Help! This new dwarf planet needs a name

Scientists using the new Vera C. Rubin Observatory have located a possible new dwarf planet beyond Neptune. What would you name it?

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:17Flora Lichtman?

  Hey, it's Flora, and you're listening to Science Friday. Move over Pluto, a new dwarf planet just dropped. Scientists announced that they've likely discovered a new tiny planet beyond Neptune in the far-out ring of icy and rocky bits called the Kuiper Belt. It was spotted by the Vera Rubin Observatory. Now, the name does need work. It's called 2026 ED 138, and we're going to talk about that. With me now is the person who made the discovery, Dr. Matthew Holman, senior astrophysicist at the Center for Astrophysics at Harvard and the Smithsonian. Matt, thanks for being here.

• 0:54Speaker 02

  Thank you for having me.

• 0:56Flora Lichtman?

  Did you have a moment where you saw the data and thought, oh, my gosh, is this real?

• 1:03Speaker 02

  Yeah, absolutely. So one of the stages that we go through after we find these Kuiper Belt objects is to vet them because the software is finding them. And there are occasionally false positives. This one in particular, we knew if it were real, it would be quite large. So there you say, OK, I'm excited about that, but I'm not yet going to let myself believe it until it goes through all the paces.

• 1:31Flora Lichtman?

  This is classic scientist. You have to manage your own expectations, I'm sure.

• 1:36Speaker 02

  Well, one of the jokes that in this sort of very small subfield of people who look for these things, because we've run across all kinds of false positives, is that we've all found Mars out beyond Neptune over and over again, and it always ends up being a false positive.

• 1:53Flora Lichtman?

  So what does it take to actually confirm that it is indeed a new dwarf planet?

• 1:59Speaker 02

  So the definition of a dwarf planet is that it has to be big enough to be spherical under its own gravity. It has to have enough mass that if it started out with kind of an oblong shape, its gravity would have pulled it into a sphere. And what we know now is that we just know how much light we're seeing from this object. That light is reflected sunlight. So we don't know whether we are seeing a large, dark object or a smaller, much more reflective object. We'd get the same amount of light. So what we need to do to determine whether it is large is use some other method to measure the size.

• 2:44Speaker 02

  And there are a couple of different ways to do that. One of them is to use thermal infrared. Right now, we're looking at the reflected sunlight. But if we look at the glow from the object itself, from its own temperature, we can use that information to estimate how big the object actually is. Another way you could do it is with something called occultations. And that is when the object itself passes in front of stars in the background. And if you can imagine measuring the light from each of the, you know, from the star that it's passing in front of, as that light gets obscured, if you know the rate at which the object is moving, and you say, OK, here's where we lost the light, and here's where we, you know, when we pick it up again, you can measure the size.

• 3:28Flora Lichtman?

  So based on what you know now, can you deduce anything about its color or its size? Where do you think it looks like? And how does it compare with, you know, other dwarf planets we might know, like Pluto?

• 3:44Speaker 02

  Well, what we know is that it's fairly red. So dwarf planets, particularly the largest ones, tend to be sort of more neutral colored and highly reflective. And that's because they actually have fresh frost on the surface. It's kind of methane frost. This one, it doesn't look like that. It looks more red. We know in terms of its size, it's somewhere between 600 kilometers and 1,500 kilometers diameter.

• 4:11Flora Lichtman?

  Where does that put it in relation to Pluto? Smaller, either way, right?

• 4:15Speaker 02

  It's smaller either way. Pluto is something like 2,400 kilometers diameter.

• 4:21Flora Lichtman?

  OK, so the redness suggests that it's not icy. That's surprising to me. I think of, you know, the farther you get away from the sun, the colder it gets, the icier it gets. Tell me what I'm missing.

• 4:33Speaker 02

  When we talk about it being red is that we're just talking about the surface. You know, the interior could be very icy. We don't know, we have no idea what the density of this object is yet. Because, first of all, we don't know its size, and we don't know its mass.

• 4:48Flora Lichtman?

  Why did we just find this now?

• 4:52Speaker 02

  That's a great question. So there's several different reasons. One is it is seen in the sky in the southern hemisphere. It will go kind of nearly right overhead from the Vera Rubin Observatory. But that means that it cannot really be seen from the northern hemisphere. So that means there's a whole category of observatories historically that could not observe this object.

• 5:18Flora Lichtman?

  Wow.

• 5:19Speaker 02

  And then the other reason is that for the last 25 years, ED 138 has been passing across the Milky Way from our point of view. And the Milky Way is, you know, our galaxy, and it has a large number of stars. And that means that, you know, that pattern you see on the sky, glowing stars, makes it really hard to find a moving object in that field. And even it's hard enough that people don't typically even try to look there. So even if they had the capacity, they tend to sort of say, well, let's look elsewhere.

• 5:58Flora Lichtman?

  Too much noise.

• 5:59Speaker 02

  Too much noise. If we have a choice of where we're going to look, let's look in some place that gives us better odds.

• 6:06Flora Lichtman?

  How many other dwarf planets are out there in this area of the Kuiper Belt? Besides, you know, we know about Pluto, but are there others?

