Does The Chinese Moon Program Pose a Threat? | Q&A 474

How bad and dangerous is the Chinese space program? How will they keep the 39 meter telescope mirror clean and dry? Can a star merger harm a human body if you get near it? And in Q&A Plus, is there an interstellar object yet to be announced? All this and more 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, in this question just write it down. I gather them up and I will answer them here. Apologies. I'm in a very echoey room, but the rest of the question show. show won't have all of this echoes. All right, let's get into the questions. Luis Carneiro, how bad and dangerous is the Chinese space program? That's a very strange question because I don't really sort of understand. How you would describe it as bad and dangerous. So there are definitely aspects of the way the Chinese Space Agency does its rocketry and space exploration that is bad. Right? So I'll give you an example, which is that for the longest time, China launched all of its rockets from an inland rocket site. And then they would have the booster stages of their rockets just land downrange. And they could just rain down on towns, forests, light things on fire, because they didn't launch them out over the ocean the way the United States does, the way they do at Arianespace in South America. That's bad. They since they now do have coastal launch facilities as well, but they still launch a lot of them from land and but they're working on reusable rocketry in the same way that SpaceX does. And so there will be a time probably in the next decade or so where China is recovering all of the rockets that they're launching. And so this time of them dropping rockets on villages will be over. And then there are, you know, obviously there are. Parts of the country which are freer and parts of the country that are less free, and yet there's a lot of rocketry, there's work that's done in some of these parts of the country, and you could say, well, that has an effect on the people who live there and the rights and freedoms of those people, so that's suboptimal. But apart from that, I mean... The Chinese obviously have a military aspect to what they're doing, but so does the United States. So does Europe, right? They have demonstrated the ability to knock out satellites. They have spy satellites that are flying overhead. But you can say the exact same thing about the United States. So I don't think there's anything unusual or special. Jamming capability, GPS capability, internet connectivity for soldiers. Like all these things exist among almost all nations. And then the sort of the question of them, for example, they've got a lot of science. work that they do, which I think is excellent. They had a rover on Mars. They're sending a sample return mission to an asteroid. They have return samples from the moon, from the far side of the moon, and they're building up their own human lunar exploration plans and probably will be landing humans on the moon by 2030, four years from now. And if they do that, then then that's great, right? Because that means people are going back to the moon. Now, I think I would prefer obviously, if it was all Canadians going to the moon, you know, but I understand that other nations want to get a shot at it. So I don't I personally don't see anything wrong with with that at all. You know, the moon is not a place that you can claim is not a it's not a place you can conquer. You know, it is essentially worthless ball of scientifically interesting ground up rock. All you're going to be, you know, the only revenue, the only profit that it's being made from the moon is scientific progress. And obviously, you know, you can demonstrate your ability to launch rockets and put humans on the moon. That's spiffy, you know, go you, but there's no kind of military aspect to this at all. And so, you know, I mean, I think like, like all nations, some of the things they do, we should celebrate some of the things they do were ambivalent about. And some of the things we, they do, we kind of wish they wouldn't. So spaghettification, unlike black holes, do magnetars and neutron stars pose a physical threat to human tissue merely by being within a given distance of said object due to the magnetic field? Yes. A magnetar, which is the most powerful form of a neutron star, and it looks like they're probably caused by colliding neutron stars, but we're not entirely sure. A magnetar has the most powerful magnetic field that's ever been observed in the cosmos. And that if you got close enough to a Magnetar. It would overcome the atomic forces that are holding your atoms together, and so you would literally be disassembled by the magnetic force of a magnetar. But you would also be experiencing just brutal levels of radiation, all the trapped radiation around the magnetar, and you'd be experiencing the tidal forces from the magnetar, so you would be having a very bad day. But it would be capped off by your body being pulled apart at an atomic level. Church discography. How will they keep the 39 meter mirror of the extremely large telescope clear of dust and moisture? How much of these can it accumulate before image quality is degraded? So I don't know exactly how they're dealing with this for the extremely large telescope. I mean, if I've had time, I would research it, but I know how they're dealing with it for the Vera Rubin telescope and the extremely large telescope is just a larger version of Vera Rubin. So Vera Rubin has a facility for recoding the mirror of the telescope. And so they got the mirror sent up to their facility and then they actually did. The anodization of the aluminum, the polishing on the mountain. And the reason is because exactly what you're talking about, which is that on a regular basis, dust, grit, wear and tear is going to degrade the quality of the primary mirror and the secondary mirror