A thoroughly sporadic column from astronomer Mike Brown on space and science, planets and dwarf planets, the sun, the moon, the stars, and the joys and frustrations of search, discovery, and life. With a family in tow. Or towing. Or perhaps in mutual orbit.



Ten years of Eris

Ten years ago today I came in to the same office I’m in at this moment, sat down in the same chair I am sitting in now, probably stared out the window at the clear blue sky much like I’m doing right now. It’s even likely that I drank coffee out of the very cup I’m drinking out of. Other than that, though, nothing was the same. Just a week earlier, on Dec 28th 2004, I had discovered the second brightest object that we had ever seen in the Kuiper belt (the brightest, of course, being Pluto). We didn’t yet know how big it was so my mind kept spinning with possibilities. Maybe it had a dark comet like surface and so to be so bright it had to be really big! Maybe as big as Pluto! Maybe bigger! (The object, now called Haumea, is now known to be about a third of the mass of Pluto and one of the strangest objects in the outer solar system).

Perhaps even more exciting, I had discovered the object while re-processing old images that I had taken a few years back. There was another year’s worth of images to re-process. Maybe there would be more!


It was that sort of head-spinning excitement that made it fun coming into the office every morning and going through the tedious and laborious process of examining everything that the computer had worked on the night before. Most mornings the computer would spit out a list of a few hundred potential objects and I would examine them, one by one, to see if the computer was on to something or, like happened nearly every time, the computer had just found a smudge in the data or a glint in the sky and thought maybe it was something out there in the Kuiper belt. But all of the false alarms from the computer were OK: every new mouse click held the possibility of discovering new worlds never seen before.

And ten years ago today, it happened. After a morning of sorting through computer mistakes a big bright object appeared on my screen. It was almost as bright as the one from 8 days earlier. But, crucially, it was moving more slowly than anything I had ever discovered before. Slowly moving means far away. Bright means big. But slowly moving and bright means bigger than anything we had ever seen before.

I did what I always do when I make what seem to be astounding discoveries: I assumed I had screwed something up. Screwing up happens all the time, and if you have to make a guess between “just found biggest object in outer solar system” or “screwed something up” you’d be smart to pick the later. Maybe I had set up the telescope wrong. Maybe the tracking was off. Maybe we were looking in the wrong spot in the sky. Shockingly – to me, at least – nothing was off. The images were perfect. We had just found a second object even brighter than the one from 8 days earlier.

This new object, found 10 years ago today, was, of course, Xena which became 2003 UB313 which finally became Eris. Ten years on, we know that Eris is about 25% more massive than Pluto, though similar in size. The reason it appeared so bright in those earliest images is that it is one of the most reflective objects in the solar system – it is so far away that its atmosphere is frozen on to the surface, reflecting almost all of the light that hits it.

That discovery 10 years ago was exciting enough that it took me a few days to get back to looking at the old images, but, soon enough, I was sitting in this chair searching through a stack of images every day. This time, I didn’t discover anything shockingly bright for almost 3 months, but, on a morning just like many of the other ones, there was yet another bright slowly moving Kuiper belt object. This one – Easterbunny then 2005 FY9 and now finally Makemake – is the second brightest object in the Kuiper belt and a fascinating laboratory for chemical and atmospheric processing on these distant bodies.

After Makemake we kept going. But there were no new bright objects to be found. In the last decade, none of the brightest new discoveries even made the top ten brightest object list.

What happened?

The simple answer is that, back ten years ago, we had scanned the whole sky and there was nothing bright left to find. This simple answer is not precisely true, though. We missed much of the southern hemisphere and avoided the regions of the Milky Way galaxy. In this past decade others have filled in much of these missing regions, but, still, nothing particularly bright.

But through this last decade one thing has always nagged at me: no survey for new objects in the solar system is going to be 100% effective. If a bright undiscovered planet happened to be lined up perfectly with a random background star at the moment I had looked, I would never have seen a planet. And when trying to cover the whole sky, you don’t have time to go back and look a second time. I always wondered when I would open the newspaper in the morning and see the headline “New Planet Discovered in the Outer Solar System” and then realize I had looked right at it but not seen it.

