Part 2 of 2! How did the observation of a kilonova change astronomy? How did that one observation kill off alternate models of gravity? What’s in store for the future of gravitational waves? I discuss these questions and more in today’s Ask a Spaceman!
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this episode of Ask a Basement is brought to you by my friends at better help. Better help provides easy, convenient, affordable access to online counseling and therapy. And, you know, the therapy has been an important part of my, uh, life experience is something I'm absolutely not ashamed to talk about. I wish more people used therapists and counselors to take better care of their own mental health, just like they take of their physical health. Uh, I know a lot of you turn tune into this show for Astro Thera as a word, but maybe if you're having a really tough time, you should talk to an actual professional, and so I encourage you to go to better help. They are convenient and professional. It's real therapy and counseling, and it is affordable and you connect online. You don't have to wait in a waiting room or any of that. You just talk to someone who who cares and and knows what they're talking about. As a listener, you'll get 10% off your first month by visiting better help at better help dot com slash spaceman, and I want you to join over 1 million people who have taken charge of their mental health again.
That's better help. HE LP dot com slash spaceman Of course, it was weird. It had to be weird. Our first ever direct observation of a black hole merger back in 2015 with the LIGO Observatory was weird. It has to do with the masses of those black holes. One of them was 35 times the mass of the sun and the other was 30 solar masses and combined. When they merged together, they made a 60 solar mass black hole, and and some of the mass went away in the form of gravitational waves. Why is that weird? Because we didn't think that nature liked making black holes that big. Like How do you How do you make a black hole? You make a black hole through supernova through giant stars dying and the this naturally sets some limits.
You need a star big enough in order to trigger a supernova explosion and reach the densities necessary for a catastrophic collapse in the formation of a black hole. So that sets a minimum size of black holes and then stars can only get so big. And so the black holes that they form can only be so big. If you want a black hole, that is 30 solar masses, you need way more than a 30 solar mass star to generate it. It needs to be 100 or 200 times the mass of the sun, and those stars just aren't around. So in order to get a 30 solar mass black hole, our best way to get that is through the mergers of many smaller black holes. You need a few mergers. You need to start with some fives and tens, and then you get some tens and twenties, and then you're up in the thirties and thirties fives. And then, as we saw with this merger, this gets you up into the sixties. But the fact that we found a merger event involving these masses basically as soon as we turned on our gravitational wave detector means that these kinds of mergers must be relatively common.
And by relatively I mean more than zero, which is more than we expected. We generally thought that black holes were two distinct populations. You had your stellar mass of a few, maybe 10 or 20 solar masses hanging out all around the galaxy. And then you had the super massive ones in the galactic centers that were millions or billions of times more massive than the sun. And we thought that supermassive black holes bulked up super quickly that there'd be a few mergers right away, and they would just consume gas, consume gas, and all of a sudden, you get this giant black hole. But here we are. As soon as we turned on a gravitational wave detector, we saw 30 35 which is weird numbers. It's too big to come directly from a star, and it was merging into something bigger, and the fact that we saw it happen as soon as we turned on our detector means it must be relatively common. But we didn't think these kinds of mergers happened at all. We thought black holes led relatively isolated lives.
They they would form in a stellar system out of the remnants of a supernova and then just sit there and maybe every once in a great while, two black holes would randomly find each other in the vast of space and collide. But But no, it happens all the time and and that's that's not expected. In order for this to happen all the time. You need black holes to be much more common than we thought. And bigger black holes, much more common than we thought. And they need to interact more often than we thought. And it was just weird. So naturally the question came up. How do we get black holes this big? How do you get a 30 solar mass black hole so easily so quickly? I've already done an episode on primordial black holes on black holes that may have been formed in the earliest moments of the Big Bang. That idea had largely been put to pasture. Of course, as soon as we thought of the Big Bang, we were like, Maybe it makes black holes and and the universe is flooded with black holes, wouldn't that be awesome? And of course, that idea had been around for a long while. But observations of the cosmic microwave background and stellar structures Yeah, we didn't really think that primordial black holes were a thing.
