Dark Matter Lecture at Stanford

JeffKeryk

JeffKeryk

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This past Tuesday wifey and I attended a lecture on Dark Matter at Stanford Uniiversity in Palo Alto. Being on the campus and especially in a classroom is, by itself, an inspiring experience.
What is Dark Matter? The correct answer is, "I don't know."

The lecturer was Dr. Rebecca Leane. The information came fast and difficult; the Q&A afterwards was more of the same. One little kid asked a really tough one... My favorite question was, "How do we know Dark Matter makes up 95% of our Universe, and are you sure?"
With the JWST and more, this is an amazing time to be alive!
 
Studied a bit of quantum mechanics in p-chem in college and then a decade later read Susskind's book which is very approachable as far as books on QM go. Bra and ket vectors and dot products oh my!

I've seen a few of his lectures online too from Stanford and it always made me want to go and visit. Living in a University town has its advantages!
 
PWMDMD said:
Studied a bit of quantum mechanics in p-chem in college and then a decade later read Susskind's book which is very approachable as far as books on QM go. Bra and ket vectors and dot products oh my!

I've seen a few of his lectures online too from Stanford and it always made me want to go and visit. Living in a University town has its advantages!
Click to expand...
I take my grand nieces to the local Universities and Community Colleges. Their father passed away years ago; I have committed to their college, should they choose to go. The promise of CA low cost, quality education is not what it was, but is still a bargain.
 
If you have not read “The Making of the Atomic Bomb” by Richard Rhodes, a Pulitzer Prize winning book, it is a must. Certainly read it before you see “Oppenheimer”.

Back to dark matter…the gravitational evidence for its existence is there, as is the gravitational evidence for the existence of dark energy.

Neither of which have been quantified, defined or observed.

Initially, dark matter was simply considered to be ordinary matter, that wasn’t luminous. That is to say that it wasn’t visible in the form of a star, or something like a gas cloud illuminated by a Star, that we could see. We knew from analysis of gravitation that there must be more mass.

How that mass is accounted for, the nature of that matter, is still not determined.

It’s been interesting to watch the theory evolve. Still have a long way to go.
 
Dr. Leane is theorizing and basing her current work on DM concentrated possibly interacting with a cold planet or exo-planet by measuring temperature change. Or whatever she was talking about!
 
I read somewhere, maybe here, that if your model relies upon the existence of matter that we can't see and can't even postulate the nature of, then maybe you need a new model.
We do know that the structure of the observable universe would require a whole lot more mass to explain than what we can account for in the absence of some yet undiscovered and not yet theorized property.
With better observational tools, like the JWST, we'll be able to observe more over time and maybe be able to unlock the secrets of this vast and finite space in which our planet and even our galaxy are like a molecule of water in our world's oceans.
The whole topic is fascinating for its scale in space and time.
 
Per Astro's post.

something that can't be seen, measured, or interacted with, and comprises 20(ish) times as much as that which we can see, touch, and measure...to me tells me there's somehting missing.

Newton nailed his field, but he, and everything that he was measuring were at speeds approximating zero (relativistically)....Einstein took in the next realm, and if you have small "v" components, describe Newton...but then Einstein's equations become infinity at near light speed. Suggesting that maybe THEY are a subset of something else that we don't know yet.

I don't think we've explored adequately potential differences between bodies (when we sent a copper probe into an asteroid, at a near distance, they had to equalise their potentials, and a huge flash occurred...and we've got a nuclear reactor pelting our planet with ions...has to have a part.

Not an expert in any of those things, and haven't really followed the last 5 or so years, being pretty well involved in power stuff.
 
Over 8 decades of searching for theoretically motivated dark matter candidates have yielded no results.

