It's just an explanation physicists came up with, but it doesn't make any sense. For gases you need temperature (energy) so molecules bump into each other, without that, electrical forces are short distance and wouldn't account for it.
Buoyancy is a law-of-averages thing: (cartoonish description follows) for every 1,000,000 particles that are flying generally in the "down" direction, there are 1,000,001 particles moving up ... so there's a net force of one particle collision "up" The difference between a bubble in the ocean and a bubble in the interstellar medium is a matter of scale in space and time
@@seb7391 Why doesn't it make sense? The fast moving gas in the buoyant 'bubbles' is hotter and less dense than the surrounding material and so there is obviously pressure between them, so you have both your temperature (energy) and 'bumping'.
TIL: There is buoyancy and wind on intergalactic scales. Mind blown. The distances they are talking about are million times larger than the size of out solar system, which is already mind boggling large.
The magnetic field spewing out electron jets is very interesting from the point of view of super conducting currents contributing as a motor action spinning the BH almost at the speed of light.
Why don't the jets just mix with the gas & then form a single mixture that is uniform? The buoyancy only comes into effect because it's not mixing, right?
Maybe a silly question....If something is moving directly towards you or directly away, you'll see a standard doppler shift.....If it's moving sideways, you'll see a lateral doppler shift, because of relativity. it might be hard to tell them apart, but I'd expect lateral shift was considered.
"Who discovered it?" "What?" "Oh, so Watt discovered it." "No; he didn't discover WAT." "What?" "Yes." "So Who did?" "No; he didn't either." "Who didn't?" "No." You know, you'd think someone could write a sketch about this stuff.. 😁
I have 2 physics questions that have been bugging me for a few days, and google has been totally unhelpful with any resources on them, so i really have no idea where else to ask this as a layman, and i would really like to know if physicists have an answer to these yet. 1)how long does the actual process of chemical bonding take? 2)how far away from an electron, does a traveling photon have to be, in order to excite the electron to a higher orbital? i will probably need to elaborate, being a layman, to make sure my questions are clear. 1)here i'm not talking about the rate at which some arbitrary volume of molecules react, but rather once the atoms or molecules have already gotten close enough to bond and share their electrons, how long does it take to "transform" or to "snap" into this new molecule? is it instantaneous like you would see in most instructional videos? or does it take some very small, but real, amount of actual time for the process to happen? 2)considering that photons are very wave-like, and that their position is uncertain....a single photon that's traveling towards an atom that can absorb it, has to have a specific point in time at which it excites the electron to a higher orbital. in other words, intuitively, the atom gets excited from one energy state to another at a very particular moment in time. (and will later emit a photon at another exact point in time.) as the electron has to be in either of the orbitals at any given moment. but considering that the photons are "wavy" you could imagine the process of atoms getting excited, to be more of a gradual process over time, as the wave-front should hypothetically hit the electron before the rest of the wave does. as well as when the photon is re-emitted, since it's a wave with a certain length to it, you wouldn't expect the photon to "come out all at once", but rather that the process of changing from an excited state to the ground state (as well as the other way around) would take some amount of time. for example, that it should take an amount of time roughly equivalent to the wavelength divided by the speed of light. (based on the formula of speed = distance\time)
It's no different from hot air rising in our atmosphere. Hot air is less dense, it eventually mixes with the cooler air, but the bulk of it keeps rising.
I think its a problem of scale. These emissions are several times larger than the galaxy, so it takes a very long time for it to equilibrate via diffusion
This is facinating, but my tiny mind can't grasp how the jets know which way is "up" when talking about the buoyancy effect. I think at 3:40 Mike explains it but I've replayed it a few times and I can't wrap my head around it. If the primary cause of the jets bending is the ram pressure through a cluster, does the buoyancy force have a centroid that is the COG of the cluster and the jets "float" away from that point? Piling missunderstanding on top of missunderstanding, but could the difference between a NAT and a WAT be partly explained by how far through the custer the Galaxy is? Ram pressure will always bend the jets away from the direction of motion, but the buoyancy force would either work against the ram pressure or with it depending where the Galaxy is in relation to the COG of the cluster?
How does one know the difference between NATs and WATs is not simply the perspective from which we observe the jets? Couldn’t a U-shaped WAT viewed nearly edge-on be seen as a V-shaped NAT? Is the Doppler shift of material from the outflowing jets used to eliminate this ambiguity?