But then this one stinking observation comes up and it reopens that can of worms. The only reason people still talk about primordial black holes is because of the LIGO Meger event, and it's really, really hard to get stellar mass black holes black holes five times the mass of the sun to merge often enough to get them up into the thirties and sixties. It's hard to get them to merge 45, 10 times. On the other hand, it's also very hard to have the Big Bang create black holes that survive all of their observational tests. So we're a bit stuck. But the weirdness didn't stop there. I'm sorry if I'm if you are feeling unsatisfied right now. There is no satisfactory answer as to why 30 solar mass black holes exist and are merging and are turning into 60 solar mass black holes. The weirdness didn't stop there. In the years since that first detection, we've gotten about 50 more merger observations with LIGO in his sister observatory, the Virgo in Italy, which is awesome. We just got started with this whole gravitational wave detection thing, and we're already turning it into its own field of astronomy with charts and plots and categories and labels.
In 2019, 4 years after that, first Nobel Prize winning detection LIGO announced yet another black hole merger, and nobody really cared or noticed because it was pretty routine by now. I know the first one gets a Nobel, and but the 40th gets a yawn. But there was something odd about that merger. One of the objects had a mass of around 25 solar masses, which was definitely a black hole. The other had a mass of around 2.6 solar masses, which was definitely a a thing. Remember the whole mass limit on black holes? You need a star big enough to make a black hole. The minimum star size necessary that we think in order to form black holes is around eight solar masses eight times the mass of the sun, and that will give you a black hole around five solar masses according to our best understanding of this extremely complicated astrophysical scenario. But it's it's worth it. It's something. And then before you get black holes, there are the neutron stars.
You know, the leftover cores of of massive stars. These are come from stars that go supernova, but don't go all the way to forming a black hole in their core. You're just left behind with a big ball of neutrons. But we can calculate the interior structures of neutron stars, and we can figure out like how stable they are for a given amount of mass. And we and once they get a little bit too big, like around two ish solar masses. 1.722 0.2 depending on the calculations. Kind of complicated physics here to give us a break. Once it gets a little over two, it it just catastrophically collapses and turns itself into a black hole. But here we have a merger event detected with LIGO unambiguous. One object was definitely a black hole, and one object was too big to be a neutron star and too small to be a black hole. Hate to disappoint you yet again, but to date the mystery is not resolved, and a repeat of that event has not yet been observed.
So we're just left hanging out here on earth, wondering what the heck happened and who the heck was involved in that collision 790 million years ago? We don't know. We don't know what that object is. Was it a record breaking neutron star that defies our understanding of how neutron stars work. Was it a record breaking black hole that defies our understanding of how black holes work? Was it something else we don't know. But that 2019 event wasn't the first time that a neutron star was involved in a gravitational wave signal. That honor goes to GW 170817. And if you figured out the code by now you've realized that this event was detected on August 17th, 2017. There were three gravitational wave detectors involved in this event, Virgo in Italy and the two LIGO sites in the US. The signal first arrived at Virgo. 22 milliseconds Later, the gravitational wave signal arrived at the Livingston site in Louisiana, and three milliseconds later it arrived at the Hanford site in Washington.
About six minutes after the gravitational wave signal passed through the earth, the automated systems at LIGO had run. The numbers, matched a pattern and alerted the team that it detected a significant signal. The gravitational wave event lasted about two minutes from beginning to end, and something was different about it. By the time the automated alert was sent to the wider astronomical community. They were already responding to a different automated alert, this one issued by the Fermi Gamma Ray Space Telescope, which had detected something called a short gamma ray burst. That alert went out about 14 seconds after the detection. UH, which makes that alert going out a few minutes before the gravitational wave alert. It's much, much easier to detect Gramma Ray bursts than it is to match templates to signals in a gravitational wave. So the alert came out sooner. LIGO isn't that great of pointing, which we talked about in part one of this series, but with three detectors, they could constrain the source of this gravitational wave to a particular point of the sky in that region included.
The source of the gamma ray burst in a little galaxy designated as NGC 4993. It's about 100 and 40 million light years away. Very boring galaxy not worth a visit. It's like a random town in the Midwest. When you see one, you see them all but the fact that Fermi was able to pinpoint the location to a particular galaxy and then LIGO said, Hey, we also got a gravitational wave signal roughly at the same time as this gamma ray burst and it's coming from the same region. The sky people got interested. Within an hour, astronomers around the world realized that the gravitational wave and the gamma ray burst were from the same event, an event predicted years before the merger of two neutron stars. To say that this was a big deal would be an understatement of both the words big and deal. The timing was good. The event occurred in the early afternoon in Europe and in the morning in the US, giving those astronomers enough time to understand what they were looking at, which was something that we have never seen before in astronomy.
