Mandalore. Thanks for another awesome episode and for using my art in the thumbnail, Fraser, it's an honor! I really appreciated how you captured the feeling of the sad situation, where a federation communicates from orbit with entities living on an inescapable planet. Hopefully, a new system of transport, beyond our current imagination, will become available, and this federation will be able to set them free.
Thankyou so much for explaining the size of the universe again. With your help along with Paul Sutter I finally get it. At last it makes some sense to me. It just goes to show we are never too old to learn something new. I am only 77 by the way and I still want to know how and why this universe got started in the first place. Keep up the great work you are doing in providing others like myself with so much interesting and fascinating information.
If the universe is finite but non-spherical and instead a torus then this 'wrap-around' concept takes on a whole new meaning. A torus is kinda like a sphere multiplied by another sphere and gives rise to multiple radii within in, not all of which will cycle back around to where they began - at least not on a single cycle or period.
Ok, I know I have heard you explain the CMB a few times, but today was the lightbulb moment. Maybe it was because of the way the question was phrased. Thanks and keep making these! [Coruscant]
Recently, plasma science has lately come into my purview and, being an electronics engineer myself, I'm blown away by the special rules that plasma obeys (electromagnetism, double-layers, dark-, glow-, and arc modes, z-pinches, etc.). But I have been shocked at how astophysics articles hardly (if ever) mention any of these things. Yet at first glance, plasma and electromagnetism seem to be good candidates for considering of possibly playing a major role in forming the massive structures we can observe in space and some of the electrical activity that occurs. And knowing electromagnetism is 1000 trillion trillion trillion times (10^39) more powerful than gravity, do you see plasma science coming into or being more and more included in astronomy and cosmology in the future? Like, maybe gravity & plasma together to help explain some of the mysteries and anomalous observations? (I'm so new at plasma, I'm not even sure I'm asking the right questions). Anyway, I'm a huge fan of Universe Today and you! Thanks for all you do!
Dagobah is for sure my favorite for this episode! We already have gravitational wave astronomy but it's still a newborn field basically, and the idea explored here will probably be in the center of developments in it in the future. Maybe very far in the future, but still.
BESPIN: In a very strong magnetic field it’s possible to flip the polarity of an ordinary magnet. An idea popping up in my mind is that the flipping of Earth’s magnetic field may be caused by events in our galaxy.
Mandalore: That question also states another fact. Can there be a planet where the escape velocity is so big that life on that planet could never leave the planet ? That also means there are planets where we shouldn't go, because we couldn't return.
Mustafar is definitely my favorite subject! Re: Naboo. Shouldn't we call the "habitable zone" the "liquid water zone," instead? Because what would sometimes be considered uninhabitable could, through something like Enceladus does, have liquid water. As for Bespin, thank you for clarifying that, since many seem not to understand it. But... "flippening?" 😂😂 That's a technical term, right? 😂😂 Thanks, Fraser, for all you do! ❤❤
What does "size" mean in the context of the universe? By what ruler is it measured?... the speed of light? If so, maybe the universe hasn't changed size. Maybe another way of looking at it is the speed of light decreasing instead of space changing size.
The singularity that created our universe must have been like a black hole, could it be processes going on in black holes, only extremely slowly? So the black holes we see is actually "exploding" like the big bang did, only very slowly?
A simulated reality is interesting in that if you were to simulate a reality within the simulated reality the energy required for the second simulation is already within the first simulation. This implies that the second simulation was known before the first simulation was created. Does this mean the idea is impossible or does this indicate 'chronodelocalization'?
I'm trying to understand what you mean about the size of the Universe just after the big bang. Previously I had pictured the Universe as only the size of a orange, just after the big bang; and then there was inflation which expanded the universe faster than light. To me the faster than light expansion seemed to explain why some of the Universe is currently not observable. So does your explanation include inflation as well? Are you saying that the universe essentially already existed before the big bang? And that the universe may have been empty before the big bang, which filled it with matter and energy? (In the observable portion).
I think the universe is a horn torus, possibly spindle torus. Atleast that is the shape we'd call it from our limited dimensional perspective. The big bang and great attractor lead to the same place/time.