The picture on the lefthand side looks like a Kármán vortex street to me. Maybe I am imagining stuff.. There are these bulges (eddies) forming, which grow in size and eventually "rip" or "tear" off. Probably talking out of my behind... anyways - cool video and visualization of the described effect :)
"Gravity works the other way..." You have no idea how many pointless discussions I've heard about whether warmer (more buoyant) gas rises or whether cooler (less buoyant) gas sinks. Thanks for the trigger, gentlemen. 😁
Wow! I have been wondering about bent jets for years. I knew about "Jellyfish Galaxies", moving at speeds like 7Gm/h, leaving trails of stripped gas which form orphan stars in their wake. I never thought about what happens if such a galaxy has jets. This explains a lot. However, some look like the jets are bent in opposite directions, as if the source was changing rotational axis direction, and I would expect inertia would resist such in the case of an object as massive as a black hole. Still a bit puzzled.
Interesting still not a place you would want to be with all the radiation my first guess was that there might be another galaxy's magnetic fields diverting them but I guess that wouldn't produce this shape as the field lines would be more complicated? AI do wonder how this was ruled out since the tenuous plasma could in principal support a magnetic field.
isn't it possible to derive the jet speed from the properties of the radio emissions? from my naive understanding, its frequency directly depends on the velocity
@@Stephan-wf1ec I'm sure they have (For example like Type-II radio bursts, when a CME plunges through the suns corona) . I would like to know why this is not applicable in this case.
wait, I thought stuff floated in water when it's less dense because of the pressure of the water being greater than the weight of the object, rather than the water above the object pulling the object by the force of gravity? I mean, obviously gravity acts between all objects with mass, but surely the upthrust of the water on the object as a result of pressure is far greater in this circumstance in comparison to the minute gravitational pull of a body of water?
Gravity directly is only pulling down. But, gravity is still the driving force behind buoyancy, by pulling down the other denser stuff (water), which then pushed up the floating object.
I have a question: since we know only the line-of-sight velocity of galaxies (as mentioned in this video), how can we be so sure that Andromeda is on a collision course with our own galaxy? Maybe it's moving sideways. Or is it so close that we can actually tell somehow?
Is this where Elton John got his idea for his song "Bentie and the Jets"? I love blasting that song with a full use of all the "wats" of my system. (sorry...)
But what are these galaxies moving into that it's creating "drag". Shouldn't, even a relativistic jet, perpendicular to galaxy motion, move with the galaxy?
Why aren't all jets from galaxies bent? I don't see how you could have straight-line jets with all the other forces from moving through space and buoyancy.
You're talking about buoyancy of a strong vacuum over a not-quite-as-strong vacuum? The pressure must be teeny-tiny. Does this really create an observable effect?
If you know how big the jet is, and what speed the jet is.. you can figure out how long it's been jetting. (1000 (kilometers per second)) * 1 million years = 3 335.64095 light years (google search)
The jet is 5000 light years long, but M87 is itself 240,000 (240 thousand) light years across, so the entirety of the jet is still within the galaxy. If I'm understanding Prof. Merrifield correctly, the jet would only bend once it exited the galaxy and collided with the intergalactic medium.
Why are "other explanations needed"? You are looking at images of the galactic core of Messier 87 as seen by the Hubble Space Telescope with its blue plasma jet clearly visible. The jet is actually much longer than you suggest with the strongest component being 5,000 light years. However the HST images do not show that this jet is of tiny extent compared to the spherical galaxy which has a radius of perhaps 500,000 light years! Obviously this jet is reacting only to local conditions as it's confined to the galactic envelope. IF the jet extends outside M87 it is too weak for us to observe with current instruments.
@@nightjarflying There are jets that loop-back on themselves, and even merge with the underside, forming a "D" shape. Magnetic fields and merging bodies (or similar) are candidate explanations. RAM induction seems short there.
Bouyancy is about pressures and gravity. Dark matter would not, I think, have any effect on the relative pressures of the two media (and would likely be at the same level anyways), but any gravity effects by the dark matter would, of course, be felt.