on, and the tertiary mirror on, on Vera Rubin until they'll be able to kind of dismantle it, run it through the car wash. But really, you know, redo the coating on the mirrors and then reinstall them back on the telescope. And so I'm assuming that that the same kind of facility is is available for for most, if not all observatories, because it is just a regular problem that they all have to deal with. David George, if a combination of infrared and gamma rays or ultraviolet and X-rays are fired or shown together, does that open up other viewing possibilities? So this is a thing that astronomers already do, which is that they will observe fields of view with different telescopes that observe different parts of the electromagnetic spectrum. But the thing that's really important to understand is that all of those things that you mentioned, infrared, ultraviolet, visible light, x-rays, gamma rays, you know, you didn't mention radio waves, microwaves, they are all the same thing. They are all photons, just with different wavelengths. And you can turn photons of one wavelength into a different kind of photon just by redshifting the wavelength of that photon, which is why James Webb is observing things in the infrared that were once invisible light and maybe even in near ultraviolet. It's just purely how much time and how much space has expanded to make these photons look different. And so you are getting, you're seeing different kind of phenomena. from the photons, but you are observing the same physics, which is you're observing this quantized packet of energy that is coming from various events in the universe. And fundamentally, really until the development of neutrino observatories and gravitational wave observatories, everything was just different versions of the same thing. But now with gravitational waves and with neutrinos, we truly have multi-messenger astronomy. Gravitational waves are something totally different than photons. Neutrinos are something that is totally different from gravitational waves and photons. And so that allows you to truly look at something from different perspectives. And the example that I love to give is, you know, at the very beginning of the universe, 380,000 years after the Big Bang, You had the cosmic microwave background radiation. This was this time when the entire universe was essentially opaque. The universe was like the surface of a star. And so you couldn't see through it. In the same that we can't see into the sun. And then the universe would become Less dense and there was enough gaps opening up between all of the particles that photons could finally escape. And when we look at the cosmic microwave background radiation, we're seeing photons that were released at time of last scattering. But this serves as this impenetrable wall. And no method of looking at photons will ever let you see earlier than that. But gravitational waves don't care. Neutrinos don't care. They were passing through that region, that time, no problem. And so you could then look at these times in the universe with your gravitational wave observatories, with your neutrino observatories, earlier than the cosmic microwave background radiation, theoretically, right back to the Big Bang. Essentially, you could see neutrinos to the earliest moment that neutrinos were created. Which is, you know, less than a second after the Big Bang, you could see gravitational waves, literally them as inflation was happening in the universe. There are probably some after echoes of gravitational waves in the universe that would allow us to observe that time in the universe. So that truly gives us new information that's different from photons, but All of the observatories have specific wavelengths that they are designed to observe in. So we have things like the Very Large Array, the big radio dishes, right? They're looking in the radio spectrum. You have microwave observatories. You have infrared, like James Webb. You have visible light, like Hubble, like the Very Large Telescope, like all the big observatories on Earth, Vera Rubin. You have ultraviolet, which... Hubble can do, but there's other dedicated telescopes. You have X-rays and you have gamma rays. And each one of them tells you a different thing. So gamma rays come from the most energetic events in the cosmos. They come from gamma ray bursts. They come from magnetars, which are, I don't know if you can get them from magnetars, but you get X-rays from extremely energetic events. So there you have magnetars that are, they have. Disconnecting, reconnecting magnetic fields, stars where their magnetic field lines are snapping. You get supermassive black holes that are feeding on material. You have gases that are out there in the cosmos that are raised to millions of degrees. This gives you x-rays. Ultraviolet, hot stars are producing enormous amounts of radiation, giant stars. Visible light, obviously, trees. reflect visible light, the sun, infrared heat, right? Think of what a snake sees when you look through an infrared camera. And so when you observe a field, and you'll see this all the time, you'll get some release, some press release coming out of NASA where they looked at the same field with multiple telescopes. You'll see, say, the Carina Nebula. There's actually a story we covered in Universe Today like last week. You've got the Carina Nebula, which is an incredible Star-forming region. And they looked at it with James Webb, which you're seeing it in the infrared. That shows you the gas, the dust, the star forming regions, the clouds. But you can also see through the clouds to see the knots where there are new stars forming. You can see protoplanetary disks, things like that. And then they partner that up with, say, the Chandra X-ray Observatory, which allows you to see in the X-ray spectrum. Now you're seeing all of the hot stars that are in the nebula. You can see