That night, astronomers around the world issued priority interruptions on their telescopes, canceling the current active programs, training them, focusing in the M on NGC 4993. It was especially opportune because our massive observatories in Chile were able to target it that night. It was in the Southern hemisphere. It was visible. It was clear skies. It only took 10 hours. For the first optical image of this neutron star merger, astronomers around the world continue to follow it that night the next day, the next week, the next month, studying it with every lens, every antenna, every orbiting observatory. Eventually, this neutron star merger was observed with every part of the electromagnetic spectrum, from radio waves all the way to gamma rays. Astronomers worked for the next two months and then made a coordinated announcement just two months later. That coordinated announcement contained over 100 papers about the neutron star merger.
There was a single paper that summarized all the observations covering the gravitational waves covering neutrinos, which were not seen in all the aspects of the electromagnetic spectrum. All the participating observatories and collaborations and teams. That one single summary paper had over 4000 coauthors representing one third of the entire worldwide astronomical community. Why was this a big deal? Because it was the first major observation in what's called multi messenger astronomy. The merger of neutron stars has long been theorized to be a possible event We had seen for a few years certain flashes on the sky that we thought might be caused by merging neutron stars. But it's impossible to see what's actually happening because you only see the explosion. It's like trying to figure out what the bomb was made of when you only see the explosion in the aftermath.
But the gravitational waves gave us a peek inside the neutron star merger as it was happening. So the gravitational waves allowed us to see the collision itself in real time. The gamma ray burst was it allowed us to see the initial flash, and then all the electromagnetic follow up allowed us to see what happened after. And we were able to develop a complete and total picture of this one singular event. A killer nova. That's the name we give to merging neutron stars. We call it that because we had long predicted that when neutron stars merge, they blow up as most merging things tend to do in the universe. And they get very, very bright, but not as bright as a supernova, but about 1000 times brighter than a typical Nova. Hence the name Gola Nova. And we care a lot about Kan Novas we've talked about before.
The elements we've talked about the Big Bang. We've talked about stellar fusion processes. Nucleosynthesis. We know that the Big Bang gave us the hydrogen, the helium, a little bit of the lithium, but who cares about lithium in the universe? Then stars fuse that hydrogen and helium into more helium into carbon into oxygen into silicon, magnesium and then eventually iron. But once you start using iron, if you want to use any heavier elements, that takes energy rather than releasing energy. And so it does not make for a great power source instead inside of stars. And so that's why stars tend to blow up once they form iron cores to get all the elements heavier than iron, of which there are a lot, you need some special conditions, you need tons of energy, you need lots of neutrons. You need it to happen quickly, and you need to not care about getting a return on your investment. Supernova explosions obviously do the trick. But when we examine the nuclear chain reactions in detail, and when we observe the remnants from supernova explosions, we seem to be missing a lot of the most common heavy elements like yeah, yeah, a supernova explosion.
You got a lot of energy. You got a lot of neutrons. It's all happening very quickly, but just how the process forms of how these elements that, uh if you take an atom, a nucleus and you shove a neutron into it and you you get a proton out and then, uh, it transforms into a new element that radioactive process of of fusion and fission and all the crazy stuff when you follow those chains with how a supernova explosion actually proceeds and then when you actually look at supernova remnants and study what elements are hanging out in that exploded aftermath, we're missing a lot. We care about killing Nova because they are the second great, heavy element factory in the universe. They have just the right kind of physics, which by which I mean more neutrons than strictly necessary to produce a lot of elements. I mean, you're colliding neutron stars. You're the neutron star is an object that weighs a few times the mass of the sun crammed into a volume smaller than Manhattan.
It is a giant atomic nucleus. It is a giant ball of neutrons, and then you're taking two of them and smashing them together and seeing what happens Well, what happens is you get massive chunks of neutron star stuff, which is just neutrons flying off splintering, radioactively decaying, combining again in the en interjects forming elements. In fact, that's where the big, bright flash comes from. The brightest part of the Kila Nova explosion is not the the event of the merger itself. It is days later or weeks later when you have all these elements radioactively decaying, releasing energy. That's when you get the bright glow and you have all the right conditions, lots of neutrons, lots of energy. It all happening very quickly. You form a lot of elements, and I mean a lot. That one single Kan Nova event that we observed in 2017. It made more than 100 Earths worth of gold, and I don't mean 100 times the amount of gold in the earth.