Halton Arp was simply wrong in all his major ideas/objections re red shift. He was working with a tiny data set & he never revised his opinions even though later, much more precise & voluminous astronomical data pointed away from his theories. Arp has no value, but he's still highly regarded among the cranks with an agenda e.g. Electric Universe proponents & also religious fundamentalists [usually creationists] who are looking for 'gaps' to exploit in astronomy & evolution. He's old, cold news.
"Motion of a galaxy" is a weird concept, to me. Is it the galaxy of the gas cloud that's moving? When talking about galaxies, there aren't that many obvious things to use as a reference for relative motion.
Since pressure comes from particles interaction electromechanically and dark matter does not interact electromechanically, I think that dark matter would not exert a pressure
It's incredible how buoyancy can still affect objects as diffuse and massive as this.
It's just an explanation physicists came up with, but it doesn't make any sense. For gases you need temperature (energy) so molecules bump into each other, without that, electrical forces are short distance and wouldn't account for it.
Buoyancy is a law-of-averages thing: (cartoonish description follows) for every 1,000,000 particles that are flying generally in the "down" direction, there are 1,000,001 particles moving up ... so there's a net force of one particle collision "up"
The difference between a bubble in the ocean and a bubble in the interstellar medium is a matter of scale in space and time
@@seb7391 could you both elaborate and give a more specific example of this principle playing out somewhere not in the earth's atmosphere?
@@seb7391 Why doesn't it make sense? The fast moving gas in the buoyant 'bubbles' is hotter and less dense than the surrounding material and so there is obviously pressure between them, so you have both your temperature (energy) and 'bumping'.
You know Brady’s mind blown when he sits quietly.
I found the floating explanation quite mind bending itself. Floating in the intergalactic medium.
I found his look of confused interest quite reassuring at that point. I might need to re-watch a couple of times before I fully get the concept.
He has a hat on, to not get his mind completely blown away! :)
Best professors
Best questions from the host
This channel is a treasure
I love how Brady’s final question to every video is “what would happen if I was in a space suit”
He knows what his audience wants.
Final question: "So could you be in one of these tails and not realise?"
Answer: "Well yes, right up until definitely no."
Impossible not to read that in Prof Merrifield's voice
Prof Merrifield is easily my favorite guest on this channel
So we *shouldn't* try it? Well, that's my plans for the weekend screwed then.
Vaxd 4 nuttin'!
Brady's face at 3:40 perfectly matched mine at the same time.
Merrifield is my favourite astronomer.
8:36. Well, I'm gonna, Dr. Merrifield. And Brady's coming with me. Try to stop us.
"It's a WAT"
"It's a wizard, Harry"
if it's pluming into greater density, couldn't we see the equivalent of mach diamonds? what would we even call them?
Yes galactic jets do have knots of gas and it is thought they might be Mach diamonds, or something similar.
We need more from this channel. And I love this format.
TIL: There is buoyancy and wind on intergalactic scales. Mind blown. The distances they are talking about are million times larger than the size of out solar system, which is already mind boggling large.
Wow. Never thought buoyancy would play such a big role in galaxies
The magnetic field spewing out electron jets is very interesting from the point of view of super conducting currents contributing as a motor action spinning the BH almost at the speed of light.
Another Prof. Mike Merrifield video! Keep up the good work!!
Why don't the jets just mix with the gas & then form a single mixture that is uniform? The buoyancy only comes into effect because it's not mixing, right?
Maybe a silly question....If something is moving directly towards you or directly away, you'll see a standard doppler shift.....If it's moving sideways, you'll see a lateral doppler shift, because of relativity. it might be hard to tell them apart, but I'd expect lateral shift was considered.
Fantastic! thank you!
2:40 close to being a comet... but in galactic proportions?
My Astro physicist senses are tingling!!
It’s actually pretty interesting to see direct evidence of a galaxy moving through a medium of some sort (assuming that’s what is happening).
2:30 the medium is just the gasses that make up the cluster through which the galaxy is moving. he says so. its not anything special
What's the speed of sound of the intergalactic medium? I guess this would be relevant to figure out this weird buoyancy property.
"We're talking about WAT"
"We're talking about *what*?"
"Yes that's right, WAT"
"Who discovered it?"
"What?"
"Oh, so Watt discovered it."
"No; he didn't discover WAT."
"What?"
"Yes."
"So Who did?"
"No; he didn't either."
"Who didn't?"
