Find cold, distant worlds with Ice Hunters

By Phil Plait | June 21, 2011 12:42 pm

In July 2015, the New Horizons probe will fly past Pluto, snapping pictures and taking data of this icy world. Whether you think Pluto is a planet or not* it’s still a fascinating object and I can’t wait to see what New Horizons sends back.

But what happens after that? The space probe will still be traveling into deep space at high speed… but space out there isn’t empty. Beyond Pluto lie the solar system’s coldest denizens, the Kuiper Belt Objects. These are lumps of ice, frozen chunks that may take millennia to circle the Sun once. We’ve identified over a thousand of these KBOs, and there are tens of thousands more waiting to be discovered. Scientists with the New Horizons mission are hoping to find one near enough to the probe’s path to plan a flyby, so we can finally see one of these things up close.

And that’s where you come in!

A new website, Ice Hunters, has been put together to help you find potential KBOs for New Horizons to visit. It’s part of the Zooniverse; a citizen science project that gets people involved in real astronomy. In this case, you can examine images from the giant Magellan and Subaru telescopes to look for targets. It’s actually not terribly hard; here’s one image I looked at:

Basically, KBOs move over time, so two images are taken some time apart. One is digitally subtracted from the other, so stars tend to go away (though they don’t erase perfectly, leaving those ugly residuals). Any whitish blobs left are things that have changed between the two images: variable stars, asteroids, cosmic rays, and, hopefully, KBOs. When you find something you simply tag it by clicking it. A circle is placed around it, and the location is logged. You can see the object I found in the image above.

Humans are pretty good at this, while computers are easily confused by the messy residuals. But just to make sure every click is saved and compared to the work of other people. The more an object is clicked, the more likely it is to be something real and worth following up. The website explains how all this works.

That’s all there is to it! You have to register to do this (unless you’re already a Zooniverse member); it’s free and easy. And who knows? You may literally be the person who finds an icy world that will get a visit from New Horizons!

New Horizons image credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)


*My opinion: defining the word "planet" is a bad bet if not impossible. If you want the longer story, check out this article I wrote for Discover Magazine.


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CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Space

Comments (30)

  1. Zooniverse is going to kill me with all of these projects. I have been classifying blurry galaxies and drawing circles in gas clouds for days and now I have to poke dots? I don’t think Al Gore invented the internet for this much work…

    Oh well I’ll do it.. and maybe I can be a person finding the object New Horizons peeps in on. Maybe they’ll name it Endyo.

  2. toasterhead

    Has the New Horizons mission decided yet if they’re going to try and catch a Neptunian trojan while on the way to 134340 Pluto? Last I heard about it a few months ago, this was still up in the air, since that part of Neptune’s orbit is intersecting the galactic plane and nearly impossible to image.

  3. George

    Unfortunately, I have Windows XP and my system will not allow the required new Explorer 9 version.

  4. Robin Byron

    Been a zooite and have worked on several of the zooniverse projects for several years now. A lot of fun and you can learn quite a bit about some really cool stuff.

    I started with GalaxyZoo and it’s neat to know that I have seen thousands (yes, thousands) of galaxies that very few people (a few tens of thousands at best) have laid eyes upon.

  5. jess tauber

    So basically if more and more people report alien encounters the higher the likelihood they’ve actually been probed? Or do they have to have been probed with the same probe. What if they circle it? I’m confused. :-)

  6. JE

    George, I have XP also. I just went and found a different web browser, other than Explorer. It worked for the other Zooniverse projects. Haven’t tried this one yet.

  7. Orlando

    About the planet topic: It’s hard to apply discrete definitions to a continuum. It is always a matter of conventions, slippery slopes, and so… Almost impossible to reach a perfect definition.

  8. toasterhead

    I think They Might Be Giants addressed the planet issue nicely in their song “How Many Planets?” Four little ones, a bunch of other stuff, then four big ones, and a bunch of other stuff.

  9. Messier Tidy Upper

    Great idea and program. :-)

    Hopefully it will find many more ice dwarf type planets one or even two of which can be visited briefly by the NewHorizons spaceprobe.

    @ 2. toasterhead :

    Has the New Horizons mission decided yet if they’re going to try and catch a Neptunian trojan while on the way to 134340 Pluto?

    I second that question – I don’t know (will have to see what I can find) & I hope they do as that would be pretty interesting and there may be lots of those objects. Recall reading that Neptune may have more trojans even than Jupiter! ;-)

    Last I heard about it a few months ago, this was still up in the air, ..

