"Absolutely not and there is no danger whatsoever" is exactly what you would say if you were recently replaced by an alien from an intergalactic civilization which recently took notice of us humans.
I recently had a women in physics lecture meet (I'm in high school) and the professor speaking was Prof. Rachel Webster and she brought up this video and encouraged us to have a look at your channel. I was really excited because I binged watched this channel the day before the lecture and I felt so proud as I had already seen this and understood what she was saying.
Hearing scientists be giddy about their work is great. Hearing a scientist _communicate effectively_ about something that makes them giddy? That's a treat.
Love that you guys always immediately dispel any hint of conspiracy theories. ITS NEVER ALIENS is one of my favourite things to say to people who believe unsubstantiated sophistry. You're a legend Matt and you've taught me and millions of others how amazing the universe and our place in it really is. Shout out to the PBS Space Time team as well. x
I swear, every time Matt ends the episode with "SpaceTime" he has the most smug smirk like "Yeah, I did it again. Yeah, I tied it back to the episode. No one can stop me"
It always blows my mind when we talk about these cosmological events in the present tense, when in reality We are observing something that happened hundreds of millions of years ago or even longer. Life is so short, and should we not be so grateful to occupy this very special moment in time, when the universe can both observe and be in awe of itself.
@@jesstar119 A couple of years ago I started going blind and since then I have been reinventing myself as a visually impaired writer. So that actually means a lot, thanks.
The things black holes do with their angular momenta -- being one of the only three measurable properties black holes are thought to have -- break my mind. When two of them collide, the models I've seen show their angular momentum vectors just... _suddenly combine_ into a new one in an instant called a kick, as though it were one gigantic quantum object. I can't imagine something physically doing that, let alone something made of billions of solar masses.
More things might happen after vectors converge. Its just that, for all practical intends and purposes, it doesnt happen in our universe. Models dont show what happens behind that newly established event horizon. We know nothing.
I wonder what happens if their axes are completely aligned and they are already rotating near light speed, where do they shed all that excess momentum?
@@Szgerle What does it mean to rotate at near light speed? Speed equals distance over time. Rotation doesn't really involve distance. Then again, if you imagine a particle spiralling towards an enormous, point-like mass, at a certain distance it may well be orbiting at the speed of light. And if it moves further in, gaining kinetic energy (?), how can it possibly go any faster? I struggle to imagine black hole singularities as point-like at all. I can't help clinging to the idea that there's a tiny-but-extensive maelstrom at the centre where everything is in orbit of the centre of mass, perhaps reduced entirely to photons.
I guess I've been watching and learning from this show for long enough that the two proposed answers here were exactly what I expected. Feels pretty good :)
If that doesn't qualify as a "death ray" I really don't want to see something that could lol. Thankfully we are out of even it's mind blowing effective range.
Love how accessible this channel has been all these years ! But I think you forgot to add captions (not auto captions) A few of us really need captions
Amazing video as always, but while I know how passionate you obviously are (along with the entire team of course), I really enjoyed you bluntly saying it! Very pleasant.
6:16 Whenever I will have trouble figuring out what to name my future pets I will remind myself of astronomers, the masters of memorable names that just rolls of the tongue beautifully
I just have to add that the visuals for this video was breathtaking. Felicitations to the video editors. Also, Matt’s enthusiasm is contagious! Loved it.
well that explains it! at first i was wondering if i was just hearing things... but after you mentioned you'd just gotten back from down under it's clear you've brought your aussie back, and laying it on thicker than ever! rawrr love it!
My first thought was it might be the Dzhanibekov effect (Intermediate Axis Theorem) in action at an absurd scale. That's usually a 180 degree flip but it's not instantaneous so it'll trace out an arc, possibly over a fairly long timeperiod. It'd require a very eccentric accretion disk, I should think. Seems unlikely.
Would be kind of scary if true, it would point to 3d rotating objects (such as earth) doing the same. The Russians discovered this effect and it was reportedly hidden for years for fear of causing panic. So far no evidence of such happening on the planetary scale however
@@justryingmybest Only if it's a fairly normal black hole and accretion disk. It's unclear if something with a very small differences in mass distribution between two would be able to flip, even given enough time. It is the result of a sort of harmonic reinforcement so it's not impossible in a simplified/idealized setup but you'd think, below a certain scale, the energy would just dissipate as heat rather than accumulating.
Terrific video as usual. I have a tech question/note - the audio for this and the last vid is strangely dulled, and makes it look like you are lip-syncing; could it be too heavily de-noised? No actual worries, just confused.
Most of the images of such jets that I've seen suggest that the black holes' spins are wobbling dramatically, so I would think that this is more the norm than the exception.
For the purposes of rotation, do you treat a black hole as a point mass or spread it out over it's Schwarzschild radius? Seems like it'd have to be non-zero radius and moment of inertia or it'd be absurdly easy to alter its rotation.
@@volbla Ah, that's a good thought. I knew that if black holes spin fast enough they could end up with an oblate, toroidal or even no event horizon but considering the singularity as going from a point to a ring that grows with any rotation suggests that the faster it spins, the harder it is to spin faster. A little different than the dynamics of a solid body.
The answer is a bit of both and even more. From our point of view (outside the black hole) the matter never falls through the event horizon, so all the causal effects it creates (EM radiation or gravity) come from the event horizon, the "surface" of the black hole. However, the matter moving towards the event horizon is not the only part of its mass. From our point of view there was matter that was already in that place where the hole now is (i hope what i said is comprehensible). But the black hole behaves like a literal hole, not a massive object. In the rubber sheet analogy it would be a hole in the sheet, not just a funnel from a massive ball. And if you try to model the insides of the hole (that cannot causally affect what's outside), they would look like a massive singularity in the center and a lot of matter moving FTL towards it. The singularity itself would be a point in a non-rotating black hole and a ring in a rotating one. The slower the rotation is the more it looks like a point.
