PBS Space Time - 2019-10-07
Learn more at https://www.brilliant.org/spacetime Black holes are crazy enough on their own – but crash two together and you end up with a roiling blob of inescapable space that vibrates like a beaten drum. And the rich harmonics of those vibrations, seen through gravitational waves, could hold the secrets to the nature of the fabric of spacetime itself. Today on space time journal club we’ll explore the papers that claim to have detected black hole harmonics. We’ll also give you the latest updates on the most recent – in some cases quite bizarre - LIGO detections. Sign Up on Patreon to get access to the Space Time Discord! https://www.patreon.com/pbsspacetime Check out the Space Time Merch Store https://pbsspacetime.com/ Hosted by Matt O'Dowd Written by Matt O'Dowd Graphics by Murilo Lopes Directed by: Andrew Kornhaber Executive Producers: Eric Brown & Andrew Kornhaber When physicists talk about black holes they’re usually referring to highly theoretical objects – static, unchanging black holes viewed from “infinitely” far away. This makes everything clean and simple enough to attempt the already notoriously complex calculations of black hole physics. But real black holes are created in the violent deaths of massive stars, and there’s nothing clean about that. And we now know that black holes merge – and in the process produce gravitational radiation that we’ve only just managed to detect with the miraculous work of the LIGO and VIRGO gravitational wave observatories. In the instant after its merger, the new, joined black hole looks nothing like the idealized theoretical black hole. Special Thanks To All Our Patreon Supporters Big Bang Supporters Anton Lifshits David Barnholdt David Boyer David Nicklas Fabrice Eap Juan Benet matt miller Morgan Hough Quasar Supporters Mark Heising Mark Rosenthal Vinnie Falco Hypernova Chuck Zegar Danton Spivey Donal Botkin Edmund Fokschaner Hank S Joe Pearce John Hofmann John R. Slavik Jordan Young Joseph Salomone Mathew Matthew O'Connor Syed Ansar Gamma Ray Burst Supporters A G Adrien Molyneux AlecZero Andreas Nautsch Bradley Jenkins Brandon labonte Brian Dan Warren Daniel Lyons David Bethala DFaulk Frederic Simon Geoffrey Short Graydon Goss Greg Smith James Flowers James Quintero John Funai John Griffith John Michael Kerr John Pollock John Robinson Jonathan Nesfeder Joseph Dillman Josh Thomas Justin Lloyd Kevin Lee Kevin Warne Kyle Hofer Malte Ubl Nick Virtue Nick Wright Paul Rose Scott Gossett Sean Warniaha Tim Stephani Tonyface Yurii Konovaliuk
My mind still breaks trying to understand the merger. I'm hung up on the idea that the limit of time dilation is infinity as the distance to the event horizon approaches zero.
So do singularities even exist inside, or is time flowing backwards inside, or is time frozen within meaning that all collected matter sits on the firewall or event horizon?
If the singularities don't actually exist, then what is happening to the colliding firewalls, or should the event horizons be impenetrable to each other since they freeze the opposing firewall to infinite time dilation?
I think space time flattens out at the border of the black holes, and thus the time dilation of the event horizons relative to each other are not infinite. Like if you have two balls on a rubber sheet, the slope to them from the outside is steep, but the slope if you go from one to the other isn't steep.
But that is just my guess.
Also, inside the black hole, time becomes spacelike and space becomes timelike.
We don't know what happens inside black holes.Relativity makes predictions but those are untestable as far as we know and singularities are essentially nonsense. (Not for nothing are they called places where the laws of physics BREAK DOWN.)
Time dilation going to infinity only works with a static black hole seen from infinitely far away, two merging black holes that are actively losing energy (Thus mass and size.) are a totally different story. The equivalent there is that the ringdown can never be seen to completely finish; it will seem to slow down infinitely as it loses energy and the merged hole becomes spherical.
As a musician, I'm surprised by just how much this made complete sense. Anyone who plays low-tuned bass guitars knows that the second harmonic is usually louder than the fundamental. Hence why tuners like to not show the note I want to tune to and instead show the perfect fifth because that overtone is louder...
It's absolutely mind boggling the amount of information we can get from vibrations that are smaller than the diameter of a proton. LIGO is an awesome project!
I can't wait for the space based observatory.
Everyone else: Does Extreme Sports
PBS: Does Extreme Space Time
Ok that was a good one.
