transcript

Speaker 1:
[00:00] What could the great filter be? How visible is the human race to outside observers? How would astronomy work in a cosmic void? And in Q&A+, what would happen if a black hole suddenly approached? All this and more in this question show. It's time for the question show. Your questions, my answers, as always wherever you are, across my channel, if a question pops in your brain, just write it down, I'll gather them up, and I will answer them here. All right, let's get into the questions. Mosquito, could a great filter event be someone saying, our species is too horrible to infect the whole galaxy and pushing a button? You know, when people talk about the responses to the Fermi paradox, like what are the answers to the Fermi paradox? The ones for me that are the most satisfying, not the ones that I like the best, but the ones that explain the paradox is we're the only civilization in the universe, that boom, done. That would explain the paradox because we're the only civilization. And so the reason we don't see any other civilizations is because we are alone. Or we're first, so other civilizations are behind us or other life forms, so just nobody's advanced as we are. Plus, they can be as advanced as we are, and then when you think about the speed of light, they could be 100,000 years ahead of us, but we've seen them 100,000 years in the past, so they appear to be at our level. But the third most plausible one, the one that neatly and tightly explains the entire Fermi Paradox is the Zoo Hypothesis, which is that we are in a Cosmic Zoo, that the Universe that we see, the one that looks like a wilderness that contains no life is actually a lie, provided to us by some more advanced civilization that is purposefully changing our view of the cosmos. You can sort of imagine a version of this, like in Star Trek with the Prime Directive, or say in The Three-Body Problem, where the Tricylarans are changing our view of the cosmos. That seems a lot more fanciful, right? You imagine the level of coordination that would be required for an advanced civilization to keep us clueless about the true nature of the Galactic Federation, but that would explain it. After that, the explanations for the Fermi products all have holes in them. Woukalar Central. The size of the moon just happens to completely occlude the sun. I read a book that suggests this remarkable coincidence proves evidence for God. There are plenty of coincidences here on earth, and that is a good example of a coincidence, that the size of the moon is roughly the size of the sun, and so that we can get solar eclipses on the surface of the earth, and that if the moon was a lot closer, then we would still get solar eclipses. We just wouldn't get annular eclipses. And if the moon was a lot smaller, then all the eclipses would be annular eclipses, where you would see the moon passing in front of the sun, but it wouldn't completely block it. Just think about the number of possible coincidences that there could have been in the solar system, right? That they just go on and on and on and on and on. This is the perfect definition of a coincidence, right? Which is you happen to be thinking about a friend, and then they call you. What a coincidence, right? But think about all the times you thought about your friend and they didn't call you. Think about all the things. We only notice the occasional coincidence, and yet there's a ton of things that happen that we don't notice, or things that are just unrelated, things that could be related that don't happen. And so when you think about the number of things that could happen here in the solar system that could be coincidences that didn't, that aren't, we got one, right? Right now, it's sort of the time that we exist on this planet. We have this one. But imagine if we were here billions of years before, then the moon would be a lot bigger in the sky, or farther in the future, then we would see something different. So you know, people always sort of describe the universe. They always talk about how the universe is like perfectly designed for life, right? And the reality is that it's just not that the universe is utterly inhospitable to life, except for this tiny little veneer on this one little planet in this backwards corner of this one galaxy supports life, and the rest of the universe is trying to kill us. Mike D, is it possible that advanced technological civilizations communicate in a way that we can't detect? Sure. There are the kinds of technologies that we are familiar with, and then there are technologies that we can imagine. So imagine communicating gravitational waves or communicating with neutrinos. We can't do it, but we can imagine it. And then maybe there are ways of communicating using laws of physics that we just don't even understand. That is less likely. We understand at broad strokes the physics that underlie the universe. There will always be further nuance, and there will be more things that we didn't understand, and we'll get a better sense on it year after year after year. But just like in general, we know that there's stuff, and we know that there's energy, and that any other civilization that lives in the universe is going to be using stuff and using energy. And then they are going to give off their presence through giving off waste heat, or how they go through the stuff that they have available to themselves. And that'll be the way that we will potentially detect them. And either they can intentionally try to communicate with us, which would be nice, like, wouldn't that be great if in the far, far future, we become super advanced and we think, well, let's make sure that we can communicate with other civilizations. Let's throw them a bone and send out some radio signals out into the cosmos just to give them a chance, give them a leg up. And we would hope that other civilizations would do that for us, that they're communicating largely with gravitational waves, but they still like leave the light on for the rest of us dummies to catch up to them. How visible is the human race? Could we theoretically see evidence of our existence from a star light years away? Mostly no. So when