I did my PhD on the final parsec problem. It's mostly covered very well, but the most important part is probably around 8:45, that "our math isn't quite right". What is actually claimed is that the final parsec *problem* results from oversimplification of the physics ("a spherical cow"), and relatively quick mergers occur otherwise. This is pretty much the consensus today. Also, at 10:04 that's a picture of Rai Weiss, not Vladimir Braginsky.
@@luudest Simulations like in this Berczik et al. paper show that if the surrounding Galaxy isn't a nearly perfect ball of stars (post-merger galaxies generally are pretty spherical), in other words, it is ellipsoidal or "triaxial", then the torques exerted by the galactic potential will lead stars to "centrophilic" orbits, which means they come close to the SMBH binary, interact with it and steal orbital energy and angular momentum, shrinking its orbit rather quickly. In a perfectly spherically symmetric stellar model (as is assumed in semianalytical calculations and early simulations) there are no such torques and the SMBH binary depletes the reservoir of stars that can interact with it by the time it gets to 1 parsec separation (this reservoir is called the "loss cone" and in this case, it is said to be in the empty regime). There are quite a few more processes (other than galactic torques) that can refill/"repopulate" this loss cone.
I think that this is likely the reality of it. Math can get you pretty far in understanding the universe but I think sometimes researchers get lost along the way. Math is a great tool but its also no 100% representative of reality, and that's apparent from its paradoxes.
@@willstack6188 I was wondering the same. I suppose supermassive blackholes would lose energy this way, but I guess it would take a very, very long time - much longer than the age of the universe...
I just have to say the audio and video on this channel are absolutely perfect. So many channels are overblown when they upgrade equipment, but this is one is flawless.
When I did my Astrophysics degree (1990-93) we did some calculations on the effect of solar bodies in a distribution being influenced under their own gravity. I looked at sub clusters. The potential energy is twice the kinetic energy of the sub cluster falling in on itself. If you have 3-4 objects close to each other that they fall together and you will find that 2 of the bodies end up in a stable orbit and the 'extra' kinetic energy is taken from the system by the other bodies and those bodies ejected from the sub cluster leaving the remaining 2 bodies (generally) in orbit. This kind of explained why we see a lot of either single or binary systems (whether Steller or galactic) but not many tertiary. Now - if you use the same simple theory to black holes, you need extra heavy bodies to take away the kinetic energy to force the bodies together. In previous videos it was mentioned that there may be multiple black holes at the centre of a galaxy, so if we have multiple bodies, one of the bodies can be ejected taking away energy from the orbits and allowing the bodies to get closer together. A 'simple' system of just 2 black holes may take a long time to merge - but that an unusual situation as in general there are more bodies about that can collapse in and fly out of the sub cluster taking energy from the system.
Well thats just the 3-body problem, isnt it. The unpredictability of 3 big objects. Mostly the third one will be ejected and then youre left with a 2 body system. Which works fine. Same will mostly happen with a 4-body system.
LIsten, I have the answer to the Final Parsec Problem: Firstly, you'll need a flux capacitor with settings to read dynamic equilibriums of stellar kinematics. Then, attach this to a Maximogaster Occidentalis using USB 3.0. Don't use 2.0, it's inferior. Then, engage the parsec pneumatic distributor on the Maximogaster Occidentalis to identify Axioms within the Novapod Majordermis sector of pre-main sequence star evolution. Turn the ignition on, wait a half hour. Then, download the memory files from NASA's Pleiades Supercomputer and you'll have your answer.
For times larger than the Lyapunov time of an N-body system the dynamics become chaotic, which means kinetic energy is exchanged between orbits and eventually some bodies may "evaporate" from the system, but there are some three-body configurations, namely S- and P- type orbits that can be metastable for long periods of time. As with anything chaos, it strongly depends on the initial configuration of the system.
That doesn't solve the issue. The point is that the closer the black holes are together, the less likely they are to have an encounter with another body. Changing the type of body (from "star" to "black hole") ironically makes an interaction less likely to happen because black holes are very rare compared to stars. A theory that could explain the "final parsec problem" would be a theory that increases the probability of an interaction.
Since I was one of the people who said they'd like a video on this topic, I figured I'd say thank you for making it. I love learning new things, especially things about space and our understanding of the universe and how it all works, and I definitely learned something today.
Man, I knew listening to physics every night for years before bed would pay off. I actually understood everything you said and even anticipated a few like LISA/PTA etc. You have a great way of explaining things.
Wow. What a time to be alive! For me, 1952 until now, amazing new knowledge EVERY DAY OF MY LIFE. In a universe capable of turning the atoms of dead stars into intelligent beings. Thank you, Dr B ❤️
Wonderful exposition - simplifying a complex topic without distorting it - and carried along by seemingly boundless enthusiasm. What a marvelous way to present astrophysics. Thank you!
Considering the time dilation effect grows the closer you get to the event horizon of any black hole, I'm afraid I'm at a loss how from an external perspective, any merger ever occurs in less than an infinite amount of time. I understand we currently think they do, but how is time dilation overcome?
@@SolnoricWhich means that from the merging black hole perspective our time appears to race infinitely into the future…and from our perspective, no merger has occurred.
Or maybe our understanding of time is still flawed somewhere. It works for every day use, and even for much of the scientific theoretical use we currently have for it, but if every now and then we run into an impossible contradictions as to the nature of time according to our understanding then the logical conclusion is our understanding is wrong somewhere. I think we have a real difficulty imagining a truly timeless space, a place that exists outside of a timeline, where time is not a factor. I know black holes are supposed to be such places at their core, but if they were NOTHING would happen or change- it would be static and frozen. For things to change takes the aspect of time. Even non-linear time of some sort would do. So even at their core, if change is possible, time must still happen in some form or another, even if completely different from what we know. I don't think there is any part of our universe that is without time, even black holes, as it is fundamental to it. Time may be more changeable and fluid than we currently understand, yet also more rigid (I have a theory that time travel is only possible one way, i.e. to short cut ahead, but not in reverse due to the directional flow of time in the very fabric of the universe- which is why we'll never find any incidents of time travelers from the future). IDK- but I have always thought that past the event horizon the laws of physics get so warped and changed that we have little chance to really know what they are, at least not currently. The same goes for time. But it doesn't mean it isn't there.
@@a.westenholz4032 I get your reasoning but remember it’s general *relativity* for a reason, if you were able to fall into a black hole, time essentially passes normally for you, it’s the perspective of outside observers seeing your clock that becomes frozen. Your view of the outside universe also becomes radically different, as all the light that’s ever entered the black hole concentrates into a smaller and smaller point. Past the event horizon our best idea is that time and space flip, since all future movements are towards the singularity, space itself becomes a one way arrow or ‘time-like’ and time becomes “space-like” since moving through it is physically moving you towards the singularity. It’s the singularity itself that’s the problem, not time dilation, which we know exists.
