A New Image of THAT Black Hole ⚫ - Sixty Symbols

[@sixtysymbols]

See our black hole playlist of videos: bit.ly/Black_Hole_Videos

[@ZeroRyoko]

Can you ask the professor how come the Telescope has an angular resolution of 25uAS (micro arc seconds) and the object is ~50uAS accross, that they get so much "detail" from about 4 pixles? And given the Signal to noise ratio of the data at arround one, how any of the can be regarded as science?

[@TheTimeDilater]

@@ZeroRyoko Yeah I also want that answer ;)

[@kevint1910]

this image is a total FRAUD it is based on approximately 4 pixels worth of data that was "filtered" from what amounts to white noise using modeling that simply disregarded anything that was not the desired result...and as if that were not bad enough the data set its self is fraudulent because several of the radio telescopes involved were in use on other observations at the time and could NOT have been part of the array.

[@ZeroRyoko]

@@kevint1910 It's worse than that even. The paper they published states that the JCMT and PV telescopes (the ones that define the angular resolution) never even observed the calibration target at the same time! That means that they can't rely on the data at all, further reducing the data integrity. It makes me sad that people allow themselves to be hoodwinked by rubbish like this in modern science. 😞

[@yobeavis7113]

My theory is all scientists and physicists and astronomers are wrong about black holes, black holes are depicted as a black pit when in reality it’s shape is a sphere( black orb) and not a hole!!!

[@RossSavill]

Whenever Mike Merrifield is back for a video I get a boost to my day. Wish he was my teacher 🙌

[@jamesmeppler6375]

If I had a science teacher like this I may have got past intro to science in high-school a.k.a past core curriculum, failed every year because teachers are all burnt out here in oregon

[@theemissary1313]

While I too wish he were my teacher, I'm actually glad I wasn't his student. (because my younger self was awful)

[@NickHermans]

He is your teacher 🙂.

[@dmeemd7787]

Man I know!

[@Cosper79]

Best on the channel now that the one bald guy retired.

[@rarelycomments]

Just want to say, Prof Mike has a fantastic sounding microphone, 10/10

[@Golinth]

It looks like it might just be the airpods mic

[@rusty_juice_tin]

I think this helped me appreciate the challenge behind visually representing complicated observations. When I first saw the new picture I didn't get it, but I really can't imagine any other way you could cleanly display the new observations in a single image, but I also feel like I only got something out of it when I heard the explanation of what is going on.

[@velikovskysghost]

+Justin Rus The image their showing of a black hole is in reality a plasmoid see the work of Winston Bostic or Brian J. Ford. Kristian Birkeland, and or the SAFIRE project for specifics.

[@Triantalex]

ok?

[@Varooooooom]

Wow, first time I’ve seen a vid with this professor. He explains everything with pristine perfection.

[@MatthijsvanDuin]

Videos with prof Merrifield are always worth watching

[@Jesse__H]

Yes he is an excellent science communicator.

[@RedBatRacing]

@@Jesse__H And Brady asks brilliant questions

[@jeromelarson6732]

You're in for a treat then

[@beeble2003]

He's done _a lot_ of videos for Sixty Symbols and they're all of this kind of quality. You'll really enjoy going through the back-catalogue!

[@steve1978ger]

"... the black hole that keeps on giving." *Schwarzschild has left the chat*

[@supertuesday600]

1990s: Blackhole takes everything. 2021: Blackhole is the gift that keeps on giving.

[@mastershooter64]

*hawking radiation has entered the chat*

[@thereisaplace]

@@mastershooter64 I believe HawkingRadiation can only ever leave the chat ;-)

[@mastershooter64]

@@thereisaplace I guess a better one would be *virtual particles have entered the chat* *Hawking radiation has left the chat*

[@alishba2007]

Kerr and einstein also left the chat

[@grahamrankin4725]

University of Notingham would be quite an experience for a grad student.

[@superscatboy]

It's even a pretty sweet experience for those of us that just watch these videos tbh :)

[@freddan6fly]

Almost top 100 ranking in the world.