I’m not worried about that anymore. Today, as a tenth birthday gift for Eris, we’re releasing the results of a new survey thatcovered the entire sky once again (soon to be published in the Astronomical Journal). This time, though, there is virtually no chance that anything bright would be able to escape our grasp, because we looked again and again and again and again at each spot in the sky making it impossible for something to be temporarily hiding.

The best part of this whole survey is that we didn’t even need to go to a telescope. All of the data was already taken, much of it years ago, for searching for near Earth asteroids. Bright Kuiper belt objects show up in the data, too, but because they are so far away they move so slowly that they appear stationary in the near Earth asteroid data. How do you detect things when they aren’t moving and they just look like stars? The trick is that they still move. Just come back a day later. Or a month later. Or next year. And they’ll be somewhere else. All we needed to do was connect the dots.

Connecting the dots was harder than it sounds. In the 7 years of data, there are 4 billion “dots” in the sky – spots where there appear to be something in a spot where there has never been something before. To figure out if any of these dots are in the Kuiper belt, we have to mathematically show that they are following a physically plausible orbit around the sun. To do that requires examining about 60 octillion potential orbits (I just had to look this up; an octillion is a 1 followed by 26 zeros). Even with a big bank of computers in the basement, this check would take about a million years. I spent a few months coming up with computational tricks to speed things along and, finally, got the processing time down to about 6 months.  I pressed “go” and let the processing churn in the background.

When it was all done I had that same feeling that I had had a decade ago. This could be the moment when suddenly something new and spectacular is found! I made a quick list of all of the objects that the processing had found. There was 8 really bright objects. The first one was detected 51 individual times. It was Makemake. Haumea was there (47 times), as was Eris (28 times). Also Orcus and 2002 TX300 and Nereid and Huya and 2002 VE95. And that was it. After 6 months of processing of 7 years worth of data, we found all of the bright Kuiper belt objects that we already knew (and also Nereid – a moon of Neptune – which I thought was new for a few minutes because I was only cross matching with Kuiper belt objects; then I noticed it was really really really close in the sky to the position of Neptune; almost screwed up again).

And, so, a decade after that discovery of Eris, a decade after that moment in life when it seemed that the next huge discovery could be a single click away, I have to announce that it is really true: we are through with discoveries of bright new objects in the outer solar system. That incredible run, which, in my mind started from the discovery of Quaoar in June 2002 and ended with Makemake in April 2005, is definitely over. Or at least probably over. Our analysis shows that there is about a 1 in 3 chance that there is still one more bright object to be found lurking in the part of the sky where the Milky Way background would make it too hard to see, even with our new technique. I hope people are looking.

Is the outer solar system through with discoveries, then? No, definitely not. Still one of the most exciting discoveries a decade ago was that of Sedna, which is in a region of space even beyond the Kuiper belt. For a long time Sedna was the only object known out there, though several different groups were actively searching. Just a year ago, a pair of astronomers found a second one – 2012 VP113. Starting around now the third and fourth new discoveries should start to be trickling in, just like that initial trickle of discoveries of faint Kuiper belt objects starting in 1992. These new objects will be distant and faint. But the fact that there are (we think) so many of them will point to the fact that, somewhere out there, the largest of them could be quite large. Mars sized? Earth sized? We don’t know.  And the largest ones are unlikely to be found with our piecemeal efforts these days. But, eventually,  someone will mount a large scale search analogous to the one we started in 2002, cover the whole sky, find whatever is out there, and then the new even larger members of this mysterious region of the outer solar system will start flooding in. Every day might be a potential new astounding discovery.

43 comments:

  1. Please explain the object sighted in antarctica in the sky after sundown. The video is on YouTube, it's bright enough to light up the sky for four hours and looks like daytime. Also what's with several sightings of a second sun , youtube again.

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    1. Probably Venus--its the brightest object in the sky after the sun and our Moon and is currently an evening "star"

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    2. Many of those Antarctica youtube videos show the over-exposed moon and claim it is Nibiru. They are more interested in drawing in viewers than presenting the truth.

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  2. Thanks for the update, Dr. Brown. The next decade should improve the odds, right, with the LSST, JWST and TMT (especially LSST) coming on?