@@a.westenholz4032look up Penrose diagrams if you’re interested in this topic, I’m not a physicist in any regard but that’s my best lay understanding. General Relativity is essentially the best tested theory in all of science, and we still haven’t found anything that disproves it, we just know it’s incomplete since we can’t work out what happens at the Big Bang or at the apparently infinite density of black holes, but the Penrose Diagram definitely helps explain the interiors past the event horizon.
What the? I literally woke up this morning wondering what the deal was about the Final Parsec. I'm not even joking, lol! So glad to see this, you saved my day ⚡
I'm not a physicist, so I appreciate that you can share things like this in such a way that I have a tiny bit of understanding of what you're speaking about. :)
Dear Dr. Becky, I would like to express my gratitude for your RUclips channel. We have an observatory oriented to the public here in Granada and you help us a lot to keep updated on the subject. My only sadness being to discover that you passed by here a couple of month ago and we weren’t at the airport with a poster commemorating your venue as the superstar you are! Let’s hope the next time we will know in order you get the reception that you deserve 🤗
So much work into making this content so very approachable. So much skill by Dr. Becky Smethurst (and clearly her team of hundreds) to create it. And shout out to the University of Oxford to carving out bandwidth for Dr. Becky to communicate to the masses when I know she has research, publishing and teaching obligations.
As one of the viewers who requested this episode, thank you!! You made it make sense to me despite me not being a physicist or an astronomer. It certainly will be exciting when we solve this mystery.
SMBHs flinging each other into the void reminds me of evaporative cooling. The higher energy particles escape the system, leaving lower and lower energy particles behind. In the case of the Einstein-Bose condensate, the remaining particles eventually get so low in energy, they collapse in on themselves and occupy the same quantum state.
Love your videos they are so entertaining even though I am only 13 great job explaining all the concepts. Not many people explain stuff in this much detail.😊
This reminds me of Zeno's Achilles paradox. You get so caught in the semantics of your mathematical definitions that it no longer describes reality. Very similar as well to a famous bit of calculus called Gabriel's Horn.
1:14 Looking at a screenshot of a creator's RUclips channel with 2 notifications is so satisfying. I always shed a small tear when I see the 99+ there, knowing they probably have thousands of notifications that they can't hope to check.
When objects interact they exchange energy in such way as for all objects have same energy (actually not same, there is specific distribution, it is just usual temperature but applied to stars). Energy is basically orbit radius*mass (again not quite, but good enough for general picture). So if SMB and ordinary star have same energy SMB will have much smaller orbit. I think this picture helps with understanding how SMB ends up in the centre of the galaxy.
Another great vid, thanks. When mentioning LIGO & Virgo, don't leave out the new kid on the block, KAGRA, which is based in Japan. It's just finished it's second observation run, and plans to fire up again next year.
Dr. Becky you’ve been putting out some great content as of late! And once again, I cannot praise you enough for these medium length videos. I find 15 mins to be just about perfect for most topics I take interest in, which is quite varied. Thanks for another good one! Also, big kudos for your “bloopers section” of your videos that you’re adding now. It gives us, your fans and supporters the chance to see your wonderful sense of humour and to somewhat take you off the pedestal of “scientific superstardom” for a moment and show us that you’re just human after all, like the rest of us “mere mortals”!! Lol 💫🙏❤️😂🍻
This might be a silly question but what happens to time dilation as black holes get closer? Also, since anything that touches or crosses over the event horizon is trapped are we detecting the merger or the instant before the merger, and as an aside: does gravitational lensing effect what we "see" ? Would a singularity generate a lense around itself ? Sorry if these have been asked and answered before. Cheers :)
I know I honestly think dilation is one of the most ignored things in astrophysics. Having time dilation affect gps merely by escaping Earth's pathetic gravity well would suggest the weight of the sun jupiter the galactic arm and smbh at the middle how much of what we see is actually stretched thin by the well.
That's a different issue to the final parsec problem which starts when the two SMBH's are around three light years apart. At that distance time dilation just isn't an issue. You could happily live out your life on a planet within 100 AU (0.00158125 light years) from a super massive black hole (assuming there's no radiation that can kill you).
Dr Becky Smethurst is my favorite astronomy channel. There are others I watch, which I like as well, but the second behind her has a Eurasian brogue that's difficult for me to readily decipher. Anyway, thank you, Dr Becky, for also making astronomy fun with your bloopers.
I just like you've started adding portraits of the scientists! It really helps to remember them, because you now have a face to associate, not just some random name.
Just a thought, but as I studied turbulence in aerospace, could there be a similar effect in between orbiting SBHs? Causing turbulence in space itself from the high gravitation? That would add another factor that would take energy out of the system.
Can you be more specific? Turbulence or not, you have to have energy carried away by something. If there is no significant gravitational wave, whether turbulent or lamina, generated to carry the energy away, there is no energy dissipation.
I was thinking about the swarm of smaller black holes that sink into the galactic core, but I'm guessing they aren't a enough of a contribution to be significant otherwise they would have been mentioned.
@@steffenbendel6031yeah, but there is evidence now from LIGO for frequent black hole mergers creating black holes with dozens of solar masses. I wonder if the maths have taken this into consideration.
@@kenashworth7672 Not really, these things are tiny and a merger would require two of them hitting head on (or somehow start orbiting each other long enough to merge). The chances for that are astronomically small, it's like trying to hit grain of sand with another grain of sand thrown from several kilometers away. Which BTW leads to another black hole problem, namely how supermassive black holes arose in the first place because stellar black holes grow way too slow over universal lifetime for it to be normally possible...
@@KuK137 I guess whole regions of space collapsed in the early universe to for the big black holes. Might be easier with a lot of black matter instead of normal one. On one hand, it can not lose energy by radiating, but probably also not resting the collapse like normal stars. And there probably was not enough time for a slow evolution anyway.
Hi! Awesome & wonderful video as always! Just a very small mistake: At 10:04 the two pictures show portraits of Kip Thorne (correct) and on the right side, instead of Braginsky, it's the portrait of Rai Weiss (the LIGO guy). Super small mistake, but I thought it's maybe good to mention :) Doesn't take away from the awesomeness of the video! (I had the privilege of interacting with both of them at some point, my impression was that they're just wonderful people. At some point I asked Kip Thorne about some fringe aspect of the black hole in Interstellar, and he just wouldn't stop talking about it. Just a very fun and kind guy. Loves talking about black holes more than anybody else I've ever had the privilege to meet.)
Two questions: 1) If two super massive black holes were only a parsec apart could we tell if it was two and not one? and 2) Could this be a mechanism for turning off a quasar?
Could tidal heating play a role? If the math assumes Black Holes are just point-like objects with an event horizon around it relative to their mass, that may neglect a part of it. Now I don't know if or how one Black Hole's gravity can affect the internal structure of another - but if it does, it would mean they could transfer part of their kinetic energy into heat, slowing down more than previously thought. And even better: The closer they get the stronger that effect, and the more they slow down. Would be interesting to see if the event horizon of Black Holes close enough to create Gravitational Waves is actually still strictly spherical, or if they perhaps managed to deform each other so much that it could be measured.