    Oh I think it’s a bit higher up and further away than the air! ;-)

    .. since that part of Neptune’s orbit is intersecting the galactic plane and nearly impossible to image.

    Well if the NewHorizons spacecraft is heading into that area it will get an increasingly better view of that region as it flies ever closer using its cameras which might help. If there are that many Neptunean trojans out there then it occurs to me that the odds that one or more of them might be in or about the right place can’t be too bad. :-)

  10. Messier Tidy Upper

    For a few links on Neptune’s trojans see :

    http://www.space.com/3398-neptune-thousands-escorts.html

    which notes the idea that Neptune may boats more trojans than Jupiter &

    http://www.space.com/8938-asteroid-neptune-gravitational-dead-zone.html

    & as this link :

    http://blogs.discovermagazine.com/badastronomy/2011/06/09/rosettas-cometary-goal-now-in-sight/

    to a recent post here shows the cameras on these spaceprobes can be pretty effective as Rosetta was able to observe its target from three years travel time and over an AU away. Course they knew where to look and Churyumov-Gerasimenko may be a bit bigger and brighter than the Neptune trojans but still.

  11. Messier Tidy Upper

    8. toasterhead :

    I think They Might Be Giants addressed the planet issue nicely in their song “How Many Planets?” Four little ones, a bunch of other stuff, then four big ones, and a bunch of other stuff.

    Way I think of it, the planets come in three zones or flavours – the rocky ones in the inner zone, the gassy ones in the middle zone and the icy ones in the outer zone! ;-)

    @7. Orlando Says:

    About the planet topic: It’s hard to apply discrete definitions to a continuum. It is always a matter of conventions, slippery slopes, and so… Almost impossible to reach a perfect definition.

    Perhaps so but I think it’s easy (& been done ) to come up with something that’s far better and make smore logical sense than the current IAU definition.

    In fact their original proposal that stated a planet is a planet if its roughly round (hydrostatic equilibrium) and not fusing and orbits the Sun rather than another planet works pretty well for me.

    If a dwarf star is still a star – and a dwarf person still a person – why the blazes should a dwarf planet NOT equally count as a planet? The current dreadful IAU “planet” definition is plain size-ist! It is also logically inconsistent*, raises more problems than it solves and isn’t sufficently inclusive. I strongly think that ice dwarfs incl. Pluto, Eris & Sedna should count and are types of planets.

    * If Earth or even Jupiter orbited where Pluto is, they couldn’t clear that orbit either. Being far from the Sun should not rule a planet out of planetary status if that’s what it is but that’s what the IAU definition effectively does. Besides no planet has a clear orbit as comets cross all planetary paths! ;-)

  12. Messier Tidy Upper

    @ ^ One better alternative definition is suggested in the link above by astronomer & author Ken Croswell who also notes here :

    http://kencroswell.com/HD45364.html

    that we already know of gas giant exoplanets having the same orbital resonance that the IAU and Pluto-bashers claim rules Pluto out of contention. They wouldn’t call HD 45364 b & c “dwarfs” surely? Just as they wouldn’t call Earth or Jupiter ‘non-planets’ if they happened to orbit in the Oort cloud and thus be “unclear” and surrounded by other bodies. Doing so would be being rather ridiculous wouldn’t it? Thus using the same idea to deny Pluto’s planethood is simply logically inconsistent and hypocritical.

    My own prefered definition of planet would be this one based on three criteria :

    1) Roundness or otherwise – if its large enough to be a globe or in the case of rapidly spinning objects like Haumea* and Achernar** a flattened egg-shape then it isn’t too small for planetary status like a comet or asteroid.

    2) Self-luminous by nuclear fusion or otherwise – if its ever shone by its own core nuclear fusion then its a star, an ex-star or a brown dwarf rather than a planet. This takes care of the upper end of the planet division.

    3) Directly orbiting another planet or otherwise – if it directly orbits another planet then regardless of size its a moon rather than a planet. If it orbits in a asteroid or cometary belt but still orbits the star directly it still counts as a planet because it isn’t orbiting another planet.

    So if a world is round and not orbiting another planet or ever nuclear fusing then it is classified a planet.

    Planets then would come in a range of size (Pluto is actually in the middle size-wise in our solar system with most planets being smaller ice dwarfs) and considerable numbers – the more the merrier – and leaving room for some stranger worlds that may yet be found.