[@bocbinsgames6745]

I live near there. It's pretty neat in general

[@sidneyr13]

Nottinghams great 😃

[@tomashin2000]

It's not. I study there.

[@MichaelEhling]

7:15 "No, I'm not going that way." -- M87*'s magnetic field and most toddlers.

[@landsgevaer]

At 10:18, he says a black hole cannot have a magnetic field itself, because of the no hair theorem. However, it can have (a bit of) charge and it can have angular momentum, so wouldn't that cause it to have a magnetic dipole moment as well?

[@michaelsommers2356]

The no hair theorem says that black holes are completely characterized by mass, charge, and spin. That does not preclude a magnetic field, any more than it precludes an electric or gravitational field, because that field would be completely described by the charge and spin. If a black hole were to have a magnetic field, it would be aligned with the spin axis. Look up the Kerr-Newman metric.

[@landsgevaer]

@@michaelsommers2356 Yes I looked that up in combination with dipole, but didn't find a definitive statement. But then the video is wrong where it says that because of the no hair it cannot have a magnetic field itself, you confirm. I thought as much, since far away the dipole should behave the same whether the charged rotating mass has collapsed into a black hole or not, was my intuition.

[@vaibhavsharma5965]

You are right. And moreover, electric and magnetic fields are not invariants and can change depending on the observer. An electric field outside a purely charged black hole can be seen as a magnetic field by a moving observer.

[@michaelsommers2356]

@@landsgevaer Since any charge on a black hole will be very small, any magnetic field it creates will also be very small, and not significant on relevant scales. For practical purposes, it doesn't matter.

[@landsgevaer]

@@michaelsommers2356 Yes, I'm aware of that. But the prof didn't say it was practically irrelevant for this observed black hole, but that it was fundamentally impossible because not even magnetic field lines can escape from a black hole. So without meaning to bash an excellent educator, that is still wrong it seems.

[@z-beeblebrox]

This video gives fantastic context to the image. It really makes you appreciate how complex it is to visualize this information

[@akulkis]

It's complex because it's a lot of handwaving to disguise the fact that this isn't valid signal processing. If such algorithms existed to clarify a data stream suffering from under-sampling in comparison to the desired sampling rate for high fidelity reproduction, then cell phone calls wouldn't sound so lousy. And being linear data, as opposed to 2-dimensional data, cleaning up cell phone calls by this same method would be exceedingly cheap. Cheap enough to put multiple processors on EVERY cell-phone tower antenna for under $5/cellular antenna (and these things have costs in the $1000 range, and that doesn't even include the additional $1000s it costs to install the antenna ON the tower. Cell-tower technicians are extremely expensive).

[@FredStam]

Mike Merrifield knows how to explain difficult things. Very nice video. Brady what kind of software are you using for this video. Is it Zoom or are you using different software.

[@AntonJansson]

I was waiting for this video. Great questions and great explanations as always.

[@freddan6fly]

Nice explanation Mike. I saw the new Image at Anton Petrov, but your explanation is much deeper. Keep up the great work.

[@MusicFillsTheQuiet]

"Enhance!" [Months later] "I know that man! We can solve the case now!"

[@philipmalaby8172]

Don’t forget to add the ‘clickety clickety’ on a keyboard

[@IronMan9771]

You spelled years wrong

[@emilmckellar4932]

One of the best episodes ever. Given in language I could follow and understand the amazement!

[@dankuchar6821]

Thank you to both of you for this excellent video!

[@StanJan]

Guys. Love the Chanell. This is NOT a PHOTO. It is an artistic rendering by computer. Higher resolution ? ! ? ! He just made more on his rendering. “We must be careful not to believe things simply because we want them to be true” Feynman

[@Phoenixeire]

Algorithm: A set of instructions created to give a 'desired' outcome. Believe me I trust in science, but given the right algorithm, a binary data set of the magnitude gathered for this project could be manipulated to create an image of absolutely anything.

[@alandyer910]

Very nicely explained. Mike does a great job. Thank you!

[@spacemarts]

Sag A* is also more difficult to observe than M87 because it is more dynamic on shorter time scales. The gravitational time dilation is so extreme with the M87 black hole that the observed accreting material does not change much between observations. Sag A* is ~1/1000 the mass of the M87 black hole, so the shape/form of orbiting material can change quicker.