What about other black holes that aren't as massive as the central supermassive black holes, but massive enough that dynamical friction causes them to fall to the centre of the galaxy, and then getting slingshotted out themselves?
0:07: 🔍 The final parsec problem is a mystery in black hole astrophysics regarding the merging of supermassive black holes. 3:11: 🌌 Objects in space, including black holes, can lose energy by interacting with other objects, resulting in a gravitational drag force. 5:58: 🌌 Supermassive black holes orbiting each other at a distance of about a parsec may not merge, challenging our understanding of galaxy evolution. 8:46: 🔬 Observations and experiments are being conducted to determine if and how supermassive black holes merge. 12:14: 🌌 The launch of the Laser Interferometer Space Antenna (Lisa) in 2037 will help detect gravitational waves from supermassive black holes. 14:37: 📚 Dr. Becky recommends Brilliant's data analysis fundamentals course for improving data skills and understanding astrophysics research. Recap by Tammy AI
Can we not resolve if SagA is a one or a multiple body system? The milky way has had mergers in the past; so there must have been SMBH mergers before in our back yard. Also, afaik we have never observed a double quasar or SMBH with multiple jets, right? If SMBH don't merge, how do they become SMBH? You have spoken before about your field of study and said one of the only hypothesys we have for them growing so big is mergers.... I am confused 😅
Would dwarf galaxies facilitate a merger? In many of the galactic mergers I'm seeing in the JWST images, there are numerous smaller dwarf galaxies dipping in and out of the galactic disks, leaving streamers behind as they gradually get pulled in. They would have much smaller central black holes, but perhaps they would be just big enough to throw things out of whack.
Silly question: With the complexity of the interactions of "merging" SMBHs, would it be at all useful to use something like Feynman diagrams to explain them? It's still about interactions of two objects, except for the scales of the objects.
In fact, if you slingshot around the Sun while traveling at high warp, you will travel back in time. 5:56 So dark matter interacts via gravity. Does this mean that the black holes also clear the galaxy center of dark matter?
AFAIK dark matter is bad at cooling, which protects it a little bit from falling into black holes. In a normal accretion disk the matter heats up a lot by friction and then radiates the energy outwards as light of various wavelengths. Thus it loses its kinetic energy and finally falls into the BH. But dark matter cannot radiate light, so it cannot use this way of losing kinetic energy. That's also why the DM halos of galaxies are spherical even when the galaxy is disc-shaped. Now, when you have TWO black holes and not only one, it gets interesting. Those should be able to slingshot dark matter outwards. But there is another phenomenon that I have seen a while ago on a picture. There has been an analysis of the Bullet Cluster and they figured out that the dark matter got separated from the baryonic matter during the merger. It fell out of the galaxies, so to speak. I have no idea how that would now interact with two SBHs orbiting each other. On the picture, the dark matter seemed to have clumped into a single halo pretty quickly while the baryonic matter masses fell through each other and came out on the other side, having been stripped of their DM halos. Therefor one would assume that the black holes also fell past each other but did not do much with the dark matter. I wish I knew more about these things, but I can only report what I've seen on that picture.
It really wouldn't be a problem if we do not see the SMBH mergers? Since we do expect to notice a considerable amount of them, then if LISA doesn't detect any, wouldn't it mean that our models regarding co-evolution of galaxies *with* their central black holes are wrong? In any case, that's some pretty exciting research to be done when LISA actually launches and then starts measurements.
What I can't get through in these matters is that besides this final parsec problem we have time slowdown in an extreme BH gravitation field for an external observer. That is, two BHs should not ever fully merge as it mathematically should take infinite time...
That's only a possible problem if the black holes are nearly touching. We can see stars orbiting our galaxy's SMBH as close as 100AU and there's no observable slowdown their orbits, so nothing extreme is going on in that final parsec regarding time dilation. You could be right, but it's not the solution to the final parsec problem.
My little brain gets so overwhelmed with Space stuff. i think Merging could be Flexible, Some Supermassive Black Holes Merge & Some don't, it just depends on the how the first date goes... I'm just gonna imagine it would be like adding Milk in my Tea, If they Merged.
A very good one . By your own teaching you have make a clear picture of new excitement for newly discovered gravitational waves. A amplified version of event horizon gravitational wave detection techniques . The problem is vivid reports are inconclusive. We all now more eager to know what is next.
Thank you for the data regarding Project Lisa. The continuing brilliance of our Astrophysicists is nothing less than astounding. As to whether the black holes merge, it sounds like a job for JWST. Our time machine see everything.
Great Video, Dr.Becky! I'm currently reading A Brief History of Time by Stephen Hawking, and I'm currently on the chapter of Black Holes. This has surely helped me! Thank youu :)
Love these video's, they are now my Friday morning ritual. One thing about you're lighting Becky, (Lighting for Broadcast is my profession) You would benefit from light hitting the tops of your shoulders and head from behind (we call it backlight) it separated you from teh background. As an example look at your left shoulder (as viewed on the screen) in this video, where your dark shirt merges with the darker background. Yes I am a geek and I'm the only person that would notice..
The graph you reference, showing the relationship between inter-black-hole distance vs time, begs to be expanded so that there is a 3rd dimension, resulting in a 3D sheet. The missing dimension is the size of the black holes. Clearly we believe that small black holes can merge and larger ones cannot. Seeing the relationship between black hole size and the other two variables would be very interesting.
Binary black holes make gravitational waves, which seem like they take a lot of energy to make. That energy has to come from somewhere, so wouldn't it come from the orbital energy of the binary pair? Would that radiate away enough energy to let the black holes merge?
4:40 Wouldn't those interactions have to be coming from one side rather than being from random directions? The more random, the less likely that it can be pulled in one direction. If there are two then they might come together, but more produces randomness as they come in from random directions.
I have a question: We know that our Milky Way has swallowed a couple of dwarf galaxies over time. What happened to their central black holes? Did they not have one?
Question! Wouldn’t two black holes both lose energy by rotating around each other (after they’ve cleared everything around them? If so, wouldn’t that bring them closer and closer together?
Yes. Very slowly. The reason the merger takes longer than the age of the universe is that the effect is quite small at ~3ly. If not for that effect, they would never merge at all and just continue in orbit around each other indefinitely.
This makes a lot of sense, and I didn't know the details before. I guess two supermassive black holes in a binary setup generally acts like one double sized one if it's all totally stable, and in any real situation they're not acting in isolation because there are thousands of stars and particle clouds and other objects that are also disrupting the final parsec? But looking forward to those results telling us what's what! I love that our understanding is always improving and being challenged - the cutting edge of real science 😊
The image of the black hole at the centre of our galaxy from last year puts the black hole's shadow at about 3.2 light minutes, i.e. well below a parsec, so we can be quite confident in that case at least :) For some very distant galaxies it might be harder to tell
I think two orbiting, spinning black holes, totally infatuated with one another, in the act of absorbing each other, would be on the final phase of galaxic merger, such that for all practical purposes, there's but one galaxy, DESPITE the "orbitation" relative both black holes. We're talking LOTS of time, though, perhaps billions of years, to get to this phase.