@@evgenijdenisov I'd argue against it being a hole... and possibly not even a singularity. Things go imaginary at the event horizon but if you rotate the interior so the time axes make sense, the inside looks pretty much like the outside, an expanding universe with the event horizon as a sort of white hole in the past. I hadn't considered the spinning variant but it should look pretty similar. I'd expect a subtle quadrupole signature in its CMB, though. Not entirely unlike what we see in ours.
@@protocol6 yes. But if you try to map this picture to a sphere, it would look like a singularity in the center. It makes me wonder: what if our inevitable future/singularity is a ring, not a point?
Thank you so much for referring to a black hole as ‘accreting’ matter, not ‘eating’ or ‘devouring’ or any other anthropomorphic nonsense. Also, don’t look up.🖖🏼
I think he said accreting to imply that the matter went into the accretion disk and not necessarily the black hole. But what's the problem with 'eating', or 'devouring'? What about 'consuming', 'assimilating', 'absorbing', or 'gaining'? And when it comes to outputs from the system what words can we use to describe the jets and light? Can we say the black hole is 'emitting', 'spewing', 'shooting', 'launching', 'distributing', or 'vomiting' out matter? What if the words used to describe incoming matter and outgoing energy are both personified? Can we say that the black hole gobbles everything up while the jets are now ejaculating particles in our direction?
Thank so you much for your great work ! Will it be possible to do a video about the Kaluza-Klein theory ? To explain how gravity and electromagnetism are viewed to be able to be bind, what are the implications, etc. Thank you again, stay strong !
Could it be possible that there are actually 2 galaxies overlapping from our perspective, where each is oriented differently so that it looks like 1 galaxy that has changed direction?
Good question. I don't think so. The distance is only 100k light years. The precision is comparable to a galaxy size. In other words, in order to overlap from our perspective the galaxies must actually overlap. It is a pretty rare possibility, and i believe the authors checked it.
Was there a change in microphone? Not sure if the normal mic wasnt at hand or if this was intended, but I think the old sound was ALOT better. This sounds very unnatural and even the quality itself seems to be worse. This is only technical feedback, but I think the old, more natural sound was alot more connecting, I dont like this "bass sound right into my ear" thing. But maybe thats just me.
So if you want to send a smoke signal across space we need a friendly compliant black hole. The inverse square law tells us that a puny human made radio signal transmission will by undetectable before it even leaves our solar systems influence
just fyi for the editor, when matt was shouting out REQ for being a big bang patreon contributor, Ian jones was shown on screen instead. Hopefully this gets fixed soon.
Big fan of the channel and content, thanks for sharing... If you don't mind a constructive criticism. Lately I see that your videos are getting darker and darker that I have to use the highest brightness level on my phone/laptop. I hope you can fix it for future videos. Thanks for the video, a learn a lot here :)
Is it possible for the magnetic flux lines around the AGN to get tangled and reconnect causing a huge burst of energy similar to how CMEs are formed? This direction would not have to be in the same direction as the jets.
Good theory and I am thinking it might be testable. If a galactic merger was large enough to change the spin direction of the black hole, wouldn't it also change the location of the black hole and thus the new black hole location (as indicated by the blazar jet) would no longer be located at the midpoint of the line between the two radio lobes?
Maybe this question is dumb, but how are these supermassive black holes formed? Do supermassive stars(suns) used to exist and dye to become this massive objects or what?
Questions for Monday: 1) What happens if a gravitational wave with a wavelength greater than the size of the black hole passes through a black hole? Will it go through ("bends around")? 2) Is the interference of a gravitational wave possible with the help of a multiple system of black holes (analogous to slits), which shield the wave? 3) Is the interference of gravitational waves able to give rise to a black hole at the interference maximum? If so, what orders of energy of grav.waves are we talking about? Sincerely, Eugene
1. From my understanding, a gravitational wave (just like a light wave) would bend towards the black hole, and if close enough, "fall in." Of course, relativity says gravity is just the curvature of space, so the curvature of space bending just means more intense gravity, which brings me to: 3: Yes! It's called a Kugelblitz black hole. Theoretically, enough gravitational lensing could focus energy such as light, similar to a magnifying glass, focusing said energy to the extent that it reaches its Schwarzschild radius, collapsing into a black hole. Gravitational waves carry energy too. Some collapsing stars have so much mass that the reach their Schwarzschild radius and form a black hole, but given e=mc2, energy == mass. A Kugelblitz black hole forms when said black hole forms entirely from focused energy/radiation as opposed to dense mass
12:34 That's what i usually think when looking up at the Moon and stars. Some people look at the sky and see a limit, they see the blue sky almost as a physical barrier, even though just beyond that, there are actual physical cosmic objects. It's amazing to look at the Moon, orbiting us, appearing small to us, but a person would easily get lost when taking a stroll on it. Same for the Sun, it's not a 2D circle of light, neither are the other stars, or what we perceive as starlight but might actually be galaxies and quasars and whatnot.
I never knew there was a reason for them not to change direction. I always though with the amount of material at any given time plus the speed that it would freely be able to turn.
In the abyss there appeared a single Eye that slowly grew, until it filled nearly all the Mirror. So terrible was it that Frodo stood rooted, unable to cry out or to withdraw his gaze. The Eye was rimmed with fire, but was itself glazed, yellow as a cat's, watchful and intent, and the black slit of its pupil opened on a pit, a window into nothing. Then the Eye began to rove, searching this way and that...