    P.S.: So now researchers are using lame acronyms for papers as well? ;)

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    1. The Oort Cloud could very well be teeming with small planets like Eris. These telescopes may very well inaugurate a new era of outer solar system discoveries.

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  3. This is interesting article, but I red about newly by WISE discovered brown dwarf close to our Sol. sys.,,, (not those two what are cca 7LY from us). Do you know more? Pavel

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    1. This comment has been removed by the author.

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    2. If you are referring to HIP 85605, it is NOT a brown dwarf and is ~22.2 light-years from the Sun. It could even be much further from the Sun if it is a more distant luminous star.

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  4. I am very grateful for the work you have done and continue to do Dr. Brown. As much as I'd like your discoveries to remain as powerful as they are, of course I am also hoping for newer and greater discoveries in the near future. Who wouldn't be? [P.S. the comments here are starting to resemble a certain free video viewing platform ;-) Entertaining, but scary as hell as a representative sampling of the public's view on all things skyward... At least folks are interested one way or another. ]

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  5. Any progress on the naming of OR10?

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    1. I've been wondering about that too. This is by far the brightest known unnamed TNO, and is long past due for a real name.

      Now that it seems very likely that there are no other objects in the Kuiper Belt of equal brightness, it's time to give it a name!

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    2. That would be 2007 OR10? I've been wondering, too.
      Isn't there a "temporary" name, until they decide to give it a permanent one?
      Or could we just call it "Hey-you"?

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    3. It had a temporary name of "Snow White".

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    4. "Snow White"?
      Oh, dear.
      Something like that could easily have as many as seven moons...
      Not hard to guess what they'd be named. 8)

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    5. (I'm the poster of the question we're addressing)
      In 2011, Mike said that enough is now known, and the body is interesting enough, that it should be assigned a name. (See "The Redemption of Snow White" in this blog.) "Snow White" is not an appropriate name (despite it being the 7th dwarf his team discovered) because it actually turned out to be quite red. So in this case the nickname doesn't work, and it's been 3½ years since Mike said he was thinking about applying for a name. I suppose we could just call it 'Orten, as in 'Orten 'Ears a 'Oo.
      Mike, have you suggested a name to the IAU?

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    6. No, we still haven't proposed anything. The good news, though, is that by 2017 anyone can propose a name!

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    7. Kuterastan, the Kiowa Apache creator would be a good choice, assuming nothing else has been suggested for that name.

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    8. As someone of Sami heritage, it would be nice to have an ice-ball to honor one of the native deities of our ice-covered homeland. The goddess of the underworld, Jabme-Akka, would be fitting.

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    9. Planety O'val McSpace

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  6. Thanks, Mike Brown! I come as sporadically as you write, but it is always worth it.

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  7. Out of curiosity, how likely would it be that telescopes could detect an object the size of Earth's moon, with its relatively low albedo, in the Kuiper Belt?

    Bob Shepard of Denver

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  8. Congratulations on the 10 year birthday! Haumea inspired a painting - http://sarahgrubb.com/haumea/

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  9. Octillion: a 1, followed by 27 zeroes. However many, it must be a multiple of 3. That's how the naming system works.

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  10. First of al Mike thanks for the article. I was waiting to read something new and interesting and as always you came through.
    Now the New Horizons is nearing Pluto, presently it is 218 million Kms or 136 million miles from it, can we estimate how close will New Horizons need to be for Pluto to look like a body of 1.0 magnitude to the naked eye?

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  11. I see on Reddit that Carlos de la Fuente Marcos is claiming that there could be two very massive planets beyond Neptune. I tracked down the actual papers (I think):

    "Extreme trans-Neptunian objects and the Kozai mechanism: signalling the presence of trans-Plutonian planets" http://adsabs.harvard.edu/abs/2014MNRAS.443L..59D

    "Flipping minor bodies: what comet 96P/Machholz 1 can tell us about the orbital evolution of extreme trans-Neptunian objects and the production of near-Earth objects on retrograde orbits" http://adsabs.harvard.edu/abs/2015MNRAS.446.1867D

    I suppose that would be consistent with your results if such bodies were very dark, but is that plausible?

