COSMOLOGY AND INFLATION

COSMOLOGY AND INFLATION

ANIL MITRA PHD, 1999, REFORMATTED June 2003

Document status, June 7, 2003

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1. Recent Observations suggest that the universe is expanding at an accelerating rate

Experimentally, distant supernovae [of Type 1a] are dimmer than predicted by constant rate of expansion [after correction for mundane effects]. This agrees with the observation that some distant stars appear older that the age of the universe as predicted by a constant rate of expansion

There are two candidates to explain the dimming. First, the amount of matter in the universe is small and so the curvature is negative which results in dimming since A ^sphere > 4p R²…a flat universe is on the [parametric] boundary between a closed universe with [+] curvature and an open one with [-] curvature. However, the supernovae appear even dimmer than predicted by a nearly empty universe. The second explanation is the presence of some “anti” or repulsive gravitation that results in expansion at an accelerating rate and so stars are dimmer than predicted by a constant rate

At the very least, however, the universe’s expansion is not decelerating as rapidly as once thought

2. Squaring these considerations with big bang theory

The standard big bang does not describe the birth but, rather, the growth and maturation of the universe - the infant universe was hot and dense; a small part broke off and enlarged to become today’s observable universe. There are associated Paradoxes. Paradox # 1: why is the universe so uniform on the large scale when opposite sides are 24B light years apart and appear identical in nature yet they could not have been in communication since the universe is only 12B years old? Paradox # 2; why do expansion and gravity balance in the production of a flat universe -- at escape velocity --if expansion were too high, the universe would seem devoid of matter and, if it were too low, we would have already experienced the big crunch

How is it known that, as stated above, the universe is flat? In more detail, it has to do with stability. A flat universe would have magnified to produce and almost empty universe with almost zero density of matter…or a “crunch.” However, the universe is not like that and, therefore, the universe must have bee flat to one part in 10¹⁸. However, all this is within the standard theory itself. The big bang explanation for the very near flatness is “luck” - or the cosmological anthropological principle that some people regard with horror. This does not invalidate the big bang theory but shows that it is [likely] incomplete

Standard inflation theory [the “force” for inflation filed is quantum mechanical in nature and anti-gravitational in its sign] implies a higher early expansion and so uniformity…but it implies that for the universe to be uniform it must be flat. [The expansion results in cosmological friction, keeping the inflation field constant so gravity weakens and the distance between objects increases at an increasing rate. Finally, the field weakens and converts its energy to radiation. Now, expansion continues as in the standard big bang.]

However, flatness contradicts an accelerating expansion in the standard big bang - as is observed

There are two explanations. 1. “Anti-gravity” - due, perhaps, to the virtual field of the vacuum - equivalent to the cosmological constant that Einstein had abandoned -- this “rescues” standard inflation and, 2. A more sophisticated version of inflation that extends inflation to times before the big bang and corresponds to the universe as one of many bubbles nucleating out of a local minimum in the inflation field…in which uniformity and geometry [flatness] need not be linked