[@heydj6857]

great video, thanks, you have a little typo in the description "and the magnetic filed" I'm sure you meant field.

[@stvp68]

I like that your visualization of the hole gives it height and not just width.

[@existenceispainforameeseeks]

black holes are so ridiculously cool 😭 i could learn about them all day and never get bored!!!

[@Abhishek-hy8xe]

Only when one makes any progress the curiosity is sustained. Otherwise all gets in the cold bag.

[@MaxenceAbela]

At 10:40, Professor Merrifield says that magnetic lines cannot "escape" from the event horizon, but I thought that magnetic fields were not carried by any particles that would be retained inside the black hole. So what is it exactly that prevents the black-hole from having it's own magnetic field ?

[@hamiltonianpathondodecahed5236]

wait a sec 2019 wasn't two years ... oh nevermind :smile_with_a_tear:

[@guyh3403]

Yeah, fast as lighting huh.

[@stardustpan]

EXACTLY-

[@mrnice4434]

I kinda mist 2020 was there something?

[@Triantalex]

??

[@priyabratadash381]

It's wonderful to hear when Professor here said the magnefield near the blackhole is concentrated and this leads to a totally different picture of blackhole than what we know so far....

[@billgaudette5524]

I love the idea that even as the infalling material orbits faster and faster, eventually the magnetic fields that it carries become so strong that it overpowers the momentum of the material. While I was intuitively guessing this during the video, I was pleased to hear Prof. Merrifield talk about it actually happening. There must be a critical density of magnetic fields and materials at which this happens...I think about the energy involved to divert material which is moving at what must be significant fractions of the speed of light into new, "non-orbital" directions. Also, unless these energies are able to break down material into quarks, would only the protons' and electrons' movement be affected, while the neutrons continue to spiral inwards according to the gravitational field?

[@bjornragnarsson8692]

Actually neutron’s would be affected because they have a magnetic dipole moment, albeit one of less magnitude than a proton. Despite having no electric charge, neutrons are hadrons, so their magnetic moment comes from the magnetic moments of the up quark and two down quarks composing them. An up quark has electric charge +2/3 e, while the two down quarks each have electric charge -1/3 e, leaving the neutron with no net electric charge.

[@smsv2806]

So since it is so far away, are we looking at and measuring a black hole as it was however many light years it is away from us?

[@circuitboardsushi]

Magnetic fields can't come out of black hole. Does the black hole reject magnetic fields that are near the event horizon?

[@aryamankejriwal5959]

10:30 I would actually be interested to know how this works with graviton, like can gravitons escape? I mean they would have to but I’m confused as to how that works

[@alexwilding8451]

Nobody knows if gravitons actually exist. Nevertheless, *nothing* can escape from the event horizon of a black hole.

[@garethdean6382]

Sort of. Black holes have three minimal properties, mass, spin and charge. The first two rely on gravity the third on electromagnetism. The charge of a hole can be modeled as imprinted on the event horizon and generating virtual photons just outside that move off into space. Likewise it's possible to model its gravity in the same way. It's not that something escapes from inside the hole so much as the properties of the event horizon itself create virtual particles that always exist outside the hole.

[@Bartooc]

@@alexwilding8451 Not true, Hawking's Radiation can

[@chrisgriffith1573]

That was a new thing for me to learn about- no hair on a black hole. I never considered the fact that magnetic line can't emanate from within the black hole itself... so these field line outside of the black hole M-87, they are created by ... what?

[@LandoCalrissiano]

The matter around it.

[@BenHBX]

The other reason our galaxy's black hole is harder to image is that the accretion disc near the event horizon revolves around it in less than an hour compared to like 30 days in the case of M87, so any features that would be present if the disc was not perfectly uniform (as was the case for M87) would not be observed without reducing the amount of data collected, as the imaging process is spread out over a significant amount of time. Some of the telescopes involved in imaging M87 were not even facing it when the imaging started and only started collecting data as the earth rotated and M87 rose above the horizon where they were.

