The Final Parsec Problem: do SUPERMASSIVE black holes ever MERGE?
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- čas přidán 17. 05. 2024
- Go to brilliant.org/drbecky to get a 30-day free trial and the first 200 people will get 20% off their annual subscription! Everything we know about the Universe suggests that supermassive black holes in the centres of galaxies should merge together, BUT the maths tells us that supermassive black holes will never merge together; instead forever orbiting each other at a distance of around 1 parsec (3ish light years). How are we going to crack this problem? That is, if it even is a problem at all...
My previous video on why we think there's a SMBH in the centre of every galaxy: • How do we know there's...
My previous video on why LIGO can't detect gravitational waves from supermassive black holes merging: • Why can't LIGO detect ...
My previous video on the gravitational waves detected by pulsar timing arrays: • Astrophysicist explain...
Hopkins et al. (2007; correlations between SMBHs and galaxies in simulations) - arxiv.org/pdf/0707.4005.pdf
Kormendy & Ho (2013; correlations between SMBHs and galaxies in observations, REVIEW) - arxiv.org/pdf/1304.7762.pdf
Chandrasekhar (1943; dynamical friction PART 1) - articles.adsabs.harvard.edu/p...
Chandrasekhar (1943; dynamical friction PART 2) - articles.adsabs.harvard.edu/p...
Chandrasekhar (1943; dynamical friction PART 3) - articles.adsabs.harvard.edu/p...
Begelman, Blandford & Rees (1980; final parsec problem outlined, BEHIND PAYWALL students should be able to access) - www.nature.com/articles/287307a0
Iwasawa, Funato & Makino (2006; a third black hole solves the FPP) - arxiv.org/pdf/astro-ph/051139...
Berczik et al. (2006; more realistic galaxy model solves the FPP) - arxiv.org/pdf/astro-ph/060169...
Milosavljević & Merritt (2003; recycling of stars solves the FPP) - arxiv.org/pdf/astro-ph/021245...
Mezcua et al. (2014; dual AGN decomposition in mergers) - arxiv.org/pdf/1401.5920.pdf
Hardcastle & Croston (2020; review of radio galaxies) - arxiv.org/pdf/2003.06137.pdf
Thorne & Braginsky (1976; gravitational wave detector proposal) - articles.adsabs.harvard.edu/p...
NanoGrav PTA research papers - nanograv.org/news/15yrRelease
EPTA & InPTA research papers - www.epta.eu.org/epta-dr2.html
Parkes PTA research papers - www.atnf.csiro.au/research/pu...
Chinese PTA research papers - iopscience.iop.org/article/10...
Amaro-Seoane et al. (2012; eLISA proposal) - arxiv.org/pdf/1201.3621.pdf
00:00 - Introduction
00:56 - Why do we think supermassive black holes merge together?
02:23 - What physical process brings supermassive black holes close to each other in a galaxy merger?
05:18 - What is the final parsec problem? Why SMBH binaries stall at 1pc separation
09:12 - What observations can help us work out if this really is a problem? (Dual AGN, radio galaxies & LISA)
13:56 - Brilliant
15:17 - Bloopers
Video filmed on a Sony ⍺7 IV
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👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
rebeccasmethurst.co.uk - Věda a technologie
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.
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.
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...
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.
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.
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.
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?
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. :)
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!
Was really looking forward to this video, thank you for reading the comments and giving us the video we wanted!
Finally, I can't believe you made us wait SO LONG for this video.
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
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. 😂
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.
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 ⚡
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?
This was a VERY interesting video. Thanks Becky! I NEVER thought about this final parsec problem....
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.
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.
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!
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.
great episode, love learning the details of this problem
Dear Dr. Becky,
I would like to express my gratitude for your CZcams 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 🤗
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!
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.
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.
Just binged 3 or 4 of your vids. I think I need to start at the beginning. I love the info and the delivery.
1:14 Looking at a screenshot of a creator's CZcams 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.
This was a phenomenal presentation tying a bow on everything that's been happening. Thanks Dr.
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.
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.
incredible video as usual dr becky, and your new fill light looks really good!
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! 👍
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
Thank you for fulfilling our wish to know more about this!! 😊
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.
You are a very inspiring explainer of science! I wish we could all learn to teach this well!
Astronomy is so amazing and facinating! Your videos do a great job of explaining everything..always love to learn new things every week!