Yeah the audio has been weird/different for the past three or four episodes. It sounds like he's got a lisp. I think the episode before this was "normal" but there is definitely something different about the way the audio is recorded and or worked with in post.
Always fascinating, thank you. Possibly a silly question: Could it be this black hole is simply exhibiting precession? (There isn't a visible 'sweep' because these things aren't always active) Or even more boring we are looking at two AGN's oriented at roughly 90deg to each other, overlaid from our perspective?
We do see precession in some AGNs, the issue is that this change is so large and quick, it's a lot like asking if Uranus' current tilt is merely precession. The effect is too large. For two AGNs we'd expect to see two galaxies and evidence of one obscuring the other. From what we can tell this is just a single object
Fascinating and very informative as always Matt!!! I wonder if the latest discoveries from Webb which seem to contradict a lot of modern cosmology might mean that the actual universe is far, far larger than the visible universe, as inflation theory suggests it could be, and that in an elephantine megaverse, supermassive black holes might indeed be the best possible candidate as the source for dark matter after all.
How about this variation on Option 2: there are two black holes in the AGN (say, from a galactic merger, but not having merged themselves yet), one producing the radio lobes and one producing the blazar? How would we be able to detect such a situation?
It would be difficult, but the big issue is that such a system isn't really stable. The two holes would tend towards merger, especially if both were surrounded by a large accretion disk allowing them to emit such strong signals.
@@garethdean6382 , yes, it would be a temporary situation lasting perhaps 100 million years, which is typical for the merger of black holes after a galactic collision, but that seems plenty of time for observations.
Could it instead be two galaxies that are just along the same line of sight, one in front of the other, and are close enough that we don't have enough precision to notice the distance difference from so far away?
The galaxy is actually reasonably close to us on a universal scale, only 600 million odd light years. This has allowed the team observing it to be quite sure there's not another galaxy lined up. It would also be long odds that their two AGNs just so happened to flip activity at the time they crossed paths and didn't leave us with two sets of jets visible.
Couldn't a simpler explanation be that there are two objects, not merged? If two objects merge, the resulting spin would be different from both objects, and it could look like the direction changes twice, or there were three different sources.
The problem is that a merging system tends not to be stable if it's so compact that it appears as one. We've seen a lot of double quasars in merging galaxies so we know what to look for there and what they tend to be.
I love the cop out at the end. "Because we've skipped so many question/answers, we're going to do just this one more before we pay it all off next Monday...."
Hey quick question! Quarks and Gluons are normally confined (Color Confinement) but in the extreme conditions within certain stars they can exist free in a state known as a "Quark-Gluon Plasma" and At the extreme energies within a "Quark-Gluon Plasma", Gluons are able to collide and produce Strange Quarks, so does this confirm that stars composed of Strange Quarks exist? Fun fact about Quark-Gluon Plasma, it exists as an almost perfect Fermi Liquid or "superfluid" and possesses the lowest resistance to flow (Viscosity) of any known substance.
Ok, so the Hagedorn temperature temperature is around 1.7×10^12 K, whereas silicon fusion happens at 2.7-3.5 billion kelvin, about a thousand times cooler. And that's one of the most energetic processes in stars. What stars are reaching the point where they can form quark-gluon plasma? Do you have a link to something? Because as far as I can tell that's just not something that's happening. Are you talking about neutron stars? Supernovae?
Hey, I never really thought about this, but does Gravity cause synchrotron radiation on charged particles too? My thoughts: 1) Yes because the particle is accelerated perpendicular to it's velocity. 2) No, because the particle flies in a straight line and but space itself is curved.
It shouldn't; such radiation is emitted when particles are *accelerated* and an object in orbit is in freefall. As you state, it's moving in a straight line in curved space.
The angular momentum of a quasar can change as it is affected by the movement of the mass surrounding it. It does make sense that the jet is created by the magnetic field generated by its spin, as particles which fall into the center have nowhere else to go but orthogonally. It's like spinning a top on an uneven surface where the angle of the surface is the relative spin of the surrounding universe and the orientation of the top is that of the jet.
Is it possible to narrow down the list of possible causes for the change in orientation by looking for evidence (or the lack thereof) of some of the predicted possibilities? For example are we able to observe and measure enough properties of the galaxy and it's supercluster to model for the possibility and properties of a past merger? What about comparing what we see (light) vs what we observe about the effects the sub-lightspeed matter has on its surroundings -- I assume that since matter travels slower than light observing that matter's effect on its local spacetime might be a way to 'look back in time'.
Yes. The paper involved looked at other possibilities (Two galaxies, twin black holes ina single galaxy and so on) and ruled them out. Further research should be able to improve our understanding and narrow down the possibilities further.
Our own planet has a magnetic flip too. In fact there's a researched phenomenon with spinning ball magnets where the flipping of the north and south poles of the magnet is shown. Although on smaller scales the ball itself will flip, whereas the magnetic center of the earth is what would flip for us.
Question, when discussing the relativistic jets from a blazar you referenced the Special Theory of Relativity. Why the Special Theory and not the General Theory?
@Nad Senoj The special theory uses a cosmological constant because at first Einstein couldn't account properly for gravity, which he eventually did in 1915, giving us the general theory. I'm just wondering if there's a reason for using the special theory as it's an older, less accurate theory beyond "the maths is easier" (which would be a totally understandable point).
How did the team rule out the trivial case that PBC J2333.9-2343 is simply two different quasars that just happened to line up along our line of sight?
