheric chemistry in a noticeable way.

    Also, we wouldn’t know that there are moons around farther-out planets. If a gas giant planet transits its star, there are some natural ways to infer the presence of moons (which is what Kipping has in mind), but if it doesn’t transit (like the more distant ones), there’s no way with current technology to discover that the planet has a moon.

    I’ll point out, though, that even if we find moons around a transiting gas giant in the habitable zone of its star, it’ll still be really tough to get a spectrum of the moon, because it’ll be right next to a much larger and much brighter object — its planet.

  17. GMJ

    The NSF already spends millions of dollars funding the national cyberinfrastructure so that researchers just like this one can have easy access to lots of computer time. The XSEDE project (xsede.org) enables researchers to apply for allocations on supercomputers and clusters at NCSA, TACC, SDSC, NICS and several other high-performance computing centers. This group should just save themselves some time and apply for an XSEDE allocation. They can easily get more time by simply filling out an XSEDE form than $10,000 would buy them. An XSEDE startup request can be up to 200,000 CPU-hours. And when the startup allocation runs out they can easily apply for more time.

  18. Chris

    @ Dave and SLC
    Let’s not also forget that Jupiter takes nearly 12 years for one orbit and you need at least three transits before you can definitely say you have a planet. My guess is you need even more data to tease out the moon. So we’re talking at least 36 years before we could say we have a Jupiter and probably another 36 before you could say we have a moon. The habitable zone ones are much faster. Yes I know the habitable zone varies for each star, but unless you are orbiting a red dwarf, it’ll take quite a few years.

  19. Radwaste
  20. Dragonchild

    The skeptic in me needs more evidence this isn’t some Quixotic pet project.

    Honestly, finding an exomoon is well beyond the resolution of our best telescopes — there’s nothing to compute if they can’t even be indirectly observed. He’s saying it would only take $10k to get this started? I know it sounds ironic, but for a target that low I’m LESS inclined to donate because it sounds far more like a waste of money. How far does he plan to go with $10k? I’d like to see a serious proposal, maybe with an itemized budget. The fundraising goal is far too modest for a goal so lofty. It isn’t to say the cause is worthwhile, but it just doesn’t sound like there’s a plan at all.

  21. errindel

    Why doesn’t he apply for Xsede time? They have plenty of computing time available, or is he looking for something smaller than that to get off of the ground?

  22. andy

    Honestly, finding an exomoon is well beyond the resolution of our best telescopes

    The sceptic in me needs more evidence this isn’t something you’ve just made up. Transit timing and duration variations of the host planet caused by the reflex motion of the moon’s orbit should certainly be detectable: there are already quite a number of published papers on this subject.

  23. amphiox

    Recall that when the first exoplanet hunters began their searches, many if not most of the scientific community thought that it was beyond the resolution of our telescopes, and we actually had to go and try it before we could find out that it was in fact doable, as well as learn how to do it better.

    Investing a small amount of resources into exomoon searches now makes sense. Even if the actual detection is not feasible, a lot will likely be learned about how to best go about the search and much fine detailed technical and practical expertise will be obtained.

    And in the unlikely event that it is a total bust and we learn nothing, the amount of money spent is very small.

  24. mikel

    This is slightly off topic, but it’s something I’ve wondered about. It’s in regard to the very hot super Jupiters that were the first planets found. I wonder if any of these bodies has its L2 point in a part of its umbra where a moon at that point would be in the “Goldilocks” zone. I don’t know enough about orbital mechanics and the other stuff I would need to know to figure out how plausible this is, but I find it to be an interesting idea. Such a moon would be an interesting place. The “sun” would look like an enormous unblinking unmoving eye in the sky. One can imagine the religions…

    Anyway, do any of the people who know this stuff have any thoughts?