    Exoplanets have been surprising us and teaching us that planets can come in some very different varieties – Hot Jupiters, Eccentric Orbiters, Pulsar Planets, Super-Earths, Hot Ice Worlds, Carbon Planets and so forth.

    Doesn’t that definition make good sense and allow easy logical classification? :-)

    Isn’t that a better option than the mess the IAU now has in place – hopefully almost certainly temporarily? ;-)

    ————–

    * See : http://apod.nasa.gov/apod/ap080923.html

    ** See : http://kencroswell.com/RegulusIsOblate.html

  13. cletus

    Regarding whether or not one believes that Pluto is a “planet”: one astute astronomer I heard on a recent radio broadcast (wish I could remember his name) pointed out that we have red dwarfs, white dwarfs, and brown dwarfs among the stars. They may be referred to specifically by those classifications when the classification is germane, but we still refer to them generically as “stars”. In that same vein, have no problem referring to Pluto generically as one of the “planets”, and I’d be glad to smack some pedant upside the head if he wants to argue with me. ;-)

  14. I’m curious why they didn’t use a good old fashioned (updated for the innertoob) blink comparator to display the two images. It seems like seeing an object pop on and off, or move slightly compared with the stationary stars, would be easier than finding dots among blobs.

    Still, I love these things. I, too, spent far too much time poring over the Galaxy Zoo images.

  15. Kim

    @kuhnigget I’ve just joined Ice Hunters (100 images! and ~90 objects), and I believe they preferred subtracting pictures because they can be of very different quality. A blink comparator would show all stars changing from sharp to blurry, for example, and it would be difficult to find something “moving” when everything is “changing”.

    As it is, subtracting pictures A-B, a moving body becomes a white clear dot (its position in picture A) and a black dot (its position in picture B). The rest, theoritically, should be zero, but in fact you can get all kind of noise.

  16. Richie

    50 minutes, 100 images, 30 potential KBO’s and 4 potential asteroids.

    My eyes are burning….

  17. toasterhead

    3) Directly orbiting another planet or otherwise
    ——
    This would still kill Pluto, though, since Pluto and Charon orbit a common barycenter. Wouldn’t it?

  18. Gary

    As a beta tester for IceHunters I’ve identified over a thousand KBOs and asteroids in this project. With millions of images to scan, many more observers are needed. It’s quite easy.

  19. MattF

    toasterhead: This would still kill Pluto, though, since Pluto and Charon orbit a common barycenter. Wouldn’t it?

    What planet/moon system doesn’t orbit a common barycenter?

    (Larger point: Rules like this tend to be fuzzy.)

  20. @ kim #16:

    That makes sense!

  21. miss k

    Still waiting/hoping for them to get some amazing volunteers to create mobile versions of their projects. I could waste *so much* more of my time on the go!

  22. Ice Road Truckers – In Space! Well, not really, but this is a very cool (no pun intended) project!

  23. Diederick

    I used to work for a protein crystallization lab, where I wrote software that let people score pictures taken by robots, based on whether the protein on the picture was crystallizing or not. We had an algorithm that could do this as well, but the lab people (especially some of their children – they had more fun doing it) were a lot better at it. At the end, we only used the algorithm to pre-sort the images.

  24. CB

    @Orlando

    About the planet topic: It’s hard to apply discrete definitions to a continuum. It is always a matter of conventions, slippery slopes, and so… Almost impossible to reach a perfect definition.

    While true in the general sense, and something to always be aware of, in the case of our solar system it’s actually ridiculously easy to apply a discrete definition. Unlike situations where there’s a nearly continuous spectrum, with our planets there’s a 5 order of magnitude gap in terms of orbit-clearing ability between the least of the things the IAU terms a planet, and the greatest of things termed a dwarf planet. So any concerns about drawing an infinitely precise, arbitrary line through objects in the solar system is moot, because no such line is necessary.

    It’s like, distinguishing exactly where Europe ends and Asia begins is difficult Distinguishing between Europe and the Americas is easy, because there’s an entire ocean between them.

    @ MTU: Your grammatical objection is noted and accepted. The wording is not really something I care about. Call the “planets” “Primary planets” and the dwarfs “dwarf planets” so all can be a subset of “planets”, or hey, rename dwarf planets into something other than planet. Either way. The key thing is, the IAU definition does lock in on a significant distinction between these objects, and that distinction should be recognized. The exact terminology for doing so is not my concern.

