I'm not sure if it's an official definition. But I've heard that if the point that two bodies orbit (the barycenter) are outside both bodies, it should be considered binary. Wich means that Pluto and Charon should be considered a binary pair. At least by this definition.
@@arnelilleseter4755 Since most orbits are elliptical, not circular, should that read at least one orbit center is outside either body? If so, a very useful definition.
@@friendlyone2706 Two bodies orbiting each other have only one barycenter regardless if it's a circular orbit or not. It may be easier to think of it as the common center of mass of the two bodies. Btw this is also true for more than two bodies, but then the orbits get pretty complicated and unstable over time.
I don't know the limit, but the limit is there because if a rocky planet gets too massive, it will attract too much gas and you won't be able to see the core. But you can't see Venus, and it's less massive. Hmmm.
“Mass limit of a planet”, “biggest” is ambiguous. Does it mean “volume” or “mass”? Mass limit is highly dependent on chemical composition. A gaseous planet of hydrogen & helium will start fusion at around 70x Jupiter’s mass. But a planet composed entirely of iron can grow much more massive since iron won’t fuse and provide net positive energy. An extremely massive iron planet starts run up against gravitational collapse into a neutron star. I don’t know the numbers but I’d bet an iron planet could be more massive than our sun.
The limit depends on the composition of elements on your "rocky" planet (rocky can mean a lot, metals, silicates; metals can mean a hell of a lot as well... You have to be more "precise" than just "rocky"). More less dense elements allow your theoretical planet to grow larger, more high dense elements will reduce that limit drastically. You reach your limit, when your gravity is so huge, that it attracts and keeps (captures) Helium and Hydrogen (Earths gravity is not able to keep Hydrogen and Helium). Once that happens, your rocky planet will inevitably turn into a gas gigant. Then it will attract more and more gas (considering, that there is still gas available). If there is so much gas available, it will further grow, get more dense, will get more powerful gravity, which will attract even more. At some point things get so dense at the core, that fusion will trigger. Then you have star. There is also a chance, that something else (a neighbouring planet for example, our your center star) will eat up all of the gas, that your planet would have collected otherwise. But at this point it will still be a gas gigant and not a rocky planet anymore.
@@dnocturn84 If, by some magic, you don't allow any gas to accumulate on the growing planet, it will at some point overcome electron degeneracy pressure and become a neutron star. The largest size would clearly be well before this.
The mass limit of a planet is currently estimates to be at 13 Jupiter masses, or 10, whoever you ask. But not just one Jupiter mass. There are heavier planets than Jupiter out there.
Mustafar! Fraser, I have a HUGE issue with the Fermi "Paradox"... Because it's not a paradox, it's just a question... A really important question, no doubt about it, but one that accepts any answer. Even "the Prime Directive"! My point is: "alien civilizations exist" is the premise of the question, not the question itself. So, in another words, "there's no one out there", although it's a real possibility... It just addresses the premise, it doesn't answer the question. I already tried to rewrite it some other way, in a way that it would be a real paradox... But I failed miserably. 😕 Anyway, stay safe there with your family! 🖖😊
The next-to-last segment, involving a planet orbiting in a binary system, has Lagrange Points mentioned -- but unless the two suns have a mass ratio greater than about 26-to-1, there can't be Lagrange Points associated with them . . . but there would be a gravitational Neutral Point located between the two suns, at a point where the gravitational pulls of each star cancel each other. If the two stars are of equal mass, then the NP would be exactly halfway between them. Granted, positioning a planet at such a Neutral Point would be precarious, with the slightest nudge away from the NP resulting in it moving ever so slightly away from one star and closer to the other. It would be a balancing act that -- without any way of moving the planet, as a "station-keeping" contingency -- would probably not last very long. There is a tendency in some circles to confuse a Neutral Point with a Lagrange Point -- especially with the L1 location in a 2-body system. In a binary system such as Alpha Centauri A and B, or the Sirius system with its famous white dwarf companion, there can be no Lagrange Points associated with those pairs of stars, since the mass ratios are nowhere near 26-to-1, but each of those binary systems DOES have a Neutral Point positioned proportionally between them, based on the mass ratio. For example, the Earth-Moon system -- which does have 5 Lagrange Points in it -- also has a Neutral Point located roughly 90% of the distance from Earth's center to the Moon's center: you take the mass ratio, which is 81.3-to-1, then take the square root, which is 9.01665, then add 1 to that, to get 10.01665 units for the distance separating the centers of Earth and Moon, and the distance from Earth's center to the Neutral Point would be 9.01665/10.01665 = 0.900166223 = 90.0166223% the total distance. This Earth-Moon Neutral Point is NOT the same thing as the L1 Lagrange Point, yet is often mistaken for such.
I don’t want to put words in Fraser’s mouth, I would suggest that Earth-life-is-alone comes out of the scientific evidence. We have no credible evidence for life beyond Earth so all we can say scientifically is that we’re alone. I don’t want that to be true. It places a heavy burden on humanity to not screw up and seed the universe with life if we hold to life being precious. Mathematically is seems implausible that Earth is the only planet with life. We know there are billions of planets in the habitable zone of their host star. We know that abiogenesis happened very early in Earth’s history, so it’s not that hard. Life on Earth is based on chemistry that’s very common in the universe.
@Fraser Cane in HOTH you said you would use a rail gun to shoot them off into space. Ok... But how do you get the material to earth? Thank you for all of the amazing & free space and science content you provide for me and all of your viewers.
most importantly: you probably would not. Bringing material down to earth is quite a waste. the most valuable thing about the material of Asteroids is, that it is not in this gravity well. That you don't need Rockets to shoot it into space. The gold of asteroid Mining will be water, not pressures metals. To think asteroid mining and to think of Gold is a bit small minded. having said that, atmospheric reentry would not really be a problem for a ball of metal.
Asteroid materials should stay in space for space construction. Every pound that we don’t have to launch from Earth is worth a few $thousand. But if you must send basic metals down to Earth the coolest idea I’ve heard of is making fuzz-balls out of it, like steel wool. Big, wide, high coefficient of friction to slow it quickly. Some might be tempted to make solid balls or cylinders but those stand a chance of drilling into the ground faster than terminal velocity.
A comment on the Alderan question: "Could a planet occupy one of the Lagrange points of a binary star system?" Assuming the stars have roughly equal mass, wouldn't there be as many as 10 Lagrange points in the system, 5 for each star? L4 and L5 for each star would be 60°ahead and behind each, and then pairs of L1, L2, and L3 aligned along the axis between and beyond the stars. If one of the stars has much more mass than the other, there would be the typical 5 Lagrange points associated with the smaller star. In this case, L4 and L5 points would be inherently more stable and would be an excellent place to park a planet, or a group of objects orbiting the Lagrange point. Also, one way of thinking about Lagrange points is that they are points in space at which an obje t simultaneously orbits both of the stars. For instance, the Jovian Trojan asteroids simultaneously orbit Jupiter and the sun.
While the gravity of the sun decreases with distance, it never goes to zero, no matter how far away you go. So after the last gravitational assist, all probes headed out of the solar system will start to slow down. (At some point the tiny gravitational pull from other stars will become stronger than that of the Sun, at which point the Sun's gravity really becomes irrelevant.) If they have escape velocity, then this slowing down will happen at a lower rate than the decrease in gravitational pull, and so they will never get pulled back to the sun.