Through a few lines of investigation. Firstly it would be very lucky for one quasar to have died down around the time another started (Since we don't see two sets of jets.) Secondly they two objects would tend to have different redshifts, which we don't see. Thirdly we'd expect two galaxies, which also weren't seen, or blocking of one quasar's light by the closer object, which we don't see. (And we have indeed found a number of double quasars in distant galaxies, so we know what those look like.)
First of all, I love how you didn’t go with the easy click bait title of “did aliens just point a death weapon at us!?” Secondly, could the jets themselves (if not perfectly symmetrical) turn the black hole?
So let me know if I'm getting these terms wrong. A *galactic nucleus* is the dense center of a galaxy, which we believe usually hosts a supermassive black hole. An *active galactic nucleus (AGN)* is a galactic nucleus with a supermassive black hole that is accreting matter (or was when the light we observe was emitted), producing relativistic jets perpendicular to the accretion disk. A *radio galaxy* is a galaxy with an AGN that is not pointed toward the Earth. Its jets heat up the gas in the galaxy, which expands to great plumes and radiates in the radio spectrum. A *quasar* is a radio galaxy (or the AGN therein) whose jet is pointed generally toward the Earth, making most of the galaxy unobservable next to the brilliant AGN and appearing as a bright pointlike source. A *blazar* is a quasar which is either of extreme intensity or whose jet is pointed so close to the Earth that it appears to be of extreme intensity due to relativistic beaming, essentially just a really bright quasar.
Pretty much all correct. The terms are more general though. For example, a *radio galaxy* is just a galaxy that produces a strong radio signal in and around itself, the term doesn't define HOW it does so. A lot of these terms were created before we knew the mechanisms involved.
So, we meet up at 5 pm Eastern Standard Time for the Q&A show... I assume this is a typo, and was meant to be 5 pm Eastern DAYLIGHT Time? Or were we meant to calculate what the EDT equivalent would be, thus showing up at 6 pm EDT? Perhaps going forward PBS Spacetime might use UTC instead, noting that their listeners come from all possible time zones, some of which do not use Daylight Wrecking Time.
"Absolutely not and there is no danger whatsoever" is exactly what you would say if you were recently replaced by an alien from an intergalactic civilization which recently took notice of us humans.
👀 I would like to be amongst the first to welcome our new alien overseers. 👽🤖👾
and all other directions in "randomly" rotated to are targets as well
Now now, he may not be replaced. He could be an Adventists. (three body problem novel)
@@_PatrickO love that book.
Changelings among us.
I recently had a women in physics lecture meet (I'm in high school) and the professor speaking was Prof. Rachel Webster and she brought up this video and encouraged us to have a look at your channel. I was really excited because I binged watched this channel the day before the lecture and I felt so proud as I had already seen this and understood what she was saying.
Hearing scientists be giddy about their work is great. Hearing a scientist _communicate effectively_ about something that makes them giddy? That's a treat.
That is great if you understand effectively. Me, i need someone like Degrasse Tyson to dumb it down. I love listening to Matt nonetheless.
I think we can assume that in this case, it's not a 'them', but a 'he'.
That was a context independent statement, though. The commenter isn't talking about Matt specifically.
@@scientificaly_restful_one Precisely, thank you. It's more of a writing habit by now.
@@Tom_Quixote It takes balls to assume anyone is a "he" these days, i admire your bravery.
Love that you guys always immediately dispel any hint of conspiracy theories. ITS NEVER ALIENS is one of my favourite things to say to people who believe unsubstantiated sophistry. You're a legend Matt and you've taught me and millions of others how amazing the universe and our place in it really is. Shout out to the PBS Space Time team as well. x
I swear, every time Matt ends the episode with "SpaceTime" he has the most smug smirk like "Yeah, I did it again. Yeah, I tied it back to the episode. No one can stop me"
LOL! By now he has conservation of momentum on his side! I'm not sure that even a black hole merger would provide enough energy to alter his delivery!
You can tell Matt is really into narrating this video in terms of his involvement in the field. Love to see it
It always blows my mind when we talk about these cosmological events in the present tense, when in reality We are observing something that happened hundreds of millions of years ago or even longer. Life is so short, and should we not be so grateful to occupy this very special moment in time, when the universe can both observe and be in awe of itself.
@bendy Bruce exactly!
@@justryingmybest kirby!!
beautiful
@@jesstar119 A couple of years ago I started going blind and since then I have been reinventing myself as a visually impaired writer. So that actually means a lot, thanks.
The things black holes do with their angular momenta -- being one of the only three measurable properties black holes are thought to have -- break my mind. When two of them collide, the models I've seen show their angular momentum vectors just... _suddenly combine_ into a new one in an instant called a kick, as though it were one gigantic quantum object. I can't imagine something physically doing that, let alone something made of billions of solar masses.
wow. i’ve never thought about it like that…
DEFINITELY an OMG moment and I think I only comprehend the tiny tip of it🤔
More things might happen after vectors converge. Its just that, for all practical intends and purposes, it doesnt happen in our universe. Models dont show what happens behind that newly established event horizon. We know nothing.
I wonder what happens if their axes are completely aligned and they are already rotating near light speed, where do they shed all that excess momentum?
@@Szgerle What does it mean to rotate at near light speed? Speed equals distance over time. Rotation doesn't really involve distance.
Then again, if you imagine a particle spiralling towards an enormous, point-like mass, at a certain distance it may well be orbiting at the speed of light. And if it moves further in, gaining kinetic energy (?), how can it possibly go any faster?
I struggle to imagine black hole singularities as point-like at all. I can't help clinging to the idea that there's a tiny-but-extensive maelstrom at the centre where everything is in orbit of the centre of mass, perhaps reduced entirely to photons.
Channels like this are where I go to stay sane in a sea of insanity. I can't stand the media when they get ahold of things like this.