If LISA picks up no GW signals, the problem will be figuring out the source(s) that are producing the background GW that the pulsar timing array detected.
Couldn't those supermassive blackholes be actually a swarm of smaller ones on the verge of merger. Too many and too close such that from far away it's indistinguishable from a single supermassive one?
First, I'm amazed by how good you are to explain these very complex astronomical questions. If I understand this correctly, one way of actually detecting a merger of SMBHs would be through detection of light year long gravitational waves. I assume that you can only detect those waves for a certain period of time. I'll expand on why I think that this is relevant. If we observe a supernova for example in visible light we can only see it on Earth for a period of time comparable to the time it took for it to explode. We can perhaps see its remnants for much longer, but that is a different matter. But there are lots of stars in the universe that can go bang, so that we actually at any time have reasonable chances of catching sight of one of them, happening somewhere. Actually we do see a lot of them. Now, there are much fewer galaxies than stars, so an SMBH merger would not occur quite as often as a supernova. I understand that the number of galaxies in the observable universe is roughly on the order of a trillion. So if one tenth of these guys have had one merger, there has been very very roughly ten mergers a year in the history of the universe. What are the chances of picking up one of these, and not just hear crickets? Well, this also depends on for how long a merger will be visible. If we saw it in visible light, the answer would presumably be "not for very long". If we observe them through gravitational waves I don't know. Lightyear long waves sound like they would take years to pass through the solar system, but what do I know. So my question would finally be: Combining those estimates, how many SBHM somewhere in the universe would one reasonably hope to pick up at a given time by a detector of very long gravitational waves?
There would be no difference once it falls below the event horizon the information is lost. It could take billions of relative years for said object to merge but it would have happened the moment it slipped below the event horizon to external observers in non dilate space. That is what dilation is we're currently in dilated space and experience a colour shift slash clocking discrepancy just between us on the ground and the satellites giving dilation corrected gps locations gps mk1 failed as there was no timing compensation.
For me it’s a paradox that the rotational speed of a collapsing star core becoming a singularity can go over the speed of light well before it becomes a singularity, it seems wrong to me but I’m no physicist, but for me, that’s impossible, kinetic energy will equate the gravity power because of E=mc squared, imo.
I love when scientists accept that they might be wrong and get excited about that. It is the BEST part of science, and it should be every scientists duty to teach it as passionately as you have here!
If I understand it right, in a galaxy with two super-massive black holes in the one-parsec distance, these would normally not be active as they've slung out or eaten most material nearby, and also without any nearby stars? So it would be somewhat difficult to observe them, except by an absense of fast-moving stars in the middle of a galaxy.
It is also possible that the discrepancy is not a problem at all. It is possible that the current understanding of physics is correct, and that supermassive black holes never merge. However, this would mean that we have to rethink our understanding of how galaxies evolve.
@@EnglishMike Yes that is correct, however it is still not clear which, if any, of these solutions is correct. However, the final parsec problem is an important one to solve, as it has implications for our understanding of galaxy evolution and the formation of supermassive black holes.
So in the final parsec problem is that assuming that each black hole is of the same mass? I would think that if the black holes are of different masses then the larger would have a higher interaction to the surrounding environment of the smaller black hole, and in turn effectively pulling the smaller BH into the field of effect of the larger BH and end up merging. If BHs do not impart gravitational effects upon each other, does that mean that as matter is absorbed into a BH it is destroyed into its smallest particles and ejected as an invisible quasar of types? Or does it mean that possibly BHs are only massless objects of purely concentrated gravity?
I did my PhD on the final parsec problem. It's mostly covered very well, but the most important part is probably around 8:45, that "our math isn't quite right". What is actually claimed is that the final parsec *problem* results from oversimplification of the physics ("a spherical cow"), and relatively quick mergers occur otherwise. This is pretty much the consensus today.
Also, at 10:04 that's a picture of Rai Weiss, not Vladimir Braginsky.
Actually, that is Vladimir.
What about simulations? How the do they resolve the problem?
@@luudest Simulations like in this Berczik et al. paper show that if the surrounding Galaxy isn't a nearly perfect ball of stars (post-merger galaxies generally are pretty spherical), in other words, it is ellipsoidal or "triaxial", then the torques exerted by the galactic potential will lead stars to "centrophilic" orbits, which means they come close to the SMBH binary, interact with it and steal orbital energy and angular momentum, shrinking its orbit rather quickly. In a perfectly spherically symmetric stellar model (as is assumed in semianalytical calculations and early simulations) there are no such torques and the SMBH binary depletes the reservoir of stars that can interact with it by the time it gets to 1 parsec separation (this reservoir is called the "loss cone" and in this case, it is said to be in the empty regime). There are quite a few more processes (other than galactic torques) that can refill/"repopulate" this loss cone.
@@mrpearson1230 I can tell you with full certainty, it is not.
I think that this is likely the reality of it. Math can get you pretty far in understanding the universe but I think sometimes researchers get lost along the way. Math is a great tool but its also no 100% representative of reality, and that's apparent from its paradoxes.
This was so well explained. Wonderful presentation. You are amazing at translating these mind bending concepts to us 'normies'. Great stuff.
What about Hawking Radiation? ( last parsec problem)
You do realize it's all theoretical.
100%
@@boathousejoed1126 judging by the fact they said "concepts" I'd take a wild guess and say yes...
@@willstack6188 I was wondering the same. I suppose supermassive blackholes would lose energy this way, but I guess it would take a very, very long time - much longer than the age of the universe...
I just have to say the audio and video on this channel are absolutely perfect. So many channels are overblown when they upgrade equipment, but this is one is flawless.
When I did my Astrophysics degree (1990-93) we did some calculations on the effect of solar bodies in a distribution being influenced under their own gravity. I looked at sub clusters.
The potential energy is twice the kinetic energy of the sub cluster falling in on itself. If you have 3-4 objects close to each other that they fall together and you will find that 2 of the bodies end up in a stable orbit and the 'extra' kinetic energy is taken from the system by the other bodies and those bodies ejected from the sub cluster leaving the remaining 2 bodies (generally) in orbit.
This kind of explained why we see a lot of either single or binary systems (whether Steller or galactic) but not many tertiary.
Now - if you use the same simple theory to black holes, you need extra heavy bodies to take away the kinetic energy to force the bodies together. In previous videos it was mentioned that there may be multiple black holes at the centre of a galaxy, so if we have multiple bodies, one of the bodies can be ejected taking away energy from the orbits and allowing the bodies to get closer together.
A 'simple' system of just 2 black holes may take a long time to merge - but that an unusual situation as in general there are more bodies about that can collapse in and fly out of the sub cluster taking energy from the system.
Well thats just the 3-body problem, isnt it. The unpredictability of 3 big objects. Mostly the third one will be ejected and then youre left with a 2 body system. Which works fine. Same will mostly happen with a 4-body system.