How about adding a link to the original live show In the description? I missed last weeks show. It would be nice if I could see it when the finished version comes out. Thanks.
Having now watched to the end, I see that your intro had a compact version of the Bespin question that PUT a different spin on it. Perhaps it was a hook to snag pedantic minds like mine, clever boy? As to my favorite question: Tatooine (mass limit for a planet) held onto the early lead into the 'far turn' so to speak, but Alderaan (LaGrange points in binary star systems) supplanted it coming down the stretch because it stimulated consideration of sci-fi scenarii as well as reminding me of some I had read. In the case of the hypothetical pair Elephantus A & B, we have to keep straight whether we're talking about the La Grange points of the two stars, or of the planet and Eleph A, or the planet and Eleph B. Only if A and B had exactly the same mass would the A-B L1 point be the same as the B-A L1 point and make it (however remotely) possible for the two suns to seem to circle the planet as it orbited their shared L1 point. If A & B were just a few AU apart, Elephantus c could be in their habitable zone, which I imagine would be a double torus that would be broader in the middle, not that that would matter, because for Eleph c to maintain its position very long, no other sizable body could be orbiting A or B in the zone. I suspect also that It could not have a sizable moon (unless it had a polar orbit?) and that it would be tidally locked with A permanently at the zenith of one point on the planet and B permanently at the zenith of the opposite point. If not, and there were oceans, the high tides (given a 24-hour day) would occur exactly 12 hours apart at noon and second noon. Dusk would merge into dawn. If there were no axial tilt, it would seem that the day was only 12 hours long given too thick an atmosphere. Otherwise, one sun would be peeking over the Eastern horizon, while the other was sinking in the West. The moon in a polar orbit would always be full, but might there be some sort of band bisecting it, with craters having shadows on both sides? At any rate, once you got away from the planet's equatorial region, the moon would disappear over the northerly horizon and reappear roughly half a "month" later. Honorary mention (for me) goes to Dagobah (AI vs. organic intelligence) and Yavin (Fermi 'paradox'). The former, for bringing up the notion of different types of intelligence. I have lately begun to wonder about that as we find that various types of animals are more intelligent than we once thought, and that their brains are not structured like the primate model. The octopods seem to have what might be called sub-brains, their natural environment is like an alien world to us, and they don't live long enough to train their young who, therefore, have to keep "re-inventing the wheel". Cetaceans have colonized that world, can communicate in it over fairly large distances (in some cases), have shown some ability to communicate fairly complex concepts, can hunt co-operatively, and can 'see' things acoustically, possibly even each other's internal organs. The intelligence of the problem solving, tool-making corvids, who monogamously mate for life, engage in play, and 'mourn' their dead, seems to have arisen in a different part of their brain than in the primate model. Elephants have a highly developed area of the brain that deals with empathy, can apparently communicate subsonically, develop strong bonds even with some humans, and have been seen using objects to distract or threaten adversaries. To what degree are these intelligences (and that of AI) convergent? Can they have an ethical consensus? Human beings mostly move around on a (geometrical) plane. To us vertical distances seem, even feel, greater than horizontal distances. But gibbons live in the 3-dimensional world of a fully arboreal creature, and routinely and casually launch themselves through empty air from one tree to another while many meters above the ground. To them a complex series of leaps and swings between branches and limbs that even takes into account the springiness of various branches and changes elevations many times is as simple as seeing what the path from the bedroom to the kitchen is for us. If that is the case with our relatively near cousins, how different do things look to Jumbo, Flipper, ravens, or octopods than they do to us? I was actually surprised that your take on the so-called Fermi paradox was close to mine. I don't really see it as a paradox, because the "Copernican Principle" which is the underlying assumption of the "paradox" is not a principle of physics, but a guideline for inquiry in science. I would really (I mean REALLY!!) like to see you discuss that with someone (like Isaac Arthur or Anton Petrov) who seems to have the opposite view. Or maybe more of a panel with David Kipping of "Cool Worlds", who has more of a middle view, and some other RUclips scientists like Dr. Becky also included. Co-ordinating that many schedules might be a problem, so maybe just getting each to record their thoughts, pro & con, on the subject would be the way to go.
Your view of a lifless universe, apart from us, is very Red Dwarf but then I've always thougt that Red Dwarf might be a more acurrate prediction of our future than Star Trek.
Is it possible to see a galaxy at the edge of the observable universe that's half cut? How smooth is the gradation around the edge of the observable universe? What about a galaxy interacting with another galaxy outside the edge of our observable universe?
re - "Will we ever see what's beyond the observable universe?" Isn't that the exact same thing as asking "Will we ever observe what we can't observe?" or "Will we ever see farther than it's possible to see?" Isn't the CMBR the absolute limit for sight? Or is there a gap between the CMBR and the 'horizon' to the observable universe? Or is that question using the word "see" to imply investigation beyond the visual spectrum? If I waited 20 minutes before writing this, I'd probably have found out the answer...
Alderaan (binary star system lagrange point question). What shape do planets in binary star systems take? Does the force of gravity or momentum suddenly shift at different positions of the orbit? Is it more likely or just as likely for planets to become tidally locked in binary star systems?
Yavin - your answer was very interesting. I kind of agree, but I don't think I can make a good argument for it. It is a very big universe 😅 Here's a question though; what would happen to a dead body in space? Would we expect it to slowly reach background temperature and remain a frozen block forever, or would solar radiation eat away at it until there's nothing left? Assuming it doesn't impact anything I mean.
Mustafar - Thought experiment... when we get to the point of having a working design for sending a probe to another star, why not do a grand tour of multiple stars, and beam the data back home after each close approach, just like we did for the solar system. For that sort of scale mission, what is the best way of fuelling such a probe for such a huge duration - both for propulsion and power? --- My thoughts, surely attaching a craft, with mining equipment, to (or in?) an asteroid has to be the easiest / lowest tech way? Would our first attempt a probe look similar to Oumuamua? How much fuel is needed for propulsion and/or power for such a journey? Is a nuclear reactor sufficient to power a potentially multi-century mission? Is there a more mass efficient / better way for the first possible attempt? A fascinating idea.
If you were to observe outside the observable universe, you'd be increasing the observable universe. It's like expanding the Observable Earth - we can only observe like 1/2 of it at a time, restricted by our 3d construction.
How are we certain of Hubble Expansion? How do we rule out Tired Light? Very distant objects exhibit red shift that we’ve ascribed to Hubble Expansion. From this we’ve deduced distance through z. And we’ve deduced that the distant object is moving away from us. How do we know that Tired Light is not the cause? Imagine a maybe-not-quite-so-distant object emits light and those photons lose some energy over the hundreds of millions of years of their journey. Less energy would show up as longer wave lengths which we associate with Doppler Shift. Tired Light could have that object be almost stationary or moving toward us.
Question: why do you have to be a certain distance for the gravity lens to work? Isn't the sun constantly bending the light? Wouldn't any angle work if you're staring at the edge of the sun?