you think about all of the capabilities that we have to be able to detect the presence of advanced civilizations out in the cosmos, we wouldn't be able to detect ourselves from even some of the closest stars. We think about our ability to detect chlorofluorocarbons in the atmosphere of the Earth or nuclear fallout from a nuclear war or city lights, and so on. There's really two things that would give us away. One is the radio signals given off by our planet. And so right now, we would just barely be able to detect the presence of our air traffic control systems, which are very, very bright radio sources from, like, say, Proxima Centauri. When the square kilometer array comes online in the 2030s, that would be able to detect the presence of humanity's air traffic control system by about a hundred light years away. But there was one thing that we did, or that we used to do with the Arecibo Observatory, which was that when astronomers would be mapping the features of asteroids, they would send out this really powerful radio pulse. And then they would measure how the radio pulse bounced off of the asteroid radar, right? And they use that to then scan and map the shape of these asteroids. And we have dozens of examples of asteroids where it's incredible. And when that radar pulse was sent out from Arecibo, it was very bright. And we would have been able to detect it from tens of thousands of light years away. If we were on the other end of that radio pulse, when Arecibo was scanning an asteroid, we would have seen it briefly. And then it would have gone away, right? And then we would have gone like, wow! Some alien would write on their sheet of paper, wow! And put a little exclamation mark, right? That would be the wow signal. That's pretty much the brightest thing that humanity has ever done. But in the coming decades, we are going to get better and better at this. So we will develop the technology that will allow us to detect ourselves. But right now, we would be really hard pressed to detect ourselves. We don't have a telescope that could detect Earth orbiting around the sun. Not to mention being able to measure the atmosphere of the Earth. So we could not detect ourselves, even if we were around Alpha Centauri. It's time to shout out all the new $5 patrons and above. Chris Burklaus, Steve Langford, JLG33, Bill, Donald Sherrill, Charles Green, Gordon, Keith Kegley, Ethan Cantrell, and JZPeterYK. Join the club at patreon.com/universetoday. And Morgan, Fraser, do you think if our solar system was in a void like Booty's, do you think we would be inclined to invent telescopes to see the universe or maybe we wouldn't? So imagine that we found ourselves placed in these giant voids, things like the Booty's void. These are hundreds of millions of light years across, where they don't have large galactic structures inside of them, that they're sort of, you know, they're a void. And then you have these walls around them, where you do have larger clusters of galaxies. But it doesn't mean that there's no galaxies in them at all, just that there is a lower density of galaxies in there. So right now, when we look out into the universe, we can see some galaxies with the unaided eye. You can see Andromeda, you see Triangulum, you can see the largest small Magellanic cloud. Without a telescope, you just look in the sky, and you can see this sort of fuzzy bit. And so we would probably be inclined to try to see those things, and that there would be other stars that would be in the galaxy that we were in. But if there was like no other stars, and it would be very hard to explain how you could get a solar system with the kind of metallicity that we have if you weren't part of a galaxy, because your star needs to form from the metals forged inside of the stars and they were then given off of the as they were as they died. But let's just like imagine that version where the sun forms in the center of one of these voids and the solar system forms around it. And there is just no other stars in our vicinity. Would we have the incentive? Because we've only owned telescopes capable of seeing that would have allowed us to see to the edges of the booty's void if we happen to be in the middle of it, probably like not until the 1950s, right? Before that point, our telescopes were not good enough for us to detect galaxies from those distances. And now, of course, we can use the Hubble Deep Field. You could see incredible things. So I think that we would have detected the cosmic microwave background radiation that maybe wouldn't have realized that we wanted to look for stars, galaxies. But we would have known that there was something weird about the universe, that it wasn't perfectly the same in all directions. We would have detected this presence of radio signals. And, you know, when you think about, say, the detection of the cosmic microwave background radiation, that was detected in the 1960s. So our radio telescopes were good enough back in the 1960s to detect the presence of the cosmic microwave background radiation. Of course, the astronomers sort of had a sense, a hint that this is the kind of thing that they would have detected to explain the nature of the universe. And so once they detected it, then that explained what it is that they were looking for. And that would have sort of led us down this path of better and better radio telescopes. We would be scanning the sky with radio telescopes. We'd be scanning our star with radio telescopes, scanning other planets inside the solar system with radio telescopes. And eventually, you would start to detect, say, fast radio bursts, other weird objects that are very, very bright, that are happening randomly across the sky. Gamma-ray bursts, right? Like gamma-ray bursts were discovered by space-based telescopes that were scanning the Earth to enforce nuclear test bands, right? And so the satellite orbiting the Earth, watching for nuclear tests, detected the presence of gamma-ray bursts, these events that were happening around the universe. I think we wouldn't have begun with this cosmology understanding of the cosmos, but there would have been enough science that Earth was doing, that humanity was