A vast improvement
Gravitational lensing of gravitational waves...
Mind blown.
@Joaquin Elio actually, that's genius. I wonder if it's possible.
so if light can't get out, how does gravity get out? Makes me think the black hole would move along eating up everyone elses' gravity fields without propogating its own field, only distorting others
...but that's evidently not right...
my head hurts
@OldGamerNoob Yep I don't get it eather. I know in theory Space Time is not confined to the speed of Causality (a better description than speed of light) with the idea of Inflation faster than the speed of Causality right after the Big Bang. So Space Time ripples which are what Gravity Waves. What is it with describing things in a not totally accurate way? Dark Matter solutions might not include matter, Dark Energy solutions might not include Energy so why they called that? actually are might not have to obey Causality but they do seam to be limited by Causality after they get away from the Black Hole.
If so it should show the same gravitational spectrum, perhaps stretched. This should be interesting.
@Joaquin Elio If we could come up with negative gravity (if it even exists) then sure, why not.
Typical Aussie, always thinking about those Waves
I'm a music theory teacher laughing at the fact that you just made a (fantastic) video on overtones and the harmonic series. 😃👍👍 Music of the spheres indeed!
@LuckyMoniker first you'd need to generate gravitational waves and considering no material in existence (of human dimensions) can survive being accelerated to close to c, I don't see how you could generate those. The toughest materials we have will oscillate, heat, deform, melt and get torn to shreds way before moving fast enough to create any detectable gravitational waves. Also, gravitational waves only move at the speed of light so measuring astronomical distances with artificial gravitational waves wouldn't be any faster...
Unless you mean using naturally occurring ones, in which case it maybe be possible if they lens off really massive things. But that would require having just the right perspective on such event.
I’d like to see the black hole harmonic series ^.^
@LuckyMoniker Yep want that on your Space Fleet. ;)
@Ronen Shtein what would we call such an instrument? The Space Banger?
@Tyler Jourdan more like The Impossible Burger... ba dum tsss
"It has a .69 spin"
Researchers:"nice"
People like you are the reason we're not exploring the stars yet.
@Jason Duvall - If XKCD is any indication, scientists can have a gross, weird, childish sense humour like anyone else, and still be great at science. Possibly grosser, weirder and even more childish than regular folks...
@Jason Duvall you should be the subject of your own comment
@Jason Duvall I disagree
Black holes: THIS ISNT EVEN MY FINAL FORM!
Kai ok en!!!!
There is an app called GW Events on IOS (android too I would assume) that reports gravitational wave detections along with all of their data, if anyone is interested in that.
I was thinking grav lensing then i saw that you thought of it..... dang it Matt, make me feel special
I'm more primitive. I could recognize "mass and spin" before he said it. Made me feel special, too.
I prefer my black holes to be hairless.
Gimme some 😋
EDIT: You are talking about a-holes right??? 🤓
@Espen Haug :))))
The replies are awful
Bald*
BBC in a BBH
Last time I was this early the four fundamental forces hasn't separated yet.
Remember: If he EVER ends an episode by saying something other than "Spacetime", we RIOT!
@paul hench :/
I hope one episode he just goes, "oh yeah, spacetime"
I follow the channel from quite a while and detected at least 2 events when this happens
The only channel with mass in 2019
This is like Linus not dropping expensive computer hardware, Yahtzee completely gushing over a game, or the Pan Piano not baiting and switching viewers with cleavage thumbnails.
I was 7+ minutes in before I realized the background was moving...
after reading your comment I saw that.
"After massive upgrades to sensitivity"
Me after a breakup :[
"Cough Cough Gravitational Lensing cough cough" LOL
This makes me think of early experiments in the electromagnetic spectrum, so when are we going to have space time radio (gradio?) and whats the range on the space time wifi
It's amazing to think that we can listen to the universe to learn about it the same way we listen to things on Earth, but instead of vibrating air, the sounds vibrate space-time. I never thought of LIGO as a gigantic space-time microphone before.
And, unlike many other waves in Astrophysics, G-waves from black hole mergers are apparently within human hearing range!
@Parnikkapore Prompt that's amazing
Space: Noise is no no
Black Holes: sans in harmonics
I came here from a gay jojo video stream
Me on guitar: I can hit some pretty sweet pinch harmonics.
Black Holes: Well, check this out...
@Akshat Saxena thats what a bassist would say
Big Bang!
