Cosmology 101

azpaul3 writes:Since this is Cosmology 101 not Personality 101 let's try to get back to the OP.cavediver or Son Goku: If it's too early for this depth of discussion please say so, but the OP specifically asked for points on inflation.One slant on the mechanism includes a scalar field energy difference (kinetic v potential) exerting negative pressure with GR saying under such negative pressure gravity becomes a repulsive force. Another hypothesis posits a scalar field of inflatons or a combination of Higgs fields (?)Can either of you enlighten us on these hypotheses?

Scalar fields have been part of space-time physics since GR was first published 93 years ago. Einstein's Cosmological Constant (CC) is effectively a trivial scalar field. The template for Inflation, the exponentially expanding de-Sitter space-time discovered a few years after GR was puclished, is driven by the CC. True scalar fields became a serious consideration in Kaluza Klein theories (1920s) and later in Brans-Dicke theory around 1960. In the 70s and 80s, scalar fields were scattered throughout Supergravity, and then onwards in all flavours of string theory and now M-theory. There is nothing new about scalar fields For a scalar field to drive an inflationary period of the Universe is trivial. However, to get the precise type of inflation that is consistent with observation requires a bit more care, and will probably involved a mixture of competing scalar fields. For those of us who have worked with supergravity and string theory, the scalar fields needed for inflation are not the ones we normally considered of old (wrong sign), but that has now been shown not to be a problem.There's a good chance we will see our first evidence of a scalar field in action as the LHC starts delivering results - the Higgs field.

agobot writes:The strentgh of the fundamental forces in the universe(force of gravity, speed of light, strong nuclear force, weak nuclear force, proton mass, etc.) is so finely tuned(to support life?), that the only good explanation for the existence of these finely tuned conditions besides god, would be a multiverse and multiple big bangs giving rise to multiple universes.

taz writes: And as I pointed out earlier, you can't do jack shit with a single data point.