Dark Matter Lecture at Stanford

[PWMDMD]

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.

We made so much progress in the early 20th century with quantum mechanics, general relativity, and special relativity - all of which are some of the most tested theories in science. Then quantum chromodynamics made a bunch of predictions and the standard model was born. Then enter string theory and the search for quantum gravity which has gone no where for decades and decades. Now we have dark matter and dark energy. It's not that there's been no action - ex. LIGO put to rest the 100 year old prediction of gravitational waves.

The standard model does such a great job of explaining our everyday experiences and it has been tested and tested and yet we still don't know what most of the universe is made up of and we don't understand why matter observed at small scales uses a completely different set of rules as the same matter observed at large scales. Why is one fundamental force, gravity, orders of magnitude weaker than the other three and why is there no quantum mechanical theory for it? Why is it different?

If we can figure out quantum gravity and dark matter/energy and it is consistent with the standard model then we are in really good shape as far as our understanding of the universe and we can explain just about everything other than very special circumstances which may or may not exist naturally.

 

[97prizm]

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!

I used to deal with alot of theoretical physicists when I worked the front desk of a hotel and I'd always pick their brain about stuff like this. My only complaint is that I'd really dislike it if I spent 30 plus years researching a topic ie dark matter then figured out it didn't exist. I do know that many theoretical physicists for some reason couldn't figure out how to use the Keurig coffee maker but could explain the universe.

 

[PWMDMD]

I used to deal with alot of theoretical physicists when I worked the front desk of a hotel and I'd always pick their brain about stuff like this. My only complaint is that I'd really dislike it if I spent 30 plus years researching a topic ie dark matter then figured out it didn't exist. I do know that many theoretical physicists for some reason couldn't figure out how to use the Keurig coffee maker but could explain the universe.

It's really hard to prove a negative and so to debunk the existence of dark matter (I mean we don't even know what we're debunking) would mean you'd have to have really solid and tested evidence for some other reason why matter is behaving the way it does and that'd probably get you the Nobel prize. I don't think any dark matter physicist who stumbled onto this solid alternative explanation would complain!

 

[JeffKeryk]

@MolaKule your schedule permitting, I would appreciate reading your review of the movie. I imagine others would as well. Thanks in advance.

Now, please excuse me as I need to go out and find some of those pesky Dark Matters... Ha!

 

[y_p_w]

@MolaKule your schedule permitting, I would appreciate reading your review of the movie. I imagine others would as well. Thanks in advance.

Now, please excuse me as I need to go out and find some of those pesky Dark Matters... Ha!

Found it.

 

[fdcg27]

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.

Very interesting take on this.
No dark matter, just plenty of ordinary mass that we haven't been able to observe.

 

[Sam_Julier]

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.

The History and Science of the Manhattan Project

link.springer.com

Chapters 7 and 8 are stunning.

and

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

The Physics of the Manhattan Project

link.springer.com

also there is:

Manhattan Project: Science

published by the US DOE.

Just bought it.

 

[PandaBear]

I used to deal with alot of theoretical physicists when I worked the front desk of a hotel and I'd always pick their brain about stuff like this. My only complaint is that I'd really dislike it if I spent 30 plus years researching a topic ie dark matter then figured out it didn't exist. I do know that many theoretical physicists for some reason couldn't figure out how to use the Keurig coffee maker but could explain the universe.

Many scientists and engineers spend their lives improving the understanding of our universe. We don't always find them individually, but we do prove and disprove stuffs that narrow down our understanding of the world around us as a whole. They are making a living, educating the next generation, and help narrowing down where things will and should go next, I think that's great even if they can't be the one out of tens of thousands hitting the nail on the head.

Regarding to dark matters, I don't like the model of "we can't test it or find it but our math says it exists, because math can't be wrong". I really hope they would be able to improve their models so they can balance the equations and find everything that they can quantify and measured, instead of leaving a big unsolved variable and call it "dark matter".

Someday, we will find a model and call this "dark matter" something else, or an improved equation that does it without "dark" something.

 

[PWMDMD]

Many scientists and engineers spend their lives improving the understanding of our universe. We don't always find them individually, but we do prove and disprove stuffs that narrow down our understanding of the world around us as a whole. They are making a living, educating the next generation, and help narrowing down where things will and should go next, I think that's great even if they can't be the one out of tens of thousands hitting the nail on the head.

Regarding to dark matters, I don't like the model of "we can't test it or find it but our math says it exists, because math can't be wrong". I really hope they would be able to improve their models so they can balance the equations and find everything that they can quantify and measured, instead of leaving a big unsolved variable and call it "dark matter".

Someday, we will find a model and call this "dark matter" something else, or an improved equation that does it without "dark" something.

That's not really the model here. General relativity which has been tested over and over again and by all accounts seems to be correct predicts that galaxies with a certain mass will move a certain way. DIRECT OBSERVATION, not math, says it is not moving the way it should based on what matter/mass we see. Math then says, gee, they are moving like there's a whole lot more mass there than we see.

If the math of general relativity is wrong then why does it predict so much locally so well? Either general relativity is some how wrong yet it predicts the time dilation we account for GPS perfectly, gravity lenses, the motion of stellar bodies locally, etc, or there's more mass there than we can see.