LIsten, I have the answer to the Final Parsec Problem: Firstly, you'll need a flux capacitor with settings to read dynamic equilibriums of stellar kinematics. Then, attach this to a Maximogaster Occidentalis using USB 3.0. Don't use 2.0, it's inferior. Then, engage the parsec pneumatic distributor on the Maximogaster Occidentalis to identify Axioms within the Novapod Majordermis sector of pre-main sequence star evolution. Turn the ignition on, wait a half hour. Then, download the memory files from NASA's Pleiades Supercomputer and you'll have your answer.
For times larger than the Lyapunov time of an N-body system the dynamics become chaotic, which means kinetic energy is exchanged between orbits and eventually some bodies may "evaporate" from the system, but there are some three-body configurations, namely S- and P- type orbits that can be metastable for long periods of time.
As with anything chaos, it strongly depends on the initial configuration of the system.
That doesn't solve the issue. The point is that the closer the black holes are together, the less likely they are to have an encounter with another body. Changing the type of body (from "star" to "black hole") ironically makes an interaction less likely to happen because black holes are very rare compared to stars. A theory that could explain the "final parsec problem" would be a theory that increases the probability of an interaction.
@@KilgoreTroutAsf I was pretty sure a 3 body system would sooner or later expel the third entity.
Since I was one of the people who said they'd like a video on this topic, I figured I'd say thank you for making it. I love learning new things, especially things about space and our understanding of the universe and how it all works, and I definitely learned something today.
Man, I knew listening to physics every night for years before bed would pay off. I actually understood everything you said and even anticipated a few like LISA/PTA etc. You have a great way of explaining things.
Wow. What a time to be alive! For me, 1952 until now, amazing new knowledge EVERY DAY OF MY LIFE. In a universe capable of turning the atoms of dead stars into intelligent beings. Thank you, Dr B ❤️
Is it the UNIVERSE turning atoms into intelligent beings, or an eternal Creator, Who is doing so?
Wonderful exposition - simplifying a complex topic without distorting it - and carried along by seemingly boundless enthusiasm. What a marvelous way to present astrophysics. Thank you!
Wouldn’t one be more Super Massive than the other?
This was a VERY interesting video. Thanks Becky! I NEVER thought about this final parsec problem....
Considering the time dilation effect grows the closer you get to the event horizon of any black hole, I'm afraid I'm at a loss how from an external perspective, any merger ever occurs in less than an infinite amount of time. I understand we currently think they do, but how is time dilation overcome?
The dilation is relative. For the black holes, it takes a nigh-infinite amount of time. External viewers see time pass differently.
@@SolnoricWhich means that from the merging black hole perspective our time appears to race infinitely into the future…and from our perspective, no merger has occurred.
Or maybe our understanding of time is still flawed somewhere. It works for every day use, and even for much of the scientific theoretical use we currently have for it, but if every now and then we run into an impossible contradictions as to the nature of time according to our understanding then the logical conclusion is our understanding is wrong somewhere.
I think we have a real difficulty imagining a truly timeless space, a place that exists outside of a timeline, where time is not a factor. I know black holes are supposed to be such places at their core, but if they were NOTHING would happen or change- it would be static and frozen. For things to change takes the aspect of time. Even non-linear time of some sort would do. So even at their core, if change is possible, time must still happen in some form or another, even if completely different from what we know. I don't think there is any part of our universe that is without time, even black holes, as it is fundamental to it. Time may be more changeable and fluid than we currently understand, yet also more rigid (I have a theory that time travel is only possible one way, i.e. to short cut ahead, but not in reverse due to the directional flow of time in the very fabric of the universe- which is why we'll never find any incidents of time travelers from the future). IDK- but I have always thought that past the event horizon the laws of physics get so warped and changed that we have little chance to really know what they are, at least not currently. The same goes for time. But it doesn't mean it isn't there.
@@a.westenholz4032
I get your reasoning but remember it’s general *relativity* for a reason, if you were able to fall into a black hole, time essentially passes normally for you, it’s the perspective of outside observers seeing your clock that becomes frozen. Your view of the outside universe also becomes radically different, as all the light that’s ever entered the black hole concentrates into a smaller and smaller point. Past the event horizon our best idea is that time and space flip, since all future movements are towards the singularity, space itself becomes a one way arrow or ‘time-like’ and time becomes “space-like” since moving through it is physically moving you towards the singularity. It’s the singularity itself that’s the problem, not time dilation, which we know exists.
@@a.westenholz4032look up Penrose diagrams if you’re interested in this topic, I’m not a physicist in any regard but that’s my best lay understanding. General Relativity is essentially the best tested theory in all of science, and we still haven’t found anything that disproves it, we just know it’s incomplete since we can’t work out what happens at the Big Bang or at the apparently infinite density of black holes, but the Penrose Diagram definitely helps explain the interiors past the event horizon.
I love how you are adding pictures of the authors for papers now. So cool to get a glimpse and help us remember names in the long run!
Luv your wide-eyed enthusiasm for knowledge the fact that you don't hold on theories if you find new evidence that disagrees with past assumptions
Was really looking forward to this video, thank you for reading the comments and giving us the video we wanted!
What the? I literally woke up this morning wondering what the deal was about the Final Parsec. I'm not even joking, lol! So glad to see this, you saved my day ⚡
I'm not a physicist, so I appreciate that you can share things like this in such a way that I have a tiny bit of understanding of what you're speaking about. :)
Dear Dr. Becky,
I would like to express my gratitude for your RUclips channel. We have an observatory oriented to the public here in Granada and you help us a lot to keep updated on the subject.
My only sadness being to discover that you passed by here a couple of month ago and we weren’t at the airport with a poster commemorating your venue as the superstar you are!
Let’s hope the next time we will know in order you get the reception that you deserve 🤗
Fantastic video. You've become one of the only youtubers I watch in recent times, you explain everything so clearly and the quality is top notch.
Thanks Becky! Haven't watched your content in a while but seeing this makes me want to watch more of your videos again. Keep up the good work!
Thank you kindly, Dr. !
I have been curious about this problem for a while, and you have addressed most of my doubts. Again, thank you.
So much work into making this content so very approachable. So much skill by Dr. Becky Smethurst (and clearly her team of hundreds) to create it. And shout out to the University of Oxford to carving out bandwidth for Dr. Becky to communicate to the masses when I know she has research, publishing and teaching obligations.
Wouldn’t hawking radiation cause for a loss of momentum between the black holes and thus an eventual merger?
@@chrishunter9294They lose energy through GW far, far faster.
As one of the viewers who requested this episode, thank you!! You made it make sense to me despite me not being a physicist or an astronomer. It certainly will be exciting when we solve this mystery.
The way you make things easy for the lay-person to understand is why I am here. The bloopers and your beauty, make me listen. TY DR. Becky!
SMBHs flinging each other into the void reminds me of evaporative cooling. The higher energy particles escape the system, leaving lower and lower energy particles behind. In the case of the Einstein-Bose condensate, the remaining particles eventually get so low in energy, they collapse in on themselves and occupy the same quantum state.
Finally, I can't believe you made us wait SO LONG for this video.
Love your videos they are so entertaining even though I am only 13 great job explaining all the concepts. Not many people explain stuff in this much detail.😊
13 is a good age to start studying harder math than what school excepts…..it will help a lot when you’re an astrophysicist.