I mean 100 earths made out of pure solid gold. One collision and not just gold. Silver, platinum, Mercury, Xenon. You wouldn't exist without killing nova. Literally you. I'm talking to you. You wouldn't exist without killing Nova. So So So think one. The next time you see it, not just the gold in your jewelry or the circuitry of your computer. Your body requires some of these heavy elements to function and it's merging neutron stars that do it. They're very rare about one every 100,000 years per galaxy, much more rare than supernova supernovae. You get a few per century per galaxy, so this is orders of magnitude more rare than a supernova. But they are much more efficient at producing these heavy elements. Billions of years ago, in this very patch of space, two neutron stars collided and seeded nearby gas clouds with these heavy elements in those nearby gas clouds eventually later collapsed to form our own solar system.
And you, the gold in your jewelry was formed by two merging neutron stars, was formed during a Kan Nova explosion in 2017 was the first time that we were able to witness one happen in real time and to know what we were looking at. We had seen Kan Nova like flashes before 2017, but we weren't exactly sure the gravitational waves cinched it, because when neutron stars merge, they give a very distinct fingerprint, a very distinct signal of gravitational waves. And that's exactly what LIGO and Virgo picked up. But that's not the only reason we cared about that killing Nova. Remember back in part one. I know. It was so long ago. I talked about the speed of gravitational waves. I talked about them being the speed of light. I know good times. We we had a lot of fun back then. That was a prediction of general relativity that gravitational waves should travel at the speed of light. No faster, no slower. But like all predictions, it needs to be tested. I mean, sure, GR has held up to every single test we've thrown at it for a century.
Thanks, Einstein. But all it takes is one little thing to be off. And all of a sudden you can start developing new theories of gravity. Why do we care about new theories of gravity? Well, you know, there are these minor mysteries of the universe called dark energy and dark matter, the accelerated expansion of the universe, which we cannot explain. We have no clue what's going on. We don't know why our universe is getting faster and faster every day at large scales. Mystery. One of the ways to potentially explain dark energy is to say, Well, maybe there's a new ingredient in the universe, you know, Maybe there's an extra little bit of salt and the salt is weird and it makes the universe expand. OK, that's one train of thought. The other train of thought is, Maybe we're maybe Einstein's wrong. Maybe Einstein's great at the solar system. Stuff pretty good at the Galaxy stuff, but the universal scale. Sorry, Einstein. We need a GR 2.0 in order to explain. Maybe there's not a new ingredient in our universe. Maybe we're just getting physics wrong. So over the years, there have been all sorts of theories of modified gravity, all sorts of crazy, wild and wonderful names.
Cortic in quinte galileans vector tensor theories generalized proa theories by gravity theories. The list goes on. It's funny in the vast majority of theories of gravity that go beyond GR predict varying speeds of gravitational ways for complicated reasons that I'm not getting into, so you're just gonna have to take my word for it. So if you can directly measure the speed of gravitational waves, you can put these extended theories to the test. How do we do the test with Patreon? You go to patreon dot com slash PM so and determine if Einstein is correct. Every contribution that you make puts Albert to the test. Just kidding. You do it by measuring gravitational waves and comparing them to the speed of light. And that's exactly what the 2017 Kila Nova provided. We saw the gravitational waves, and we saw the light in the form of a gamma ray burst from the exact same event. In this case, according to our measurements, the gravitational wave hit the earth first, about 1.7 seconds before the GRB gamma ray burst. Before you start freaking out, the that the gravitational wave might be going faster than light.
You should remember that we detect neutrinos before the light from a supernova hits us. It's no big deal. The gravitational waves don't interact with matter. They can just escape the event and go on with their lives. But the light gets all tangled up because the matter is so dense it actually takes a while for the light to break out of the merger event itself. So it's no surprise that the gravitational waves came first. 1.7 seconds. Sounds like a lot, especially when you're talking about precision tests of GR. But that's 1.7 seconds after traveling 140 million light years when the dinosaurs were still rocking the earth, these neutron stars collided, emitting the gravitational wave and the electromagnetic radiation. 1.7 seconds difference after 140 million years is basically the same. That's one part in 10 million billion. It's like trying to measure the speed of two cars in the difference. One car is going 30 miles an hour. In the other. Car is going 30.00000000000000 001 MPH.
