Dark matter: the next frontier – Public lecture by Dr. David E. Kaplan

There is significant evidence that the majority of matter in the universe — roughly 85% — is not made of atoms. Whatever that matter is, it gravitates, does not interact with light the same way normal matter does, and is responsible for the formation of galaxies and most other large-scale structure in the universe. In this public lecture, recorded on April 21, 2023, David E. Kaplan presents historical context and evidence for dark matter. He describes the many attempts to find other properties of this invisible substance, including efforts to directly detect it in laboratories.

Kaplan received his Ph.D. from the University of Washington in 1999. He held postdoctoral positions at the University of Chicago/Argonne National Laboratory and SLAC National Accelerator Laboratory. He joined the faculty of Johns Hopkins University in 2002. An American Physical Society Fellow, Kaplan was also awarded a National Academy of Sciences Kavli Frontiers of Science Fellowship and an Alfred P. Sloan Fellowship. He was named Outstanding Junior Investigator by the U.S. Department of Energy.

Kaplan created and produced the documentary “Particle Fever” about the discovery of the Higgs particle. The film premiered in 2013 and won an Alfred I. DuPont-Columbia University Award and other accolades.


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[markphc]

David Kaplan is always a pleasure to listen to

[Sonex]

This is probably the best lecture on YouTube regarding Dark Matter. For the most part it stays away from confusing simplifications and gives an advanced layman the 'how' a basic theory is made by physicist and why current explainations all lead to 'we don't know what Dark Mater is'. All why Dark Mater is not a thing and only an observation.

[bentationfunkiloglio]

Really great lecture. So incredibly informative!

[AllenProxmire]

if Dr Don likes it, I like it. nuff said.
I'll watch every dark matter vid y'all make.

[RedcoatsReturn]

Excellent explanations! 👏👏👏👏👏👏👏👏👏👏 😊 Understandable for the average educated man 😊👍👍 Very honest…we don’t know…a new type of matter 😊 Could dark matter be graviton fields…appears as gravity…but its a wave…a fault (not a particle)…in spacetime…created by the Big Bang/Big Crunch😉

[theultimatereductionist]

DON'T JUST SAY THAT SOMEONE HAS SAY WHAT THE DEGREES, CERTIFICATIONS, LICENSES ARE IN!!!

[Dr_LK]

Very good and clear explanation. Thank you.

[brianmcdaniels]

Jon Evans got it right. The whole problem with cosmology are these three very simple things: There is no Dark Matter, The Universe is NOT expanding, and the age of it is around 80 billion years or so. It's a tri-fold problem and each one keeps rotating back to the next in a nice circular pattern. It's all due to bad measurements when it comes to Dark Matter. Expansion of space is pretty much the same thing. And the age of the universe causes a ton of problems because you simply keep trying to cram everything into a tiny little window and you come up with things such as Crinkle Quazi Matter bubbles.

Dark Matter in perticular I almost believe was some high end troll to keep funding for other projects while they kept this nonsense going. Then I came to realize it's just a bunch of hacks that can't visualize space. Heres a cool part to shut down some genius like Kaplan. I'm sorry. Dr Esquire lord of the nonbinary David E. Kaplan. Ok SO Let's just start with this one. The smoking "gun" they use as the biggest indicator of Dark Matter is that bullet? cluster image where they go: SEE, YOU CAN "sEE" The dark matter, move freely between the galaxies while the regular matter gets held up. OK I think some simple analysis takes care of this one. So you say It does not interact with matter except by gravity. However, why would the "Dark matter" just sit magically outside the galaxies to keep them together? but then in this "SMOKING GUN" it basically floats right through both the galaxies AND THE OTHER DARK MATTER it self. uH? What? oh this is the part when you catch them in nonsense that they can't dispute they go "THATS WHY ITS DARK MATTER ITS CRAZY" .

It doesn't exist. These people promoting it are nothing more than philosophers who sit around finding lil logic loops in thinking so they can argue about it for years and stay relevant.

PS: Heard if you take just the age of the universe on its own and start from the bottom up with no time constraints, you can easily come up with a model of how the universe looks today. Oh, It's funny how "space is expanding" but then when you look at the giant map of the cosmos weve been piecing together, all you do is see a giant web of interaction.. oh and that thing called gravitational waves I mean, they show things are connected from far distances or something. Silly me.

