What is the Universe expanding into..

Do you think there was anything before the big bang?

  • I don't think there was anything before the Big Bang

    Votes: 56 12.5%
  • I think something existed before the Big Bang

    Votes: 200 44.7%
  • I don't think the big bang happened

    Votes: 54 12.1%
  • I think the universe is part of a mutiverse

    Votes: 201 45.0%

  • Total voters
    447
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I have always been clear that ANY number to power 0 is 1.

exp(0) is 1.

0^0 is 1.

Now you might admit to negative solutions with roots. So -1 is probably OK too.

Might need some care with a discontinuous function. Always be careful with them in algebra.

What about factorials? 🙂

1! is 1
2! is 2
3! is 6

What is 0! 😕

The answer drops out of the Gamma function.
Factorial - Wikipedia

It's 1.
 
I also spent some time on this Terrell Rotation thing at close to the speed of light. Does it rotate, or does it shorten due to Lorentz-Fitzgerald contraction?

The invisibility of length contraction – Physics World

900984d1607709685-universe-expanding-penrose-terrell-rotation-jpg


Looks like it is an optical illusion. The Dice isn't actually rotating. Just looks like it is. But I am in a bit of a muddle with it, so could be wrong.

The main takeaway seems to be this, our old view was wrong:

A previously popular description of special relativity's predictions, in which an observer sees a passing object to be contracted (for instance, from a sphere to a flattened ellipsoid), was wrong.
 
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0^0 sounds like a job for Andrew Wiles.

About the length contraction thing, I’ve seen two versions of what it must be like traveling at c for the observer:-

1. The observer feels as if they are stationary. Everything rushes past. Objects approaching have a blue hue to them. If the observer looks behind them, the objects receding away from them appear to be red shifted.

2. Everything is flattened as in a sheet of paper ie it exists only in 2D. The whole experience of moving at c passes by in an instant.

Which is it?

Roger Penrose has shown that as light passes through space it twists, or rotates.

Many theories. Few real answers.
 
Does it rotate, or does it shorten due to Lorentz-Fitzgerald contraction?
According to the above source, "An object approaching an observer at relativistic speeds would actually appear elongated, and even appear to rotate, allowing the back side of the object to be 'viewed' before the object had arrived. Only when receding from the observer does that fast-moving body appear squashed."
 
The Terrell-Penrose effect is mathematically real, but no one will ever observe it visually since the object would be moving at an unimaginable speed.

Our only chance of observing the effect is if an object the size of our solar system passed by at 99% of the speed of light. Now that would be spectacular and very scary sight! 😱

Terrell-Penrose Effect
 
I found some more good ones, though I had to download them to get them to play:

The Ball is Round

I was nagged by Roger Penrose's original paper "The apparent shape of a relativistically moving sphere."

His idea was the outline of the sphere or football always looks circular. But it appears to rotate and the panels on the football get bigger and smaller. But the ball is round!

I don't think working with rectangles and cubes has the same symmetry. Old Joan Baez is on it, but a deepish paper:

Can You See the Lorentz–Fitzgerald Contraction?
 
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