I guess I've been watching and learning from this show for long enough that the two proposed answers here were exactly what I expected. Feels pretty good :)
Dang! It's never an intergalactic death ray!
You'll never see it coming.
Well. Until it is. As always.
If that doesn't qualify as a "death ray" I really don't want to see something that could lol. Thankfully we are out of even it's mind blowing effective range.
I'm actually happy about that.
BFG11000
Love how accessible this channel has been all these years !
But I think you forgot to add captions (not auto captions)
A few of us really need captions
Were already added! ❤
Amazing video as always, but while I know how passionate you obviously are (along with the entire team of course), I really enjoyed you bluntly saying it! Very pleasant.
I really love this channel! It's one of the only ones I get excited about when the new one comes out
This show has changed my life for the better thank you all.
Ikr
6:16 Whenever I will have trouble figuring out what to name my future pets I will remind myself of astronomers, the masters of memorable names that just rolls of the tongue beautifully
I just have to add that the visuals for this video was breathtaking. Felicitations to the video editors. Also, Matt’s enthusiasm is contagious! Loved it.
I always wondered what the tools and processes used to make these visualisations look like.
I dream of a video game co-designed by the Space Time & Outer Wilds teams; I'd love to get to solve puzzles with quasars
well that explains it! at first i was wondering if i was just hearing things... but after you mentioned you'd just gotten back from down under it's clear you've brought your aussie back, and laying it on thicker than ever! rawrr love it!
My first thought was it might be the Dzhanibekov effect (Intermediate Axis Theorem) in action at an absurd scale. That's usually a 180 degree flip but it's not instantaneous so it'll trace out an arc, possibly over a fairly long timeperiod. It'd require a very eccentric accretion disk, I should think. Seems unlikely.
That was my thought as well. Had to look up the name... I just remember the spinning wingnut.
You are not alone with this line of thought.
Would be kind of scary if true, it would point to 3d rotating objects (such as earth) doing the same. The Russians discovered this effect and it was reportedly hidden for years for fear of causing panic. So far no evidence of such happening on the planetary scale however
@@justryingmybest Only if it's a fairly normal black hole and accretion disk. It's unclear if something with a very small differences in mass distribution between two would be able to flip, even given enough time. It is the result of a sort of harmonic reinforcement so it's not impossible in a simplified/idealized setup but you'd think, below a certain scale, the energy would just dissipate as heat rather than accumulating.
I was wondering this, too. Glad to see someone bring it up with a (by the looks of it) better familiarity with the topic than I!
Not a native speaker of English here, I love the way you pronounce and you are one of my models to imitate. Where are you from?
For once, I was able to understand everything from start to finish in a PBS Spacetime video.
Not a good sign if you ask me
@@maxmusterman3371 why’s that? It would mean he has successfully comprehended prior learnings?
They like to mix it up
Which makes me sad
Try the earlier ones from the very beginning. A lot more layman-friendly than the stuff they been cranking out these past few years.
Excellent video as always! In the thanks to the patreon at minute 13 you say Req, but you wrote Ian Jones
Hi, just love your content, please could you share your views on Dr. Unzicker's approach, in relation to variable speed of light.
I like the "New Laboratory" conclusion.
Terrific video as usual. I have a tech question/note - the audio for this and the last vid is strangely dulled, and makes it look like you are lip-syncing; could it be too heavily de-noised? No actual worries, just confused.
Agreed. There is usually more sound effects/music in the background
I'm glad I'm not the only one. It sounds like ADR.
When you said you have a tech question, i thought you are about to ask about some doubts in videos.
But it turns out to be this.
😮
@@Griffin_xDragon ha I never doubt Matt O'Dowd! :D
@@DThron of course, no one can doubt him.
15:01 I'm so glad that your doing a live event Monday!
Quasars are cool and all but there is nothing like a good old supernova💥
Hey.... nice vídeo.!!!
I really like this channel and I would support this kind of content: explanation of recent discoveries! Tks!!! Keep on!
Most of the images of such jets that I've seen suggest that the black holes' spins are wobbling dramatically, so I would think that this is more the norm than the exception.
kudos on 10:58; that's impressive whoever made that - Takayukison
For the purposes of rotation, do you treat a black hole as a point mass or spread it out over it's Schwarzschild radius? Seems like it'd have to be non-zero radius and moment of inertia or it'd be absurdly easy to alter its rotation.
@@volbla Ah, that's a good thought. I knew that if black holes spin fast enough they could end up with an oblate, toroidal or even no event horizon but considering the singularity as going from a point to a ring that grows with any rotation suggests that the faster it spins, the harder it is to spin faster. A little different than the dynamics of a solid body.
The answer is a bit of both and even more.
From our point of view (outside the black hole) the matter never falls through the event horizon, so all the causal effects it creates (EM radiation or gravity) come from the event horizon, the "surface" of the black hole.
However, the matter moving towards the event horizon is not the only part of its mass. From our point of view there was matter that was already in that place where the hole now is (i hope what i said is comprehensible). But the black hole behaves like a literal hole, not a massive object. In the rubber sheet analogy it would be a hole in the sheet, not just a funnel from a massive ball.
And if you try to model the insides of the hole (that cannot causally affect what's outside), they would look like a massive singularity in the center and a lot of matter moving FTL towards it. The singularity itself would be a point in a non-rotating black hole and a ring in a rotating one. The slower the rotation is the more it looks like a point.
@@evgenijdenisov I'd argue against it being a hole... and possibly not even a singularity. Things go imaginary at the event horizon but if you rotate the interior so the time axes make sense, the inside looks pretty much like the outside, an expanding universe with the event horizon as a sort of white hole in the past. I hadn't considered the spinning variant but it should look pretty similar. I'd expect a subtle quadrupole signature in its CMB, though. Not entirely unlike what we see in ours.