[@Draxis32]

One thing that maybe was missed out is that black holes can accelerate things to 40%+ of the speed of light. To have a magnetic field strong enough to be able to halt any mass at 40% the speed of light is incredibly impressive.

[@Pranav-un2ek]

The legends are back

[@fluffigverbimmelt]

Off topic: The professor's audio is fantastic for true wireless buds. Is the sound coming from that source? Anyone know what brand that is?

[@marksimpson2321]

Is there any commection between those different types of magnetic field Professor Merrifield mentions and the research on nuclear fusion in tokamaks?

[@DeathBringer9000]

black hole simulations and renderings thereof are surprisingly easy to make.

[@EMBer3000]

Silly question, but if magnetic field lines can't originate at a black hole, can they terminate there? Depending on the answer you get two quite intriguing scenarios, either a black hole is a magnetic monopole or magnetic fields will follow material as it falls in but will be "left behind" as that material passes the event horizon. The second scenario seems like it would leave you with a VERY intense magnetic field just outside the event horizon that sort of gets locked there...

[@064junaid8]

I'm in love With Messier-87

[@GapWim]

10:19 (magnetic lines can’t emerge from a black hole) But then how can a black hole still a have charge?

[@akumar7366]

Very humbling lisenting to the wonder of our space time , it's such a exciting time for sceintist.

[@davidsweeney111]

Could we have an emergency video on the Muon discovery that is rocking physics to its core, cheers!

[@stephensheppard]

Interesting, as usual, but it made me wonder. Polarization is a feature that can characterize any wave. Are gravitational waves polarized? Are we able to detect the polarization, or are our current generation of gravitational wave detectors too crude to detect it? Or are they sensitive enough but we need more of them?

[@inyobill]

I'm a bit surprised that the orange color being synthetic is not mentioned.

[@lnope403]

was waiting for this video!!

[@smitemus]

Sure would love a picture of our own cute monster

[@kingkilla777]

0:20 OK thats much better I really wanna be able to observe a black hole up close ever since I was a kid ive always had this fascination with black holes I find them to be the most interesting objects in space.

[@JesusMartinez-mk6fc]

Briliant video! Dr. Merrifield's wonderful explanation of the new picfure of M87 showing the polarization of light, prompted by great questions from the interviewer, puts this new informartion into much clearer context.

[@kgirishchandra]

Such an articulate explanation!

[@gustavgnoettgen]

Is it certain at what angle that black hole rotates relative to our point of view?

[@nauthic3p0]

Why isn’t the view on M87 not blocked in the same was as it is blocked on the center of the Milky way? Wouldn’t there also be ‚rubble’ around M78?

[@nickking6371]

I really feel like this polarized light picture shows so brilliantly that blackholes are tunnels. Not spheres. I juxtappsed the polarized picture wuth drain swirls and looks pretty clear cut

[@MartinB_Art_Design]

I'd love to see one in absolute lifelike detail... from a safe distance.

[@michaelsommers2356]

You'd have to be able to see radio waves, too.

[@Linkwii64]

Too bright to look at with the naked eyes. Real black hole will disappoint everyone.

[@pianochannel100]

@@Linkwii64 just need a really big welding helmet :P

[@thomasplower367]

Merrifield is the best!

[@Archiekunst]

6:06 I think he mixed up the toroidal and radial ones?

[@rbkstudios2923]

This is sooo coool I've so much more to learn about Magnetism

[@nicovandyk3856]

Just love these videos; wish we can have these more regularly, please!!!

[@pepega3344]

Scientists are trying their best, ok?

[@Tom_Tom_Klondike]

This professor is a great speaker

[@TecraX2]

13:50 - Haven't we moved beyond it merely being a "suspected BH" by this point?!?

[@barnowl2832]

Where is the footage of the stars revolving around Sagittarius A from? Looks awesome

[@lucidbeing618]

This is the gift that keeps on giving🍄

[@ruben307]

I would have assumed the electric field would be more dominant with lots of charged particles going into a circle with the force of attraction towards the black hole would mean the magnetic field would go outward wouldnt it?

