19 Subatomic Stories: How we know black holes exist

Black holes live up to their name.  They emit no light and they’re usually very far away.  This makes it hard to take pictures of them and, indeed, some people claimed that they might not exist.  But that’s no longer true.  In Episode 19 of Subatomic Stories, Fermilab’s Dr. Don Lincoln tells us how we are quite sure that black holes are real.

Fermilab physics 101:

Fermilab home page:

ALPHA-g footage - CERN
"The Thinker" photo - Douglas O'Brien from Canada
Thermometer vector- Vecteezy

[brothermine]

An intermediate black hole was recently observed, contrary to Don's claim. Unexpectedly, it was located outside a small galaxy, not at the center of a small galaxy. Astronomers always looked for intermediate black holes at the centers of small galaxies, since the centers of galaxies is where supermassive black holes have always been found and the well-established pattern is that the mass of a supermassive black hole is proportional (roughly speaking) to the mass of the galaxy around it. It should also be noted that a fourth type of black hole has been theorized: primordial black holes created at the big bang, small enough that most would have already evaporated if Hawking's theory about black hole evaporation is correct.

[SlowToe]

You are a wonderful Science communicator Don. This channel on YouTube will definitely inspire the next Generation of curious minds.

[NicleT]

Dr. Lincoln, as always you present the best science channel of all. Thank you.

[scudder]

Dr.Don, thanks for fully explaining what is meant by the concept "temperature of space".

[nmccw]

Thanks for the weekly videos Don. They are very much appreciated.

[bobbourke]

Another great show, thank you. Now for a suggestion / request. I'd love to see "A day in the life" style show.
A show where you show us what one of these experiments actually looks like at FERMILAB. The warts and all theory behind the experiment, the actual experiment and the hours of what the data looks like before those incredible brains make sense of it.

[kylebowles]

Thanks for the back story Don that was awesome! The predictive power and precision of science persuaded me

[davesutherland]

At 9:22 you start to discuss theoretical vs. experimental physics considerations for Swapnil Kumar who currently appears to be studying engineering. I have another suggestion. It was about 40 years ago when I graduated, but I studied engineering physics. At the end of that course you could do further studies in various engineering disciplines, experimental or theoretical physics. I found it to be a great course for those who were not sure which way they wanted to go when starting university, and my classmates took a variety of paths. Considering that one that took the pure physics route won a noble price for her work, this certainly was not a path that result in limited opportunities for those that chose physics over engineering after undergrad work was complete.

[XxfishpastexX]

You put a smile on my face, Fermilab ;P

[ayushichhipa]

Thank you for this amazing series professor!!

Question 1: How the supermassive blackholes were formed in the beginning of the universe ?
Question 2: Supermassive blackholes present at the centre of radio galaxies become active when they burp after eating matter from accretion disk, but this is not a continuous process, Why??

[theultrapixel]

Hi Don! Do you think that we as a species have enough data and know enough phenomena to derive a theory of everything if only someone looked at things the right way, or do you think we are missing critical pieces of the puzzle that will keep an answer out of reach until we observe them? Where in between those two extremes do you think we are, and what are some of the more promising lines of investigation going on today to find the missing pieces and/or reinterpret the existing data?

[richtalk]

I'm reading an excellent book on anti-gravity. I can't put it down.

[goofygangster]

Amazing episode as always.. thank you Doc for putting in all the effort for us mortals..
Physics as we know of it right now leads us to believe that the time exists because of gravity.. however in ancient indian physics books we've been given to understand that gravity is a curve, a bend in time and exists only cuz time exists..

Would be great if you could pls reflect upon the idea and some ramifications of the same.

Thanks for the lovely stuff!! :)

[litigioussociety]

14:55 "It's both unpleasant, and lonely." 😄

[EddySunMusicProbe]

Thank Don for this nice and illuminating series! Thanks for the answers to the many questions too! Cheers, Eddy.

[captaincruise]

That was an unexpectedly thorough explanation about the temperature of space. So I guess when physicists refer to the temperature of space, they just mean the (current) temperature of the cmb. The temperature of the photons black holes always absorb and thus they can’t leak energy until the cmb cools off some more. Thanks!

[SquirrelASMR]

I wish I could go back and do grad school, but I cant so it's so nice to have channels like these.

[Cronos]

I would like to see the math for why no energy is gained by fusion after iron.
I do have a math degree but i lack the physics knowledge to even guess where to look.

[davidgreenwitch]

Hi, another week, another question.

If a black hole makes us loose information how does it work with entangled particles?

Say I have two photons entangled so knowing one's polarization I also know the other one's.
But if that one falls into a black hole, shouldn't these properties get "lost"?
To me it sounds like I could have additional information about the interiours of a black hole that way.
Is that possible?

[Dragrath]

Technically we have finally gotten convincing evidence for an intermediate mass black hole and there are other unverified sources which increasingly seem to hint that intermediate mass black holes do exist. Many of these candidates are surprisingly in the outskirts of their host galaxies which according to models should actually be expected in the case of direct collapse black holes thanks to galactic mergers easily displacing them and the low cross sectional area of interaction for an intermediate mass black hole not yet sufficient for run away accretion if not in the right place at the right time since they are unlikely to come close enough to any stars to actually become active and any that did become active would have already grown into supermassive black holes in the early universe.

The one strong candidate that seems highly likely to be one of these black holes is as these models predict in the outskirts of its host galaxy as are the majority of other known candidates the major exception being the still contentious claim for a few thousand solar mass object in orbit around Sagittarius A* though a few alternative explanations exist for that object. Interestingly if direct collapse models hold up there might even be up to a dozen or so of these black holes lurking in the halo or disk of the Milky Way. And there is even potentially a hyper velocity star which traces a trajectory back into the disk of the Milky Way suggesting a black hole in excess of a thousand solar masses.

Of course as with everything in science this is just a model which may or may not be true. Only further evidence will allow us to better resolve this question but I think it is still too soon to say they don't exist.