@@protocol6 yes. But if you try to map this picture to a sphere, it would look like a singularity in the center. It makes me wonder: what if our inevitable future/singularity is a ring, not a point?
Another fine piece by PBS Space Time. 👏👏
Thank you so much for referring to a black hole as ‘accreting’ matter, not ‘eating’ or ‘devouring’ or any other anthropomorphic nonsense. Also, don’t look up.🖖🏼
I think he said accreting to imply that the matter went into the accretion disk and not necessarily the black hole. But what's the problem with 'eating', or 'devouring'? What about 'consuming', 'assimilating', 'absorbing', or 'gaining'? And when it comes to outputs from the system what words can we use to describe the jets and light? Can we say the black hole is 'emitting', 'spewing', 'shooting', 'launching', 'distributing', or 'vomiting' out matter? What if the words used to describe incoming matter and outgoing energy are both personified? Can we say that the black hole gobbles everything up while the jets are now ejaculating particles in our direction?
Thank so you much for your great work ! Will it be possible to do a video about the Kaluza-Klein theory ? To explain how gravity and electromagnetism are viewed to be able to be bind, what are the implications, etc. Thank you again, stay strong !
Could it be possible that there are actually 2 galaxies overlapping from our perspective, where each is oriented differently so that it looks like 1 galaxy that has changed direction?
Good question. I don't think so. The distance is only 100k light years. The precision is comparable to a galaxy size. In other words, in order to overlap from our perspective the galaxies must actually overlap. It is a pretty rare possibility, and i believe the authors checked it.
I think you would see double spectrum peaks from different cosmological redshift
@@alep1010 agreed, there would be evidence of the overlap. More evidence required!
I would think that you'd be able to see the galaxy behind it via gravitational lensing.
@@johng6436 the gravi-lensing could be only noticeable without an acretion disc.
Matt, I realise you may come back Down Unda on holiday, but PBS should consider doing a live show in Melbourne next year! ~ Ryan, Warburton VIC
wow... imagine the amount of energy and torque necessary to rotate an object of that scale, already possessing massive angular momentum
Slow and steady wins the race. Even galactic core Black Holes only make up a fraction of the mass of the host galaxy.
@@Mernom And a very small fraction at that.
Particle in the accretion disk: "Oh noooooo!"
Particle in the radio jet: "Whew! That was close!"
A Blazar video on 420? Well played Space Time :)
Stellar presentation on the update and the larger significance alike =)
Was there a change in microphone? Not sure if the normal mic wasnt at hand or if this was intended, but I think the old sound was ALOT better. This sounds very unnatural and even the quality itself seems to be worse. This is only technical feedback, but I think the old, more natural sound was alot more connecting, I dont like this "bass sound right into my ear" thing. But maybe thats just me.
Completely agree the sound is unsettling to my ears.
So if you want to send a smoke signal across space we need a friendly compliant black hole. The inverse square law tells us that a puny human made radio signal transmission will by undetectable before it even leaves our solar systems influence
Audio is a little . . . . strange on this video.
*We are now in Daylight Savings Time. 5PM EST is 6PM Eastern Daylight Time. So which is it?*
Great content as ever! I'd love to see an episode on M theory and the Ekpyrotic universe sooner or later!
Wow! Any Ferengi would be proud of those lobes!
just fyi for the editor, when matt was shouting out REQ for being a big bang patreon contributor, Ian jones was shown on screen instead. Hopefully this gets fixed soon.
May be, REQ is Ian's nickname.
@@evgenijdenisov 🤔 true, didnt think of that
Big fan of the channel and content, thanks for sharing... If you don't mind a constructive criticism. Lately I see that your videos are getting darker and darker that I have to use the highest brightness level on my phone/laptop. I hope you can fix it for future videos. Thanks for the video, a learn a lot here :)
maybe your backlights burning out. brightness hasn't changed for me watching on a monitor.
I hope you feel better soon, Matt. O7
That’s the same veritasium thumbnail but flipped for his “the universe is hostile to computers” video.
Is it possible for the magnetic flux lines around the AGN to get tangled and reconnect causing a huge burst of energy similar to how CMEs are formed? This direction would not have to be in the same direction as the jets.
Sounds interesting!
6:15 Naming a galaxy: *scientist bangs head on keyboard*. Great video as always! Awesome channel.
Matt's voice is pitched up and he's moving too quickly. Did the editors speed the video up by a few percent? It's weird...
Nah he's just excited
He's just REALLY happy about blazars LOL (6:20)
I was wondering if he's nursing a cold.
Set playback speed to .75x 🤣 you're welcome
Good theory and I am thinking it might be testable. If a galactic merger was large enough to change the spin direction of the black hole, wouldn't it also change the location of the black hole and thus the new black hole location (as indicated by the blazar jet) would no longer be located at the midpoint of the line between the two radio lobes?
The audio of Matt over the last few videos sounds very muffled.
Maybe this question is dumb, but how are these supermassive black holes formed? Do supermassive stars(suns) used to exist and dye to become this massive objects or what?
Questions for Monday:
1) What happens if a gravitational wave with a wavelength greater than the size of the black hole passes through a black hole? Will it go through ("bends around")?
2) Is the interference of a gravitational wave possible with the help of a multiple system of black holes (analogous to slits), which shield the wave?
3) Is the interference of gravitational waves able to give rise to a black hole at the interference maximum? If so, what orders of energy of grav.waves are we talking about?