It only starts to kick in at about 500+ AU, but it's lost in the glare of the Sun. Once you get to about 1000 AU, you can block the Sun and see the lens around it
[ Mustafar ] I believe Prof Loab stance is not exactly "Hey this is Alien Craft" but more on the lines of, "Why is everyone so quick to dismiss such an idea despite all our estimation suggesting there should be TONS of Alien trash rolling around". That all being said I believe its some sort of metallic dust bunny to be honest evident but its behavior, speeds, LSR etc.. but my hypothesis is not any better than the Alien hypothesis and this push to dismiss it and never exploring the Alien concept means if it is Alien... we will never know because we never checked. Our ignorance is quite possibly the answer to the Fermi paradox in that we simply dont know natural and unnatural when we see it.
I agree. In science we should not make up our mind before we have evidence. None of alternative explanations is good. So it could still be alien, or not. Those who criticize Avi have not understood most important principle in science. Avi Loeb is a theoretical astronomer. So I trust his calculations: It cannot be hydrogen emitting ice.
Can a planet of a binary star system follow a stable "figure-eight" path around (and between) the two stars, orbiting one star clockwise and the other star counterclockwise?
Hey Fraser. You mentioned several times already that the kind of telescope that will use solar gravitational lens will only be able to view one planet. But why is this? I know 1k AU is far, but why not put a telescope in orbit around the Sun at 1k AU so that it can continuously image explants as it goes around the Sun?
Yes, the telescope would not be observing a single point but instead a circle across the sky. But you would be stuck on that circle, and I assume the circle would be a very narrow band, so infinitesimal unlikely that there happen to be multiple nearby star systems exactly on that band. However, because of geometry, there should always be a possible orbit to have any two star systems on that ring that the telescope observes. But, at 1000 AU, one orbit around the sun would take 32,000 years. So it likely would take a very long time that you have to wait until your second planet comes into view.
It would be cool to do an episode that does address Avi's points. I don't know either way I just watched a recent episode of Event Horizon with him and he said the hydrogen theory had been debunked because the math didn't work due to temperatures or something.
That's exactly right. He's debunked (along with several colleagues over the years) all of the natural explanations that have been put forth. I don't intend to speak for Dr. Loeb here, but my take on Avi's perspective is that he's not saying that Oumuamua MUST be an artificial object. He's never even said he believes it IS an artificial object. All he's saying is that an artificial origin should be allowed to be considered, scientifically and without bullying and senseless ridicule, just like any natural explanation, ESPECIALLY when all of the natural explanations that have been brought forth so far to attempt to explain all of the anomalies collectively have been natural objects that *we have never seen before.* Avi is trying to change the culture. That's his motivation, and that's his stated goal. He set up the Galileo Project at Harvard and over 100 credible scientists of all different beliefs and backgrounds have joined on to, on one hand, look for MORE Oumuamuas, with store bought instruments, and on the other hand, try to identify any UAP in the sky. They're collecting actionable scientific data, without fear, preconceptions, or prejudice, to help all of us understand more about the universe NO MATTER WHAT they may find. That's why I respect and admire Dr. Loeb as much as I do. People who just want to gratuitously dismiss his proposals out of hand can do as they will, but that's never going to stop him from looking up at the sky, out into the universe, because he remains just as curious today as he was when he was a kid. I don't know what could possibly be wrong with that. And let me say one last thing, Stuart. This is actually something Dr. David Kipping talks a lot about, and it's that it's okay to be agnostic on something until you have the evidence to convince you one way or another. It's okay to say you don't know what Oumuamua was, and it's the most accurate and honest response in that case. We don't know what it was. And until we can prove one way or the other, all we can do is go look for more objects like it. Take it easy, man.
@@realzachfluke1 Avi didn't originate the papers postulating Oumuamua could be artificial, but he read the papers and was impressed with their quality. He has the reputation he can afford to say the unpopular and prestige to avoid problems that would besiege others.
@@realzachfluke1 But very sad even Avi has lost some "points" with much of moribund academia. The possible but improbable should never be dismissed a priori, which is what too many do.
I vote Tatooine. I did not know that gas giants any bigger than Jupiter would start to contract by its own gravity. I have read about "hot Jupiter" exoplanets orbiting close to their stars, and I sorta assumed that some of them had many Jupiter masses. It could have been a brown dwarf in a binary system, but that didn't work. Does anyone remember the novel "2010" ? The unknown alien unleashed a black spot onto Jupiter, which coallesed it, and made it into a star with fusion. The alien said, "All these words are yours, except Europa. Don't go there."
@ Fraser If you're fond of Von Neumann probes, etc, I recommend that you check out an old game called Sword of the Stars. It's a 4-X game (explore, expand, exploit and exterminate) initially released almost 20 years ago. If you get all the expansions and updates for it and you give it a good play-though, I guarantee that you'll come out absolutely freakin' HATING Von Neumann and the probes that bear his name.
Imagine there are Lagrange points around binary black holes. Maybe rocks at those points will be subjected to intense time dilation. Perhaps future space geologist could go there to mine rocks that are very old and have not aged.
Hi, what opportunitys do you think are there for near earth orbital manufacturing, like for organ growth, crystal growth and other things is there much research out on what might be worth pursuing, can you melt metal down to liquid and move them magneticly to do cool things?
Hello, if humanity managed to build a spaceship faster than light! Would the people in it be able to see stars and other objects as they'll be moving faster than light, and their brains may not have enough time to process images. Thanks
Railguns would not be good for asteroid mining unless you can invent some kind of super material for the rails. If not they will probably be slag after a a hundred shots or perhaps even fewer. You need mass drivers that work on a different principle (Gauss guns).
Bringing a giant ball of metal down to earth would not crash the world economy. It would definitely put downward pressure on whatever metals were contained in said giant ball, but the metals would still have to be processed and prices aren't always a function of actual rarity on earth. Think diamonds and gold. Some sectors would of the economy would benefit from the lower prices.
Fraser, I'd love to hear your take on the rapidly developing "the AI Singularity is here - and we're all doomed!" story due to the latest and upcoming iterations of ChatGPT.
Question. If we are the only life in our observable universe do you think we should spread life as far and wide as we can even if that’s genetically engineered bacteria to other planets?
@@frasercain I agree. We should tread with caution to see if there is life there already but if not spreading the gift of life far and wide would be good.
@@frasercain Carl Sagan said something like: If we are the only intelligent life in the galaxy then we have a duty to spread. The universe is pointless without someone to appreciate it.
maybe we will send several 3-d printers and when we have new target the closet printer squeezes one out , has a hasta la pasta party, and says bon voyage.
I vote for Yavin. Main reason is first of all I agree with Fraser that we are the only life. Second the more I look at the chaos of the universe, I don't see how life can get a foothold. Having a scientific mind, I hope I am wrong but I am right in my mind until proven otherwise.
Life originated on Earth soon after Earth had cooled enough. It is extremely unlikely that this has happened only on one planet out of at least 100000000000000000000000 planets in observable universe. If we are only one, universe is extremely dangerous place for life.
I love your coverage of space topics but I just can’t understand your perspective on the fermi paradox. Like it seems like the least probable scenario and it seems to be completely based on emotion rather than evidence. You said it yourself that it’s your choice just because you like it.
