Everything Everywhere Daily: History, Science, Geography & More - The Largest Known Things in the Universe

Starting point is 00:00:00 The universe is big, really, really big, so big that it's hard to intuitively grasp its size because we have nothing in our lives that we can compare it to. And not only is the universe big, but within it are things that are really big as well. The discovery of these big things have been some of the biggest discoveries in the history of science, and the discoveries will probably keep continuing into the future. Learn more about the largest known things in the universe on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may

Starting point is 00:00:53 have gone unnoticed. It effectively turned day into night and how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. If you're going to talk about the biggest things in the universe, you have to start the discussion with the biggest thing there is and the biggest thing that there can be, the universe itself. But before I get into that, I should note that when it comes to the size of the universe, there is much we simply do not know, and in fact, we can never know. We are ultimately limited by the speed of light. In a previous episode, I addressed the age of the universe and how we

Starting point is 00:01:36 can estimate its age. As we have developed better telescope, such as the James Webb, we have been able to gather more and better information. However, we can only see what we can see. That means our knowledge is forever limited to just the observable universe. The observable universe is the part of the universe that is close enough to us that light has had time to reach us since the universe began. If we take the generally accepted age of the universe at 13.8 billion years, and this number has come into some dispute in the last few years,

Starting point is 00:02:09 then the furthest we would be able to see is 13.8 billion light years away. That is the size of the observable universe. However, that isn't quite true. The universe is expanding. So if the furthest light that we can see is 13.8 billion light years away, that means that the light was emitted 13.8 billion years ago. We are literally looking into the past. In the 13.8 billion years since the last,

Starting point is 00:02:39 light was emitted, space has expanded, which means that we are actually seeing something that is currently much further than 13.8 billion light years away. The best estimate, based on the expansion of the universe, is that the edge of the observable universe that we can see now is actually about 46.5 billion light years away. As the edge of the observable universe can be seen in all directions, and because the universe appears to be expanding equally in all directions, then the diameter of the observable universe would be about 93 billion light years. And of course, that is only what we can see. There's no reason to believe that what we can see is everything in the universe. The problem is that there is no way to know what or how much

Starting point is 00:03:30 is beyond what is in the observable universe. Because it is beyond the limit light, can travel, there is no way for any information from this part of the universe to ever reach us. It is entirely possible that the universe is infinite in size, but at least as of right now, there is no way to know. So if we take a step back from the entire universe, what is the biggest thing inside of it? Astronomers have done a mapping of the observable universe, and what they found is that the universe is not equally distributed. There are enormous areas that are seemingly devoid of anything. And then there are vast chains of galaxies known as galaxy filaments and galaxy walls.

Starting point is 00:04:16 Filaments are long stretches of galaxies and walls are the same thing stretched out like a sheet. The largest of these is the Hercules Corona Borealis Great Wall. It is literally the largest structure in the universe, measuring about 10, billion light years in length. These large galaxy filaments and galaxy walls are not necessarily held together by gravity. They're simply too large. The largest gravitationally bound objects are galaxy clusters and superclusters. They are collections of hundreds to thousands of galaxies that are gravitationally bound to each other. The largest known galaxy supercluster is the Lania Kea Supercluster. The Lania Kea Supercluster consists of approximately one

Starting point is 00:05:02 100,000 galaxies, including the Milky Way. The diameter of the Lanierkeia supercluster is about 520 million light years. The fundamental unit of a cluster or supercluster is the galaxy. A supercluster is a collection of galaxies that are gravitationally bound, just as a galaxy is a collection of stars that are gravitationally bound. There are many different types of galaxies. There are spiral, elliptical, lenticular, and irregular galaxies. The largest galaxy ever observed is IC-1101.

Starting point is 00:05:37 It is a supermassive lenticular galaxy located in the Abel-2020 galaxy cluster. It has a diameter of approximately 500,000 light years. It's located approximately 1.5 billion light years from Earth. And the galaxy is so big that it was discovered as early as 1790 by William Herschel, the discoverer of the planet Uranus. As I mentioned, galaxies are collections of stars, and at the center of most galaxies are supermassive black holes. If you remember back to my episode on black holes, they're created when large stars collapse onto themselves. The result is something so massive with a density so great that light itself can't escape.