[@michaelsommers2356]

If charges are moving in a circle, their magnetic field will be orthogonal to the plane of the circle.

[@johnmurrell3175]

The video frequently mentions magnetic field lines but do they exist ? If I had a very small magnetic field detector would it show an increase when it crossed a magnetic field line ? The videos of the plasma above the sun seem to show some liner structure like field lines. However if field lines exist what is different where they exist to the space between them ?

[@beeble2003]

No, field lines don't exist _per se._ Field lines are just a visualization of the local direction of the field. Suppose you're looking at a dry, sandy beach on a windy day. You see the grains of sand being picked up by the wind and moved around. If you took a photograph with a slow-ish shutter speed, you'd see the grains turn into streaks, and those streaks would indicate the field lines. In this case, the field is the velocity (speed and direction) of the wind. The statement in the video about field lines "not liking to be close together" comes with an implicit idea of scale. Think of contour lines on a map. Obviously, if you draw your contour lines at one-metre elevation intervals, they'll be much closer than if you drew then at ten-metre intervals. But whatever interval you choose, you'll find that the contour lines tend to be relatively far apart (relative to your interval), corresponding to the fact that, in most places, the ground doesn't slope steeply. The same is true of magnetic fields: you don't tend to get very steep gradients in magnetic fields, i.e., places with a strong magnetic field that are close to places with a much weaker magnetic field.

[@will2see]

0:25 - 6.5 billion times the mass of the Sun (best estimate)!

[@ThePinkus]

I find it sort of funny that the "Event Horizon Telescope" is not at all a telescope to see event horizons (of black holes, of course), even in a wider sense for "telescope". There seems to be a widespread notion that the EH is there where the BH is. Even when some account is given for infalling energy-matter to be slowed down and 'freezed' (or time-Zenoed?) at the EH, when "seen" from an "outer" observer, it's often still the notion of the EH surface "being there" and things getting 'freezed' as they fall onto it. All of this is a very pre-relativistic notion, and it is not consistent with GR. The EH, by its defining properties, does not affect the outer universe. Simply, future cones from the EH and the "inside" of the EH do not reach the "outer" universe. I want to stress, it is not that light or other things can't come out of it and yet the EH "is there", as a "hole which looks black". No, it is rather that the EH, as a spacetime geometrical configuration, is not present in any past cone of events of the outer universe. It does not affect the outer universe not just in the sense that it doesn't emit light, but also gravitationally (or better, geometrodynamically). If it did, it would violate causality. And it doesn't according to GR. GR is surprisingly raffinate and elegant in assuring causal consistency, as what is presented to the outer universe is never the EH, but rather always the proto-BH, that is the matter-energy undergoing gravitational collapse before the formation of the EH. It is in this sense that EHs are not there relative to any event of the outer universe, or that there are no EH in the visible universe. Now, in a paradoxical sense, a proto-BH physically looks just like a "mature" BH (aside from the non-negligible fact that the latter should not appear at all to the outer universe, if one thinks of it, which makes the look-alike totally non-sensical, as it is non-sensical to analyze how an EH "looks" from the outside -- it just doesn't) and proto-BHs is indeed what we are observing. But the theoretical conclusion is essential to the theoretical consistency, 'cause if we combine that the EH+inner of the BH does not affect the outer (by the geometry of causation represented by future cones), and also that it affects the outer (when indulging the pre-relativistic notion that it "is there"), e.g., determining the spacetime geometry "surrounding" the EH, and maybe in some thermodynamical and radiative sense, then we might be expected to produce inconsistencies from these premises. "Some" information loss might just be the tip of the iceberg here. If we instead realize that according to GR it is only and always the proto-BH that accounts for the entire causations by which the BH affects the outer universe, these inconsistencies have no possibility to occur, because, of course, the proto-BH is by definition within the outer universe and its causal structure. So, Wheeler can't hide his broken tea-cup behind the event horizon, the EH doesn't present a Bekenstein's temperature or entropy to the outer universe, and it doesn't cause the emission of Hawking's radiation. What "is there relative to" the outer universe and what affects it is always the entire mass-energy of the proto-BH, with its information, temperature and entropy, and its geometrodynamical effects on the surroundings, never hidden behind an EH. So, I think, EHT is one of those names we might keep for sake of conventions, well knowing they might be misleading when taken too literally. After all, I've been calling the phenomenon BH, even though it's not quite a hole, and it's not exactly black.