Wish this narrator would stop using the word miracle when referring to these great discoveries.
Akshat Saxena 0 3 6 5
Black Holes: The Universe's base players.
As a chemist, I can't help but notice some at least superficial parallels between black hole harmonics and atomic orbitals.
9:52 Argh, showing magnetic field for electric charge. [ OCD twitching intensifies ]
Use me as a “THAT’S AWESOME” button.
8:55 Nice
sockrdude nice
I think "no hair" black holes should be called bald holes.
@KungKras I am not able to find a good reference for it being intentional, only heresay and others looking for a source. It seems people did hear it somewhere. It could be that I got it from A Universe From Nothing, or perhaps A Short History of Nearly Everything. I don't feel like manually searching those physical books, though, so I'll just accept it as a myth.
However, it does have dirty connotations in French: http://erkdemon.blogspot.com/2009/12/black-holes-are-rude-in-french.html
@Magnus Bergmark Nice.
If those books are good, I might read them myself someday.
Well, it's a good thing they are bald, otherwise we'd have to invoke the hairy ball theorum and we'd get hairy black balls.
@Magnus Bergmark "black hole emissions"... /sigh
@KungKras Oh, I can promise you those books are good. A Universe From Nothing actually started out as a presentation here on YouTube that was so popular he wrote a book on it expanding (pun intended) on everything.
Look for the presentation on YouTube and watch it. If you liked it, you should read the book. If not, then you only wasted around an hour on learning things.
This episode brings back aggravating memories for me. Twice I've lent my harmonica to a black hole... I never got them back.
12:34 Are you saying that we got the signal of the same merger of black holes twice but time delayed due to them bending around some massive object in between us and the merger? If this can be at all confirmed this would be an incredible opportunity to do "insanity checks" on both LIGO and the theory right?
Thank you for putting a time scale. I get so annoyed when things are said to happen "quickly" but don't actually say how quickly.
"WhaT Is ThaT MeLODY!?"
What's that M'Lady
Anugrah Mathew Prasad Quoting Overwatch’s astrophysicist character “Sigma”.
Darude Sandstorm
Karnage Reaver
Dam it you beat me to it
Loooool
FUN FACT: Your farts also create a gravitational ripple in spacetime
It's insane how fast this has all developed, from the first photo of a black hole just a few months ago, to scientists proving Einstein right yet again!
Isn't there like 3 of them out there about to collide with each other soon?
Did someone do the 'Great band name' joke yet? Yeah? 472 times? Oh, alright.
So a lame physics joke : a neutron enters a bar, gets a drink and finds out "It's free of charge"
I'll leave now
This thread was awesome! My brain felt like a pinball.
Tomi so original
@night k thank you Corvo
@Mortimer Hasbeengud | Oh, that one's great.
Mortimer Hasbeengud Bruh
Making music with gravitational waves be like :Ｏ00Ｏ0Ｏ0ＯＯ0 ( ik it's bad )
so very much like two drops of water merging together, interesting. Or two vortexes
Hey hey we're the Monkees!
People say we oscillate around!
Takes quadrillions of us to make black holes!
But only gravity will keep us down!
Then this harmonics and its decay have the information about how stiff and how viscous spacetime is, right? is there any conclusión about that? and what does stiff and viscous mean for spacetime? mind blown would this viscosity have anything to do with the speed of light / the Higgs??
13:10 Extreme space time. Could be an industrial electro band.
What do these harmonics sound like, is it something that pbs space time can do a video on? Perhaps cosmic sounds such as the resonance of Jupiter?
So this is the "music of the spheres" I've been hearing so much about?
4:04 hehe THeYRe gRoOvIn
Computer Scientist here, forgive my ignorance.
Question: sounds exactly like a discrete time Fourier transform (or something of the sort for the sine/2D waves to which you allude).
What is the problem/confusion/skepticism in decomposing the waves with an algorithm just as an FFT might based on the properties? This seems very straightforward in the way you explained it.
If the experiments yielded different results, can you explain such implications?
How can I learn more about implementing this sort of harmonic algorithm/transform in my own program, similar to how the SXS implements it, aside from the papers you mentioned?
Never mind, I’m not a Computer Scientist, after listening to this, I will update my LinkedIn to “Armchair Astrophysicist, PBS Spacetime Univeristy”.
Thanks for the great content.