So beautifully explained. Thank you
To us, observing from outside they do. But to them, time dilation makes it look like it takes until the end of the universe
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?
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.
Wow... this video really blew my mind....
Many thanks for taking the time to create a simple explanation.
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.
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).
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. Always a pleasure listening to smart people.
Pretty interesting indeed! Thanks, dr. Becky! 😊
Stay safe there with your family! 🖖😊
Before you merge you have to discover if you are compatible. Maybe one black hole is an Aires and the other a Taurus.
I never get tried of watching your videos, Dr. Becky.
“Rude”. I love it. It’s been a while sense I’ve heard it used like that. Brilliant. Thanks for being awesome.
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.
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.
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.
It's very obvious. We don't understand near as much as we like to think we do, especially theoretical physicists. The final 'parsec' problem, is in fact simply hubris.
Thank you for making a video on this! 😁
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?
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!
Excellent video. Great work. As a scientist as well, I love your video!
Great video, one of your better omes, imo❤
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
💫🙏❤️😂🍻
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
Thank you for this work (really appreciate the references). 👍🏻👍🏻
I enjoyed your 4:05 fling affect videography, expressing what you were talking about. That was keen. 😊
Thank you. So good. What makes us think supermassive binaries have stable orbits?
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 :)
I have some observations:
1. Gravitational waves from black holes suck in all particles around them, thus meaning that the clouds of gas are being absorbed by the black holes as it gets close enough to them. This means that they're slowly accreting matter as they spin around each other and through these clouds. Even light being emitted from these clouds that falls onto the black hole can be considered to be a small contribution to it's mass.
2. If one black hole is even slightly smaller than the other black hole, the larger black hole will start feeding off the smaller black hole. This is due to immense gravitational waves that cause the black hole to suck everything around it into itself. If the smaller black hole can't gain enough matter through accretion, it will eventually become a part of the larger black hole through accretion and through loss of matter.
3. Since both black holes are spinning, this means there is a force that started that spinning motion. Some amount of this force might have come from the black holes themselves. If there are external forces that caused the spinning motion, the laws of motion come into play. When the motion is sufficient, it will cause both black holes to merge. If it is insufficient, it might cause them to spin around each other. We are witnessing spinning in our own lifetime, but it could take longer than the age of the current universe to notice enough motion for supermassive black holes to merge together. That's just the timescale they operate on.
"Pulsar timing array" sounds so badass as a name, it feels like we've built a galactic scale superstructure for detecting gravity waves. A fitting instrument for exploring supermassive black holes.
I keep thinking "galactic" has something to do with icebergs for some reason. 😅
.. maybe I'm seeing "arctic" somehow in it. 🎉
Hey Becky, I love your videos. I know black holes can get massive, but how small can they get?
Well, with dieting & proper exercise...
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.
She's back ya'll. Gonna save this for later.
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.
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?
Thank you for a truly fascinating video
I believe SMBH’s spontaneously appear within the centre of gravity of a galaxy in its early formation where the whole galaxies mass pinches space-time right at the centre
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 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?
Interesting video Thanks Dr Becky
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.
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.
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".
Didn't know this - Thank you!
Amazing video, thank you so much for such an excellent and enjoyable subject. Also massive kudos for resisting having an intro thingo.
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.
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?
just been going through all your vids, then new vid! yay!
We asked for this in the last video and got it. Wow
You surely keep your promises, Dr Becky ☘️
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.
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.
You're so cool! Thanks for doing what you do!
Thanks so much for your explanations.
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?
Would dark matter contribute to dynamical friction?
dark matter is a myth, its not prove able science.
I wondered the same thing.
Great video, you always make this stuff super interesting and make me curious to learn more. Now you've got me wondering, do black holes experience tidal forces when orbiting in close proximity like that?
Yes and no. Yes: you can see the event horizons deforming on the merger simulation videos. No in that tidal force generally means second (tensor) derivative of the gravitational potential energy….but by the time you get near a black hole the whole thing is so nonlinear that thinking in terms of potential energy, gravity force, tidal deformation just isn’t appropriate anymore
Great episode!
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. 🎵
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.
another fun research about black holes is the low mass gap between neutron stars and low mass bhs (~2-5 solar masses)
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.
Well this episode was bit of a _speed learning_ with quite a lot crammed into it. But definitely enjoyed, keep up the good work Dr. 👍