[shawns]

There is an elephant in the room explanation for "dark matter". Most people don't know that Einstein said that singularities are not possible. In the 1939 journal "Annals of Mathematics" he wrote "the essential result of this investigation is a clear understanding as to why the Schwarzchild singularities (Schwarzchild was the first to raise the issue of General relativity predicting singularities) do not exist in physical reality. Although the theory given here treats only clusters whose particles move along circular paths it does seem to be subject to reasonable doubt that more general cases will have analogous results. The Schwarzchild singularities do not appear for the reason that matter cannot be concentrated arbitrarily. And this is due to the fact that otherwise the constituting particles would reach the velocity of light"
He was referring to the phenomenon of dilation (sometimes called gamma or y) mass that is dilated is smeared through spacetime relative to an outside observer. This is illustrated in a common 2 axis dilation graph with velocity on the horizontal line and dilation on the vertical. It shows the squared nature of the phenomenon, dilation increases at an exponential rate the closer you get to the speed of light.
General relativity does not predict singularities when you factor in dilation. Einstein is known to have repeatedly spoken about this. Nobody believed in black holes when he was alive for this reason.
Wherever you have an astronomical quantity of mass, dilation will occur because high mass means high momentum. There is no place in the universe where mass is more concentrated than at the center of a galaxy.
According to Einstein's math, the mass at the center of our own galaxy must be dilated. In other words that mass is all around us. This means that there is no valid XYZ coordinate we can attribute to our own galactic center, you can't point your finger at something that is smeared through spacetime. Or more precisely, everywhere you point is equally valid.
This is the explanation for the abnormally high rotation rates of stars in spiral galaxies (the reason for the theory of dark matter) the missing mass is dilated mass.
According to Einstein's math, galaxies with very, very low mass would not have dilated mass because they do not have enough mass at the center to achieve relativistic velocities.
To date, this has been confirmed with 5 very low mass galaxies all showing no signs of dark matter, in other words they have normal star rotation rates.
There is no black holes or dark matter, relativity explains the phenomenon we see.

[Corvaire]

Your "friend" is on the right track. ;O)-
Unfortunately, for more accurate results it will need to be done in space.

[carnsoaks]

Enjoyable and informative lecture. Thanks Kappers, as a lay-lover of all things physics, your review was great. Concise, structured, without hyperbole and precise, one of the easiest lectures to listen to in a long time.
Q, does Weakly Interacting mean, interacting in the Regime of the Weak Force, or is it more-so "interacts very weakly with some particular forces".
My understanding was the first, that it doesn't couple to the EM Field at all. But Gravity, yes, maybe Weak Field, unlikely Strong Field.
Tx H&K.

[gongfei]

Dr. Carter, your image in the video is blurred, I think you'd check the focus of the camera.

[lgme]

Why still use the world Force about GR ? And it's not the human eye, a machine would see the same light following the curved spacetime in a strait line, nothing is bending anything.

[stevethompson]

I hope I’m still alive when this all gets figured out.

[fremtidenkommer]

Can MOG (STVG) by John Moffat be ruled out, or is it a viable alternative to dark matter?

[hoba]

Can the slower rotation of inner parts of galaxy being caused by time dilation?

More mass in the center, thus time moves slower there (from our point of view).
And vice versa - not much matter in the outer rims of galaxy, thus time ticks faster and they seem to orbit faster.

Did anyone tried to calculate the effect for an average galaxy?

[Bob-Fields]

Sooo, Dark(matter) Arts with Severus Snape. I'm in.

[brianwade]

I have always believed that the person who knows the material the best is the one that is clearest to understand. Dr. Kaplan is a gem.

[shafikhan]

I see your video and it does not look real to me so I'm in doubt?

[SimonJackson]

Those old energy time, momentum position relationships. What, wait, gravity has a field of energy uncertainty for a time? It might have a 1/r^2 dependence as a delta on the 1/(r+x)^2-1/(r-x)^2 .... oh well mass might appear a bit heavier as radius goes up.