The more important thing for our civilization is not the seven hundred thousand a-year reversal cycle but the 6,000 year magnetic excursion cycle. It appears to bring disaster on a 6,000 year cycle. It's been about 6,000 years, and the poles are moving rapidly. The field strength is dropping, also, which shields us less from space and the Sun
Third The Plasma Magnet can achieve velocities of > 750 km/s when ~ 25° above or below the eccliptic. As to braking from .2 of see Jeff Greason has calculated tha a complete delta V maneuver (braking) could be accomplished in a period of two years.
Bespin. Is there any evidence of how much the magnetic pole axis changes when it flips? The north pole is wondering at an historically high rate recently. I assume the south pole is too, but i never hear about that. I assume even large movements, while still relatively close to the planet rotation axis, aren't enough of a change to show up in new lava cooling. (Any slight change in orientation of the locked-in magnetic field would be demoted by slight rotations of the cooled lava.) After a flip in the Atlantic rift lava, can we tell how far a new south pole was from the previous north pole?
That planet swapping thing is very unlikely but I would not exclude the possibility. Take Saturn who has two moons (Epimetheus and Janus) which actually switch orbit every 4 years and it seems to be very stable.
Mangalore. But gravity isn’t the only problem. You said clouds on Venus are so thick it like molasses or treacle. Assuming Earth temperature, but Venus atmosphere - would this make it impossible to take off into space? How much extra atmosphere makes it impossible to leave a planet?
If the universe had infinite density/singularity in the past, then surely the density at every point would remain infinite regardless of the size? i.e. no matter how much you expand infinite density - its still infinite.
I thought that while Hydrogen is the smallest atom, but because it naturally forms into a diatomic H2, a single He atom is smaller. Is that different with liquid Hydrogen? (I know Helium will migrate through glass and can over time "poison" vacuum tubes, in my experience photomultiplier tubes.)
I think it is true that He is smaller than H2. But hydrogen has another trick which causes problems, in the presence of certain metals it can undergo a cleavage reaction catalyzed by the metal which breaks it up into two hydrogen atoms. These atoms can then take up residence inside and migrate through the metal lattice. This makes a lot of metals more brittle and can cause serious structural issues.
Could you please share your thoughts on the validity of the Ancient Apocalypse hypothesis from netflix? Asteroid hitting earth 20,000 years ago and human civilizations having to restart from almost scratch
The toba eruption bottlenecked the species. But yeah, I would not trust Netflix, trust published research from anthropologists. Sensationalism is not science
In the butter simulation answer - how could you not mention that according to quantum mechanics the universe is not deterministic, thus if we "restart" it from the big bang you would probably (pun intended) get a different result
What if we find some "non intelligent" life, like for example some lizards of fish or even microscopic organisms, would we be disappointed, would we be able to not interfere or we would cause the big evolution event unintentionally or by mistake or even intentionally?
Im a big believer in the multiverse proposal. To me i imagine an infinite amount of round universe's with sometimes Dark matter in-between these multi Verses and the dark matter pulling some universe's towards each other Eventually example 2 universe's colliding or bouncing off each other creating with dark matter a unimaginable amount of energy pushing apart those two universe's creating a new universe. With the dark matter almost pulling into two masses with starts the process of rapid exspantion with the dark matter being the driving force causing the universe to almost spread in all equal directions. And over and over. My theory and many others. But my extra spin on the hypothesis. ??? Its an idea as we truly dont know with any certainly as yet. Cherrs. Patrick Wilson Bridgetown Western Australia 👍🇦🇺❤
Fraser, The current theory for the universe is based on the assumptions that; it is expanding; it is flat; it is homogeneous (roughly the same no matter where you look) among other assumptions. Standing on earth, no matter which direction we look with our best telescope, JWST, we see galaxies at 13.8 bly and we can calculate that due to expansion the furthest galaxies we can know about are at up to 46 bly away. But that is not because we are in some privileged position at the centre of the universe. What is rarely mentioned is that if we were standing on a planet in one of those galaxies 46 bly from the Milky Way we would have the same view in EVERY direction and so on ad infinitum (forever). Get your head round that and you are begining to understand what infinity means. However if this is not the case then the universe has an edge, is not flat and so the whole basis for our understanding of the universe comes crashing down. Mike Egan Meath Ireland 02 Jun 2023
I talk about this concept all the time. No matter where you go, you'd see roughly the same thing. Travel to the edge of the observable universe and you'd see a new observable universe with a CMB at the very limit in all directions.