"No."
You know, you'd think someone could write a sketch about this stuff.. 😁
Tremendous ❤️
I have 2 physics questions that have been bugging me for a few days, and google has been totally unhelpful with any resources on them, so i really have no idea where else to ask this as a layman, and i would really like to know if physicists have an answer to these yet.
1)how long does the actual process of chemical bonding take?
2)how far away from an electron, does a traveling photon have to be, in order to excite the electron to a higher orbital?
i will probably need to elaborate, being a layman, to make sure my questions are clear.
1)here i'm not talking about the rate at which some arbitrary volume of molecules react, but rather once the atoms or molecules have already gotten close enough to bond and share their electrons, how long does it take to "transform" or to "snap" into this new molecule? is it instantaneous like you would see in most instructional videos? or does it take some very small, but real, amount of actual time for the process to happen?
2)considering that photons are very wave-like, and that their position is uncertain....a single photon that's traveling towards an atom that can absorb it, has to have a specific point in time at which it excites the electron to a higher orbital. in other words, intuitively, the atom gets excited from one energy state to another at a very particular moment in time. (and will later emit a photon at another exact point in time.) as the electron has to be in either of the orbitals at any given moment.
but considering that the photons are "wavy" you could imagine the process of atoms getting excited, to be more of a gradual process over time, as the wave-front should hypothetically hit the electron before the rest of the wave does.
as well as when the photon is re-emitted, since it's a wave with a certain length to it, you wouldn't expect the photon to "come out all at once", but rather that the process of changing from an excited state to the ground state (as well as the other way around) would take some amount of time.
for example, that it should take an amount of time roughly equivalent to the wavelength divided by the speed of light. (based on the formula of speed = distance\time)
8:04
-... but now you've portrayed them as these incredibly diffuse... farts.
-Fart, I like this name.
1:17 Did he just casually did the hand-split? My tendons creaked just from looking at it!
Hahah, exactly. Hand-split. I've got flexible hands, but not thát flexible:)
Wonderful stuff.
How is it less dense? Wouldn't whatever is spewing out just mix with what is already there and increase its density?
That's exactly what I thought.
I guess you can think of it like a pocket of hot air rising in cold air. It can take a good while for these to mediums to actually mix.
It's no different from hot air rising in our atmosphere. Hot air is less dense, it eventually mixes with the cooler air, but the bulk of it keeps rising.
Layman here but you could use the same intuitive argument for oil and water
I think its a problem of scale. These emissions are several times larger than the galaxy, so it takes a very long time for it to equilibrate via diffusion
This is facinating, but my tiny mind can't grasp how the jets know which way is "up" when talking about the buoyancy effect. I think at 3:40 Mike explains it but I've replayed it a few times and I can't wrap my head around it. If the primary cause of the jets bending is the ram pressure through a cluster, does the buoyancy force have a centroid that is the COG of the cluster and the jets "float" away from that point?
Piling missunderstanding on top of missunderstanding, but could the difference between a NAT and a WAT be partly explained by how far through the custer the Galaxy is? Ram pressure will always bend the jets away from the direction of motion, but the buoyancy force would either work against the ram pressure or with it depending where the Galaxy is in relation to the COG of the cluster?
The answer to your first question seems to be that "up" means directly away from the center of gravity of the galaxy cluster.
We need an "anthology" / "highlight" video for this and Numberphile like there is for Periodic Videos!
these bent streams do look like they are hitting some fields.
but what are these particles spit by any black hole am wondering about?
It must be an intergalactic Elton John..."Bending of the Jets"...sorry I'll see myself out.
I thought 'Bending of the Jets' was an Elton John song....
Sixty symbols still as good as ever!
3000 km*s^-1 (or 1% the speed of light) is "not hugely fast." 7:39. I'm definitely using this when I get pulled over for driving 0.04 km*s^-1.
I imagine those environments would still be hazardous because of bremsstrahlung, but I haven't run the numbers!
Surprising. Thank you
Thank you!
Underrated video.
This seems to suggest that the source of the radio jets are co-orbiting other massive bodies which are not producing radio jets.
How does one know the difference between NATs and WATs is not simply the perspective from which we observe the jets? Couldn’t a U-shaped WAT viewed nearly edge-on be seen as a V-shaped NAT? Is the Doppler shift of material from the outflowing jets used to eliminate this ambiguity?