    And as usual, the rest of your argument for how the IAU definition is illogical or inconsistent are really just errors or misrepresentations on your part. Jupiter most likely would clear its orbit were it in Pluto’s place, as Neptune is rather close and has amply succeeded in doing so. And comets passing through orbits would not count as they aren’t part of the objects neighborhood, just occasional visitors. If they were counted their mass would not significantly change the Planetary Discriminant for any of the objects in question.

    It has never been the case that “cleared the orbit” implied “completely free of any other object”; that is pure misrepresentation on your part, and evidence that your objections to Pluto’s classification are not rational, but rather a rationalized emotional response.

    I can understand that, but get over it. I don’t care if you want to be called a planet. Fine, it’s a planet. But it is not the same as the other 8 bodies called planets. There is a 5-orders-of-magnitude difference between Pluto, Ceres, and objects that have cleared their orbit. This distinction is not subtle or small, and must be recognized somehow. I don’t care what you call that, either. But the point is that whatever you call these categories, Pluto does not belong in the same one as the 8 orbit-dominating objects in our solar system. IAU correctly observed this. Protests ignore this. Grammatical issues aside, they were more correct.

  25. CB

    @ MattF:

    toasterhead: This would still kill Pluto, though, since Pluto and Charon orbit a common barycenter. Wouldn’t it?

    What planet/moon system doesn’t orbit a common barycenter?

    (Larger point: Rules like this tend to be fuzzy.)

    I think their point was that the barycenter for Pluto/Charon is between the two objects, while all planet/moon combinations have their barycenter in the planet.

    I’m not sure that would make a good criterion though, for the ‘fuzziness’ reason you mention. Minor changes in object mass could move the barycenter above/below the planet-candidates surface.

    Orbital clearing, however, is not fuzzy at all — no minor tweaking, counting comets or not, etc would come anywhere close to changing the current categorization — and so, like hydrostatic equilibrium, makes for a good criterion.

  26. Messier Tidy Upper

    @20. MattF :

    toasterhead: This would still kill Pluto, though, since Pluto and Charon orbit a common barycenter. Wouldn’t it? What planet/moon system doesn’t orbit a common barycenter? (Larger point: Rules like this tend to be fuzzy.)

    Ah, hence my deliberate wording there of *Directly* orbiting another planet.

    I would therefore count Pluto-Charon as a double planet since neither is directly orbiting the other.

    The IAU definition does NOT allow for the existence of double planets because neither has – or could clear its orbit. That I think is too limiting because I fully expect (& hope) we may one day discover (more) double planet systems.

    In fact had our Moon been more massive our Earth-Moon system could’ve ended up as such! ;-)

    @26. CB : Orbital clearing, however, is not fuzzy at all

    But, that’s wrong – “orbital clearance” is fuzzy – very. It raises a whole set of question s of how do you define what is meant by “cleared” how long does it have to clear it, how far outrt does it have to clear it and so forth. By raising these unnecessary superflous questions and issues that can easily be dispensed with by dropping the whole “orbital clearence” (OC) criterion that OC criterion violates Occams razor. The definition of planet should be as simple and as striaghtforward as possible, round, never fusing like a star, not orbiting another planet directly pass the Occam’s Razor test, OC does NOT.

  27. Messier Tidy Upper

    @25. CB :

    While true in the general sense, and something to always be aware of, in the case of our solar system it’s actually ridiculously easy to apply a discrete definition. Unlike situations where there’s a nearly continuous spectrum, with our planets there’s a 5 order of magnitude gap in terms of orbit-clearing ability between the least of the things the IAU terms a planet, and the greatest of things termed a dwarf planet.

    Big deal. :roll:

    How is that important unless you regard orbital clearing as important in the first place which many (incl. me & Alan Stern who called the IAU definition “idiotic”) don’t?

    Ever looked at the order of magnitude change in diameter, luminosity and mass for the smallest red dwarf stars up to the most massive red supergiants? Stars differ vastly and come in huge range over many diferent aspects. So do asteroids and comets. So do the great biological classes plants range from algae and single celled forminifera all the way through to giant redwoods bigger than blue whales. Animals range from the smallest fleas to the largest dinosuars in size. We still call ‘em animals -these are very broad categories – and planets should be similar. Just as we have major genera of animals (eg. mammels, reptiles , insects, molluscs) with the smaller classes generally being more numerous in population numbers, it make sense that planets will be similar with broad classes – gas giants, rocky earth-like worlds and ice dwarfs and there’s likely far more smaller planets than larger ones. If you count the dwarf planets as planets then Pluto is in fact above average in size.