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  12. Have just read about the possible super-Earth planets in the Oort Cloud. What does Mike Brown think about it? Is it possible with today telescopes to detect them photographically? What apparent magnitude would they have? And would this be a project for Mike in the future if possible?

    Greetings from Germany

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    1. Mike thinks ... give us more money and we will find them all :)
      They have just realized that they are running out of new TNOs, so they have invented "super-Earths", just to keep people interested :)

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  13. After ten years, you're still using the same desk chair?
    For goodness' sake, man. Get a new one!

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  15. Hello Mr Brown,

    I read you book last year about killing Pluto and I have to say I really enjoyed it. I like that even though I am not a PHD I was able to follow all the explanations and information in your book. I really felt that through reading your book that you were witty, intelligent and honorable. I kind of felt that even though we'd never met that I had found a friend and a person I could respect. I was very disappointed when, toward the end of you book, that you choose to imply that creationism is absurd and to entertain it as reality is ridiculous. You didn't use those words but, that was the implication. I was actually hurt. Here I was reading a book on a subject that I enjoy, and while I expected that you would not be Christian, I didn't expect such a disrespectful written slap in the face to something that I hold sacred. I know that that is an outdated idea now a days, to hold something sacred but, I do hold my faith sacred to me and you lost my respect. And I am sure that you lost the respect of other people as well. Such actions are not that of a respectful and honorable person.
    -A LDS Science Fan

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    1. I'm not sure that any religion insists that Pluto be a planet. (Could be wrong, but doubt it.)

      As for the common complaint that Science does not leave room for Faith... I could refer you to Global Cooling / Global Warming / Climate Change; where some of the same people have insisted that Science proves that the world will have another ice age, and/or an extended hot age, both due to Mankind's irresponsible (sinfull?) actions. They ask you to believe their "computer models" and "data", while refusing to let anyone see the actual, "uncorrected" data or the source code for the models. We just have to take it on faith... there's that word again!

      If we can step back, and actually look at how the Universe is organized, it's clear that it does not /require/ outside intervention to keep it going. The northern hemisphere of the Earth warms in the Spring, not by Divine Decree, but because the Sun is up higher and longer. The planets (even Pluto and Eris) move in their courses without Divine guidance. To say this is not to deny that there is an Organizer, but to acknowledge that He is good at it; it works without constant tinkering to keep it going. (Would you buy a car that needed a mechanic on duty at all times to keep it working?) The apparent absence of His actions is to His credit, not evidence of His non-existence.

      But suppose you want Scientific evidence of His existence. Surely He left His fingerprints somewhere, if only to sign His work? Read the first part of Genesis, with the Big Bang (etc.) in mind. Obviously, ignorant savages aren't going to fully comprehend nuclear physics, quantum theory, or Multiverse Membrane blah-blah. Me neither. So turn it down a bit; make a "children's version" that's recognisable, but re-phrased to suit the audience. According to the Big Bang theory, at first there was no light (In the beginning, there was darkness...). Then, at some point there was. ("Fiat Lux!") Substitute plasma, gas, dust; gravitational and magnetic fields with "waters", and you can separate the "waters" above from the "waters" below as planetesimals accrete. And so it goes; creatures appear *in their proper order*, and Mankind names them. If you look at Genesis as a beginner's guide to local cosmology, it tracks pretty well. Well enough to be more than random... well enough to suggest that it's a story, with a Storyteller. ;)

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  16. Between morons asking or commenting about Nibiru / Nemesis conspiracies, and religious people getting hurt that a scientist might have offended their views, it's no wonder Dr. Brown doesn't blog very often, and never makes appearances here in the comments section.

    Seriously guys... a film like "Melancholia" is science fantasy, not a government conspiracy to repress the truth. Further, science and religion aren't mutually exclusive... but if you actually start studying science at the university/grad school level... you'll start to see why the finer points of religion don't hold up very well to any prolonged or rigorous scrutiny.