  25. Messier Tidy Upper

    @ ^ mikel : Great idea. I like it. :-)

    I’m not sure how likely it is, nothing like that exists in our solar system as far as I know and I’m not sure how truly stable that L-2 orbit would be especally if there are other planets in the system. But, the exoplanets keep surprising us with things we didn’t think were likely or even possible such as Hot Jupiters in the first place so who knows? 8)

    @13. Brett :

    Is it really likely that gas giants will have a moon large enough to have habitable surfaces in the habitable zone of a star? I think we under-estimate how big and massive the Earth is by comparison to any of the gas giant moons in our solar system. All of the four Galilean moons combined only add up to about 7% of the Earth’s mass. Even a Mars-copy moon is about 50% more massive than that. I’m wondering if the gas giant would suck up most of the matter in its vicinity, leaving its moons too little material to form in large size like that.

    OTOH, Several moons – Titan, Ganymede, Callisto are larger than Mercury so I don’t think its all that much of a stretch especially when these exoplanets can be superjovian planets with triple or more Jove’s mass.

    Titan and Ganymede are pretty huge moons that have varied terrains – lakes or even a sea that is possibly seasonal in nature in Titan’s case – so it seems there is potential there for life even earth-like life if such exo-moons were closer and different in geology but as large or larger relative to such moons in our solar system.

    I suppose you could have a captured moon really early on (when the gas giant is migrating inwards), but that’s very gravitationally tricky

    Although Neptune seems to have captured Triton into orbit around it – not sure when – disturbing its original moons system. I can certainly imagine this analogously happening in an exoplanetary system where a superjovian migrating inwards captures an earth-like world into orbit around it.

    How “earth-like” such a world would remain given tidal forces, increased radiation and increased risk from incoming asteroids and comets drawn in by the superjovian’s deeper gravity well is another question or three again but still.

    @23. amphiox :

    Recall that when the first exoplanet hunters began their searches, many if not most of the scientific community thought that it was beyond the resolution of our telescopes, and we actually had to go and try it before we could find out that it was in fact doable, as well as learn how to do it better. Investing a small amount of resources into exomoon searches now makes sense.

    ^ This! Well said, agreed and seconded by me. :-)

  26. Andrei

    I wander how stable would be a moon orbit around a hot jupiter – how big the Hill sphere is for a hot jupiter (compared also with the Roche limit)?

  27. L Ron Hubbub

    @ Kappy. See, there’s this movie called Avatar ( http://en.wikipedia.org/wiki/Avatar_(2009_film) ) where the story takes place on the moon of a gas giant that orbits in the habitable zone of its star. The moon in the movie is named Pandora.

  28. Sunny D

    WIll this allow us to see alien bases on the far side of our OWN moon?

  29. amphiox

    It may well turn out that earth-sized moons are very rare around giant planets, and that it is very difficult to form an object that big in those circumstances. But given that a gas giant moon as small as Enceledas has potential for habitability, that may not necessarily be that much of a problem, as far as habitability goes.

    I wonder if there are any circumstances in which the parent Jovian’s magnetic field may serve to protect its moons from stellar winds, allowing much smaller bodies to retain water and other volatiles in their atmospheres for longer periods of time. Or a parent planet with a dense icy ring system like Saturn might provide a source for continuously replenishing volatiles on moons with the right orbital circumstances, again allowing for much smaller bodies to retain a thick watery atmosphere for much longer than they would if they had been planets alone on their own.

  30. Benjamin

    @Satan Claws, @VinceRN, @Radwaste and all others wondering why they don’t use distributed platform computing like BOINC, David Kipping gives an answer on his kickstarter page. They studied the possibility but decided against it because the computing necessary cannot be efficiently broken down into small chunks. The calculations don’t adapt well to distributed computing.

  31. Matt B.

    @24 mikel: I think you mean “penumbra”. If the moon were in its planet’s umbra, the star wouldn’t be visible. But in the penumbra, the planet would look like a pupil in the eye of that star. Sounds like a cool basis for a sci-fi story.

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