Perimeter Institute Launches Modern Physics Resource

An anonymous reader writes "You can find six new online sources of info about hot topics in modern physics at the 'What We Research' outreach page of Perimeter Institute. The info includes text, graphics and online presentations dealing with Cosmology, Superstring Theory, Quantum Gravity, Quantum Foundations, Quantum Information and Particle Physics. The resource section at the bottom of each page recommends a wealth of interesting online lectures by some famous scientists. PI is an independent, nonprofit scientific research and outreach organization."

Comments

Wrong site?

[dotancohen]

Cosmology, Superstring Theory, Quantum Gravity,...

For a minute there my subconscious thought that I had browsed to a women's magazine by accident...

Re:Wrong site?

[Anonymous Coward]

You mean Quantum Gravity!

Re:Wrong site?

[ioshhdflwuegfh]

This is what they say about them(selves):

They cluster in Waterloo, Ontario, to forge new, mind-bending ideas about the ultimate nature of our universe, from space and time to matter and forces. Driven by curiosity, their mission is to unlock nature's most profound secrets hidden deep inside the atom and far across the universe.

As Big Lebowski would say: "far out... far fucking out!"

Re:Goatse

[Anonymous Coward]

Brought to you by AC's who love it!

All AC?

[Anonymous Coward]

This whole thread will be populated by AC's?

Web page is wrong

[mangu]

The Einstein portrait caption reads "1870-1955". Einstein was born in 1879, the same year when Maxwell died.

Let's hope their theoretical physicists are more careful than their webdesigners.

Re:Web page is wrong

[Anonymous Coward]

Are you happy?

what's old is new again

[Potor]

From one of the resources on superstring theory

Why do we see only point-like entities? The answer is simple: elementary strings, if they exist, are far too tiny to see. It is unlikely that even the most sophisticated microscope or particle accelerator that could be constructed would ever have enough resolution to directly "see" the strings of string theory.

Sounds like Epicurus all over again - small, indivisible, and invisible particles whose motion explain everything. Only he called them atoms.

I know superstring theory has better explanatory power than Epicurus' atomism, but I am intrigued by the invisibility of the strings, which the resourse above seems to make elementary, just like Epicurus.

Re:what's old is new again

[Ambitwistor]

Technically you can "see" the strings, since in string theory every elementary particle is a string. In string theory, any time you detect an electron or a photon, you're looking at a string. It's just that they're so small, we may never be able to tell that they're actually strings and not point particles.

Re:what's old is new again

[dotancohen]

Technically you can "see" the strings, since in string theory every elementary particle is a string. In string theory, any time you detect an electron or a photon, you're looking at a string. It's just that they're so small, we may never be able to tell that they're actually strings and not point particles.

Correct me if I'm wrong, but as I understood it the particles are strings in x dimensions, and in the superplane of our 3d existence they appear as points. Just as a line passing through a plane appears as a point on the plane.

Re:what's old is new again

[Karma Bandit]

AFAIK that isn't a requirement, though it does lead to some neat things to think about.

For example, imagine one string with both of its ends stuck on our 3D "plane", but with the bulk of it floating "above" the plane. The point at one end is an electron and the other end a positron. When they meet, the loop closes, forming a photon, which is a closed loop type of string.

Re:what's old is new again

[Potor]

Correct me if I'm wrong, but as I understood it the particles are strings in x dimensions, and in the superplane of our 3d existence they appear as points. Just as a line passing through a plane appears as a point on the plane.

that's corresponds with what little I know of string theory, and i must admit i find the concept esoteric, if not mystical.

but then surely it is incorrect to say that they are too small to see? that's a serious question (IANAPP) and i will be happily corrected.

Re:what's old is new again

[John Hasler]

An electron and a positron usually react to produce two photons (never just one). Sometimes other particles such as neutrinos are produced.

Re:what's old is new again

[Ambitwistor]

Strictly and classically speaking, that's correct. However, since the string is always vibrating, you're going to see more or less its full extent in our 3D space as different parts of it pass through our 3D hyperplane at nearby instants of time. If you could take an instantaneous (or Planck time) snapshot of a string, you'd only see a few points of it at once (wherever it intersects at that moment). In reality, if we could detect spatial structure on such small scales at all, we'd see it smeared out spatially (think "camera blur"), not a pure point.

Another way of looking at it is that since all our constituent strings are constantly vibrating in all the higher dimensions, there is no such thing as "our 3D hyperplane" — it's fuzzed out over the higher compact dimensions, so we're never really seeing a specific slice of it.

(In the braneworld scenarios with large extra dimensions, this is somewhat less true: the endpoints of non-gravitational strings are trapped on a specific 3D hyperplane. However, the rest of the string can vibrate a little off of it.)

More concretely, if we could scatter strings off each other at Planck-scale energies in a particle acclerator, their behavior would deviate markedly from that of point particles (basically because strings breaking and merging is a "smoother" process than particles bouncing off each other).

Re:what's old is new again

[dkf]

An electron and a positron usually react to produce two photons (never just one). Sometimes other particles such as neutrinos are produced.

If my scanty topology is correct, a loop intersecting a plane will (normally) do so at two points.

But realistically, it's probably not a good idea to try to reason about superstrings by analogy with normal 3D entities. After all, it's pretty tricky to just go from 2D to 3D, and strings have rather a lot more dimensions than that...

Re:what's old is new again

[Iamthecheese]

meh

Re:what's old is new again

[Anonymous Coward]

string theory.. hmmm.. can it explain why things are quantum?

LHC Compact Muon Solenoid Experiment Webcams

[trinity93]

Live! LHC Compact Muon Solenoid Experiment Webcams

What's old is what's old again.

[Anonymous Coward]

So what you're saying is that it's turtles all the way down.

High in his Transylvanian castle

[David Gerard]

At this point, Lubos Motl, high in his Transylvanian crag-side castle, let out a shout of anger, causing even his henchmen to scatter. "SMOOOOO-LINNNNN!"

mod parent up!

[Tsaroth]

Exactly!

videos don't work

[Inovaovao]

If you follow the links and try to actually see one of the nice presentations on the PI website you'll find that these don't always work. In particular I can't hear any sound (I'm on OS X).

Anybody the same problem?

Re:videos don't work

[Anonymous Coward]

yah.. osx problem though... google for a solution, i can't remember what i did (i think playing with midi options)...

Re:They seem to be missing one important field of

[exp(pi*sqrt(163))]

It's no good just taking or leaving the meds whenever you feel like it. The whole point is to have a constant level in your brain, and that is only going to happen if you take them regularly, even on the days when you feel good. Otherwise, this is just the sort of comment you're going to keep writing.

Re:They seem to be missing one important field of

[3seas]

Imagine the argument the Elite Roman Numeral Accountants had against the concept that nothing can have value in the much easier to use Hindu Arabic decimal system with it zero place holder. It took 300 years for the Decimal system to over come the roman numeral system of mathematics.

Is it really any supprise the initial post was modded a troll?

Someone needs to go back to school.

[Glassagate]

"PI is an independent, nonprofit scientific research and outreach organization" Wrong. Here's what it is (to 20 decimal places) 3.14159265358979323846

Last post? Anybody?

[ioshhdflwuegfh]

Total of 30 posts, incl. 2 of mine... not exactly a hot topic is this PI launch, is it?