@@DrDeuteron
Thank You for the advice
Pretty interesting indeed! Thanks, dr. Becky! 😊
Stay safe there with your family! 🖖😊
This reminds me of Zeno's Achilles paradox. You get so caught in the semantics of your mathematical definitions that it no longer describes reality.
Very similar as well to a famous bit of calculus called Gabriel's Horn.
Very intriguing. They must have very complex calculations. Those smbh's must have a whole lot gas, stars and black holes following in their wake.
Astronomy is so amazing and facinating! Your videos do a great job of explaining everything..always love to learn new things every week!
I actually understood all of this one!!
I’m sure it’s not me getting smarter, but rather because you’ve explained it very well!!
Very interesting.
This was a phenomenal presentation tying a bow on everything that's been happening. Thanks Dr.
1:14 Looking at a screenshot of a creator's RUclips channel with 2 notifications is so satisfying. I always shed a small tear when I see the 99+ there, knowing they probably have thousands of notifications that they can't hope to check.
When objects interact they exchange energy in such way as for all objects have same energy (actually not same, there is specific distribution, it is just usual temperature but applied to stars). Energy is basically orbit radius*mass (again not quite, but good enough for general picture). So if SMB and ordinary star have same energy SMB will have much smaller orbit. I think this picture helps with understanding how SMB ends up in the centre of the galaxy.
Sorta.
WE'RE IN A BLACK HOLE, MAN! 👍
I enjoyed your 4:05 fling affect videography, expressing what you were talking about. That was keen. 😊
You are a very inspiring explainer of science! I wish we could all learn to teach this well!
Another great vid, thanks. When mentioning LIGO & Virgo, don't leave out the new kid on the block, KAGRA, which is based in Japan. It's just finished it's second observation run, and plans to fire up again next year.
great episode, love learning the details of this problem
Just binged 3 or 4 of your vids. I think I need to start at the beginning. I love the info and the delivery.
Every time Dr. Becky said “The Final Parsec,” I played the Europe anthem in my mind too. We were on the same wavelength for this episode. 😂
Bedankt
Thank you. So good. What makes us think supermassive binaries have stable orbits?
“Rude”. I love it. It’s been a while sense I’ve heard it used like that. Brilliant. Thanks for being awesome.
Dr. Becky you’ve been putting out some great content as of late! And once again, I cannot praise you enough for these medium length videos. I find 15 mins to be just about perfect for most topics I take interest in, which is quite varied. Thanks for another good one! Also, big kudos for your “bloopers section” of your videos that you’re adding now. It gives us, your fans and supporters the chance to see your wonderful sense of humour and to somewhat take you off the pedestal of “scientific superstardom” for a moment and show us that you’re just human after all, like the rest of us “mere mortals”!! Lol
💫🙏❤️😂🍻
Wow... this video really blew my mind....
Many thanks for taking the time to create a simple explanation.
This might be a silly question but what happens to time dilation as black holes get closer? Also, since anything that touches or crosses over the event horizon is trapped are we detecting the merger or the instant before the merger, and as an aside: does gravitational lensing effect what we "see" ? Would a singularity generate a lense around itself ? Sorry if these have been asked and answered before. Cheers :)
I know I honestly think dilation is one of the most ignored things in astrophysics. Having time dilation affect gps merely by escaping Earth's pathetic gravity well would suggest the weight of the sun jupiter the galactic arm and smbh at the middle how much of what we see is actually stretched thin by the well.
That's a different issue to the final parsec problem which starts when the two SMBH's are around three light years apart. At that distance time dilation just isn't an issue. You could happily live out your life on a planet within 100 AU (0.00158125 light years) from a super massive black hole (assuming there's no radiation that can kill you).
Dr Becky Smethurst is my favorite astronomy channel. There are others I watch, which I like as well, but the second behind her has a Eurasian brogue that's difficult for me to readily decipher. Anyway, thank you, Dr Becky, for also making astronomy fun with your bloopers.
I never get tried of watching your videos, Dr. Becky.
incredible video as usual dr becky, and your new fill light looks really good!
Hey Becky, I love your videos. I know black holes can get massive, but how small can they get?
Well, with dieting & proper exercise...
I just like you've started adding portraits of the scientists!
It really helps to remember them, because you now have a face to associate, not just some random name.
Just a thought, but as I studied turbulence in aerospace, could there be a similar effect in between orbiting SBHs? Causing turbulence in space itself from the high gravitation? That would add another factor that would take energy out of the system.
Can you be more specific? Turbulence or not, you have to have energy carried away by something. If there is no significant gravitational wave, whether turbulent or lamina, generated to carry the energy away, there is no energy dissipation.
When you mentioned the final parsec a few weeks ago, I had "🎵The Final Parsec🎵" stuck in my head too. You're not the only weird one. 😀
I was thinking about the swarm of smaller black holes that sink into the galactic core, but I'm guessing they aren't a enough of a contribution to be significant otherwise they would have been mentioned.
Only the relatively heavy objects should sink due to (dynamical) friction. Stelar black holes are lighter than the original stars.
@@steffenbendel6031yeah, but there is evidence now from LIGO for frequent black hole mergers creating black holes with dozens of solar masses. I wonder if the maths have taken this into consideration.
@@steffenbendel6031 Would it be possible for those stellar black holes to merge until the resultant merged black holes are massive enough to sink?
@@kenashworth7672 Not really, these things are tiny and a merger would require two of them hitting head on (or somehow start orbiting each other long enough to merge). The chances for that are astronomically small, it's like trying to hit grain of sand with another grain of sand thrown from several kilometers away. Which BTW leads to another black hole problem, namely how supermassive black holes arose in the first place because stellar black holes grow way too slow over universal lifetime for it to be normally possible...
@@KuK137 I guess whole regions of space collapsed in the early universe to for the big black holes. Might be easier with a lot of black matter instead of normal one. On one hand, it can not lose energy by radiating, but probably also not resting the collapse like normal stars. And there probably was not enough time for a slow evolution anyway.
Hi! Awesome & wonderful video as always!
Just a very small mistake: At 10:04 the two pictures show portraits of Kip Thorne (correct) and on the right side, instead of Braginsky, it's the portrait of Rai Weiss (the LIGO guy). Super small mistake, but I thought it's maybe good to mention :) Doesn't take away from the awesomeness of the video!
(I had the privilege of interacting with both of them at some point, my impression was that they're just wonderful people. At some point I asked Kip Thorne about some fringe aspect of the black hole in Interstellar, and he just wouldn't stop talking about it. Just a very fun and kind guy. Loves talking about black holes more than anybody else I've ever had the privilege to meet.)
Two questions: 1) If two super massive black holes were only a parsec apart could we tell if it was two and not one? and 2) Could this be a mechanism for turning off a quasar?
Could two super massive black holes mechanically turn off a quasar? Is that the question ❓ Do we even understand what causes quasars?