there. Their locations and how much X-ray radiation they're pumping out into their environment. And then you can kind of overlay the two together. And you see like, I can see where the stars are and I can see where the clouds of gas and dust that's feeding stars are. And I can understand the mechanisms of how they connect. And so these kinds of multi-wavelength views are done all the time. Astronomers will look at one field. in microwave and they'll look at the same field in radio, they'll look at the same field in gamma radiation. And often when there is some big energetic event like a supernova, you'll get the world's observatories all focusing on the same target because they all have something to give. The infrared telescopes are going to tell you something different from what the x-ray telescopes are going to be telling you. It's time to shout out all the new $5 patrons and above. Skyward, John F. Taylor, Richard St. Clair, Adam Badura, Borg Transformers, Jack Laflamme, Jonathan Passi, Lou Hamilley, Clem Ski, and Biker V. James. Join the club at patreon.com slash universe today. Andre Foisy, is it possible to see an object like, say, a star merger before it happens and also while it happens with gravitational lensing, like at the Einstein Cross? So this is a great question. And like for starters, the answer is no, you can't see it before it happens. The speed of light is the ultimate limit. And so all you can see is things that are a little slower than the speed of light, but you can never see something that's going to happen faster than the speed of light. And so even with a gravitational lens, you're not seeing something ahead of when it actually happens. All it is, is that it is acting like a telescope lens. And so you are seeing something magnified. You're seeing light that would have gone in all directions or in several directions and not reached your eyeballs. The gravity of the galaxy cluster that's in the way is pulling the light back towards your direction. And so you're seeing more of the photons than you would see without the gravitational lens. You're seeing more of the photons through the lens of your telescope than you would without the telescope. It's the exact same process. The part that's really cool with gravitational lenses is that the light has to take this journey around the gravitational lens. And so some of the light can take a longer journey. And the distance in that is not very much, but it's enough to make it so that when we see, say, a supernova go off in a galaxy that's being lensed by some foreground object, You will see multiple versions. That's what the Einstein cross is. You're seeing multiple versions of the same galaxy around this, that the light is taking multiple journeys around this lens to reach us. And the light can take enough of a difference in that journey that we actually see events unfold in the different versions of the galaxy at different times. So we'll see the supernova go off. and not in the other examples. And then a year later, we see the supernova go off again, and then we see the supernova go off again, and then we see it go again. And what makes that really powerful is that it tells you, like you know, like normally we don't know where supernova are going to go off. We find them, and then telescopes turn to try and image them after they're happening. And that's the best that we can get is, you know, you want to get within a couple of minutes, maybe a couple of hours of a supernova going off. But with a gravitational lens where the light is taking these different journeys and you see it happen once and then you know it's going to happen several other times, you can calculate. When it's going to happen in these other versions of the galaxy, and then at the appointed time, you point your telescope at the galaxy, and then you wait, and then boom, the supernova appears. And you can then observe it through the entire process. Now, that's the dream. That's the ideal. The reality is these things are incredibly far away. Even with a gravitational lens, you are seeing a supernova go off in a galaxy. Where, you know, the image that you're seeing is 2 billion light years away. And so you're not able to resolve very much inside that galaxy and not, you know, wouldn't it be incredible if you could look at different spots in the sky and then see that star and the star collapse? And then explode, and you know what's going to happen, and you know exactly where to look, and you're like, wait for it, wait for it, there it is. That would be incredible. But astronomers can still measure the chemical fingerprint of the atoms that are in the explosion and try and get a better understanding of what happens with these supernovae. And it's super rare, but it's an incredible thing to see. Nunia, are neutrinos affected by gravitational lensing? Yeah, absolutely. Anything that has mass. And not even mass. I mean, photons are affected by gravitational lensing. But yeah, as neutrinos fly through the gravity well of a galaxy cluster, what they think is a straight line is curved spacetime, and they're going to follow the path of the curved spacetime. So could you perceive a gravitational lens of neutrinos released from a supernova explosion? Theoretically, yes. Practically, no. Did you know that you can watch the same video with no ads and get a bonus question over on Patreon completely for free? We call it Q&A Plus. This week's bonus question, is there an interstellar object yet to be announced? And I'll put a link down in the show notes. All right, those were all the questions that we had today. Thank you everyone who asked your questions into the YouTube comments, everybody who joined me for the live show, everybody asked their questions over on Patreon. I'm going to talk about AstronomyCast, but first, I'd like to thank our patrons. 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