8:16 lol prof. That's funny.
That is sooo cool!!!🤩
Yeah truly awesome!
Awesome 👍
The picture on the lefthand side looks like a Kármán vortex street to me. Maybe I am imagining stuff..
There are these bulges (eddies) forming, which grow in size and eventually "rip" or "tear" off.
Probably talking out of my behind... anyways - cool video and visualization of the described effect :)
Professor got the airpods in, flexing on us lol
"Gravity works the other way..." You have no idea how many pointless discussions I've heard about whether warmer (more buoyant) gas rises or whether cooler (less buoyant) gas sinks. Thanks for the trigger, gentlemen. 😁
The answer is "yes", naturally.
Colder flows sink.
(Heat flows down gradients, high to low. Always.)
[Why is your eye twitching like that? ;) ]
Wow! I have been wondering about bent jets for years.
I knew about "Jellyfish Galaxies", moving at speeds like 7Gm/h, leaving trails of stripped gas which form orphan stars in their wake. I never thought about what happens if such a galaxy has jets. This explains a lot.
However, some look like the jets are bent in opposite directions, as if the source was changing rotational axis direction, and I would expect inertia would resist such in the case of an object as massive as a black hole.
Still a bit puzzled.
Now, that IS interesting.
Interesting still not a place you would want to be with all the radiation my first guess was that there might be another galaxy's magnetic fields diverting them but I guess that wouldn't produce this shape as the field lines would be more complicated? AI do wonder how this was ruled out since the tenuous plasma could in principal support a magnetic field.
3:30 - Everything floats out there.
1:17 I cannot make my hands that flat
isn't it possible to derive the jet speed from the properties of the radio emissions? from my naive understanding, its frequency directly depends on the velocity
I'm sure nobody has thought of that. Here's your Nobel prize.
@@Stephan-wf1ec I'm sure they have (For example like Type-II radio bursts, when a CME plunges through the suns corona) . I would like to know why this is not applicable in this case.
Make more videos pleaaaaaase . About James webb or the new black hole images
Perhaps the low pressure in the plume is a Dyson vacuum
The idea of a galaxy moving at 300 km/s is actually something I can relate to, but it's immense.
B-b-b-bending and the jets!
wait, I thought stuff floated in water when it's less dense because of the pressure of the water being greater than the weight of the object, rather than the water above the object pulling the object by the force of gravity? I mean, obviously gravity acts between all objects with mass, but surely the upthrust of the water on the object as a result of pressure is far greater in this circumstance in comparison to the minute gravitational pull of a body of water?
Gravity directly is only pulling down. But, gravity is still the driving force behind buoyancy, by pulling down the other denser stuff (water), which then pushed up the floating object.
its kinda like the chicken and the egg , does gravity cause the pressure or pressure cause the gravity
Very interesting.
I have a question: since we know only the line-of-sight velocity of galaxies (as mentioned in this video), how can we be so sure that Andromeda is on a collision course with our own galaxy? Maybe it's moving sideways. Or is it so close that we can actually tell somehow?
Hubble was used to plot stars in Andromeda against the background stars to determine its lateral motion.
@@anomalousresult Thank you! That's a fascinating insight.
Is this where Elton John got his idea for his song "Bentie and the Jets"? I love blasting that song with a full use of all the "wats" of my system. (sorry...)
I think if there is force like buoyancy in space that means there is some kind of matter in space otherwise how buoyancy works without any matter?
But what are these galaxies moving into that it's creating "drag". Shouldn't, even a relativistic jet, perpendicular to galaxy motion, move with the galaxy?
Could that "tossed out of the galaxy" stuff be related to dark matter?
No where near enough of it. There is about four times as much dark matter as there is normal matter.
Why aren't all jets from galaxies bent? I don't see how you could have straight-line jets with all the other forces from moving through space and buoyancy.
Ever seen three at once? You know, them Triple wide angle tail sources?
I'm Slowly becoming an astrophysicist with every episode
Super
@@sixtysymbols salty?
@@sixtysymbols - I hope there will still be more collabs with you and Dr. Becky. Thanks for sharing all of these!
Like a bird tweets to a NAT and duck quacks to WAT
You're talking about buoyancy of a strong vacuum over a not-quite-as-strong vacuum? The pressure must be teeny-tiny. Does this really create an observable effect?