@@frasercain Ah! That's answered a few questions. Not sure I can fully comprehend everything but I think I have an answer to my confusion about infinitely dense. Thanks!
i know nothing about science, but i have a question about how can people measure the flatness or curvature of the universe when it is empty space? and when you or anyone refers to the universe as "flat", i am not sure what that means. do people mean that, theoretically, there is an "end" to the universe in particular directions before another? and, to determine this, people have observed that there is a shape which they refer to as flat? and, if the universe did loop around itself and we still cannot measure curvature, is that what people are referring to as "flat"? because it is somehow being measured in a certain axis but not another? ... i'm really confused to this idea of referring to the universe as flat.
It means that if you fire out two lasers side by side in parallel, they'll remain parallel forever. Think about how the lines of longitude on Earth meet at the poles but are far apart at the equator. If you fired out lasers and they curved away from each other, then you'd know the Universe was curved. So the Universe can't be a sphere. But there are 3D shapes that would work, where parallel lines remain parallel, like a cube or a torus. Astronomers look at the largest structures in the Universe and that's how they can measure its curvature.
The word 'flat' in topology just means measured lines through a space are straight in every direction. Near a heavy mass space is curved and so not 'flat'. Measurements of the universe (in particular the study of 'lumps' in the CMB) show that the universe is 'flat'. Imagine a ray of light travelling across the universe that does not deviate from a straight line, although in reality some fraction of those rays are deflected by the mass of nearby galaxy clusters or stopped by a passing monkey!.
re - Black Holes still a mystery? Michio Kaku thinks he knows what's inside Black Holes now. Do a google search for "Kaku inside black holes" to see the video where he talks about it. I didn't watch it myself, as I don't have a particularly high opinion of Kaku.
Love show! Here's a Therory! A singularity in a Donut! A VAST Universe with a blender singularity in the middle. Goes in one end and recreated on the other. Explains alot........ Thus the Donut none stop sound of creation. And or destruction.... Norcal...
If the CMB was once high energetic / high frequency radiation and then got “streched” to today’s microwave frequency, there must have been a time when it passed through wavelengths of the visible spectrum. Was the light intensity at this time high enough that the background of space was blue, green, and then red insted of black? Or was the intensity already so low that we could not have detected this light with our eyes?
The CMB started out as a hot 'orange' glow of about 2700 Kelvin (like a hot piece of metal, or the hot surface of a small star), 380,000 years after the big bang.
The universe was always infinite in size, just not always infinite in density. Remember Space and Time are inextricable aspects of the same thing, so space can't expand or time pass in isolation of the other. I think the problem is this requires an infinite amount of imagination to grasp.
How did you miss the word “minimum” so many times? Alternatively, how do you define “observable universe” that gives you a different answer for size of the observable universe? Hella hubris
Your description of curious properties of this finite universe pretty much matches what would expect to experience if we existed on the event horizon of an ultra massive black hole.
Kind of both. If you mash matter and energy so closely you'll get an escape velocity that is higher than the speed of light. It's like a star that you can't see because even the light can't get away.
the cosmic horizon is, i believe exactly what we would see if we were in s black hole, but that doesn't mean we are in one. the universe, however is mathematical singularity like a black holeis a singularity; a place where the msths stops working; matt o'dowd has done videos on these topics and concepts if you have time to dig through the PBS spacetime catalog.that's a lot of ground/space to cover, though; there's a good chance i got specific wording wrong, so my question for next QA is, are you able to clarify, raiser?
Only you can answer that question. The universe itself by itself doesn't have an inherent meaning. However, your life can very well have a meaning, but that meaning is personal. Live, enjoy life, and find your very personal meaning :)
@@fabzter - questions like this, "meaning" are like who created god, what is outside the universe, etc etc etc, it never ends, questions that only produce new questions
Mustafa. E, E, Doc Smith wrote a series (mid 70s to mid 80s) called 'Family d'Alembert'. The main characters were human but born and raised on a high gravity planet. One of of my favourite series in SciFi.
Perhaps we're not looking at the 'edge' when we look back 13+ billion years ago, but the center. Mindblowing, but it's true. 13+ billion years ago, that was the center, but now we call it the edge, even though we're whizzing away from it at a godzillion meters a second.
Hey Fraser, what do you think? Should scientific educators on social media and YT make an effort (quasi an oath) of always making a distinction between the Universe and the Observable Universe? I’ve seen many renowned content creators using Universe when they were clearly talking about the OU.