Yes, they're called the Trojan regions. There are as many objects in Jupiter's L4/L5 regions as there are objects in the asteroid belt. NASA's Lucy mission is going there now and will fly past about 10 of them.
When it comes to the Fermi paradox, I think we vastly overestimate the ability of technologically advanced life to make an impact on the observable universe that we could actually detect. Life could be abundant, and we may never be able to see it.
I believe the idea is that there "should be" self-replicating automated probes all over the galaxy that we would detect in our own neighbourhood, not that there should be observable megastructures or something that we can see from vast distances. They've calculated that at reasonable travel speeds (for an advanced civilization), there's been orders of magnitude more time for this to happen than is needed for one such probe to spread through the entire galaxy. Nothing I've heard about computers and interstellar space suggests that such a technology will ever be feasible, though.
You said galaxy’s are moving away faster than the speed of light. Is their time moving backwards? How fast is the Milky Way moving? Is our time dilated? My brain hurts
When you say that that much metal would crash the world economy, are you taking into consideration that in the right conditions, we could have so much resources that it could be possible for everyone on earth to have whatever kind of lifestyle they please from luxury to modest without money needing to be a factor anymore?
Mustafar - Question::: If a threeD person stuck his hand through a 2dunverse, close to a 2d guy, and the 2d guy just saw a multicolored line, what would a 4d guy sticking hand into our 3d'verse look like to us?
I've always heard, (I think from you also), the universe is at lease 500 times larger than the observable universe. Now you're saying 1000 time. what new research has changed that figure.
17:17 Ethan Siegel thinks the whole Universe is at least "250x greater in diameter* -- 10M times greater on volume, in his Forbes article "How Much Of The Unobservable Universe.."
Alderaan: Depending on the relative mass of the two stars, the L4 and L5 points of the smaller star might be stable. Not exactly what the question asked for, but close.
Did you mean L4 & L5 ? L3 is a point 180 degrees around the orbit of the smaller body and is unstable. L4 & L5 are points 60 degrees in front and behind the smaller body and these are stable. It’s where Jupiter’s Trojan asteroids reside.
Yavin It seems to me that a better answer is we are effectively the only life in the universe. Space is just too big to be explored by creatures that are not immortal. As for AI, I spent my career in electrical engineering and have seen far too much of just really crappy software to believe that AI will produce anything more than really crappy results also. I am willing to be wrong just really skeptical. When I left college in '76 AI and nuclear fusion were to be here 'real soon'. To be kind, they have both made great strides, but also we should be willing to admit they were both vastly oversold.
Wow, that's an unexpected position to hear on extraterrestrial life: a trillion galaxies, not a microbe? Really? Still, it's falsifiable, unlike my personal opinion, which is that civilizations (in addition to being very rare) MUST fall, and that in any particular galaxy most of the time there aren't any. I'd like to see the asteroid mining discussion move beyond the "Let's go get a billion tons of platinum!" stage; no wonder most people think it's a silly idea. Very obviously the main thing that's going to be mined from asteroids is rocket propellant, and when that moves on to solid resources the stuff will be used in space. I can see moderate amounts of rare Earth elements brought back, for strategic purposes, but not huge amounts of traditional "precious" stuff, that really is silly.
If any of you guys are interested in the Pyramids in Egypt there is a brand new video on RUclips where a guy explains exactly how the Pyramids were built to be large scale chemical plants to make fertilizer. The name of the video is "The Original Purpose of the Pyramids." After you watch it, let me know your thoughts.
I'm barely 10 seconds in, but right away I have to say that "will we ever be able to see what's outside the observable universe?" is an absurd question. If we could "see" it, it would, by definition, be observable and, therefore, NOT be outside the observable universe. Oh. 25 seconds in and it seems that Fraser just invited such questions. "Wherever you are..., if a question pops in your brain, just write it down. I'll...answer [it] here..." Don't bother your pretty little head about whether it makes sense or not; just ask whatever cerebral flatulation detonates in your cranium, and I'll try to make sense of it.
If we hasd a Psyche-sized asteroid of (say) platinum-iridium available, it wOULD Make PtIr a nice useful industrial metaL. It wouldn't crash the price, because as the price comes down, the uses for the metal increrase. Think Aluminium.
We are the only/advanced life in the universe and when life gets to a certain stage is wiped out, are not mutually exclusive statements. Don't feel safe.
To mine an asteroid you set up a rail gun. Will this change it's orbit? Could we mine a near earth asteroid into a orbit so it will not be a danger? Sorry I don't have a cool name like everybody else here.
Wow meat computers is pretty a dismal description of something you don't and cannot fully understood. It would be depressing if I thought you were in anyway right.
![State of Play | September 24, 2024 [ENGLISH]](http://i.ytimg.com/vi/fVs0suPHAX8/mqdefault.jpg)
Are Charon and Pluto considered a binary pair yet?
I'm not sure if it's an official definition. But I've heard that if the point that two bodies orbit (the barycenter) are outside both bodies, it should be considered binary.
Wich means that Pluto and Charon should be considered a binary pair. At least by this definition.
@@arnelilleseter4755 Since most orbits are elliptical, not circular, should that read at least one orbit center is outside either body? If so, a very useful definition.
@@friendlyone2706 Two bodies orbiting each other have only one barycenter regardless if it's a circular orbit or not. It may be easier to think of it as the common center of mass of the two bodies.
Btw this is also true for more than two bodies, but then the orbits get pretty complicated and unstable over time.
@@arnelilleseter4755 Thank you -- my misunderstanding.
The world is eagerly waiting for a trick to do multibody orbitals.
Make Pluto a planet again.
Hiya Fraser. What's the biggest a rocky planet (rather than gas) can become? And why is there a limit?
I don't know the limit, but the limit is there because if a rocky planet gets too massive, it will attract too much gas and you won't be able to see the core.
But you can't see Venus, and it's less massive. Hmmm.
“Mass limit of a planet”, “biggest” is ambiguous. Does it mean “volume” or “mass”?
Mass limit is highly dependent on chemical composition. A gaseous planet of hydrogen & helium will start fusion at around 70x Jupiter’s mass. But a planet composed entirely of iron can grow much more massive since iron won’t fuse and provide net positive energy. An extremely massive iron planet starts run up against gravitational collapse into a neutron star. I don’t know the numbers but I’d bet an iron planet could be more massive than our sun.
The limit depends on the composition of elements on your "rocky" planet (rocky can mean a lot, metals, silicates; metals can mean a hell of a lot as well... You have to be more "precise" than just "rocky"). More less dense elements allow your theoretical planet to grow larger, more high dense elements will reduce that limit drastically.
You reach your limit, when your gravity is so huge, that it attracts and keeps (captures) Helium and Hydrogen (Earths gravity is not able to keep Hydrogen and Helium).
Once that happens, your rocky planet will inevitably turn into a gas gigant. Then it will attract more and more gas (considering, that there is still gas available).
If there is so much gas available, it will further grow, get more dense, will get more powerful gravity, which will attract even more. At some point things get so dense at the core, that fusion will trigger. Then you have star.