    It should strike people as troubling that for a scientist to be able to write or blog with any authority, he has to earn a Ph.D. (from a competitive university) and contribute to furthering current scientific understanding (a very difficult undertaking that requires a lifetime's worth of work in a peer-reviewed setting, with your work vetted by the brightest minds in your field). But for a pastor/minister/rabbi/imam/religious figure... they only have to go to a religious school / bible college / madrassa (of variable to potentially zero credibility), and have to prove nothing in any sort of peer-reviewed setting. And yet, few people bat an eyelid that so many trust these religious leaders blindly... hell, even give them money, or their lives even (suicide bombers, for example).

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    1. No, really, it is just that I have way too much science and teaching to do to be able to blog regularly like I wish I could.....

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  17. i really do not see that sidebar of Creationism/ Science as one we should care to discuss. Religion should be a private thing between ourselves and our idea on "necessary being", and whatever it may be interesting to discuss if at all, it should certainly be discuss in an appropiate (sp?) venue NOT HERE. IMHO

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  18. 're. a name for 2007 0R10, why not call it Brigid, as that Irish goddess's name means exalted or on high, and it's extremely far away out in the solar system - and, it's a beautiful Goddess who's the chief goddess of my country and I would love it �� Why not honour some Irish/Celtic mythology?

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  19. I see that we (NASA's Dawn spacecraft) have reached the world Ceres.
    (Hat tip to Isaac Asimov for the pun!)

    Is Dr. Brown in on that, or just watching?
    (And is it possible to get "custom" photos taken by any of the Mars Rovers, etc.? I'd love to get one, at Jovan opposition, with a newly risen (or setting) Jupiter over a twilit Martian landscape. Should be awesome.)

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  20. Could Eris be worth sending a mission near? I've been doing a lot of research but it doesn't seem like we know much about this dwarf planet. Even NASA didn't have much information on it. I understand it is not likely ever going to happen, but it would be good to expand our knowledge of our solar system by going to one of the farthest objects in our solar system. If I am correct, It's orbit goes to the very edge or beyond the Kuiper Belt. It would certainly be a better idea to send a mission to Eris than other places, Eris is the most unique. The data could also be compared to that of Pluto, who is said to be it's "twin". I know no one may reply because this was posted a while ago but I find the topic of Eris really interesting.

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  21. Maja Zwicky-Saudhi, MaldivesJuly 2, 2015 at 11:06 PM

    A thought about life on other planets: What if life forms on other planets do not need the same amount of water, temperature, oxygen etc as e do, but have exactly the amount of gas, temperature and life-giving elements they need in their environment?

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  22. What is expected to be the next large survey data set to use that is significantly more sensitive to faint objects? Second, would your approach have picked up bight objects at, say 100 AU? Given the algorithm depends on motion, at what distance is the motion simply too slow to trigger a recognition event ?

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  23. Is your search algorithm available for others to use/improve for future searches?

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  24. The old algorithm doesn't exist anymore, I suspect. But we've got new ones we're working on that we will make open source, I think. If we can figure out how....

    And, for @unknown: most of our searches are senstive to ~120 AU or so. We've done some specialized searches for more distant things, but so far haven't found them.

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  25. Hello,

    Sorry if this is off-topic. I just finished reading your book, I've thoroughly enjoyed it. Reading about the transition to the digital astronomy was very interesting for me. I remember reading James Herriot's books a long time ago, I was similarly fascinated by his description of the many major transitions going on in his profession (okay, now this is definitely off-topic). I'm going to remember the part about the sign language for infants -- for the future, just in case.

    I couldn't help wondering about a couple of things. One is when you mention that the coordinates of Xena and Easterbunny were found by someone else as well and sent to "the place where you announce discoveries". Does that mean that it was sent anonymously? Because if it was sent by the same Spanish team, I think nobody would be able to argue a coincidence. Also, does it mean that if the authorities had formally followed the protocol, the guys who sent the announcement would have been recognized (at least initially) as the discoverers of Xena and Easterbunny?

    The second thing is that I couldn't help thinking that maybe it would have been possible to use more advanced methods than flipping between two images to detect the differences. Morphological image processing was well developed at that time already, so wouldn't it make sense to, say, find morphological components in the image and discard the artifacts based on their shape measurements?

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