Vote: ALERAAH. An excellent question! It's indeed true that the restricted 3-body problem (with one mass negligible compared to the others) doesn't have an _analytic_ solution: the only provable analytic solution is Euler-Lagrange with the 5 stationary points, and stable orbits exist only at L₄ and L₅ of the binary, aren't figure-8 (F8). It's unknown, AFAIK, whether or not a numeric solution exists. Considering the Roche potential of the binary, it's easy to spot an equipotential F8 orbit passing through L₁, but it is indeed unstable. It should be noted that a stable _one-period_ F8 orbit, or “free-return orbit,” has been used by the Apollo missions. Without a Moon orbital insertion burn, the free orbit closes back at the Earth after self-intersecting near the Moon. I don't know if the solution can be extended further (assuming exactly circular Moon orbit, for example), but I suspect that it can't It is remarkable, however, that a stable F8 orbit exists for 3 equal mass bodies (Chenciner and Montgomery 2000, ArXiv math/0011268), KAM-stability proof (Simó 2002, MR1884902), linear, stronger stability proofs by (Moore and Nauenberg 2006, ArXiv math/0511219), (Roberts 2007, DOI-10.1017/S0143385707000284) show that the solution remain stable within a certain mass difference margin. Animation: ru-vid.comNifhFOPk7h8. In fact, Simó found multiple regular KAM-stable solution of n-body problems, called “choreography solutions.” This is a whole area of research in chaotic dynamics. For example, a 3D solution for a “corkscrew orbit“ _(not_ F8!) of the restricted problem has been found (Oks 2015, DOI-10.1088/0004-637X/804/2/106, corr. in DOI-10.3847/0004-637X/823/1/69).
As above so below. If the quantum wave turns to a particle when observed and comes into reality from superposition. is there an observing making the universe arrive from superposition?
Question: From my understanding the higgs boson does something (possibly creates a field) that gives everything its mass. If it decays in less than a fraction of a second, how can it do anything?
Question: is there a way we can still do the artemis mission in 2025 even if NASA cancels starship? At this point, Starship doesn't seem like its ever going to be human rated. I just want to get to moon as fast as possible, and i worry that starship is a Spruce Goose that will delay artemis indefinitey
If the universe is so flat it can't be measured. It was always flat. The result of that the inflation is infinite in all terms. No heat death of the universe, but regions of the universe might suffer heat death. This also means that you can't travel for so long in the universe that you are going to start on the same location as you left, even accounting for inflation. The universe is never going to run out and it was always infinite and start of the universe started from a infinity point that might or might not have contained all the matter in the universe. No big bang, more like infinite inflation with infinite matter to create stars, planets, galaxies and so on.
Hi Fraser! Your newsletter is so rich that I'm almost afraid to open it every week as I may not get a single other thing done that week if I do! You do FANTASTIC work. Just wondering whether questions are limited to those with a financial subscription, or whether anyone can submit one? Assuming the latter, I have two probably pretty lame ones: a) you know how when you look at a star, you're seeing the light as it was when it began its journey from that star and when you see it, it's that light finally hitting your eyeball on Earth however many light years later? I get that part, but what wrecks my head is that if you look at the same star the next night, why is more light coming? I mean surely its light hit your eye the previous evening, so game over? (This is kinda like the question I used to ask my parents as a kid: ie, if the Earth turns around during the night, how come our house isn't on the other side of the street in the morning?! My parents patiently explained that it was because the WHOLE PLANET turned around, not just our street, but as a kid I just couldn't grasp this) b) You know how the atoms in your right hand may have originated in a different supernova than the ones in your left? How does the fact that you're built from your mother and father's DNA affect this? This is another primary school level question, I know, so apologies for the overall lameness, but I can't get my head around that either! I think it's wondrous that we are made of materials blown off by stars at the end of their life cycle, but can't separate out the atoms coming direct from stars into either of my hands, from the atoms coming from your parents' combined DNA, if you see what I'm getting at? Again, if Qs are just for paying subscribers, I understand, but that wasn't clear from your EXCELLENT presentation above. Regards Katherine
Hey Fraser is there any connection between the physical phenomena where for example they take the T shape spanner in the ISS and spin it, and it flips direction by itself, and the magnetic pole shift ?