Starting point is 00:06:22 So far, everything I've mentioned in this episode, even the universe itself, I've been able to provide an estimate using some measurement. of length. But you can't really do that with a black hole. Once a black hole starts to collapse on itself, there isn't any known force in nature that can stop it. That's why they're often called singularities. We have no clue if they have actual length, width, width, or depth because it's impossible to observe and measure them. So when determining what the largest black hole is, we can measure it in one of two ways, either through the size of its event horizon or by its mass. The largest black hole that has ever been found is known as T-O-N-618. It was first observed in 1957 as it powers an incredibly powerful quasar, but at the time, astronomers didn't know what it was. T-O-N-618 has a mass

Starting point is 00:07:14 of 40 billion times the mass of our sun, and the quasar that it powers has the luminosity 140 trillion times that of the sun. Black holes are ultimately made of stars. So as we step down our cosmic ladder, what's the biggest star that we know of? A few things about stars. For starters, it's difficult to observe individual stars outside of our own galaxy. Other galaxies are so far away that all the stars in them tend to blend together, making it difficult to identify individual ones. So for the most part, what we know of individual stars are stars located in our galaxy, the Milky Way. There is a limit to how large a star can get in terms of mass. Beyond a certain point, the star will just explode. However, stars can grow quite large in

Starting point is 00:08:08 terms of volume. If you remember back to my episode on stars, depending on the mass and age of a star, they can become red giants. The largest known star in terms of volume is UY Scooty. UY. Scootty. UY Scootie is classified as a red super giant and a pulsating variable star. A pulsating variable star is a star whose brightness, as seen from Earth, changes over time. U.Y. Scootie is way larger than our sun. The radius of U.Y. Scootie is 909 times greater than that of the sun. And the volume of U.Y. Scootie is 750 million times that of our sun. If U.I. Scootie were to be placed in our solar system in the current location of the sun,

Starting point is 00:08:58 it would completely swallow up Mercury, Venus, the Earth, Mars, the asteroid belt, and even Jupiter. Eventually, U.Y. Scootie will end up as a massive supernova millions of years from now. As we take a step down from stars, we encounter things that orbit stars, aka planets. You're probably pretty familiar with the planets orbiting the sun and know that Jupiter is the largest planet in our solar system. However, just because something is big in our solar system doesn't mean that it's big in galactic terms. It's been almost 30 years since the discovery of the first exoplanet. As of the time of this recording, 5,653 exoplanets orbiting other stars have been discovered. While everything I've mentioned in this episode is subject to change pending new discoveries,

Starting point is 00:09:50 The thing that's most likely to change is probably going to be the largest exoplanet. As of my recording this episode, the largest exoplanet that has been discovered so far is PDS70B. PDS70 is the name of the star and B indicates that it's the second planet discovered around the star. It has a mass of about three times that of Jupiter, and if it were any more massive, it would probably just turn into a brown dwarf star. While it is the most massive, it isn't the largest exoplanet by volume. The largest exoplanet by volume is HAT P67B. HAT P67B is known as a hot gas giant. It's a gas giant like Mercury or Saturn, but it's extremely close to its star like Mercury.

Starting point is 00:10:39 The mass of the planet is only about 60% that of Jupiter, but it's 2.08 times the diameter of Jupiter. Given its mass and volume, that makes it the least dense exoplanet ever discovered. As we get below planets, we have to look closer to home because we can't observe anything that small further away. What is smaller than a planet then? Well, that was resolved with the whole is Pluto a planet controversy, which provided the currently used definition in astronomy. The largest thing we know of smaller than a planet would be a trans-Neptunian object. The largest trans-Neptunian object ever discovered is named ERIS. ERIS is slightly larger and more massive than Pluto, which is also a trans-Neptunian object. It is, on average, 67.8 astronomical units from the sun,

Starting point is 00:11:32 and astronomical unit being the average distance from the Earth to the sun. However, trans-Neptunian objects are not the only subplanetary objects in the solar system. There are also moons that orbit around planets. The largest moon, that we know of is Jupiter's moon Ganymede. Ganymede has a diameter of 5,268 kilometers, making it larger than the Earth's moon and even the planet Mercury. As we shrink in size once more, there are a host of rocks that are just flying about the solar system in erratic orbits, and these are known as meteorids. When they strike the surface of the Earth, they become meteorites. The largest meteorite that is believed to have ever hit the Earth did so approximately 2 billion

Starting point is 00:12:16 years ago. Known as the Verdfort meteorite, it hit what is today the country of South Africa. It was over twice the size of the meteorite that hit the Yucatan Peninsula in Mexico that killed the dinosaurs and is estimated to have been 12 to 15 miles or 20 to 25 kilometers in diameter. There are a lot of really big things in the universe. And obviously this list only scratches the surface. But the next time you ponder something that you think is big, Just remember that there's always something much, much bigger. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Benji Long and Cameron Kiever.

Starting point is 00:13:01 I want to give a big shout out to everyone who supports the show over on Patreon, including the show's producers. Your support helps me put out a show every single day. And also, Patreon is currently the only place where Everything Everywhere Daily merchandise is available to the top tier of supporters. If you'd like to talk to other listeners of the show and members of the Completionist Club, you can join the Everything Everywhere Daily Facebook group or Discord server. Links to everything are in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - The Largest Known Things in the Universe

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