Speed of Light barrier

[IMAMONKEY!]

Whats a tachyon? :shrug:

[maddog]

Whats a tachyon?

A theoretical particle with property of having a velocity faster than that of light (> c). It is thought to

do so it would have an imaginary mass (sqrt(-1) factor), a negative kinetic energy and other strange

properties. Currently not to be in vogue though some string theories have some variation allowable

(often called Ghost particles).

 

maddog

[IMAMONKEY!]

SO... it has negative mass and hence it moves faster than light... I dont know if a tachyon is merely theoretical or not, but i dont think it could exist, because if it had negative mass, either there are a few more scientific laws we have yet to learn, or it cannot exist merely because it violates a few laws in our universe. If it had negative mass, then wouldn't it try to balance itself? Like antimatter? :eek:

[Aki]

But recently, I attended a String Theory lecture for the public, and someone asked about tachyons. The prof said that they don't exist and that people have "created" them just because they couldn't solve some of the problems in the String Theory.

[infamous]

But recently, I attended a String Theory lecture for the public, and someone asked about tachyons. The prof said that they don't exist and that people have "created" them just because they couldn't solve some of the problems in the String Theory.

I have a sneaking suspicion that they will never be able to solve all the problems with string theory. Theory built with the top down method has absolutely no foundation and is destined to fail.

[Erasmus00]

I have a sneaking suspicion that they will never be able to solve all the problems with string theory. Theory built with the top down method has absolutely no foundation and is destined to fail.

 

As suspicious as I am of top down theory, it has worked once. The field equations of GR were discovered top down.

-Will

[infamous]

As suspicious as I am of top down theory, it has worked once. The field equations of GR were discovered top down.

-Will

 

That may be true but, GR can be tested experimentally where string theory has maybe only a slightly better than zero chance of ever being tested experimentally. Unless you can provide evidence for your theory, don't call it science.

[Erasmus00]

That may be true but, GR can be tested experimentally where string theory has maybe only a slightly better than zero chance of ever being tested experimentally. Unless you can provide evidence for your theory, don't call it science.

 

The ultimate goal of string theory is like the ultimate goal of relativity. Produce a working model of the world, complete with prediction. Its just a long way from that goal. However, so many theorists are working on strings, it can't be that long before some testable predictions start falling out.

-Will

[infamous]

The ultimate goal of string theory is like the ultimate goal of relativity. Produce a working model of the world, complete with prediction. Its just a long way from that goal. However, so many theorists are working on strings, it can't be that long before some testable predictions start falling out.

-Will

 

This may come to pass Erasmus00 but I'm putting my money against it. By the time they sort out all the possible dimensions, which by the way reach into the thousands, we will all be in our graves. By that time a better mouse trap will surely emerge.

[Erasmus00]

This may come to pass Erasmus00 but I'm putting my money against it. By the time they sort out all the possible dimensions, which by the way reach into the thousands, we will all be in our graves. By that time a better mouse trap will surely emerge.

 

By dimensions, I'm assuming you mean solutions. And yes, its true, solutions number much higher than even the thousands. However, simple considerations, like energy conservation, tend to cut down the number. I'm skeptical of the string theorists' methods, but I'm hesitant to rule it out as a complete waste of time.

-Will

[Aki]

What do you guys mean by the "top down method"?

[Erasmus00]

What do you guys mean by the "top down method"?

 

Instead of starting from a physical observation, you start with a mathematical model, make predictions with it, and see if they match reality.

-Will

[EWright]

:xx:

Instead of starting from a physical observation, you start with a mathematical model, make predictions with it, and see if they match reality.

-Will

 

But be careful, because some physicists then warp reality to match the math. :)

[Erasmus00]

:)

 

But be careful, because some physicists then warp reality to match the math. :)

 

You can't. Either your prediction is valid, or it isn't. If one experimenter decides to lie, he/she almost invariably is caught, as the experimental data can't be replicated. Science is remarkably self correcting in this regard.

-Will

[EWright]

You can't. Either your prediction is valid, or it isn't. If one experimenter decides to lie, he/she almost invariably is caught, as the experimental data can't be replicated. Science is remarkably self correcting in this regard.

-Will

 

Not if their peers don't accurately understand what they are perceiving in the first place.

[coldcreation]

My opinion, for whatever it's worth is that we should not rule anything out for the moment—especially not those contentions proposed in theories (string, brane, M-theory, etc) that disproportionately benefit both from commercial success and official recognition—but we should not rule everything in either.

 

Stephen Hawking professes rather dovishly “we could never be quite sure that we had indeed found the correct theory, since theories can’t be proved” (1988 p.167). With this type of argument one is sure to get nowhere quickly. But he’s right!

 

With respect to string theory, despite some reserve, Hawking is not sure yet whether all the incongruous infinities cancel out, or how to relate the particular types of particles we observe in nature with the waves on a string: ”Nevertheless,” he speak clearly, “it is likely that answers to these questions will be found in the next few years, and that by the end of the century we shall know whether string theory is indeed the long sought-after unified theory of physics” (1988 p. 165).

 

Always a resourceful polemicist, Hawking does well to omit which century he is referring to. In this way the trough of disillusionment may last, and last, and last, and last, and last, and last, and last, and last, and last, and last, and last, and last.

 

Coldcreation

[EWright]

My opinion, for whatever it's worth is that we should not rule anything out for the moment—especially not those contentions proposed in theories (string, brane, M-theory, etc) that disproportionately benefit both from commercial success and official recognition—but we should not rule everything in either.

 

Stephen Hawking professes rather dovishly “we could never be quite sure that we had indeed found the correct theory, since theories can’t be proved” (1988 p.167). With this type of argument one is sure to get nowhere quickly. But he’s right!

 

With respect to string theory, despite some reserve, Hawking is not sure yet whether all the incongruous infinities cancel out, or how to relate the particular types of particles we observe in nature with the waves on a string: ”Nevertheless,” he speak clearly, “it is likely that answers to these questions will be found in the next few years, and that by the end of the century we shall know whether string theory is indeed the long sought-after unified theory of physics” (1988 p. 165).

 

Always a resourceful polemicist, Hawking does well to omit which century he is referring to. In this way the trough of disillusionment may last, and last, and last, and last, and last, and last, and last, and last, and last, and last, and last, and last.

 

Coldcreation

 

That's a pretty old source to be referencing regarding string theory, isn't it? I'm beginning to understand where your disbelief in black holes stems from.