Redlined my brain trying to understand physics

[triangleforge]

http://xkcd.com/171/

[He Man]

Actually, I think physicists/cosmologists are moving away from string theory these days.

really? where the hell are they headed to now then?

I dont know what the next theory of everything is, but it all sure sounds like none of it will be solved anytime soon.

[superjohn]

really? where the hell are they headed to now then?

I dont know what the next theory of everything is, but it all sure sounds like none of it will be solved anytime soon.

And when it is you know what will happen? Universal apocalypse.

[yotogi]

really? where the hell are they headed to now then?

As I understand it by watching and reading this stuff casually, string theory has been extended into "membrane theory" aka "brane theory" or "m theory". It works much the same way but extends the "strings" into membranes. This is what takes the math to 11 dimensions from the 10 of string theory I believe.

Scientists don't even know what gravity is yet.  Of the four fundamental forces is physics, it's both the most powerful and least understood.

This is a bit misleading. Scientists understand how gravity manifests but are stumped by 2 things.
1.) Where does mass come from? Hopefully the Higgs will be seen at the LHC and that will take care of that little problem.
2.) Why is gravity so weak? As I understand it, M-theory hopes to answer that by showing that we only see part of the force of gravity in this dimension, with the greater portion of it acting in another one.

Even with a lot of casual interest in this, an 18 minute talk about high dimension symmetry with very little lead in will confuse more than it will inform.

Neat idea though. It will be interesting to see if we can create those missing particles. Hell, I will be excited if we can find the Higgs.

[EDIT: String theory works in 10 dimensions, m-theory, 11]

[NorDog]

As I understand it by watching and reading this stuff casually, string theory has been extended into "membrane theory" aka "brane theory" or "m theory". It works much the same way but extends the "strings" into membranes. This is what takes the math to 12 dimensions from the 10 or 11 of string theory I believe.

This is a bit misleading. Scientists understand how gravity manifests but are stumped by 2 things.
1.) Where does mass come from? Hopefully the Higgs will be seen at the LHC and that will take care of that little problem.
2.) Why is gravity so weak? As I understand it, M-theory hopes to answer that by showing that we only see part of the force of gravity in this dimension, with the greater portion of it acting in another one.

Not sure what understanding "how gravity manifests" really means.  But answering where mass comes from doesn't explain what gravity is.  There is an observational correlation between mass and gravitational force, but that's not nailing down what that force is.

And gravity is not weak, it's the strongest of the four fundamental forces.  Think "Black Hole".

[Monsterlover]

[yotogi]

Not sure what understanding "how gravity manifests" really means.  But answering where mass comes from doesn't explain what gravity is.  There is an observational correlation between mass and gravitational force, but that's not nailing down what that force is.

"How gravity manifests" was a bad way to express that thought. Gravity works on mass, we have not found how the fundamental particles attain mass. That is the search for the Higgs. I should have said, we can see gravity working, but we have yet to show how mass gets there.

And gravity is not weak, it's the strongest of the four fundamental forces.  Think "Black Hole".

Sorry, that is not true. Gravity is in fact very weak. It takes a lot of matter in a very small space to create a black hole. Once you do, it can overcome the other forces, ripping atoms apart. But consider gravitation in the normal sense. A tiny magnet can create enough of a magnetic force to overcome the entire gravitational force of the earth.

This is a quote from an article talking about the weakness of gravity in New Science.

"Take a moment to try a jump into the air. Have you ever thought about how remarkable it is that so little effort is required to jump a few inches off the ground. Your puny muscles, weighing just a few kilograms, can overcome the gravitational force of the Earth, all 6 × 1024 kilograms off it. Gravity is a real weakling - 1040 times weaker than the electromagnetic force that holds atoms together."

http://www.newscientist.com/article/mg20227122.900-gravity-mysteries-why-is-gravity-so-weak.html?haasFormId=46aa9eea-8158-4b87-8d70-3994c2a1bd64&haasPage=0

All of that coupled with the fact that can't account for where most of the mass in the universe come from (dark matter), why it is accelerating (dark energy), how it was able to expand so quickly (cosmic expansion) and why it doesn't fit at all into the standard model. We have an excellent model for gravity on the large scale but the "theory of everything" is making it work with the rest of the Standard Model.

[NorDog]

Sorry, that is not true. Gravity is in fact very weak. It takes a lot of matter in a very small space to create a black hole. Once you do, it can overcome the other forces, ripping atoms apart. But consider gravitation in the normal sense. A tiny magnet can create enough of a magnetic force to overcome the entire gravitational force of the earth.

It is true.  Of the four forces, gravity overcomes the other three.  Just because it only does so in certain places under certain circumstances, it is still the strongest.  The gravitaional force of a Black Hole counts.

I'm interested to know which of the forces you consider the strongest?  Electromagnatism?  Weak Nuclear?  Strong Nuclear?

[ducpainter]

Actually, I think physicists/cosmologists are moving away from string theory these days.

Two pieces of string walk into a bar and the bartender looks at them suspiciously. He says "Sorry, boys, we don't serve your kind here." So the pieces of string walk out again.

They're sitting in the gutter outside and feeling really thirsty when one piece of string says "Hey! I've got an idea to get me into the bar."

So he starts twisting and turning, wriggling this way and that, pulling out a few threads here and there. His mate's looking at him and thinks he's gone completely nuts.

Then the piece of string walks back into the bar. The bartender looks at him a little suspiciously again and says "Here, you're not a bit of string, are you?"

The piece of string replies "No, I'm a frayed knot."

[brimo]

I did pretty well in calculus and physics, but I can't believe how content I am to just go about my daily life and not stress over this kind of stuff.

Call me small minded, but I'd rather spend my time learning about things in the physical world that are more applicable (probably the wrong word) to me.

However, I am glad that there are people that understand this stuff and make it more applicable to me through advances in technology in a way that I can see and appreciate in my daily life.

Well said.
Still enjoying this thread though, wouldn't get one like this on the gixxer forum I'm sure.

[Grampa]

I was hoping he would explain countersteering.

[superjohn]

I was hoping he would explain countersteering.

And if the airplane was on a conveyer belt that was spun in 8 dimensions would it take off, or travel through time.

[yotogi]

It is true.  Of the four forces, gravity overcomes the other three.  Just because it only does so in certain places under certain circumstances, it is still the strongest.  The gravitaional force of a Black Hole counts.

I'm interested to know which of the forces you consider the strongest?  Electromagnatism?  Weak Nuclear?  Strong Nuclear?

I cannot argue my point. I am going with what I have read in many places and seen in many science tv shows. If I were to try to make an argument, I would say that strength would have to have some metric. One that you might use would be measure of effect per unit weight. This sets up gravity to fail as it is a function of mass.

The quote from New Scientist magazine that I quoted and linked would lead me to say that any of them are stronger, electromagnetism at 1040 times stronger.

But what is the point of going on about it? There is current research attempting to find out where the expected strength of gravity is going. If you really want me to try and dig it up I can do some searching.

[He Man]

When you are doing quantum mechnics, you always ignore gravity since you are dealing with a small quanta of whatever it is your looking at, gravity is so weak, it can be ignored.

However, you can add up gravity with mass. So in some cases it is the strongest force and we must take it into account, but in other cases, it is the weakest force and we can ignore it.

to argue which is stronger is a moot point because all 4 forces are fundamental and cannot be compared to any of the other 3 forces, without looking at the whole picture of what you are trying describe.

[NorDog]

Perhaps a bit of Aristotelean potency and act can help here.

Gravity has the greatest potential for strength, and sometimes that maximum strength is actualized.