There is an On-line paper out there that deals with the detection of DM:

Dark Matter Detection Materials
James E. Harrison IV
Department of Physics
University of North Florida

I do however appreciate his honesty in the paper:

"...A more likely solution would be that our understanding of dark matter is incorrect. Most of the current detectors for dark matter assume that dark matter exists as some weakly interacting particle that may collide with the detector. However, other theories for dark matter are currently being developed, such as primordial black hole remnants or even dark stars. While these theories are speculative, they demonstrate the possibility of alternate theories. A final potential solution would be the simplest. Similar to the accidental discovery of Pluto, it is possible that the observations are flawed in some way. There is currently no evidence outside of dark matter to suggest this, but I felt that it was worth mentioning for the sake of completeness."
 
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Astro14 said:
If you have not read “The Making of the Atomic Bomb” by Richard Rhodes, a Pulitzer Prize winning book, it is a must. Certainly read it before you see “Oppenheimer”.

Back to dark matter…the gravitational evidence for its existence is there, as is the gravitational evidence for the existence of dark energy.

Neither of which have been quantified, defined or observed.

Initially, dark matter was simply considered to be ordinary matter, that wasn’t luminous. That is to say that it wasn’t visible in the form of a star, or something like a gas cloud illuminated by a Star, that we could see. We knew from analysis of gravitation that there must be more mass.

How that mass is accounted for, the nature of that matter, is still not determined.

It’s been interesting to watch the theory evolve. Still have a long way to go.
Click to expand...
Great book, I can already kinda tell the new movie will be quite embellished but still seeing it with a friend this weekend. I have a few chunks of green stuff from the trinity site and I swear they tingle a little bit.

Also, if anyone has the opportunity to see Neil Degrass Tyson in person, its well worth the money. He appreciates down to earth people, and I mean that from having a very basic conversation with him that wasnt starry eyed blindness.
 
fdcg27 said:
I read somewhere, maybe here, that if your model relies upon the existence of matter that we can't see and can't even postulate the nature of, then maybe you need a new model.
We do know that the structure of the observable universe would require a whole lot more mass to explain than what we can account for in the absence of some yet undiscovered and not yet theorized property.
With better observational tools, like the JWST, we'll be able to observe more over time and maybe be able to unlock the secrets of this vast and finite space in which our planet and even our galaxy are like a molecule of water in our world's oceans.
The whole topic is fascinating for its scale in space and time.
Click to expand...
What the JWS has shown so far is that are many more galaxies out there at farther distances than we thought.

These galaxies are composed of Baryonic (real) matter. I don't think there is dark matter, just more real matter than we ever knew existed.
 
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cptbarkey said:
Great book, I can already kinda tell the new movie will be quite embellished but still seeing it with a friend this weekend. I have a few chunks of green stuff from the trinity site and I swear they tingle a little bit.

Also, if anyone has the opportunity to see Neil Degrass Tyson in person, its well worth the money. He appreciates down to earth people, and I mean that from having a very basic conversation with him that wasnt starry eyed blindness.
Click to expand...
And even more interesting set of books with better accuracy and more detail (written by a physicist) is by

Bruce Cameron Reed,
The History and Science of the Manhattan Project,
published by Springer.

link.springer.com

The History and Science of the Manhattan Project

link.springer.com link.springer.com

Chapters 7 and 8 are stunning.

and

Bruce Cameron Reed,
The Physics of the Manhattan Project,
published by Springer.

link.springer.com

The Physics of the Manhattan Project

link.springer.com link.springer.com

also there is:


published by the US DOE.
 
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I remember back in high school I attended a couple of lectures on theoretical physics by some professor at Cambridge. It was during our spring break and they were free. I think dark matter might have been discussed in relation to black holes. I barely understood practical physics, so a lot of this stuff was well over my head. Also - the Q&A sessions took a while and he only managed about 3-4 questions in the time allotted.

 
MolaKule said:
Over 8 decades of searching for theoretically motivated dark matter candidates have yielded no results.