[@thomasolson7447]

You gotta like because you went straight to the subject. Other people got dislikes because they took ten or so minutes to get to the point.

[@phillyg7661]

The charged plasma is the toroid. The magnetic field of a doughnut is the same as a sphere. The size of event horizon r=mv/qB. Mass is not size, mass is energy, please refer to electron volts rather than solar “masses”.

[@Joemama555]

Brady always has the best videos!

[@SuperCameronMan]

Great explanation. Thanks prof mike!

[@thephuntastics2920]

you mean the "reverse image search pixelpuzzle algorithm v2.01 name subject to change Mk1 "?

[@kimwelch4652]

So, light is an electro-magnetic wave, and it bends in a strong gravitational field. Does that mean that magnetic fields are bent or compressed by a strong gravitational field. Do the magnetic field lines of the in-falling material get compressed by the gravity field of the black hole?

[@jeffkaylin892]

You mentioned that light oscillates. Well, if you look at it differently, to the observer it looks like the fields move. But, to the light it is just moving. Like when a train crosses in front of you -- the box cars go UP----down UP-----down UP. But they don't, they just move. And are photons really like continuous Sine waves? Solitons were a big thing back in the 70's. I'm actually wondering if there are ANY continuous Sine waves, even radio. Are they made up of photon packets? Thanks for giving it a thought.

[@FHBStudio]

I like how interstellar focused a lot on gravity and time dilation (obviously) but I'm curious to see where we'll go with this new research in terms of electromagnetism. Gravity may spaghettify you, but who knows what this electromagnetic activity may do to you?

[@SernasHeptaDimesionalSpace]

The jet of light that we see here is just the center of a much, much bigger electromagnetic tunnel that all galaxies count with - this electromagnetic tunnel is the medium that galaxies use to spread ENERGY-MASS to both sides so to keep on with the system and at the same time is the connection to a higger level so to connet with.

[@TCBYEAHCUZ]

A plasmoid, not a black hole, that's why the magnetic field is so strong. The sum of the magnetic field is *stronger* than the condensation of magnetic fields from the mass of the black hole.

[@ShaneOsborne]

When light or magnetism oscillates, what causes it to travel? Why doesn't it just as oscillate in place???

[@StephenJohnson-jb7xe]

Very powerful magnetic fields were mentioned but how powerful? weaker, equal to or stronger than a magnetar for instance. Also of the modeling the magnetic fields that most resembled the data from M87 was the vertical magnetic fields, it would be interesting to know if that is at least partially responsible for the jets coming from the poles.

[@garethdean6382]

1-30 Gauss, or roughly twice to 60x Earth's field. On the one hand, this isn't very 'powerful' in terms of absolute field strength. We can exceed that easily. On the other hand though, the field is very large, and size really does matter here. A field of that strength stretching over such vast distances has a LOT of power behind it.

[@Raven1015]

April 11th, 2017 was when this paper was published. That was 4 years ago and we are just now getting this. What else are we four years behind on?

[@subjectline]

That's the date the photons were collected, the publication date is just now. The first image was 2019 and if you look up Katie Bouman's lectures in 2019 you can hear a detailed explanation of the process in between that created the image from the data.

[@nohero23]

Wait, 10:30 - I learned that a black hole can have a charge, and wouldn't a charged black hole also produce a magnetic field?

[@fendoroid3788]

Next Firefox logo?

[@MrBjs007]

Forgive my ignorance but what is the shape of a black hole? Is it a disk or an orb or a cone - or something else?