doing, that the bright things that the universe does, fast radio bursts, quasars, gamma-ray bursts, pulsars, these things would have happened with enough regularity that we would have realized that there is more to the universe than we anticipated. And we would build the tools that would close that gap between us and the galaxies at the very edge of what we can see. So eventually, we would find it. It would be delayed by a few decades, maybe a few centuries, but eventually, we would figure it out. You can adapt that question and say, well, in the far, far future, after the galaxies have fallen over the cosmological horizon, and there will be no evidence for the cosmic microwave background radiation, will future civilizations, will future astronomers develop a history of the cosmos? And chances are they will, that they will just build really powerful radio telescopes, and they will detect the incredibly redshifted light from the cause of microwave background radiation that our curiosity knows no bounds. Afish, why do scientists call a black hole a singularity? We can see neutron stars, and if mass added, so escape velocity is faster than the speed of light. Astronomers or scientists call a black hole a black hole, and then the part of the black hole where all of the mass is concentrated in the black hole, they call that a singularity. We don't know if whatever the black hole is, is this infinitely small, essentially singular object with no size, and yet has all of the mass of the entire star that was there before. Like that's where you get this idea of the singularity, essentially you've got a mass several times the mass of the sun compressed into an area that is approaching zero, right? And that's how you get this idea of a singularity. We don't know if that's true, that it could be that a black hole is like a neutron star, that it's just a little bit smaller than a neutron star inside the event horizon, that you compress down a neutron star one more level and you end up with an object. This black hole, the escape velocity of this object is now exceeding the speed of light, and so you can no longer see it because the light can't escape. But the actual physical nature of that thing, we don't know. And we may never know. The problems that all the tools that we may have to try to analyze these objects is, you know, they all require you to be able to travel at the speed of light or slower. And since you have to be going faster than the speed of light to be able to theoretically escape a black hole, you can't see them. So it is more that the math, right? The mathematical description of a black hole, that's where the term comes from. But the actual physical reality of what it is, we still don't know. And we may never know. Dean Kovacs, what would happen if a primordial black hole passed inside the heliopause? I mean, it just depends on the size and mass of the black hole. You know, if it's a stellar mass black hole with several times the mass of the sun, primordial or not, then it would influence the orbits of the planets, and we would absolutely detect its presence. But if it was a lot smaller, say it was the mass of a planet, that would be planet nine, right? Had the mass of planet Earth and it was out beyond the helios, we wouldn't even detect it. So it really just depends on the speed and the mass of the thing. Whether or not it is a black hole doesn't really matter. It just matters how much mass does it have. All right, those are all the questions that we had this week. Thank you, everyone who joined me for the live stream. Everybody put your questions into the YouTube comments. I'm going to talk about a new citizen science project and a very cool Artemis video. But first, I'd like to thank our patrons. Thanks to Abe Kingston, Andrea Pretretti, Bailey Griffin, Brian Bodie, Karevon, Chuck Hawkins, Commander Bailock, Dirk Vanga, David Gilton, David Matz, Evan.Pro, James Clark, Janice Smith, Jeremy Madden, Jim Burke, Jordan Young, Josh Schultz, Marcel Smith, Michael Purcell, NordSpace, oneself4animals.org. Please follow my nephew VBRIC6994, Renkai Du, Richard Williams, Sean Sargent, Stephen Fathom, on the Team 49, Tailsoaps Canada, Vlad Shiplin, Wolfgang Klotz, and Zelda Borg, Galactic Defenders who support us at the Master of the Universe level and all our patrons. All your support means the Universe to us. So I hope you enjoyed the Artemis 2 mission as much as I did, and there was a lot of footage. They took thousands of photographs. There was video leading up to the launch, video of the launch, live streams, while they were on their way out to the moon. There was video clips of them going around the moon, taken by their phones, taken by cameras on board, taken by cameras attached to the spacecraft. And then we saw them come back through the atmosphere all the way down to splash down in the Pacific Ocean. And it was all amazing. But there was a lot, a very long series of footage, like 10 days, if you wanted to just watch the whole thing. So if you want to watch a shorter version, I think it's about 40 minutes. My friends over at CosmoQuest have edited down the highlights, the best stuff, the stuff that makes you just so happy to know that humans went out to the far side of the moon and came back. And in addition to this, the folks at CosmoQuest are starting a new citizen science project. Now, there have been a bunch of these in the past. If you remember, you were able to count craters on Mars. You were able to help find targets for the New Horizons spacecraft. You were able to figure out the perfect landing spot for the Osiris-Rex mission to grab a sample from asteroid Bennu. Well, the folks at CosmoQuest have a new citizen science project, something to do with the moon, and they're going to be announcing it this week. So by the time you're watching this, they will have announced it. They have released their new Artemis video. And I want you to go and check it out. So I'm going to put a link down in the show notes so you can go over there and watch that and participate in this new Citizen Science Project. You got a computer, you got a brain, you got fingers, do some science. All right, we'll see you next time.