 Welcome to In The Studio. I'm your host, Vinita Domeyer, and today our guest is my husband and co-coordinator of the Davis Astronomy Club, Calvin Domeyer. Calvin and I both love to share love of astronomy. We are both amateur astronomers, and we love to share the wonders of the sky with everyone who comes to our Davis Astronomy Club meetings. Today, Calvin will be discussing the January 20th announcement by Caltech astronomers. These were the two planetary astronomers from Caltech who made a momentous announcement on January 20th regarding a potential ninth planet in our solar system. Now, most of us grew up learning that there were nine planets in the solar system, and we learned their names by rote. But in 2006, the International Astronomical Union demoted Pluto. It did not qualify as a planet according to the new definition, and we were left with only eight planets in our solar system. And some kids were disappointed that they only had to learn eight names. But now there's a potential for another ninth planet in the solar system, adding to another planet in our family of planets in our solar system. This is a momentous announcement, and with me today is Calvin, and we will discuss why we think there is a ninth planet in the solar system. Welcome. Thank you. So first, tell us how did the planetary astronomers from Caltech figure out that there's a potential ninth planet in the solar system? Well, first let me get their names right. This is Konstantin Batagin and Mike Brown, those are the two astronomers. They were looking at the orbits of some of the planets that they found in the trans-Pluto orbits. These are the ones that have been spotted by various telescopes. So these are Kuiper Belt objects, which are just little bodies of planetoid bodies floating in space. They're so far away right now, we don't really know if they're cometary type bodies, meaning mostly ice, if they're gas giants. Well, none of these are really giant bodies, but things like Neptune, Uranus. But they've been able to spot those in various telescopes and watch them over a number of months to years so they can figure out what the orbit is of each of these. Now, what's very interesting is most of the objects in our inner solar system all fall on one plane, sort of an ecliptic plane. That's the case of all of our major planets, the asteroid belts. But a lot of these objects are spotted in the Kuiper Belt or outside of the plane, or they have orbits which take them in and out of the plane. And so these two particular astronomers were trying to figure out if they could come up with any reason for why they should be out of there. Because when the solar system formed, the thought was everything was kind of all orbiting together. And so everything should kind of stay with that sort of an orbit. But these ones, obviously, are not. And they tried some different models and different things. And then one of them hit upon the idea that maybe there's some object that perturbs it. It's well known, for example, by watching Jupiter, that you can have comets or different things that come close to Jupiter, and then their orbits get bent around the planet, just like things can get bent around the sun. And so they had this kind of idea at the back of their mind. The other thing they noticed for a lot of these, I can't really call them planets, but a lot of these bodies that they looked at, social system bodies, is that they all came in and out of the plane of the solar system. And they had certain characteristics that were very common, that they would meet in sort of the same sort of general location and then go back out again and meet again in the general location. So they're sort of gravity locked together. So that put credence on the possibility that maybe there was some large object out there that these solar system bodies maybe were normally just going around the solar system. They got too close to this planet and they got pushed out. And as they started looking at these, they first tried with one or two. They came up with an algae, OK, this would sort of work. And they kept going and going. Now they've got seven objects that they found in this region that all fit the same basic scenario, that a very large object and the models say maybe something about 10 times the mass of the Earth which could be out there. And that could perturb the orbits enough to account for what's happening. Now no one's seen that object. But if you look at the models, we think it's fairly far out in the solar system. And it's probably been observed if it's there. And the models say it's extremely likely it's there. It's probably been observed in photographs, but no one's made the connection. So what people are doing right now is organizing big observatories in the Earth are doing hunts in the general region where they think this planet is. And they're also looking at old photographs that were taken. Basically the way they found Pluto, for example, they had an idea of where it was based on how the orbits got changed of interplanets. And then they took lots of photographs and they would look to see which stars basically changed from one night to the next or from one week to the next. Stars are obviously so far away that they don't move in the sky. But anything that's interior to the solar system does. And so now they're trying to look through and figure out where this is. And that method was used, as you said, to find Pluto. And before that, Neptune. There were perturbations on Uranus's orbit. And they said, wait, something is perturbing Uranus's orbit. So it has to be some massive object out there. And so they started hunting for Neptune and found it where they actually predicted it'll be. And same thing went with Pluto. Now in this case, they can't really look at perturbations of other objects inside or outside in terms of perturbations in the orbit. Because we're talking about objects that take 10,000 or more years to actually orbit across the solar system. So we've only been looking at these objects for 5, 10 years. So we don't have enough data to be able to look for that sort of effect. But there's enough confidence in the math how this looked at. And so far, we don't have another theory that would explain what's happening to all these extra solar system bodies other than what we call the ninth planet. So it's the best theory around. It fits all the facts we'll be able to look at. In fact, as they've advanced this model and gone through more of the math, they found more and more things that agree with this model that they hadn't thought about before. So it's extremely exciting. Now, they think based on all the stuff that they know roughly what the orbit of the planet is. But they said the math would accept an orbital period, how long it takes to go