[@ps.2]

It is a complicated question! I can think of 4 answers: 1. You *can* think of a black hole as as point in space with some mass, which is packed into infinite density and no volume. With no volume, it also has no "shape". 2. But what we usually mean by _black hole_ is not just the point (or "singularity") but the sphere around it that nothing can escape, not even light or a magnetic field. This is a perfect sphere. (I forget whether the sphere is theorized to be "hairy" or "smooth". I'm not sure whether theoretical physicists agree on this.) The size of the sphere is the *Schwarzschild radius,* and its surface is the *event horizon.* 3. But that's not all. If the black hole is rotating - and they always are - the space around the sphere (or "spacetime") is distorted, not unlike spinning a spoon handle in a bowl of honey. Even if the handle doesn't change shape, the honey around it is distorted. This is gravitational *frame dragging,* and all rotating things do it, but it's particularly noticeable in black holes. So, due to this distortion of spacetime, I'm not sure how that would affect the shape you would perceive. 4. Finally, there's all the debris that is rotating around a black hole but hasn't fallen in. This is the *accretion disk* and, as the name implies, is roughly disk-shaped. The reason for the disk shape is the same as the disk shape of our solar system and our galaxy. Basically, any matter that rotates around the black hole but isn't in the same plane as the accretion disk will eventually have enough collisions with matter in the accretion disk that its momentum will be altered and it will join the disk. (And vice versa: the orbits of everything else in the accretion disk will be altered slightly as well. So the accretion disk can wobble around as new matter comes in, but it will remain disk-shaped.)

[@vaibhavsharma5965]

I don't think the statement at 10:28 is correct. Black holes can have electric and magnetic fields of their own. Even outside a non rotating charged black hole, a stationary observer can see an electric field and moreover, in a different moving rest frame, that same electric field can be transformed into an electric and magnetic field. Outside a rotating charged black hole, I think there would be a magnetic field by the black hole. Since massive charged bodies are rare in our universe, the M87 black hole is probably uncharged with no EM field of its own.

[@MrJamesWhitford]

Please unravel "Faraday rotation thing" at 13:46

[@mcvrs1223]

Does anyone know why the polarization was only measured on that part of the image? Was the signal too small on the rest?

[@garethdean6382]

Pretty much. It's the brightest part of the image and the most clear. We expect a lot of the image to be warped, such as the parts on the side, where the image of the disc is being warped 90 degrees, and the top part is from behind the hole. This was just the best that could be done with the current data.

[@jansenart0]

Right next to the event horizon, you've got to be orbiting at close to the speed of light. Magnetic fields propagate at the speed of light, but when you're going at relativistic speeds, like when you're orbiting close to the event horizon, time is dilated. What is the effect of one on the other? I have no idea!

[@mcarp555]

The faster you travel, the slower time gets, depending on your frame of reference. For an observer a safe distance away, watching something fall into a black hole (as in crossing the event horizon), they would see the infalling material become frozen in time. If you were to fall into a black hole (assuming for the moment you can do so intact), the 'outside' Universe would appear to freeze. You can think of yourself now as traveling at the speed of light through time, so your motion through space is much, much slower. There is always that balance between motion through space and motion through time.

[@jansenart0]

@@mcarp555 Well, the "infalling" material would be shredded into component parts, then compounds, molecules, atoms, etc until photons reach the event horizon and add to it. Nothing actually "falls into" a black hole because gravity shreds everything into photons, many of which get blasted off as they get close, hence the beautiful imagery we see. What I was wondering is how the magnetic fields change within matter as you get closer to the event horizon and time starts to dilate, like how some models explaining things get red/blue shifted.

[@stevelehel3625]

I would imagine that this image is why keeping the wave front data not as much as for the first image. Thanks folks!

[@tim40gabby25]

Would love to see what's in that DIY manual... :)

[@hansgmberg]

How does the black hole looks from the other side?

[@macronencer]

That image might not represent reality directly, but it's still cool :) By the way, would love a video going into more detail about how the magnetic field is "pulled along by material". I realise there wasn't time to explain that further here, but the explanation felt kind of vague to me, and I'd like to know what's really meant by it.

[@swistedfilms]

Dr. Tyson says that time is severely warped near a black hole and that if we fell into one we would see the universe end, our spaghettification notwithstanding. That makes me wonder: what does a black hole see from *its* point of view? Has the universe ended as far as it knows? Has it seen all of time play out and the heat death of the universe?