Sincerely,
Eugene
Excellent questions
1. From my understanding, a gravitational wave (just like a light wave) would bend towards the black hole, and if close enough, "fall in." Of course, relativity says gravity is just the curvature of space, so the curvature of space bending just means more intense gravity, which brings me to:
3: Yes! It's called a Kugelblitz black hole. Theoretically, enough gravitational lensing could focus energy such as light, similar to a magnifying glass, focusing said energy to the extent that it reaches its Schwarzschild radius, collapsing into a black hole. Gravitational waves carry energy too. Some collapsing stars have so much mass that the reach their Schwarzschild radius and form a black hole, but given e=mc2, energy == mass. A Kugelblitz black hole forms when said black hole forms entirely from focused energy/radiation as opposed to dense mass
What do you think about hypothesis of rydberg matter as an explaination for dark matter? Could you make a video on the subject?
12:34 That's what i usually think when looking up at the Moon and stars.
Some people look at the sky and see a limit, they see the blue sky almost as a physical barrier, even though just beyond that, there are actual physical cosmic objects.
It's amazing to look at the Moon, orbiting us, appearing small to us, but a person would easily get lost when taking a stroll on it.
Same for the Sun, it's not a 2D circle of light, neither are the other stars, or what we perceive as starlight but might actually be galaxies and quasars and whatnot.
For me what really brings the universe to life is videos like the pulsations of NGC 2261 or time lapse of stars orbiting Sagittarius A*
I never knew there was a reason for them not to change direction. I always though with the amount of material at any given time plus the speed that it would freely be able to turn.
In the abyss there appeared a single Eye that slowly grew, until it filled nearly all the Mirror. So terrible was it that Frodo stood rooted, unable to cry out or to withdraw his gaze. The Eye was rimmed with fire, but was itself glazed, yellow as a cat's, watchful and intent, and the black slit of its pupil opened on a pit, a window into nothing.
Then the Eye began to rove, searching this way and that...
2:23
I love how one of the most epic picture in the history of photography is named as "basic picture of Active Galactic Nucleus" :D
Does Matt have lisp now?
Maybe he went to a dentist right before shooting the episode, but ye that threw me off too.
Yeah the audio has been weird/different for the past three or four episodes. It sounds like he's got a lisp. I think the episode before this was "normal" but there is definitely something different about the way the audio is recorded and or worked with in post.
Always fascinating, thank you.
Possibly a silly question: Could it be this black hole is simply exhibiting precession? (There isn't a visible 'sweep' because these things aren't always active) Or even more boring we are looking at two AGN's oriented at roughly 90deg to each other, overlaid from our perspective?
We do see precession in some AGNs, the issue is that this change is so large and quick, it's a lot like asking if Uranus' current tilt is merely precession. The effect is too large.
For two AGNs we'd expect to see two galaxies and evidence of one obscuring the other. From what we can tell this is just a single object
Very nicely explained! This is such a wonderful channel!
Would have been nice to get other time zones for the comment response in the video.
24th apr:
CEST: 23:00
UK: 22:00
25th apr:
IST: 02:30
Aus: 07:00
Fascinating and very informative as always Matt!!! I wonder if the latest discoveries from Webb which seem to contradict a lot of modern cosmology might mean that the actual universe is far, far larger than the visible universe, as inflation theory suggests it could be, and that in an elephantine megaverse, supermassive black holes might indeed be the best possible candidate as the source for dark matter after all.
Dark matter exists _within_ the visible universe. It doesn't really matter how many supermassive black holes there are beyond the cosmic horizon.
Deadpan humor is one of the best kinds! Way to go.
Did they use AI to make the audio in this video?? Seriously am I the only one that notices this change? It’s all I can hear lol
I know "Thank you" doesnt pay the bills, however, I offer it irrigardless. Thank you.
Audio is strange in this one or Matt has a head cold.
How about this variation on Option 2: there are two black holes in the AGN (say, from a galactic merger, but not having merged themselves yet), one producing the radio lobes and one producing the blazar? How would we be able to detect such a situation?
It would be difficult, but the big issue is that such a system isn't really stable. The two holes would tend towards merger, especially if both were surrounded by a large accretion disk allowing them to emit such strong signals.
@@garethdean6382 , yes, it would be a temporary situation lasting perhaps 100 million years, which is typical for the merger of black holes after a galactic collision, but that seems plenty of time for observations.
Could it instead be two galaxies that are just along the same line of sight, one in front of the other, and are close enough that we don't have enough precision to notice the distance difference from so far away?
The galaxy is actually reasonably close to us on a universal scale, only 600 million odd light years. This has allowed the team observing it to be quite sure there's not another galaxy lined up. It would also be long odds that their two AGNs just so happened to flip activity at the time they crossed paths and didn't leave us with two sets of jets visible.
I understand nothing. But I feel clever by watching this channel.
Couldn't a simpler explanation be that there are two objects, not merged? If two objects merge, the resulting spin would be different from both objects, and it could look like the direction changes twice, or there were three different sources.
He covered that, with the suggestion that two AGN's from two merging galaxies can merge changing the orientation.
The problem is that a merging system tends not to be stable if it's so compact that it appears as one. We've seen a lot of double quasars in merging galaxies so we know what to look for there and what they tend to be.
I love your videos so much i learn so much about space time and causality
4/20 blazar it
Underrated comment
I love the cop out at the end. "Because we've skipped so many question/answers, we're going to do just this one more before we pay it all off next Monday...."
Hey quick question! Quarks and Gluons are normally confined (Color Confinement) but in the extreme conditions within certain stars they can exist free in a state known as a "Quark-Gluon Plasma" and At the extreme energies within a "Quark-Gluon Plasma", Gluons are able to collide and produce Strange Quarks, so does this confirm that stars composed of Strange Quarks exist? Fun fact about Quark-Gluon Plasma, it exists as an almost perfect Fermi Liquid or "superfluid" and possesses the lowest resistance to flow (Viscosity) of any known substance.