Shoulda called this one "The Music of the Spheres"
Yeah, stuff happens that distorts the shape of the event horizon. It even happens from inside a black hole when the Planck core breaches the poles and jets Planck plasma. See https://johnmarkmorris.com/2019/10/14/neoclassical-physics-and-quantum-gravity/
I just realized that the beginning audio clip of PBS Digital Studios is the Mr. Rogers Remix, reversed.
“A so-called ‘Dimensionless Spin Magnitude’ of .69-“
Nice.
Same way an electron spins, probably.
So, if there’s a “dimensionless spin magnitude “ between 0 and 1, what is 1 in this case? What happens to spacetime and the black hole at this spin magnitude?
@Phil Biehl It would become a naked singularity. But physicists are prudes and so came up with the "cosmic censorship hypothesis" which says that can't happen.
@HolyMith Thanks for a example that allowed me to understand that.
I could do with more details on the formalism of that, HolyMith.
I always try to say spacetime with him in the end but this time I feel played 😒
Special EDy - 2019-10-08
A thought that has caused me to lose a lot of sleep, the Legrange Point between two colliding black holes. Imagine you had two black holes traveling at 99% of light speed, on a collision course where the event horizons temporarily overlapped, but the singularities at the centers missed the opposing original event horizon. Is it possible for the two to be on an escape trajectory, or does the overlapping and momentary merger of the event horizons disallow any escape trajectories? If they can escape, it would be possible to put balance a spacecraft on the Legrange point between the two objects, pass within the event horizons, and escape.
Special EDy - 2019-10-08
@Martijn Bouman I've wondered if the event horizons would repel one another, since you are near a point, the Legrange Point, where the net gravity is zero. So you might be inside a bubble of space time surrounded by event horizon.
Special EDy - 2019-10-08
@Jay The Amazing Toaster in the example I used, the singularities are on an escape trajectory moving just past each other's event horizons, but the event horizons themselves overlap.
Gareth Dean - 2019-10-08
No, the holes wold have to merge.
One issue is that at near light speed length contraction applies. It's possible to see two holes coming towards you from opposite directions at 99%c but each hole would only see the other approaching at 99.75%c. (SO even in a collision objects can't move faster than light.) Since the event horizon is where something must move at light speed to escape, if the event horizons overlap at all the holes will not be going fast enough to pull apart. They might spiral around a hundred times before settling down, but their fate would be sealed.
Now if you try to fly between two identical holes, what happens? WLet's imagine a perfect balance point between them with no total gravity.
Well you can 'escape' one hole or the other by moving towards its partner, even if you were between two singularities inside a merged hole you could do this. The problem being of course that you're escaping one hole by feeding yourself to the other.
Can you fly between them, using their gravity cancellation to escape? Not really no. Imagine you leave that balance point and head 'up' between the two holes. Now the left and right pull of the holes will cancel,so neither hole will pull you left or right towards it.
BUT, as soon as you move upwards both holes are below you, BOTH will pull you down. The balance point between the holes is like a hole itself; if the holes are distant you can still escape, but if they've already merged and you're inside the event horizon, you can calculate that there's no escape.
Once you're inside, you're inside forever.
Martijn Bouman - 2019-10-09
@Special EDy and @Gareth Dean
If you treat the black holes as point masses then no, at least a naive calculation will show that you won't be inside an event horizon and can escape. Suppose you have a black holes with a Schwarzschild radius of 1, i.e. if your distance to the black hole is equal to r, your gravitational attraction is equal to c/r^2. Set c=1 and it is equal to 1/r^2. Now suppose you have two of these black holes, one at point (-1,0) and one at point (1,0). You travel across the y axis. Suppose you are at point (d,0). Your distance to 1 black hole is sqrt(1+d^2), so your gravitational attraction towards that black hole is 1/(1+d^2). Your attraction among the y axis, though, is just equal to d/sqrt(1+d^2) times this. Then the attraction you feel is in total is 2 * 1/(1+d^2) * d/sqrt(1+d^2). Plot and see that this never exceeds 1 (it never exceeds 0.8, even).
IDCGaming - 2021-02-15
@Jay The Amazing Toaster not quite true. You see, black holes aren't technically made of matter, but rather are essentially gravitational anomalies. Think of gravitational waves like you would an EM wave. They have peaks and troughs, maxima and minima. They have an amplitude and a frequency. Black holes, are essentially the extreme points on those waves (namely the extreme positive point).