Wednesday, November 02, 2005

The Cyclic Theory

In 2003 Steinhardt from Princeton and Turok from Cambridge published their landmark paper on what will be the next paradigm: the cyclic theory.

Here are its salient features:
- space and time exist forever
- the big bang is not the beginning of time; rather, it is a bridge to a pre-existing contracting era
- the Universe undergoes an endless sequence of cycles in which it contracts in a big crunch and re-emerges in an expanding big bang, with trillions of years of evolution in between
- the temperature and density of the universe do not become infinite at any point in the cycle; indeed, they never exceed a finite bound (about a trillion trillions degrees)
- no inflation has taken place since the big bang; the current homogeneity and flatness were created by events that occurred before the most recent big bang
- the seeds for galaxy formation were created by instabilities arising as the Universe was collapsing towards a big crunch, prior to our big bang

Why a new theory? For different reasons, but one very important one was the fact that the universe is accelerating.

Now in the Big Bang Theory (BBT), one uses the analogy of sending a rocket into space. To do that, one must calculate the escape velocity of the rocket. What we do is to look at its total energy, its kinetic energy – how fast must it go – and its potential energy – due to the attraction of the Earth on the rocket. To escape the Earth’s gravitational attraction, we calculate that the rocket’s energy at infinity will be zero.

½m(v squared) + - GMm/R = 0

Where: v is the escape velocity of the rocket
m is the rocket’s mass
M is the Earth’s mass