There is also a chance, that something else (a neighbouring planet for example, our your center star) will eat up all of the gas, that your planet would have collected otherwise. But at this point it will still be a gas gigant and not a rocky planet anymore.
@@dnocturn84 If, by some magic, you don't allow any gas to accumulate on the growing planet, it will at some point overcome electron degeneracy pressure and become a neutron star. The largest size would clearly be well before this.
Alderaan was a really cool question, so that's my vote!
What ever microphone and sound room you are using, it's the best I've ever heard on ytube.
I agree! It's very warm and highlights the deeper parts of his voice nicely
The mass limit of a planet is currently estimates to be at 13 Jupiter masses, or 10, whoever you ask. But not just one Jupiter mass. There are heavier planets than Jupiter out there.
I loved the shot of Scotland near the end of episode
Mustafar!
Fraser, I have a HUGE issue with the Fermi "Paradox"... Because it's not a paradox, it's just a question... A really important question, no doubt about it, but one that accepts any answer. Even "the Prime Directive"!
My point is: "alien civilizations exist" is the premise of the question, not the question itself. So, in another words, "there's no one out there", although it's a real possibility... It just addresses the premise, it doesn't answer the question.
I already tried to rewrite it some other way, in a way that it would be a real paradox... But I failed miserably. 😕
Anyway, stay safe there with your family! 🖖😊
Tatooine is a lightly mind bending concept 👏
The next-to-last segment, involving a planet orbiting in a binary system, has Lagrange Points mentioned -- but unless the two suns have a mass ratio greater than about 26-to-1, there can't be Lagrange Points associated with them . . . but there would be a gravitational Neutral Point located between the two suns, at a point where the gravitational pulls of each star cancel each other. If the two stars are of equal mass, then the NP would be exactly halfway between them. Granted, positioning a planet at such a Neutral Point would be precarious, with the slightest nudge away from the NP resulting in it moving ever so slightly away from one star and closer to the other. It would be a balancing act that -- without any way of moving the planet, as a "station-keeping" contingency -- would probably not last very long. There is a tendency in some circles to confuse a Neutral Point with a Lagrange Point -- especially with the L1 location in a 2-body system. In a binary system such as Alpha Centauri A and B, or the Sirius system with its famous white dwarf companion, there can be no Lagrange Points associated with those pairs of stars, since the mass ratios are nowhere near 26-to-1, but each of those binary systems DOES have a Neutral Point positioned proportionally between them, based on the mass ratio. For example, the Earth-Moon system -- which does have 5 Lagrange Points in it -- also has a Neutral Point located roughly 90% of the distance from Earth's center to the Moon's center: you take the mass ratio, which is 81.3-to-1, then take the square root, which is 9.01665, then add 1 to that, to get 10.01665 units for the distance separating the centers of Earth and Moon, and the distance from Earth's center to the Neutral Point would be 9.01665/10.01665 = 0.900166223 = 90.0166223% the total distance. This Earth-Moon Neutral Point is NOT the same thing as the L1 Lagrange Point, yet is often mistaken for such.
Bespin was my favorite question and answer
Tatooine
🧡 thank you for your content!!!
Zowie I’m in shock on your last answer that we are the only life in the universe!!! You need to expand on what made you come to that conclusion.
I don’t want to put words in Fraser’s mouth, I would suggest that Earth-life-is-alone comes out of the scientific evidence. We have no credible evidence for life beyond Earth so all we can say scientifically is that we’re alone.
I don’t want that to be true. It places a heavy burden on humanity to not screw up and seed the universe with life if we hold to life being precious. Mathematically is seems implausible that Earth is the only planet with life. We know there are billions of planets in the habitable zone of their host star. We know that abiogenesis happened very early in Earth’s history, so it’s not that hard. Life on Earth is based on chemistry that’s very common in the universe.
@Fraser Cane in HOTH you said you would use a rail gun to shoot them off into space. Ok... But how do you get the material to earth? Thank you for all of the amazing & free space and science content you provide for me and all of your viewers.
most importantly: you probably would not. Bringing material down to earth is quite a waste. the most valuable thing about the material of Asteroids is, that it is not in this gravity well. That you don't need Rockets to shoot it into space.
The gold of asteroid Mining will be water, not pressures metals. To think asteroid mining and to think of Gold is a bit small minded.
having said that, atmospheric reentry would not really be a problem for a ball of metal.
Asteroid materials should stay in space for space construction. Every pound that we don’t have to launch from Earth is worth a few $thousand.
But if you must send basic metals down to Earth the coolest idea I’ve heard of is making fuzz-balls out of it, like steel wool. Big, wide, high coefficient of friction to slow it quickly. Some might be tempted to make solid balls or cylinders but those stand a chance of drilling into the ground faster than terminal velocity.
A comment on the Alderan question: "Could a planet occupy one of the Lagrange points of a binary star system?" Assuming the stars have roughly equal mass, wouldn't there be as many as 10 Lagrange points in the system, 5 for each star? L4 and L5 for each star would be 60°ahead and behind each, and then pairs of L1, L2, and L3 aligned along the axis between and beyond the stars.
If one of the stars has much more mass than the other, there would be the typical 5 Lagrange points associated with the smaller star. In this case, L4 and L5 points would be inherently more stable and would be an excellent place to park a planet, or a group of objects orbiting the Lagrange point.
Also, one way of thinking about Lagrange points is that they are points in space at which an obje t simultaneously orbits both of the stars. For instance, the Jovian Trojan asteroids simultaneously orbit Jupiter and the sun.
Ive heard that the voyagers actually have slowed down at the limit of the solar system. I read about it in a magazine 10 years ago...
While the gravity of the sun decreases with distance, it never goes to zero, no matter how far away you go. So after the last gravitational assist, all probes headed out of the solar system will start to slow down. (At some point the tiny gravitational pull from other stars will become stronger than that of the Sun, at which point the Sun's gravity really becomes irrelevant.)
If they have escape velocity, then this slowing down will happen at a lower rate than the decrease in gravitational pull, and so they will never get pulled back to the sun.
How about adding a link to the original live show In the description? I missed last weeks show. It would be nice if I could see it when the finished version comes out. Thanks.
Great channel
I read somewhere that your telescope need to be 12km by 12km to get a complete image of the exoplanet?
What is theoretical maximum size of a terrestrial, rocky planet?
Having now watched to the end, I see that your intro had a compact version of the Bespin question that PUT a different spin on it. Perhaps it was a hook to snag pedantic minds like mine, clever boy?