Could tidal heating play a role? If the math assumes Black Holes are just point-like objects with an event horizon around it relative to their mass, that may neglect a part of it. Now I don't know if or how one Black Hole's gravity can affect the internal structure of another - but if it does, it would mean they could transfer part of their kinetic energy into heat, slowing down more than previously thought. And even better: The closer they get the stronger that effect, and the more they slow down.
Would be interesting to see if the event horizon of Black Holes close enough to create Gravitational Waves is actually still strictly spherical, or if they perhaps managed to deform each other so much that it could be measured.
What about other black holes that aren't as massive as the central supermassive black holes, but massive enough that dynamical friction causes them to fall to the centre of the galaxy, and then getting slingshotted out themselves?
0:07: 🔍 The final parsec problem is a mystery in black hole astrophysics regarding the merging of supermassive black holes.
3:11: 🌌 Objects in space, including black holes, can lose energy by interacting with other objects, resulting in a gravitational drag force.
5:58: 🌌 Supermassive black holes orbiting each other at a distance of about a parsec may not merge, challenging our understanding of galaxy evolution.
8:46: 🔬 Observations and experiments are being conducted to determine if and how supermassive black holes merge.
12:14: 🌌 The launch of the Laser Interferometer Space Antenna (Lisa) in 2037 will help detect gravitational waves from supermassive black holes.
14:37: 📚 Dr. Becky recommends Brilliant's data analysis fundamentals course for improving data skills and understanding astrophysics research.
Recap by Tammy AI
So, basically, we’re either wrong or we’re wrong and we’ll find out in 14 years? I unironically love this.
Science is a very lucrative field because every time you solve a problem there's a new problem to solve.
Can we not resolve if SagA is a one or a multiple body system? The milky way has had mergers in the past; so there must have been SMBH mergers before in our back yard. Also, afaik we have never observed a double quasar or SMBH with multiple jets, right? If SMBH don't merge, how do they become SMBH? You have spoken before about your field of study and said one of the only hypothesys we have for them growing so big is mergers.... I am confused 😅
Would dwarf galaxies facilitate a merger? In many of the galactic mergers I'm seeing in the JWST images, there are numerous smaller dwarf galaxies dipping in and out of the galactic disks, leaving streamers behind as they gradually get pulled in. They would have much smaller central black holes, but perhaps they would be just big enough to throw things out of whack.
Good question!
Silly question: With the complexity of the interactions of "merging" SMBHs, would it be at all useful to use something like Feynman diagrams to explain them?
It's still about interactions of two objects, except for the scales of the objects.
In fact, if you slingshot around the Sun while traveling at high warp, you will travel back in time.
5:56 So dark matter interacts via gravity. Does this mean that the black holes also clear the galaxy center of dark matter?
AFAIK dark matter is bad at cooling, which protects it a little bit from falling into black holes.
In a normal accretion disk the matter heats up a lot by friction and then radiates the energy outwards as light of various wavelengths. Thus it loses its kinetic energy and finally falls into the BH.
But dark matter cannot radiate light, so it cannot use this way of losing kinetic energy. That's also why the DM halos of galaxies are spherical even when the galaxy is disc-shaped.
Now, when you have TWO black holes and not only one, it gets interesting. Those should be able to slingshot dark matter outwards.
But there is another phenomenon that I have seen a while ago on a picture. There has been an analysis of the Bullet Cluster and they figured out that the dark matter got separated from the baryonic matter during the merger. It fell out of the galaxies, so to speak. I have no idea how that would now interact with two SBHs orbiting each other.
On the picture, the dark matter seemed to have clumped into a single halo pretty quickly while the baryonic matter masses fell through each other and came out on the other side, having been stripped of their DM halos. Therefor one would assume that the black holes also fell past each other but did not do much with the dark matter.
I wish I knew more about these things, but I can only report what I've seen on that picture.
I saw a documentary about this. I think it was called Star Trek IV.
@@robertbryner3414isn’t there an earlier one with Teri Garr?
Excellent video. Great work. As a scientist as well, I love your video!
When the SMBHs fling the stuff away, is it hard enough for the galaxy to lose the stuff or will it fall back in to sap more energy?
Thank you. Always a pleasure listening to smart people.
It really wouldn't be a problem if we do not see the SMBH mergers?
Since we do expect to notice a considerable amount of them, then if LISA doesn't detect any, wouldn't it mean that our models regarding co-evolution of galaxies *with* their central black holes are wrong?
In any case, that's some pretty exciting research to be done when LISA actually launches and then starts measurements.
What I can't get through in these matters is that besides this final parsec problem we have time slowdown in an extreme BH gravitation field for an external observer. That is, two BHs should not ever fully merge as it mathematically should take infinite time...
That's only a possible problem if the black holes are nearly touching. We can see stars orbiting our galaxy's SMBH as close as 100AU and there's no observable slowdown their orbits, so nothing extreme is going on in that final parsec regarding time dilation. You could be right, but it's not the solution to the final parsec problem.
My little brain gets so overwhelmed with Space stuff. i think Merging could be Flexible, Some Supermassive Black Holes Merge & Some don't, it just depends on the how the first date goes... I'm just gonna imagine it would be like adding Milk in my Tea, If they Merged.
A very good one . By your own teaching you have make a clear picture of new excitement for newly discovered gravitational waves. A amplified version of event horizon gravitational wave detection techniques . The problem is vivid reports are inconclusive.
We all now more eager to know what is next.
Thank you for the data regarding Project Lisa. The continuing brilliance of our Astrophysicists is nothing less than astounding. As to whether the black holes merge, it sounds like a job for JWST. Our time machine see everything.
just been going through all your vids, then new vid! yay!
Great Video, Dr.Becky! I'm currently reading A Brief History of Time by Stephen Hawking, and I'm currently on the chapter of Black Holes. This has surely helped me! Thank youu :)
Love these video's, they are now my Friday morning ritual. One thing about you're lighting Becky, (Lighting for Broadcast is my profession) You would benefit from light hitting the tops of your shoulders and head from behind (we call it backlight) it separated you from teh background. As an example look at your left shoulder (as viewed on the screen) in this video, where your dark shirt merges with the darker background. Yes I am a geek and I'm the only person that would notice..
Wouldn't there be a difference in expansion rate of space due to GR and cause a net "squeeze" resulting in the black holes to merge?
Is GR Gamma Ray, or General Relativity, in your question ❓
Gravitational Resistance?
The graph you reference, showing the relationship between inter-black-hole distance vs time, begs to be expanded so that there is a 3rd dimension, resulting in a 3D sheet. The missing dimension is the size of the black holes. Clearly we believe that small black holes can merge and larger ones cannot. Seeing the relationship between black hole size and the other two variables would be very interesting.
Binary black holes make gravitational waves, which seem like they take a lot of energy to make. That energy has to come from somewhere, so wouldn't it come from the orbital energy of the binary pair? Would that radiate away enough energy to let the black holes merge?
4:40 Wouldn't those interactions have to be coming from one side rather than being from random directions? The more random, the less likely that it can be pulled in one direction. If there are two then they might come together, but more produces randomness as they come in from random directions.