Hey Fraser, great show as always. Question for you... has there been, or are there any planned, earth orbital stations that uses a polar or sun synchronous orbit? All of them so far are equatorial with varying degrees of inclination based on launch location (40-50 degrees for all of the ones I can think of like Mir, Skylab, ISS, Tiangong). A sun synchronous orbit would have some power and observation benefits wouldn't they?
you know the big bang is just a way to explain how the universe got started they don't really know how it all got started. it is just a point to start from to get the ball rolling.
@@MCsCreations the hole point about asteroid mining is, that their are a lot of asteroid, that are qutie close to earth orbit. (in terms of deltaV) so bringing mass from Asteroids is in a way easier, than from earth. The viability of asteroid mining pretty much stops for asteroids that are further away, than the surface of the moon. because if you need actually that much mass, you might as well start mining there. So why the hell would you mine comets?
Would you care to answer my sonnet? DARK ENERGY QUESTION Could inflation have done more than we know, shortly after the Big Bang’s first salvo, and created a dense matter halo beyond the horizon where we can go? Beyond the horizon that we can see, is there a remote possibility of a most massive field of gravity that pulls the strings of our reality? Perhaps it’s just dense matter that’s the source, accelerating expansion perforce, and not some new and mysterious force, or change of gravity’s attractive course, as though we are bound by a black hole’s skin, that stretches space to surface dimension.
The Universe couldn’t have been an exploding grapefruit because there would be a plethora of pulp everywhere and not just those little glasses of juice like we have today. 🤔
The universe must be infinite. It's possible that our physical universe is "contained" in some way, but there must be something infinite beyond that. Nothing else would make any sense.
In the digital world it's an infinite universe. There is never a border as you can always go through it or know what's beyond it even if it crashes you know it extends forever. The only limit is te numbers that can be inputed to some extent. But it's still infinite. So the real world must be infinite too
@@soaringstars314 My reasoning is simply that "absolute nothing" cannot exist in a universe with something/anything in it. It's a binary choice. It's 0 or 1, and our universe is clearly a 1. "Nothing" means no possibilities, and that includes the possibility of something arising out of that nothingness.
2nd It is of utmost importance to distinguish what "type" of mag sail you are talking about...there are four "types": 1st is the Mag Sail by Zubrin and Andrews 2nd is the electric mag sail by Janhunnan 3rd is the Winglee static dipole bubble sail. (not considered viable) 4th is The Plasma Magnet John Slough NIAC phase I and II U of W.
Answer 1st question can be read on Quran 51:47 which say, "We constructed the universe with power, and We are expanding it." Come to Muhammad from His God 1.400 years ago. So Yes! Universe is expanding to the limit allowed, not to the infinite as scientist think it will
Assume the universe was said grapefruit in size and gravity is unified with all the other fundamental forces, all of a sudden the pressure and density and energy thats confined had a place to finally release its pent up aggression. It would be like a big bang, only without the exploding. For all intent and purpose space could expand for as much as it likes if this was all inside a singularity, we wouldnt ever reach the event horizon
How did they determine the CMB came from a big bang and not say stars, galaxies, planets, moons, comets, asteroids, dust, debris and gas floating in the vacuum of space beyond our planet and solar system? How were all the foreground objects not in the cold WMAP cosmic microwave background (CMB)? Surely the temperature of microwaves radiating from stars and other bodies are much much warmer than 3° above absolute zero.
I get your comments about The Webb Telescope being much more powerful and capable than Sofia. But, I just heard on another Astronomy Blog that Webb has 5000 observation hours per year. This year there were proposals for 37,000 observation hours. Surely a FEW of 32,000 excess hours could have been handled by Sofia. I feel it is more likely that the airframe has reached the end of its safe operational life. If you have a chance, please dive a little deeper into this.
If the universe curves back on itself then there would be a maximal size of a theoretical!y large object that does not overlap itself. Like an expanding circle on a globe, the scale of the circle increases and then decreases despite continuously expanding in the same direction. This would also happen with a 3d object expanding in a universe that curved into itself. That means scaling up loops back around to scaling down.
Q: Why do all the systems ( planets and galaxies ) rotate? Q; Do all systems rotate in the same direction? Q: Where does that energy come from? Q: Is the universe trying to balance E =E or G=G ? Q ; What percent clockwise & percent counter C.? Thank you