    Is OC something that should define whether an object is a planet or not. No, I don’t think it is. Why do you think otherwise?

    So any concerns about drawing an infinitely precise, arbitrary line through objects in the solar system is moot, because no such line is necessary.

    [Nitpick] Is infinite precision ever possible? Surely not! Itwould take an infinite time to arrive at, discuss and double check> Will we ever get to the last digit of Pi? ;-)

    Clearly objects in our solar system and planets generally do range in a continuum of size from Jupiter down to Ceres. Just as there is a range of mountains down to hills in geography.

    It’s like, distinguishing exactly where Europe ends and Asia begins is difficult Distinguishing between Europe and the Americas is easy, because there’s an entire ocean between them.

    FWIW; The Caucasus mountains I gather marks the spot Europe-Asia~wise. Oh and the start of Turkey -the dardanelles channel between the Greek side and the Asia minor one.

    @ MTU: Your grammatical objection is noted and accepted. The wording is not really something I care about.

    So why are you arguing here then? ;-)

    Call the “planets” “Primary planets” and the dwarfs “dwarf planets” so all can be a subset of “planets”, or hey, rename dwarf planets into something other than planet.

    The first option makes sense, the latter is what the IAU is effectively doing and does not.

    Either way. The key thing is, the IAU definition does lock in on a significant distinction between these objects, and that distinction should be recognized. The exact terminology for doing so is not my concern.

    Significant? To a degree, yes but *how significant* is OC and should it mark the division between whether something is a planet or just a division between *types* of planets? Clearly I think the latter.

    And as usual, the rest of your argument for how the IAU definition is illogical or inconsistent are really just errors or misrepresentations on your part. Jupiter most likely would clear its orbit were it in Pluto’s place, as Neptune is rather close and has amply succeeded in doing so.

    Not necessarily. Pluto does go a bit further than Neptune and Neptune itself hasn’t exactly cleared its orbit since Pluto and other objects cross it. Then there are the Neptune trojans which are hardly cleared – dominated perhaps but still there.

    And comets passing through orbits would not count as they aren’t part of the objects neighborhood, just occasional visitors.

    Depends on the comet – some are in stable or unstable inner solar system orbits well inside Jupiter’s. Some asteroids are just extinct comets. Most pass through – but some do stay.

    If they were counted their mass would not significantly change the Planetary Discriminant for any of the objects in question.

    Yes and I’m not arguing that comets are planets because they are too small – too small for being in hydrostatic equilibrium. Pluto is different as are Eris, Ceres and others.

    It has never been the case that “cleared the orbit” implied “completely free of any other object”; that is pure misrepresentation on your part, and evidence that your objections to Pluto’s classification are not rational, but rather a rationalized emotional response.

    So how clear is clear and who draws the line and who needs it to be clear anyhow?

    Plus aren’t the Pluto-bashers equally being swayed by tehir anti-Pluto sentiment as thepro-Pluto people are?

    I can understand that, but get over it. I don’t care if you want to be called a planet. Fine, it’s a planet. But it is not the same as the other 8 bodies called planets. There is a 5-orders-of-magnitude difference between Pluto, Ceres, and objects that have cleared their orbit. This distinction is not subtle or small, and must be recognized somehow. I don’t care what you call that, either. But the point is that whatever you call these categories, Pluto does not belong in the same one as the 8 orbit-dominating objects in our solar system. IAU correctly observed this. Protests ignore this. Grammatical issues aside, they were more correct.

    I disagree. The panets are all digfernt and while pLuto is very different from the gas giants and rock dwarfs , it and its fellow ice drafs ar estill best described as planets.

  28. Craig

    I was one of the beta testers for Ice Hunters, and I’ve looked through several thousand images by now. During the site building days, the counters had to be reset a couple of times so I don’t have a complete count of how many objects I potentially identified, but it’s a really easy project to dip your toes into if you are just starting with Zooniverse projects.

    So many images, so little time! :)

  29. Thanks for the awesome link! I regret that I have not been able to afford my membership with the Planetary Society as of late, but at least with this website, I can contribute to astronomy in another fashion.

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