21 Subatomic Stories: What mysteries might dark matter solve?

There are mysteries in the cosmos that general relativity can’t explain, things like how galaxies rotate and how clusters of galaxies move. Scientists have ideas as to possible explanations. In this episode of Subatomic Stories, Fermilab’s Dr. Don Lincoln lists some of the most pressing mysteries. In the next episode, he’ll talk about the quest for solutions.

Natural nuclear reactor in Africa

Complex dark matter long form video

Scientific American article on complex dark matter (paywall)

Fermilab physics 101:

Fermilab home page:

Wu experiment schematic credit:
Pen88, with English translation by Stigmatella aurantiaca

Neutron star animation credit:

[navinsingh]

I love how nicely Dr. Don Lincoln explains physics, he should get a Nobel prize form us! :)

[mikec]

Question: Dr. Lincoln, I understand that heavier elements are unstable because each proton experiences electromagnetic repulsion from all other protons but only experiences strong force attraction from adjacent protons and neutrons. That being the case, why can't we make heavier elements more stable by adding more neutrons to make the protons further apart? Is there some other mechanism, perhaps the weak force, that causes these high neutron isotopes to decay more rapidly as you add neutrons?

Edit: Thank you for all of your responses. I'm also looking forward to see what Dr. Lincoln has to say about it.

[truecerium]

Hello Dr. Lincoln, I am catching up on the Subatomic Stories. Some episodes back you were asked whom you would award two Nobel Prizes to and you chose Vera Rubin and Chien-Shiung Wu. I´d like to add another brilliant physicist: Lise Meitner for the discovery of nuclear fission, but only Otto Hahn had been on the ticket for the Nobel Prize in 1944

[smbleesing]

Dark matter is like my hopes and dreams, invisible.

[Alekzbizkit]

This series is an amazing rundown of physics topics. I can imagine showing it to someone not at all interested in physics to get them hooked.

[michaelblacktree]

I've always wondered why dark matter doesn't form its own version of stars, planets, black holes, etc. Thanks for the explanation.
Side note: wouldn't it be neat if it did? I wonder what a "dark matter star" would look like...

[BothHands]

love that you point out how women in STEM have been sleighted by the nobel organization. love you <3
i'm doing a neuro degree with specialization in wernicke's and broca's areas of the neocortex (psycholinguistics), and i'm glad to see more women being recognized these days in STEM. i doubt i'll ever get a nobel prize, but at least i can hopefully look forward to more role models in the future <3

[SlowToe]

Thanks Don (if I may be so casual) Another excellent and informative video.

[letbe]

I would also be extremely interested to hear you talk about the shape of the nucleus and its inner structure, a hypothetical island of stability for super heavy elements!

[tomaszmakowski]

Good Morning Dr. Lincoln. You are an amazing and great person. 
I have two questions.  I recently watched a physics program on cable 
where I heard something like this -- "Why is there something instead 
of nothing? In the beginning there was ZERO but even ZERO is unstable
and because ZERO is unstable bubble forms." So my questions are -
what does it mean that ZERO is unstable and why do we have probably 
"multiverse" instead of nothing or at least our universe instead of nothing.
Thank You very much.

[benjaminshropshire]

I don't have the background to comment on the work of Chien-Shiung Wu, but it did get me thinking: Assume there there are two people in cooperation, the one poses a profound question and proposes an experiment that could revolutionize our understanding, but lacks the technical skill and insight needed to bring to practice the experiment and get the answer. The other person, the one who didn't come up with the question, takes knowledge and techniques, refines and extends them and thought great skill and ingenuity develops the ability to construct, assemble and execute the experiment to get the answer to the question, despite very possibly not actually knowing (or caring) about it implication to the grating understanding of the universe. Both are clearly exceptionally skilled people but in different ways. They both deserve accolades for their application of those skills, but for different reason. (I'm not a scientist, but rather an engineer by training, but this strikes me as rather similar to the traditional rivalry between engineers and technician, between the people who "merely" design something and those who "merely" build and maintain it.)

Granted, that described case is an intentionally extreme division of labor, and I don't know how Chien-Shiung Wu relates to that, but the thought does, I think, suggestion that there may be good cause to formally acknowledge exceptional advancements in experimental technique and practice as a distinct endeavor from the questions and result those experiments are in pursuit of.

[michaeldamolsen]

On the Nobel question, those were the same two that I immediately thought of :)

[gyozakeynsianism]

Hi, Dr. Lincoln. Thank you so much for teaching us about two great physicists who don't seem to get much attention: Rubin and Wu.

[Nishant-usil]

If was giving nobel I would have given it to Nicola tesla to stop him from going mad and make new inventions

And SN Bose who did a lot for scientific community by his work in particle physics

[altortugas]

Brilliant picks for a posthumous Nobel, even if they were a bit obvious for fans of Fermilab and the Good Doctor Don.

[pieterjanvandecasteele]

Black hole question. What happens with space if a black hole evaporates due to Hawking Radiation? A black hole has a singularity which has infinite density and infinite curvature of space.

[richtalk]

Gravity seems to exert a pull over distances great enough to bind together not just galaxies, but whole galaxy clusters. Yet we observe galaxies flying away from us - accelerating actually. So at what scales does the repulsion that causes everything to fly apart "win over" gravity?

[ManuTheGreat]

Do you guys agree that invisible matter is a better than dark matter? I mean it's a better description. Dark matter might be a better term for PR reasons...

Dark things absorb light, invisible things are transparent . Dark matter is clearly the latter.

[hungrybirder]

Yes, Wu deserved that Nobel prize definitely!

[oisnowy]

Hey Dr. Don, if we can both watch the Sun grow into a Red Giant from a nice bar, I'll buy you a drink!