There is an On-line paper out there that deals with the detection of DM:

Dark Matter Detection Materials
James E. Harrison IV
Department of Physics
University of North Florida

I do however appreciate his honesty in the paper:

"...A more likely solution would be that our understanding of dark matter is incorrect. Most of the current detectors for dark matter assume that dark matter exists as some weakly interacting particle that may collide with the detector. However, other theories for dark matter are currently being developed, such as primordial black hole remnants or even dark stars. While these theories are speculative, they demonstrate the possibility of alternate theories. A final potential solution would be the simplest. Similar to the accidental discovery of Pluto, it is possible that the observations are flawed in some way. There is currently no evidence outside of dark matter to suggest this, but I felt that it was worth mentioning for the sake of completeness."
Click to expand...
Dr. Leane mentioned those other theories to understanding DM. The 2nd half was discussing her approach and the reasons in support of that approach.
One of the follow up questions asked how long it might take to identify and perhaps understand DM. She laughed and said something like, "I wish I knew! Maybe in my lifetime, maybe in 100 years?"

Stanford offers these lectures free to the public on a monthly basis with breaks from time to time. The mix of attendees is pretty varied, from students, to interested people like Sue and I and parents with pretty young children. One young man asked a pretty involved question. Amazing...

I'm not sure, but I think I am smarter today.
 
MolaKule said:
Yep, taking the whole family tomorrow afternoon to see it.

I have one Grandboy who is going with us that wants to become a Physicist. I told him that physicists do other things than make A and H bombs. :cautious:
Click to expand...
FYI, if you didn't click on the link, I am not referring to the movie.
I am attending a panel discussion about his pre-war life at Berkeley on the Berkeley Campus.

"To provide a different perspective on that history, four UC Berkeley faculty members and a nuclear physicist from Los Alamos National Laboratory will assemble for a panel discussion at 11:30 a.m. on Friday, July 28, to discuss Oppenheimer’s pre-war UC Berkeley years and his scientific and human legacy."

Gonna see movie soon!
 
JeffKeryk said:
FYI, if you didn't click on the link, I am not referring to the movie.
I am attending a panel discussion about his pre-war life at Berkeley on the Berkeley Campus.

"To provide a different perspective on that history, four UC Berkeley faculty members and a nuclear physicist from Los Alamos National Laboratory will assemble for a panel discussion at 11:30 a.m. on Friday, July 28, to discuss Oppenheimer’s pre-war UC Berkeley years and his scientific and human legacy."

Gonna see movie soon!
Click to expand...
No, I fully understood you were to be attending a conference at UC Berkeley on Oppenheimer's pre-war years and not the movie.

You may hear in this conference that Oppenheimer had laid the foundation for the physics of Black Holes:

The Reluctant Father of Black Holes

Albert Einstein's equations of gravity are the foundation of the modern view of black holes; ironically, he used the equations in trying to prove these objects cannot exist
www.scientificamerican.com www.scientificamerican.com

Oppenheimer’s Folly: On black holes, fundamental laws and pure and applied science

On September 1, 1939, the same day that Germany attacked Poland and started World War 2, a remarkable paper appeared in the pages of the journal Physical Review.
blogs.scientificamerican.com blogs.scientificamerican.com

physics.aps.org

Landmarks—Forgotten Black Hole Birth

The modern concept of a black hole came from a 1939 paper by atom bomb physicist J. Robert Oppenheimer.
physics.aps.org physics.aps.org

Oppenheimer, Wheeler, black holes, and the atom bomb. - Knight Science Journalism @MIT

[Ann Finkbeiner emailed to say she had learned that Oppenheimer died before the phrase "black holes" came to be used. Updates to correct.] On a single day in 1939, J. Robert Oppenheimer explained how a star implodes when it runs out of fuel; John Archibald Wheeler published the explanation of...
ksj.mit.edu ksj.mit.edu

I also happen to be a member of the APS as well as the STLE.
 
Nibblonians.jpg

The Nibblonians are Subject Matter Experts on Dark Matter
 
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