I have a question: We know that our Milky Way has swallowed a couple of dwarf galaxies over time. What happened to their central black holes? Did they not have one?
Possibly not, or possibly just floating around the disc. There's one Galaxy without a black hole that JWST spotted.
there is no such thing as black holes. its all BS
@@davehart9972 so sayeth Dave, some guy on the internet.
prove me wrong, wont happen face it, its a giant $cam. @@Alex-dh2cx
"🎵it's the final parsec🎵" You are a nerd of cosmic proportions. Keep it up ✊❤️
Question! Wouldn’t two black holes both lose energy by rotating around each other (after they’ve cleared everything around them? If so, wouldn’t that bring them closer and closer together?
Yes. Very slowly. The reason the merger takes longer than the age of the universe is that the effect is quite small at ~3ly. If not for that effect, they would never merge at all and just continue in orbit around each other indefinitely.
This makes a lot of sense, and I didn't know the details before.
I guess two supermassive black holes in a binary setup generally acts like one double sized one if it's all totally stable, and in any real situation they're not acting in isolation because there are thousands of stars and particle clouds and other objects that are also disrupting the final parsec?
But looking forward to those results telling us what's what! I love that our understanding is always improving and being challenged - the cutting edge of real science 😊
The final parsec problem is only an issue for those who are trying to make their ship do the Kessel run in less than twelve parsecs!
yeah, comment of the day! seems like most of physics is sci-fi and not real science doesn't it?
Not at all, I just couldn't resist the meme, because back in the day, it was Sci-Fi that got it wrong, not the other way around '-)@@michaelfried3123
Thank you for fulfilling our wish to know more about this!! 😊
Would dark matter contribute to dynamical friction?
dark matter is a myth, its not prove able science.
I wondered the same thing.
another fun research about black holes is the low mass gap between neutron stars and low mass bhs (~2-5 solar masses)
Would it be trivial for an astronomer to tell, if there’s a single massive black hole in a galaxy center or there are two orbiting a parsec apart?
I'm not certain, but I think it would depend greatly on the distance of the galaxy. It would be harder to tell the difference the farther the galaxy.
The image of the black hole at the centre of our galaxy from last year puts the black hole's shadow at about 3.2 light minutes, i.e. well below a parsec, so we can be quite confident in that case at least :)
For some very distant galaxies it might be harder to tell
I think two orbiting, spinning black holes, totally infatuated with one another, in the act of absorbing each other, would be on the final phase of galaxic merger, such that for all practical purposes, there's but one galaxy, DESPITE the "orbitation" relative both black holes. We're talking LOTS of time, though, perhaps billions of years, to get to this phase.
I don't think it would be trivial, but difficult, especially the ginormous distance from whence we have to observe it.
Amazing video, thank you so much for such an excellent and enjoyable subject. Also massive kudos for resisting having an intro thingo.
Before you merge you have to discover if you are compatible. Maybe one black hole is an Aires and the other a Taurus.
If LISA picks up no GW signals, the problem will be figuring out the source(s) that are producing the background GW that the pulsar timing array detected.
Couldn't those supermassive blackholes be actually a swarm of smaller ones on the verge of merger. Too many and too close such that from far away it's indistinguishable from a single supermassive one?
"swarms" of blackholes would not be stable.
Generally three body systems kick out one and form a binary unless one of them is so much bigger than the rest that it becomes "a planetary system".
First, I'm amazed by how good you are to explain these very complex astronomical questions. If I understand this correctly, one way of actually detecting a merger of SMBHs would be through detection of light year long gravitational waves. I assume that you can only detect those waves for a certain period of time. I'll expand on why I think that this is relevant. If we observe a supernova for example in visible light we can only see it on Earth for a period of time comparable to the time it took for it to explode. We can perhaps see its remnants for much longer, but that is a different matter. But there are lots of stars in the universe that can go bang, so that we actually at any time have reasonable chances of catching sight of one of them, happening somewhere. Actually we do see a lot of them. Now, there are much fewer galaxies than stars, so an SMBH merger would not occur quite as often as a supernova. I understand that the number of galaxies in the observable universe is roughly on the order of a trillion. So if one tenth of these guys have had one merger, there has been very very roughly ten mergers a year in the history of the universe. What are the chances of picking up one of these, and not just hear crickets? Well, this also depends on for how long a merger will be visible. If we saw it in visible light, the answer would presumably be "not for very long". If we observe them through gravitational waves I don't know. Lightyear long waves sound like they would take years to pass through the solar system, but what do I know. So my question would finally be: Combining those estimates, how many SBHM somewhere in the universe would one reasonably hope to pick up at a given time by a detector of very long gravitational waves?
What if any black holes really merge and are still furiously orbiting each other under the event horizon?
There would be no difference once it falls below the event horizon the information is lost. It could take billions of relative years for said object to merge but it would have happened the moment it slipped below the event horizon to external observers in non dilate space. That is what dilation is we're currently in dilated space and experience a colour shift slash clocking discrepancy just between us on the ground and the satellites giving dilation corrected gps locations gps mk1 failed as there was no timing compensation.
For me it’s a paradox that the rotational speed of a collapsing star core becoming a singularity can go over the speed of light well before it becomes a singularity, it seems wrong to me but I’m no physicist, but for me, that’s impossible, kinetic energy will equate the gravity power because of E=mc squared, imo.
Actually, isn't there another problem with the mechanics for the creation of supermassive black holes if they never merge?
Does antigravity mean negative energy? I mean we have repulsive forces, and they don’t make negative rest energy.
I love when scientists accept that they might be wrong and get excited about that. It is the BEST part of science, and it should be every scientists duty to teach it as passionately as you have here!
They're father than Venus, and still rather small, but science's genius says they won't merge at all. It's the Final Parsec. 🎵
If I understand it right, in a galaxy with two super-massive black holes in the one-parsec distance, these would normally not be active as they've slung out or eaten most material nearby, and also without any nearby stars? So it would be somewhat difficult to observe them, except by an absense of fast-moving stars in the middle of a galaxy.
It is also possible that the discrepancy is not a problem at all. It is possible that the current understanding of physics is correct, and that supermassive black holes never merge. However, this would mean that we have to rethink our understanding of how galaxies evolve.
That's basically what she said in the video.
@@EnglishMike Yes that is correct, however it is still not clear which, if any, of these solutions is correct. However, the final parsec problem is an important one to solve, as it has implications for our understanding of galaxy evolution and the formation of supermassive black holes.
Thank you for making a video on this! 😁
So in the final parsec problem is that assuming that each black hole is of the same mass? I would think that if the black holes are of different masses then the larger would have a higher interaction to the surrounding environment of the smaller black hole, and in turn effectively pulling the smaller BH into the field of effect of the larger BH and end up merging. If BHs do not impart gravitational effects upon each other, does that mean that as matter is absorbed into a BH it is destroyed into its smallest particles and ejected as an invisible quasar of types? Or does it mean that possibly BHs are only massless objects of purely concentrated gravity?
Not limiting my thoughts, just brainstorming.