You know just how much I love reading out long strings of zeros to you on this show. In other words, gravitational wise traveled the speed of light, and that one single event provided a measurement a million billion times better than previous limits. And it killed essentially every single theory of modified gravity. Seriously, almost all of our attempts at pushing past general relativity with a new theory of gravity and Einstein 2.0 a GR 2.0 were simply wiped off the map with a single observation That's powerful. That's a big deal Now you know why one third of the astronomical community was interested and involved. So what's next for gravitational wave? Astronomy? More more detectors, more facilities, more events. First up, more ground based detectors. LIGO, like instruments, are only sensitive to a particular frequency range. You know, you have telescopes that are sensitive to a certain part of the electromagnetic spectrum. Like I'm an optical telescope. I am a radio telescope. I'm an infrared observatory. You have different detectors for different parts of the electromagnetic spectrum.
There's a gravitational wave spectrum. There's low frequency, middle frequency, high frequency. LIGO is only sensitive to a particular frequency range that is best for detecting mergers for black hole mergers. But if you build more LIGO like instruments, you're gonna broaden the reach of what we can see. You can push farther out into space. You can catch fainter signals. You can catch more signals. You can get better sense, more pinpointed direction. So first up over the coming years is more ground based observatories, and then the ultimate sequel to gravitational wave detectors on land is gravitational wave detectors In space, there's Lisa Deyo, deigo. I don't know how to pronounce that one. The Big Bang Observatory. These are space space detectors aiming for lower frequency stuff. Stuff like small, nearby black holes. Supernova going off giant black hole mergers. This is incredibly difficult.
It's it's decades away technology. I mean, it took us 25 years to figure out the ground based detectors, so don't be surprised if the space based ones are going to take a little bit of time. These are going to consist of multiple satellites, all orbiting the sun together and bouncing lasers back and forth. And then the gravitational waves wash through and subtly change the distance between the satellites. And we can measure that somehow we like we don't have the tech yet. We're working on it. Expect to see some pathfinders. Some work on it coming up in the next few years. But besides the space based observatories, there are the indirect measurements. Remember, these are these are direct. This is like we have a laboratory. We have an experiment, and we see the effect of the gravitational waves on our instrumental apparatus. But gravitational waves were first detected back in the 19 seventies. In fact, there was a Nobel Prize awarded in 1993. This is the the LIGO collaboration getting their Nobel Prize. That was the second gravitational wave Nobel Prize.
The first one was for an indirect detection. This was a binary system of a neutron star and a pulsar. Pulsar is also a neutron star, but it happens to be flashing at us. And what the astronomers noticed was that as these two stars orbited each other, the pulsar was subtly changing its pulsation rate. They were using the timing variations in the pulsar. They were able to measure the decay of the orbit. The neutron star and the pulsar were slowly getting closer together, and the decay was from the emission of gravitational waves. Gravitational waves take away energy from systems and put it somewhere else. And when you take away energy from an orbiting system, things get closer together. And the rate that the pulsar and neutron star were getting closer together was exactly what we predicted from gravitational waves. Hence Nobel Prize. More lately, astronomers have been expanding on this idea with something called pulsar timing arrays, which is to measure a whole bunch of pulsars all across the galaxy and universe. If you can get away with it.
And as gravitational waves just ripple through the cosmos, you'll see these subtle little variations. Uh, like a little wobble in the pulsar, like the pulsar is doing his thing like pulse, pulse, pulse, pulse balls. And that gravitational wave sneaks by and goes. Pulse the pulse pulse pause like a little hiccup. And the idea is to use. If, if the gravitational wave has, like, passed through a big portion of the galaxy, then all these pulsars will shift in concert and by observing a whole bunch of pulsar altogether. Hopefully, you can do it. This is great for measuring generic background or gravitational waves from supermassive black holes colliding and eating stuff. You know, it's the super low frequency stuff that you can never hope to dig out of the noise in a ground based detector. If if this signal takes a really long time, the stuff on the ground is really good at detecting brief signals like the chirp from black holes was 0.2 seconds long. Neutron star mergers was a couple of minutes long. That's brief enough that you can see it, but if the signal washes over you over the course of hours.