[@dziban303]

That method of visualizing magnetic fields has thin lines atop the base data is not unique to the EHT team, it's been used plenty in other studies of astronomical magnetic fields

[@Mmouse_]

Correct me if I'm wrong but isn't that image just a reconstruction and that there were several rejected "reconstructions"... This is touted as a "picture of a black hole" but it really doesn't seem to be anything like that.

[@connorspangler510]

It's a reconstructed picture of the accretion disk of the black hole, as you can't really take a picture or capture the light required to take a picture of a black hole, since a black hole by definition emits no light because no light can escape from it. Something a lot of people in the mainstream, outside of statistical or physics or even basic mathematical fields don't realize is that there are just absolutely mind-bogglingly intricate models and tests in order to verify these kinds of observations and "visual representations" of data. The scientific field at large applies such a sharp and aggressive knife to what is and is not STATISTICALLY verifiable that it is astronomically improbable if not impossible for misidentification or misrepresentation to take place.

[@Mmouse_]

@@connorspangler510 fair enough, but is it a "picture"?... I'm gonna say no.

[@connorspangler510]

@@Mmouse_ who said it was a literal photograph?

[@Mmouse_]

@@connorspangler510 no one... But it is touted as that, and a lot of people think it is.

[@Mmouse_]

@Mary Terwiliger what conspiracy? That's how this image was formed.

[@MarxistKnight]

Turns out... it’s a new Mike Merrifield video!

[@Jake-nw4yh]

Crazy to think that all these things, whether discovered or not, are just happening and gonging on all around us. And us humans are just trying to piece it together.

[@xhyhbdka]

I'm sorry but I'm struggling to understand how it's the same looking at M87 and looking at Sgr A*. Isn't M87's density a lot stronger than the density of a smaller black hole? Especially thousands of times smaller... Greater density means less volume, so it's surely not the same even if the ratios of distance and size are the same! Someone please correct me if I'm wrong

[@Waffles8800]

Never get rid of the bloopers

[@adios2011]

Do neutrinos get absorbed by black holes too?

[@LeoSutic]

Amazing stuff. I'm just trying to understand what the magnetic field lines are. Flow lines in the magnetic field, which is a vector field, ok. But magnetism is moving electric charges. So I guess the moving charges set up forces that affect other charges in such a way that the field lines appear as concrete objects?

[@michaelsommers2356]

Moving charges cause the electric field to change, which causes the magnetic field to change, but moving charges are not the same as a magnetic field.

[@garethdean6382]

The two are discrete. This can be seen in a bar magnet. There electrons are the moving charges, with their spins aligned. Though they exist only inside the metal bar, the field lines they create extend outwards (In theory to infinity.) and it's possible for a magnet to guide the path of matter (Smaller magnets) without that matter being anywhere near the charges involved in producing the field.

[@keagan0000]

I don't think there's anything more satisfying than his British accent saying "polarization information"

[@veqv]

How do we account for the relativistic effects of the event horizon? I guess I'm wondering how we know that the disc is magnetically arrested and we're not just seeing a consequence of the 'imprint' of the accretion disc on the event horizon. (both would appear halted, no?)

[@garethdean6382]

In this case the physics works itself out. There's a minimum distance where no accretion disk will be stable, matter must just fall straight into the hole. This is part of the big black sphere in the center of the image and is a greater distance than detectable (>1%) time dilation occurs. There WILL be 'imprints' of the infalling matter as its redshifted and appears to slow, but it's... redshifted and significantly so as >10% time dilation sets in. As such it should be too dim for us to detect with current technology. The third point is that it's not that the disc appears halted as in frozen in time, but rather it's *magnetically halted*, which is different. In systems like the sun gas moves freely and warps magnetic fields. In this system gas also moves, but cannot carry the field with it, instead it flows along field lines, still moving but in a different way. And it does seem like the disc is changing over time.

[@WorksopGimp]

Where do the magnetic fields come from?

[@garethdean6382]

Moving plasma. How gas splits into nuclei and electrons and when that flows the moving charges make a magnetic field. Similar phenomena power our sun's field.