Heads up Tonight SBS Two 8.30pm - 9.30pm

[supernova1965 (Warren)]

The Elegant Universe

Einstein's Dream (Repeat)

• 8.30pm - 9.30pm
• SBS TWO
• Tonight

ALT. TIMES

Albert Einstein, the inventor of general relativity, dreamed of finding a single theory that would embrace all of nature's laws. But in this quest for the so-called unified theory, Einstein came up empty-handed, and the conflict between general relativity and quantum mechanics has stymied all who've followed. That is, until the discovery of string theory. Physicist Brian Greene leads a tour of this seemingly strange world.

[Mliss (Mel)]

thanks Warren!

[astroron (Ron)]

Warren,
Cheers

[mswhin63 (Malcolm)]

Thanks Warren.

[GeoffW1 (Geoff)]

You are our Doug Anderson

[supernova1965 (Warren)]

Originally Posted by GeoffW1

You are our Doug Anderson

Thanks I googled to find out why I was him and thought maybe the second one but I am unsure which to pick.

Douglas Anderson may refer to:

• Douglas A. Anderson (born 1959), writer, editor and Tolkien scholar
• Douglas Anderson (writer), head writer of the TV series Guiding Light
• Doug Anderson (fighter) (born 1982), American television personality
• Doug Anderson (ice hockey) (1927–1997), Canadian ice hockey player
• Doug Anderson (journalist), Australian journalist
• Doug Anderson (singer) (born 1975), American gospel singer
• Douglas Anderson (mayor), mayor of Dayton, Minnesota
• Doug Anderson (poet) (born 1943)

[iceman (Mike)]

Did anyone watch last nights one about String Theory?

[spacezebra (Petra)]

Yes, watched it last night! Brilliant.

Cheers Petra d.

[iceman (Mike)]

Agreed!

[Suzy]

This is a great 3 part series produced by NOVA. Have watched the series a couple of times. Beautifully explained by Brian in a fairly easy to understand manner. I am a Brian Greene fan.

What we do without Warren here to remind us of programmes! You're a good man Warren.

[g__day (Matthew)]

It was very well explained, but it ended before discussing its limitations - the main ones seem to be:

1) It could fit any reality - literally 10^500 realities could be described by String theory - its just too broad and adaptive

2) It isn't predicitive - it doesn't (yet) postulate things that may or may not happen

3) It deals with scales so far below the sub-atomic (10 ^ -20 metres) - we are right at Planck levels here (10 ^ -45) there are unreachable by any man made or naturally occuring event.

So if theoretical physicists have to choose from M-theory, SuSy etc - eventually you want a model that:

1. Dervives the 20+ constants that describe our reality - to high precision - and show why they take on those exact values

2. Unites General and Special Relativity with Quantum Mechanics (the world above the size of an atom with the world far smaller) - it would be brilliant if it describes what happens when two sub atomic particles get really really close (interactions between the four forces and spacetime itself).

3. Fits observable data, including expansion, big bang, inflation, dark energy, dark matter and dark flow.

4. Describes ultra high energy desnisty physics and how space time and the four forces react when energy levels approach that of the big bang or a black hole implosion within the event horizon (i.e. energies well above 10 ^ 45 Joules per cubic metre)

I love watching these series but I'd love for them to compare and contrast how they each progress towards final undderstanding based on a set of criteria they have to cover - like those above.

Myself - I tend towards M-Theory + MOND + scale relativity (saying the universe - spacetime is approximately 2.61 dimensional - i.e. fractal in large observable dimensions - at very, very small and very, very large scales).

[CraigS]

I've been doing some reading up on this and as I understand it, the way all this works is that we start out with classical theory that describes vibrating strings (eg: violin strings). This is then extended to describe relativistic strings by incorporating Special Relativity (SR). This in turn is then made into a quantum theory (QM), by quantising things (ie: frequencies etc). As a by-product of these operations, full General Relativity (GR) then 'pops' out in the mathematical workings !

In this sense, it could be argued that String Theory's greatest 'prediction' is gravity ... which turns out to be indistinguishable from General Relativity. (Indistinguishable that is, in the range where GR has been observed (demonstrated) to work). Even though we already know about GR, it is one of the curious aspects of Superstring theory, that GR is produced … without any prior GR thinking/assumptions. So, in other words, postulating strings leads invariably to GR !

GR and String theory deviate at the planck scale (which is because the combination of Quantum Mechanics, (QM), and GR become inconsistent at that scale anyway).

At the moment, it appears that string theory handles the GR singularities at these scales in a better way, but I don't think anyone has developed the calculations to demonstrate this yet.

String theory is not constrained properly yet … and allows way too many solutions. The 'extra dimensions' can only be detected at extremely high energies .. not really able to be replicated any time soon.

Oh .. and 'yes' .. apparently, string theory can also derive black holes.

Cheers