We we just it's It's too hard for our ground based detectors to spot it. There's too much noise, too much interference. You can't pick the pattern out of that data set because the noise is too bad. But maybe with pulsar timing, arrays might be able to do it. You know, if they can get it to work. This is all hypothetical. We're all I'm sure pulsar timing arrays will eventually give us a gravitational wave signal. I'm sure that we'll have space based observatories someday. It's just not today, so we just got to be patient about. But before I go, there's one more gravitational wave source that we haven't talked about yet. A source like we talked about supernova and black holes colliding and killer nova and and black holes eating stuff. There's also inflation. Inflation is this event that we strongly believe happened when our universe was very, very young. Less than a second old. Our universe underwent a radical phase. Transition got a little bit bigger and by a little bit I mean at least 10 to the 62 times bigger. This has important implications. It means our observable universe is just one tiny fraction of a much larger universe.
Cosmologists believe that inflation exists and happened for a variety of reasons. I did a couple episodes on inflation. You should check them out. But the event of inflation itself, the event of our universe getting very, very big, very, very quickly released a tiny bit of gravitational waves. These gravitational waves, when they were released were probably enough to rip you apart. But also good luck surviving in our universe when it was less than a second old and smaller than an atom. But these gravitational waves, called primordial gravitational waves, would be revolutionary to see those gravitational waves exist. They're washing over you right now. They Where did they go? I mean, when you fill up the universe 13.7 billion years later, you're still gonna fill up the universe. Where are you gonna go? Outside the universe. We talked about that. The primordial gravitational waves released when our universe was less than a second old still exist today. They are here. They are washing over you right now. But they are, as you might imagine, incredibly small and almost impossible to detect. We hope to directly observe them someday with something called the Big Bang Observatory, but that is decades away at best.
But you can search for it indirectly because there's something between us right now at the present day age of the universe and when the universe was less than a second old. It's the cosmic microwave background. The cosmic microwave background is the radiation released when our universe was around 380,000 years old, a transition from being a hot, dense, opaque plasma into a cooler, clear universe. A bunch of radiation was released. That radiation has flooded the universe and is present today, and it's also very, very weak and small. It's in the microwaves, but when you turn on microwave goggles and block out the sun because it's generating microwaves, too, it's It's the brightest source of radiation in the universe. And we've mapped it really, really, really, really, really, really well. It gives. It's a baby picture of when our universe was 380,000 years old. The primordial waves would be a a baby picture of when our universe was a second old. That'd be even awesome closer to the real exotic physics that we don't understand about the early universe. But those gravitational waves were around when the CMB was being generated.
And so they influence this the CMB. And so the idea is, if you can study the light of the cosmic microwave background good enough, you might be able to tease out a signal of the gravitational waves. It wouldn't be a direct detection of the gravitational waves, but you'll see their imprint on the background radiation. There's a few collaborations that are attempting to measure this. One of them was called bicep. I have no idea. I do not remember what bicep stood for. It is not important. B, I CE P. And in 2014, they announced they made a big announcement. They said we have found direct evidence of inflation. Oh, by the way, I need to mention cosmologists. Astronomers believe that inflation exists. We do have some evidence that it did happen. Uh, but we don't have direct observations of that event. Of course. So Bicep said, Hey, we found direct evidence of gravitational waves in our measurements of the cosmic microwave background. They're right there. We have a picture of inflation. We have this signal. It is there Where's my Nobel Prize?
I remember when that news story broke. At the time in 2014, I was working at the Paris Institute of Astrophysics as one of the many things I did. I was a member of the plank collaboration. The plank was a satellite that was measuring the cosmic microwave background we were producing. We were generating maps of the entire cosmic microwave background. The CMB, uh, surrounds us like a sphere on the sky. We are generating maps of the whole thing at all sorts of different frequencies, doing lots of cool science. Bicep was focused on a very, very, very tiny window. Tiny little speck on the sky. Super super high resolution, much higher resolution than plank, but on a much smaller part of the sky. In order, uh uh, or should say, the the imprint of gravitational waves on the CMB. It's It's not exactly clear there are other things that can mimic it. Things like dust. If the cosmic microwave background light passes through, say, a cloud of dust on its way to our instruments.