Ok, so the Hagedorn temperature temperature is around 1.7×10^12 K, whereas silicon fusion happens at 2.7-3.5 billion kelvin, about a thousand times cooler. And that's one of the most energetic processes in stars. What stars are reaching the point where they can form quark-gluon plasma? Do you have a link to something? Because as far as I can tell that's just not something that's happening. Are you talking about neutron stars? Supernovae?
@@garethdean6382 within neutron stars.
Giddy Matt still keeps very close to his normal, excellent pace and tone. Impressive! :)
Are black holes' poles static, or do they wobble?
"...and collaborators"
Ah, the kindest et al I've ever heard. ;)
I volunteered for a bit at ICRAR who work on the Australia square kilometre radio telescope. Very very good bunch of people
Awesome job on this vid, keep making more
Hey, I never really thought about this, but does Gravity cause synchrotron radiation on charged particles too? My thoughts: 1) Yes because the particle is accelerated perpendicular to it's velocity. 2) No, because the particle flies in a straight line and but space itself is curved.
It shouldn't; such radiation is emitted when particles are *accelerated* and an object in orbit is in freefall. As you state, it's moving in a straight line in curved space.
Great Video! and now we also have BH that are even expelled away from their own Galaxy (i guess during a Merge with an other Galaxy)
The angular momentum of a quasar can change as it is affected by the movement of the mass surrounding it.
It does make sense that the jet is created by the magnetic field generated by its spin, as particles which fall into the center have nowhere else to go but orthogonally.
It's like spinning a top on an uneven surface where the angle of the surface is the relative spin of the surrounding universe and the orientation of the top is that of the jet.
I felt this video was quite personal one for you, glad to see it.
Is it possible to narrow down the list of possible causes for the change in orientation by looking for evidence (or the lack thereof) of some of the predicted possibilities? For example are we able to observe and measure enough properties of the galaxy and it's supercluster to model for the possibility and properties of a past merger? What about comparing what we see (light) vs what we observe about the effects the sub-lightspeed matter has on its surroundings -- I assume that since matter travels slower than light observing that matter's effect on its local spacetime might be a way to 'look back in time'.
Yes. The paper involved looked at other possibilities (Two galaxies, twin black holes ina single galaxy and so on) and ruled them out. Further research should be able to improve our understanding and narrow down the possibilities further.
Our own planet has a magnetic flip too. In fact there's a researched phenomenon with spinning ball magnets where the flipping of the north and south poles of the magnet is shown. Although on smaller scales the ball itself will flip, whereas the magnetic center of the earth is what would flip for us.
Would love a video on relativistic beaming!
Question, when discussing the relativistic jets from a blazar you referenced the Special Theory of Relativity. Why the Special Theory and not the General Theory?
@Nad Senoj The special theory uses a cosmological constant because at first Einstein couldn't account properly for gravity, which he eventually did in 1915, giving us the general theory. I'm just wondering if there's a reason for using the special theory as it's an older, less accurate theory beyond "the maths is easier" (which would be a totally understandable point).
Love your show, guys!
How did the team rule out the trivial case that PBC J2333.9-2343 is simply two different quasars that just happened to line up along our line of sight?
Through a few lines of investigation. Firstly it would be very lucky for one quasar to have died down around the time another started (Since we don't see two sets of jets.) Secondly they two objects would tend to have different redshifts, which we don't see. Thirdly we'd expect two galaxies, which also weren't seen, or blocking of one quasar's light by the closer object, which we don't see. (And we have indeed found a number of double quasars in distant galaxies, so we know what those look like.)
First of all, I love how you didn’t go with the easy click bait title of “did aliens just point a death weapon at us!?”
Secondly, could the jets themselves (if not perfectly symmetrical) turn the black hole?
Great , video , well explained , thank you , Farhad ( Fred)
Thank you for sharing this that was very interesting and fascinating. Great video.
Well so much for the Voyager discs using pulsars to give our position.
So let me know if I'm getting these terms wrong.
A *galactic nucleus* is the dense center of a galaxy, which we believe usually hosts a supermassive black hole.
An *active galactic nucleus (AGN)* is a galactic nucleus with a supermassive black hole that is accreting matter (or was when the light we observe was emitted), producing relativistic jets perpendicular to the accretion disk.
A *radio galaxy* is a galaxy with an AGN that is not pointed toward the Earth. Its jets heat up the gas in the galaxy, which expands to great plumes and radiates in the radio spectrum.
A *quasar* is a radio galaxy (or the AGN therein) whose jet is pointed generally toward the Earth, making most of the galaxy unobservable next to the brilliant AGN and appearing as a bright pointlike source.
A *blazar* is a quasar which is either of extreme intensity or whose jet is pointed so close to the Earth that it appears to be of extreme intensity due to relativistic beaming, essentially just a really bright quasar.
Pretty much all correct. The terms are more general though. For example, a *radio galaxy* is just a galaxy that produces a strong radio signal in and around itself, the term doesn't define HOW it does so. A lot of these terms were created before we knew the mechanisms involved.
So, we meet up at 5 pm Eastern Standard Time for the Q&A show... I assume this is a typo, and was meant to be 5 pm Eastern DAYLIGHT Time? Or were we meant to calculate what the EDT equivalent would be, thus showing up at 6 pm EDT?
Perhaps going forward PBS Spacetime might use UTC instead, noting that their listeners come from all possible time zones, some of which do not use Daylight Wrecking Time.