As to my favorite question: Tatooine (mass limit for a planet) held onto the early lead into the 'far turn' so to speak, but Alderaan (LaGrange points in binary star systems) supplanted it coming down the stretch because it stimulated consideration of sci-fi scenarii as well as reminding me of some I had read. In the case of the hypothetical pair Elephantus A & B, we have to keep straight whether we're talking about the La Grange points of the two stars, or of the planet and Eleph A, or the planet and Eleph B. Only if A and B had exactly the same mass would the A-B L1 point be the same as the B-A L1 point and make it (however remotely) possible for the two suns to seem to circle the planet as it orbited their shared L1 point. If A & B were just a few AU apart, Elephantus c could be in their habitable zone, which I imagine would be a double torus that would be broader in the middle, not that that would matter, because for Eleph c to maintain its position very long, no other sizable body could be orbiting A or B in the zone. I suspect also that It could not have a sizable moon (unless it had a polar orbit?) and that it would be tidally locked with A permanently at the zenith of one point on the planet and B permanently at the zenith of the opposite point. If not, and there were oceans, the high tides (given a 24-hour day) would occur exactly 12 hours apart at noon and second noon. Dusk would merge into dawn. If there were no axial tilt, it would seem that the day was only 12 hours long given too thick an atmosphere. Otherwise, one sun would be peeking over the Eastern horizon, while the other was sinking in the West. The moon in a polar orbit would always be full, but might there be some sort of band bisecting it, with craters having shadows on both sides? At any rate, once you got away from the planet's equatorial region, the moon would disappear over the northerly horizon and reappear roughly half a "month" later.
Honorary mention (for me) goes to Dagobah (AI vs. organic intelligence) and Yavin (Fermi 'paradox'). The former, for bringing up the notion of different types of intelligence. I have lately begun to wonder about that as we find that various types of animals are more intelligent than we once thought, and that their brains are not structured like the primate model. The octopods seem to have what might be called sub-brains, their natural environment is like an alien world to us, and they don't live long enough to train their young who, therefore, have to keep "re-inventing the wheel". Cetaceans have colonized that world, can communicate in it over fairly large distances (in some cases), have shown some ability to communicate fairly complex concepts, can hunt co-operatively, and can 'see' things acoustically, possibly even each other's internal organs. The intelligence of the problem solving, tool-making corvids, who monogamously mate for life, engage in play, and 'mourn' their dead, seems to have arisen in a different part of their brain than in the primate model. Elephants have a highly developed area of the brain that deals with empathy, can apparently communicate subsonically, develop strong bonds even with some humans, and have been seen using objects to distract or threaten adversaries. To what degree are these intelligences (and that of AI) convergent? Can they have an ethical consensus? Human beings mostly move around on a (geometrical) plane. To us vertical distances seem, even feel, greater than horizontal distances. But gibbons live in the 3-dimensional world of a fully arboreal creature, and routinely and casually launch themselves through empty air from one tree to another while many meters above the ground. To them a complex series of leaps and swings between branches and limbs that even takes into account the springiness of various branches and changes elevations many times is as simple as seeing what the path from the bedroom to the kitchen is for us. If that is the case with our relatively near cousins, how different do things look to Jumbo, Flipper, ravens, or octopods than they do to us?
I was actually surprised that your take on the so-called Fermi paradox was close to mine. I don't really see it as a paradox, because the "Copernican Principle" which is the underlying assumption of the "paradox" is not a principle of physics, but a guideline for inquiry in science. I would really (I mean REALLY!!) like to see you discuss that with someone (like Isaac Arthur or Anton Petrov) who seems to have the opposite view. Or maybe more of a panel with David Kipping of "Cool Worlds", who has more of a middle view, and some other RUclips scientists like Dr. Becky also included. Co-ordinating that many schedules might be a problem, so maybe just getting each to record their thoughts, pro & con, on the subject would be the way to go.
Your view of a lifless universe, apart from us, is very Red Dwarf but then I've always thougt that Red Dwarf might be a more acurrate prediction of our future than Star Trek.
Alderaan was fabulous. Looks like further research might be necessary. You know, with all of your free time. LOL
Is it possible to see a galaxy at the edge of the observable universe that's half cut? How smooth is the gradation around the edge of the observable universe? What about a galaxy interacting with another galaxy outside the edge of our observable universe?
Alderaan, Great sci fi idea for an advanced civilization, can't wait for the book.
re - "Will we ever see what's beyond the observable universe?"
Isn't that the exact same thing as asking "Will we ever observe what we can't observe?" or "Will we ever see farther than it's possible to see?" Isn't the CMBR the absolute limit for sight? Or is there a gap between the CMBR and the 'horizon' to the observable universe? Or is that question using the word "see" to imply investigation beyond the visual spectrum?
If I waited 20 minutes before writing this, I'd probably have found out the answer...
Alderaan (binary star system lagrange point question).
What shape do planets in binary star systems take? Does the force of gravity or momentum suddenly shift at different positions of the orbit? Is it more likely or just as likely for planets to become tidally locked in binary star systems?
Yavin - your answer was very interesting. I kind of agree, but I don't think I can make a good argument for it. It is a very big universe 😅
Here's a question though; what would happen to a dead body in space? Would we expect it to slowly reach background temperature and remain a frozen block forever, or would solar radiation eat away at it until there's nothing left? Assuming it doesn't impact anything I mean.
Yeah, I don't have any evidence that we're alone, just no evidence that we're not alone.
Tatooine. Can I vote for my own question? I'm not biased, I swear.
Mustafar - Thought experiment... when we get to the point of having a working design for sending a probe to another star, why not do a grand tour of multiple stars, and beam the data back home after each close approach, just like we did for the solar system. For that sort of scale mission, what is the best way of fuelling such a probe for such a huge duration - both for propulsion and power? --- My thoughts, surely attaching a craft, with mining equipment, to (or in?) an asteroid has to be the easiest / lowest tech way? Would our first attempt a probe look similar to Oumuamua? How much fuel is needed for propulsion and/or power for such a journey? Is a nuclear reactor sufficient to power a potentially multi-century mission? Is there a more mass efficient / better way for the first possible attempt? A fascinating idea.
If you were to observe outside the observable universe, you'd be increasing the observable universe. It's like expanding the Observable Earth - we can only observe like 1/2 of it at a time, restricted by our 3d construction.
How are we certain of Hubble Expansion? How do we rule out Tired Light?
Very distant objects exhibit red shift that we’ve ascribed to Hubble Expansion. From this we’ve deduced distance through z. And we’ve deduced that the distant object is moving away from us.
How do we know that Tired Light is not the cause? Imagine a maybe-not-quite-so-distant object emits light and those photons lose some energy over the hundreds of millions of years of their journey. Less energy would show up as longer wave lengths which we associate with Doppler Shift. Tired Light could have that object be almost stationary or moving toward us.
Question: why do you have to be a certain distance for the gravity lens to work? Isn't the sun constantly bending the light? Wouldn't any angle work if you're staring at the edge of the sun?
It only starts to kick in at about 500+ AU, but it's lost in the glare of the Sun. Once you get to about 1000 AU, you can block the Sun and see the lens around it
[ Mustafar ] I believe Prof Loab stance is not exactly "Hey this is Alien Craft" but more on the lines of, "Why is everyone so quick to dismiss such an idea despite all our estimation suggesting there should be TONS of Alien trash rolling around". That all being said I believe its some sort of metallic dust bunny to be honest evident but its behavior, speeds, LSR etc.. but my hypothesis is not any better than the Alien hypothesis and this push to dismiss it and never exploring the Alien concept means if it is Alien... we will never know because we never checked. Our ignorance is quite possibly the answer to the Fermi paradox in that we simply dont know natural and unnatural when we see it.
I agree. In science we should not make up our mind before we have evidence. None of alternative explanations is good. So it could still be alien, or not. Those who criticize Avi have not understood most important principle in science. Avi Loeb is a theoretical astronomer. So I trust his calculations: It cannot be hydrogen emitting ice.