Oh, and it has over the past 13.7 billion years, it mimics a signal similar to what you expect gravitational waves to produce on the cosmic microwave background. So when you see these weird signals, you don't know. Am I looking at a signal from when our universe was just a second old? Or am I looking at a bunch of stupid dust? You have to get rid of your dust. You have to know what the signal from the dust looks like. Subtract that from your image, and if there's anything left over, you can be like, Well, that's That's the primordial gravitational waves, right? The bicep collaboration was nervous of getting scooped. They thought they had a signal. They thought they had something, but they were nervous that another competitive team called Polar Bear These are They're based at the South Pole. If that helps explain, the names were also had the signal and that they were going to publish. What they were waiting on were the plank results because our all sky maps from plank would provide a very, very exquisite map of all the dust in the sky so they can take their little patch, subtract off our dust measurements, and if there's anything left over, they could see their gravitational waves but they were waiting on us to release our results.
Our results were not public yet, but at a conference, someone from the plane collaboration showed a picture of our dust map of like, Here's what the dust in our universe looks like. According to Plank, They weren't supposed to show this. They didn't get permission to show it, but they showed it anyway. They were just not harmless, so it was just like, Hey, look, here's what I'm doing Someone from the bicycle collaboration was there at the conference, and they took a picture of that slide, and they used a picture to calibrate their understanding of dust subtracted from their signal. And they had a little bit left over which they claimed to be primordial gravitational waves they published. The news went crazy. They had videos of people going up to the theorist behind the inflation idea and telling them that they had been, You know, they had been proven correct decades later, and there were tears. There were news interviews everywhere in the plan collaboration. We had a big meeting. We saw what was happening and we knew that they were wrong.
Their understanding of dust was flawed. The slide shown at that conference was preliminary, and it was incorrect. We knew that once you accounted for an accurate dust model or like had an accurate picture of the dust in our universe that this primordial gravitational wave signal would go away. But we had to take our time because our data weren't public yet. So for two or three months, the public was convinced that we had detected gravitational waves while everyone in plank, including me, knew that they didn't. We were finally able to draft a paper. We released our data shortly thereafter on schedule, and we showed that this bicep signal was wrong. That event shook a lot of confidence in me. In the process of science and the relationship of science to the public, it was obvious it was it was people. And and one of the leaders of that collaboration, Brian Keating, wrote a book called Losing the Nobel.
He blamed the system. He said, like Well, US scientists are incentivized to do big results. Scientists are in incentivized to chase after Nobel prizes, and so we got. We got cocky and we rushed things and and he's right and he's wrong He's right that scientists are incentivized to rush results. Scientists are incentivized to get big results quickly. But just because you're incentivized to do something doesn't mean you have to do it. The bicep collaboration could have waited two months for Plank to release their data, and they would have an interesting paper, but not a bombshell paper. They thought they were right, and they were arrogant enough to believe that they were right, even though they were working with incomplete data. And they were arrogant enough to go to the press to try to convince the world to give interview after interview that they were right. When they hadn't checked their numbers, they hadn't waited on accurate assessments. They hadn't waited on accurate dust models. To date, we have not seen a signal of primordial gravitational waves, either directly or indirectly in any searches of the cosmic microwave background. To date, the bicep fiasco has upset me.
I believe it has hurt the relationship between science and the public. I believe it has lowered trust between scientists and the public. I'm writing a book about it. It's called the Sickness and Science. It's about a lot more stuff, but One of the reasons I wrote this book was this event in 2014. I'm sure gravitational waves will have a much brighter future in a much more positive future, and I'm looking forward to seeing what comes next. Thank you so much for listening. Thank you to my top patreon contributors. Thank you to all my patreon contributors. Patreon dot com slash PM Sutter Especially Matthew K Justin Z, Justin G, Kevin Duncan, M Coy Barbara K, Neuter Dude to Robert M, Nate and or F Chris Cameron, NAIA aone, Tom B, Scott M Rov H and Lowell T That's patreon dot com slash PM Sutter Thank you to all the people who asked all the gravitational wave ques questions that inspired this two part series. Yes, it's over. I'm not. I'm not doing an eight part string theory here. It's just a two parter. Please keep those questions coming. I really do appreciate it. I love the questions I love keeping this show going.
I love sharing all this cool stuff with you. I hope you enjoy it as much as I do. Keep the questions coming to ask us spaceman gmail dot com or go to ask US space man dot com for all the links, and I'll see you next time. For more complete knowledge of time and space, the United States Border Patrol has exciting and rewarding career opportunities with the nation's largest law enforcement organization. Earn great pay, outstanding federal benefits and up to $20,000 in recruitment incentives. Learn more online at CBP dot gov slash career slash USB P.