The observable effect is in the images you saw, thus it is observable.
You have to remember this is over vast distances and over vast amounts of time, and it's all near vacuum.
WATS .... Alien Brady testing theory ?
It's unfortunate they didn't bring up TWATS.
Bending, bending, ... bending and jettss ... jettss...
If you know how big the jet is, and what speed the jet is.. you can figure out how long it's been jetting.
(1000 (kilometers per second)) * 1 million years =
3 335.64095 light years (google search)
M87 galaxy has a laser-straight astrophysical jet extending 5 Light Years. Are we to assume M87 is motionless? (Seems other explanations are needed).
The jet is 5000 light years long, but M87 is itself 240,000 (240 thousand) light years across, so the entirety of the jet is still within the galaxy. If I'm understanding Prof. Merrifield correctly, the jet would only bend once it exited the galaxy and collided with the intergalactic medium.
@@siarles The jets are perpendicular, out of the galactic plane. There are examples shown in the video of jets bent well within that distance.
@@onebylandtwoifbysearunifby5475 M87 is elliptical, so it doesn't have a galactic plane. It has roughly the same radius in every direction.
Why are "other explanations needed"? You are looking at images of the galactic core of Messier 87 as seen by the Hubble Space Telescope with its blue plasma jet clearly visible. The jet is actually much longer than you suggest with the strongest component being 5,000 light years. However the HST images do not show that this jet is of tiny extent compared to the spherical galaxy which has a radius of perhaps 500,000 light years! Obviously this jet is reacting only to local conditions as it's confined to the galactic envelope. IF the jet extends outside M87 it is too weak for us to observe with current instruments.
@@nightjarflying There are jets that loop-back on themselves, and even merge with the underside, forming a "D" shape. Magnetic fields and merging bodies (or similar) are candidate explanations. RAM induction seems short there.
What’s that Elton John song? “Bending of the jets”
Question: could dark matter contribute to the buoyancy--or is it too weakly interacting? (Full disclosure--I'm a dark matter skeptic)
Bouyancy is about pressures and gravity. Dark matter would not, I think, have any effect on the relative pressures of the two media (and would likely be at the same level anyways), but any gravity effects by the dark matter would, of course, be felt.
Halton Arp
It's like herding NATS
I would love to hear the Prof discuss Halton Arp and intrinsic red shift....
Halton Arp was simply wrong in all his major ideas/objections re red shift. He was working with a tiny data set & he never revised his opinions even though later, much more precise & voluminous astronomical data pointed away from his theories. Arp has no value, but he's still highly regarded among the cranks with an agenda e.g. Electric Universe proponents & also religious fundamentalists [usually creationists] who are looking for 'gaps' to exploit in astronomy & evolution. He's old, cold news.
the NATS look like vortex shedding
Wow..🦄🙆♂️🧙♂️🐺👽
I am surprised Dark Matter was not mentioned as a factor.
Let's put some ewes in the galaxy to counteract the ram pressure.
OK, we can all dive now in galactic jets, knowing that there's only so few highly radioactive particles per volume. I feel much safer now. ;)
🔥🔥🔥🔥
B- b- b- b- Benty and the Jets
And MATS are Medium Angle !
MATS have lots of ruby in them.
B-b-b Benties and the Jets
"Motion of a galaxy" is a weird concept, to me. Is it the galaxy of the gas cloud that's moving? When talking about galaxies, there aren't that many obvious things to use as a reference for relative motion.
Either way. They are equivalent ways to examine the same situation.
You have Great attractor for example.
@@icvetnic Sure, but is it moving? :P
happy pride to the not straight jets 🏳️🌈
How does dark matter factor into this? Does dark matter only gravitate or does it have a pressure?
Since pressure comes from particles interaction electromechanically and dark matter does not interact electromechanically, I think that dark matter would not exert a pressure
What WAT that?
Does our own solar system have a bunch of gas in and around it?
The solar wind goes somewhere
I am vietnamese and i can’t understand what you say ;(
☝️🤓 I love this.
🙏💚
I hope some astronomer has had the presence of mind to name one of these galaxies Bennie.
B B B B B B B B B Bending of the jets.
B-B-B-Bending of the Jets