Can a planet of a binary star system follow a stable "figure-eight" path around (and between) the two stars, orbiting one star clockwise and the other star counterclockwise?
This is called the "three body problem". It may be possible for a short time, but such orbits are very unstable.
Hey Fraser. You mentioned several times already that the kind of telescope that will use solar gravitational lens will only be able to view one planet. But why is this? I know 1k AU is far, but why not put a telescope in orbit around the Sun at 1k AU so that it can continuously image explants as it goes around the Sun?
Yes, the telescope would not be observing a single point but instead a circle across the sky. But you would be stuck on that circle, and I assume the circle would be a very narrow band, so infinitesimal unlikely that there happen to be multiple nearby star systems exactly on that band.
However, because of geometry, there should always be a possible orbit to have any two star systems on that ring that the telescope observes. But, at 1000 AU, one orbit around the sun would take 32,000 years. So it likely would take a very long time that you have to wait until your second planet comes into view.
qustion: where should we mine/ process asteroids?
- where ever they happen to be.
- In lunar orbit.
- on L4/L5
or
- somewhere else
21:40 This one really should have been Tatooine, not Alderaan.
It would be cool to do an episode that does address Avi's points. I don't know either way I just watched a recent episode of Event Horizon with him and he said the hydrogen theory had been debunked because the math didn't work due to temperatures or something.
That's exactly right. He's debunked (along with several colleagues over the years) all of the natural explanations that have been put forth.
I don't intend to speak for Dr. Loeb here, but my take on Avi's perspective is that he's not saying that Oumuamua MUST be an artificial object. He's never even said he believes it IS an artificial object. All he's saying is that an artificial origin should be allowed to be considered, scientifically and without bullying and senseless ridicule, just like any natural explanation, ESPECIALLY when all of the natural explanations that have been brought forth so far to attempt to explain all of the anomalies collectively have been natural objects that *we have never seen before.*
Avi is trying to change the culture. That's his motivation, and that's his stated goal. He set up the Galileo Project at Harvard and over 100 credible scientists of all different beliefs and backgrounds have joined on to, on one hand, look for MORE Oumuamuas, with store bought instruments, and on the other hand, try to identify any UAP in the sky. They're collecting actionable scientific data, without fear, preconceptions, or prejudice, to help all of us understand more about the universe NO MATTER WHAT they may find. That's why I respect and admire Dr. Loeb as much as I do. People who just want to gratuitously dismiss his proposals out of hand can do as they will, but that's never going to stop him from looking up at the sky, out into the universe, because he remains just as curious today as he was when he was a kid. I don't know what could possibly be wrong with that.
And let me say one last thing, Stuart. This is actually something Dr. David Kipping talks a lot about, and it's that it's okay to be agnostic on something until you have the evidence to convince you one way or another. It's okay to say you don't know what Oumuamua was, and it's the most accurate and honest response in that case. We don't know what it was. And until we can prove one way or the other, all we can do is go look for more objects like it. Take it easy, man.
That's a weird object indeed. And we're probably never going to know for sure what the heck it is...
@@realzachfluke1 Avi didn't originate the papers postulating Oumuamua could be artificial, but he read the papers and was impressed with their quality. He has the reputation he can afford to say the unpopular and prestige to avoid problems that would besiege others.
@@friendlyone2706 That's a great point, thank you. I appreciate it
@@realzachfluke1 But very sad even Avi has lost some "points" with much of moribund academia. The possible but improbable should never be dismissed a priori, which is what too many do.
How do we get the images back from the solar gravitational lens telescopes 1000 AU away?
For light, I think it would just take 1,000 x 8 minutes.
I agree, I think we are alone or the first, good call 👍
I vote Tatooine. I did not know that gas giants any bigger than Jupiter would start to contract by its own gravity. I have read about "hot Jupiter" exoplanets orbiting close to their stars, and I sorta assumed that some of them had many Jupiter masses. It could have been a brown dwarf in a binary system, but that didn't work. Does anyone remember the novel "2010" ? The unknown alien unleashed a black spot onto Jupiter, which coallesed it, and made it into a star with fusion. The alien said, "All these words are yours, except Europa. Don't go there."
@ Fraser
If you're fond of Von Neumann probes, etc, I recommend that you check out an old game called Sword of the Stars. It's a 4-X game (explore, expand, exploit and exterminate) initially released almost 20 years ago. If you get all the expansions and updates for it and you give it a good play-though, I guarantee that you'll come out absolutely freakin' HATING Von Neumann and the probes that bear his name.
Imagine there are Lagrange points around binary black holes. Maybe rocks at those points will be subjected to intense time dilation.
Perhaps future space geologist could go there to mine rocks that are very old and have not aged.
For next questions video - what would a lunar eclipse look like from the moon ?
Alderaan is my favorite
Hi, what opportunitys do you think are there for near earth orbital manufacturing, like for organ growth, crystal growth and other things is there much research out on what might be worth pursuing, can you melt metal down to liquid and move them magneticly to do cool things?
Hello, if humanity managed to build a spaceship faster than light! Would the people in it be able to see stars and other objects as they'll be moving faster than light, and their brains may not have enough time to process images. Thanks
If we capture CO2 on Mars, could we dig so a better density to get from?
Can you address the Taurids Meteor stream and the potential risks to earth?
Railguns would not be good for asteroid mining unless you can invent some kind of super material for the rails. If not they will probably be slag after a a hundred shots or perhaps even fewer. You need mass drivers that work on a different principle (Gauss guns).
Wow just wow, to truly believe that we are the only intelligence an infinite universe, wow.
Bringing a giant ball of metal down to earth would not crash the world economy. It would definitely put downward pressure on whatever metals were contained in said giant ball, but the metals would still have to be processed and prices aren't always a function of actual rarity on earth. Think diamonds and gold.
Some sectors would of the economy would benefit from the lower prices.
Fraser, I'd love to hear your take on the rapidly developing "the AI Singularity is here - and we're all doomed!" story due to the latest and upcoming iterations of ChatGPT.
Tattonie
Jupiter is a gaseous planet; what would the size of the biggest rocky planet be? Exclude hydrogen and helium.
Question. If we are the only life in our observable universe do you think we should spread life as far and wide as we can even if that’s genetically engineered bacteria to other planets?
Yes, if we're alone then we should spread life to the cosmos.
@@frasercain I agree. We should tread with caution to see if there is life there already but if not spreading the gift of life far and wide would be good.
@@frasercain Carl Sagan said something like: If we are the only intelligent life in the galaxy then we have a duty to spread. The universe is pointless without someone to appreciate it.
maybe we will send several 3-d printers and when we have new target the closet printer squeezes one out , has a hasta la pasta party, and says bon voyage.
I vote for Yavin. Main reason is first of all I agree with Fraser that we are the only life. Second the more I look at the chaos of the universe, I don't see how life can get a foothold. Having a scientific mind, I hope I am wrong but I am right in my mind until proven otherwise.
Life originated on Earth soon after Earth had cooled enough. It is extremely unlikely that this has happened only on one planet out of at least 100000000000000000000000 planets in observable universe. If we are only one, universe is extremely dangerous place for life.