around the sun anywhere from 10,000 to 20,000 years. And they think right now, again, according to the math, that it's most likely that it's farthest point from the sun in its orbit. So of course, that makes it the hardest for us to see. But they've been able to narrow down the region of the sky to still a fairly large area, but a manageable area that they're now going to be looking, again, through old photos and taking new photos. So to recap about what we think this planet nine might be like, it's going to be 10 times as massive as the Earth and it's about 20 times further than Neptune is from Earth. And it might take between 10,000 to 20,000 years to go around the Earth. That's an amazing planet. Yeah. Now, most likely because the mass is so high, it's not going to be a planet with a solid core, like the Earth, like Mars, like Venus. It's more likely going to be a planet similar to Jupiter, Saturn, Uranus, Neptune, a gas giant. So mostly hydrogen gas and things, maybe with a little solid core at the bottom. Unlike Pluto, which is mostly an icy object. You could consider Pluto as a very, very large comet, for example, that got stuck out in the outer solar system. This is most likely a gas giant that probably formed inside our solar system, along with Neptune, Uranus, and things like that. And for some reason, drifted out. Maybe a near collision with one of the other big gas giants, we don't really know what happened or what could have happened. They don't think it's very likely that a gas giant could have formed that far out. But it seems to be there. So that's the most likely explanation. So right now, it's obviously very hypothetical. It's come out of math modeling to explain these locked orbits of these type of objects. So how will we know that there really is a planet out there? Well, the only way to really know for sure is to see it in a photograph. We've got enough very good telescopes on the Earth, also with the Hubble. Hubble, in this case, would be asked to confirm a sighting. They wouldn't want to spend a lot of Hubble's time just searching randomly through the sky. But we've got enough good telescopes that we should be able to see the reflection of the sunlight off that planet coming all the way back here. Even though it's so far away, we have enough sensitivity to see that. The trouble is just going to be distinguishing it from other background stars. But once we can see that, we can get that visual confirmation, then they can take Hubble and have Hubble point at it and possibly actually be able to determine the extent, like the diameter, by looking at the size of the light. Then we'll have some idea of the density. Is it really a gas giant? And then comes the fun part where people get to decide what to call it. Pluto was named by an 11, 12-year-old British girl. So yeah, that's fun. I mean, the kids have been missing Pluto as one of the planets, but now they'll have to learn. People are already throwing names out. And they vary from names along the same sort of line that you have with Pluto and Chiron, things from mythology to a lot of kids who have their own things. One of the contenders is Olaf, because they think it's going to be a frozen planet. Well, I have a feeling the Celtic astronomers who discovered it through mathematical modeling may get a say in who gets to name it or what it gets named. They very well could. Yeah. But that's an amazing discovery. I mean, we've known about five planets from millennium, from ages on through the Babylonian times. And then in the last century and a half, we discovered Uranus, Neptune, Pluto. Pluto, of course, is not a planet anymore. So this is revolutionary for our time to discover a planet in our solar system. We have discovered about 2,000 extra solar planets confirmed, and maybe another 3,000 unconfirmed. But a new planet in our solar system is big news, very exciting news. Yeah, now there are lots of Kuiper-built objects out there that they've been able to find over time. And many of them are the same size as Pluto or bigger. I think there's at least one or two that are larger than Pluto. That's one of the reasons they demoted Pluto as a planet. Because if we included Pluto with its old definition, anything that's about the same size as Pluto would have to keep getting added to the list. So the kids would have nine planets, then 10, then 11, then 12. And then thousands, maybe. So the new definition of a planet would have to apply to this ninth planet, that it has cleared its orbit and its hydrostatically spherical in shape, and it revolves around the sun. It would be very strange to call it a dwarf planet if it was 10 times the math of the Earth. If it hasn't cleared its orbit, it will be a dwarf planet. That's the definition. A very large dwarf planet. It was in 2006. That's what happened. So I see our time is up. I would like to thank Calvin for discussing this exciting new development about a new planet in our solar system. Yay. As I said, host the Davis Astronomy Club, you're welcome to contact us at explorat.org. And we hold our meetings there on Saturdays, which we do it on a Saturday that we think is convenient and there's something to see in the sky. Saturday meetings at Explorat are free and open to all ages. We welcome 9 to 90 and even younger kids. We usually do a topic and a little discussion on that topic, followed by a star party outside, where the permitting, of course, we have club members who bring telescopes, binoculars, and we look at whatever we can see in the sky that evening. It could be a planet, moon, deep sky objects. Sometimes you looked at comets. So it's always exciting. Meetings are roughly once a month or so. We try. In fact, our next meeting is going to be on the 27th of February, Saturday. And we're going to discuss another new revolutionary discovery, the gravitational waves. And we've been hearing a lot about it in the news. It was announced on February 11th a week ago from today about detecting these ripples in space time, which are called gravitational waves. They only happen when you have some uneven mass spinning or a cataclysmic explosion like a supernova. Or in this case, it was two massive black holes colliding with each other that caused these ripples in space time. And we actually detected them on Earth. The signal was received on Earth on September 14th of last year. And so this new discovery has revolutionized. It's given us another tool to look at the universe. Because right now we are really looking at the stars only through electromagnetic spectrum. And this gives us another way. So I would like to thank my guest, Calvin Domeier, again for coming to the in the studio. I'm your host, Venita Domeier. And I'd like to also thank all the studio staff for producing this show. Thank you.