• 6:14Speaker 02

  I'm going to split that into two questions. One question is how many objects that are as bright as ED 138? So just for scale, people have taken the orbit of ED 138 and wound it back in time. And you can see it in photographic plates from 1937. So it's been observable for a long time. I would think that there are, say, one to three of those that are that bright left to be found. It's mostly because other people have done a pretty good job of searching both the northern and southern hemisphere. But as we just demonstrated, they didn't find them all. So I think there should be, you know, one to three of those.

• 6:58Speaker 02

  And then the other part of the question is, what about the farther things away? So something could be even bigger but fainter because it's farther from the sun and farther from us. You don't have to move something very far away before it's, you really can't see it. And that's because, as you know, you probably learned in a physics class, that as you move something away from the source of light, the amount of light drops off as one over the distance squared. So what that means is if I move the object twice as far away, it's 16 times fainter.

• 7:32Flora Lichtman?

  Yeah, yeah, yeah.

• 7:33Speaker 02

  So you could hide a lot of stuff out there. So I would say I can't enumerate how many dwarf planets are out there, but there must be a very large number.

• 7:45Flora Lichtman?

  Yeah, wow. We have to talk about its name.

• 7:49Speaker 02

  You are the thousandth person who has said that to me.

• 7:53Flora Lichtman?

  Matt, then this seems like, first of all, this seems like a dream come true for someone like you. Like, you have found the thing, probably, that you have been looking for for the last, how many decades?

• 8:05Speaker 02

  Well, I've been doing this for more than 30 years. I mean, I wouldn't say that I have been constantly looking for this object. I've done a lot of different things in my career, but I keep coming back to this. So it is a dream. But honestly, the dream is to find something even bigger, right? That, you know, that's like, of course, that's the greedy, you know, greedy scientist. Like, what we really want is find something where we don't say, OK, this is the dwarf planet. It's like, indisputably, here's a planet.

• 8:33Flora Lichtman?

  Yeah, OK. Well, let's take baby steps. I don't want to throw 2026 ED 138 under the bus, you know, because it seems cool in and of itself. But I feel like we do need a better name.

• 8:45Speaker 02

  We do need a better name. So there's a process.

• 8:49Flora Lichtman?

  First, I want to hear what you would name it.

• 8:52Speaker 02

  I cannot say because I will not, I will not let my heart settle on a name. Because I'll tell you, I have discovered moons of Uranus, Neptune, and I once had this, so we found a bunch of moons of Saturn. And I thought, let's call them, let's name them after dances. Every culture has a dance. We could, you know, everybody would be happy.

• 9:17Flora Lichtman?

  Like the tango or the...

• 9:19Speaker 02

  The tango or whatever, Charleston. And I spoke to the members of the nomenclature committee. There's a nomenclature committee. And they said, well, we don't name them after dances. We name them after people. And I said, you mean you name them after mythological beings? And they said, yeah, that. And, you know, my idea was shot down. So since then, I've been very, I would say, hesitant about letting my heart settle on any particular name.

• 9:54Flora Lichtman?

  You've been protecting your heart. But Matt, here's what you have now that you didn't have then. You have 2 million Science Friday listeners who are ready to be the groundswell that you need to get your name across the finish line. We can all just start calling it whatever we want to call it and manifest this name. So please, what would you name it? Please tell me.

• 10:19Speaker 02

  You cannot arm twist me as much as you, my arm rotates in the socket on this one.

• 10:25Flora Lichtman?

  Would you be open to hearing suggestions from our listeners?

• 10:30Speaker 02

  I would be open, sure.

• 10:31Flora Lichtman?

  OK, because I think our listeners, they're so clever, and they're so smart, and I feel like they will have good ideas. The number is 8774-SYFRAY. We want to hear your best name. And Matt, before we go, any tips for people who are trying to brainstorm a name? Like, anything that they should keep in mind?

• 10:50Speaker 02

  Well, so up until, I think, very recently, the names for these objects out beyond Neptune were kind of creation gods. They've been named after creation gods from lots of different cultures, and that's great. I've had suggestions of the Wampanoag creation gods, you know, here in Massachusetts. There are suggestions to honor groups in Chile, and that makes a lot of sense. So people have suggested names that are, indicate like something that was hidden for a long time, you know, something that we're only seeing now. I'm sure your listeners can come up with some fabulous names.

• 11:30Flora Lichtman?

  Is that, do you think that's the theme that people should be thinking of? Something that was hidden and has just come into sight? Like, is that the heart of the narrative of this dwarf planet?

• 11:39Speaker 02

  That's sort of the way I see it. I see it as something very positive, too, that one of the things that has always kept me motivated about this kind of research is to know that we haven't found everything. There's this, you know, enormous solar system that we're still exploring. And I think this sort of represents that kind of hope.

• 12:01Flora Lichtman?

  I think that's the perfect place to leave it. Matt, thank you so much for being here today.

• 12:05Speaker 02

  Thank you.

• 12:06Flora Lichtman?

  Dr. Matthew Holman, senior astrophysicist at the Center for Astrophysics at Harvard and the Smithsonian.

• 12:21Flora Lichtman?

  This podcast was produced by Shoshana Buxbaum. I'm Flora Lixman. Thank you for listening.