Naboo (exo mag fields)
I love your coverage of space topics but I just can’t understand your perspective on the fermi paradox. Like it seems like the least probable scenario and it seems to be completely based on emotion rather than evidence. You said it yourself that it’s your choice just because you like it.
No, I prefer that we're alone to the possibility that all intelligent civilizations destroy themselves, since I don't want us to destroy ourselves.
Are Brown Dwarfs planets?
I think they actually like to be called dwarves of colour
Stars.
[Q] Hi Fraser. Is there anything in Jupiter's stable Lagrangian points now?
Yes, they're called the Trojan regions. There are as many objects in Jupiter's L4/L5 regions as there are objects in the asteroid belt. NASA's Lucy mission is going there now and will fly past about 10 of them.
Mustafar
When it comes to the Fermi paradox, I think we vastly overestimate the ability of technologically advanced life to make an impact on the observable universe that we could actually detect. Life could be abundant, and we may never be able to see it.
I believe the idea is that there "should be" self-replicating automated probes all over the galaxy that we would detect in our own neighbourhood, not that there should be observable megastructures or something that we can see from vast distances. They've calculated that at reasonable travel speeds (for an advanced civilization), there's been orders of magnitude more time for this to happen than is needed for one such probe to spread through the entire galaxy.
Nothing I've heard about computers and interstellar space suggests that such a technology will ever be feasible, though.
Jeremy Mattern??
If you are reading this, HI JEREMY! I was friends with your brother in HS.
You said galaxy’s are moving away faster than the speed of light. Is their time moving backwards? How fast is the Milky Way moving? Is our time dilated? My brain hurts
When you say that that much metal would crash the world economy, are you taking into consideration that in the right conditions, we could have so much resources that it could be possible for everyone on earth to have whatever kind of lifestyle they please from luxury to modest without money needing to be a factor anymore?
Mustafar - Question::: If a threeD person stuck his hand through a 2dunverse, close to a 2d guy, and the 2d guy just saw a multicolored line, what would a 4d guy sticking hand into our 3d'verse look like to us?
Alfred E Neuman
Coruscant
I've always heard, (I think from you also), the universe is at lease 500 times larger than the observable universe. Now you're saying 1000 time. what new research has changed that figure.
Yavin. Definitly.
17:17 Ethan Siegel thinks the whole Universe is at least "250x greater in diameter* -- 10M times greater on volume, in his Forbes article "How Much Of The Unobservable Universe.."
Yavin: I'd say, at this time (fsvo time.) CF Vlad the Astrophysicist?
Alderaan: Depending on the relative mass of the two stars, the L4 and L5 points of the smaller star might be stable. Not exactly what the question asked for, but close.
Did you mean L4 & L5 ? L3 is a point 180 degrees around the orbit of the smaller body and is unstable. L4 & L5 are points 60 degrees in front and behind the smaller body and these are stable. It’s where Jupiter’s Trojan asteroids reside.
@@CarFreeSegnitz yes, oops on that typo thanks will fix.
Yavin It seems to me that a better answer is we are effectively the only life in the universe. Space is just too big to be explored by creatures that are not immortal. As for AI, I spent my career in electrical engineering and have seen far too much of just really crappy software to believe that AI will produce anything more than really crappy results also. I am willing to be wrong just really skeptical.
When I left college in '76 AI and nuclear fusion were to be here 'real soon'. To be kind, they have both made great strides, but also we should be willing to admit they were both vastly oversold.
❓Have we found a gravity lense within a gravity lense yet?
Wow, that's an unexpected position to hear on extraterrestrial life: a trillion galaxies, not a microbe? Really? Still, it's falsifiable, unlike my personal opinion, which is that civilizations (in addition to being very rare) MUST fall, and that in any particular galaxy most of the time there aren't any.
I'd like to see the asteroid mining discussion move beyond the "Let's go get a billion tons of platinum!" stage; no wonder most people think it's a silly idea. Very obviously the main thing that's going to be mined from asteroids is rocket propellant, and when that moves on to solid resources the stuff will be used in space. I can see moderate amounts of rare Earth elements brought back, for strategic purposes, but not huge amounts of traditional "precious" stuff, that really is silly.
If any of you guys are interested in the Pyramids in Egypt there is a brand new video on RUclips where a guy explains exactly how the Pyramids were built to be large scale chemical plants to make fertilizer. The name of the video is "The Original Purpose of the Pyramids." After you watch it, let me know your thoughts.
I'm barely 10 seconds in, but right away I have to say that "will we ever be able to see what's outside the observable universe?" is an absurd question. If we could "see" it, it would, by definition, be observable and, therefore, NOT be outside the observable universe.
Oh. 25 seconds in and it seems that Fraser just invited such questions. "Wherever you are..., if a question pops in your brain, just write it down. I'll...answer [it] here..." Don't bother your pretty little head about whether it makes sense or not; just ask whatever cerebral flatulation detonates in your cranium, and I'll try to make sense of it.
Tatooine
Tatooine.
I vote Yavin,
I think the same, we probably the first, or currently the only civilization in the universe, but the universe is still yang.. So..
I hope I'm wrong.
At the heat death of the universe would the universe essentially become frozen solid. If so wouldn't then collapse in upon itself due to gravity.
The heat death just means that all the atoms lose their kinetic energy, but they could still be far apart.
If we hasd a Psyche-sized asteroid of (say) platinum-iridium available, it wOULD Make PtIr a nice useful industrial metaL. It wouldn't crash the price, because as the price comes down, the uses for the metal increrase. Think Aluminium.
Aluminum did come down in price considerably when electricity became cheap. In Napoleon’s time aluminum was more valuable than gold.
Alderaan
We are the only/advanced life in the universe and when life gets to a certain stage is wiped out, are not mutually exclusive statements. Don't feel safe.
i you ae more te two stars orbiting eachother o you get more lagrange points/
Naboo
Kamino. Would a baby born on Mars ever be able to visit Earth without the crush of gravity crippling it?
Alderon
Hi
Hypothetical: if I do the patron thingy and make my name something like "Im a poopie head" will you say it?
The question Alderaan should have been named Tatooine. It would have been made it lore accurate. Great missed opportunity. 😢
There are planets thats bigger than jupiter becausen of the superheated atmosphere.
endor
tatooine
dagobah
To mine an asteroid you set up a rail gun. Will this change it's orbit? Could we mine a near earth asteroid into a orbit so it will not be a danger? Sorry I don't have a cool name like everybody else here.
Yes rail gun would change asteroids orbit. Solar sails would be better.
Of course we can cut solid metal. We need energy source and tools.
Wow meat computers is pretty a dismal description of something you don't and cannot fully understood. It would be depressing if I thought you were in anyway right.
Do you think that the human brain is the only possible form of intelligence?
@@frasercain obviously not and the issue was with the description meat computers.
I'm not saying the human brain isn't amazing, a fantastic organ developed through hundreds of millions of years of evolution.
Question: What name would you choose for your self if you became a professional WWF wrestler?
Great show! I vote Yavin. Also, if the Voyager missions were re-done with today’s tech how different would they be?