Over in the Relativity forum, in the thread "Metrics and Forces", I have been brought (in fact dragged kicking and screaming, by Pervect) to the following view: In the FRW universe with matter, as gravity slows expansion, compressive tidal stresses develop in any entity that is bound by non-gravitational interactions. These stresses are due to accelerations of H ^ 2 per unit separation of the bound entity's elements, where H is the Hubble constant in units of (sec ^ -1).(adsbygoogle = window.adsbygoogle || []).push({});

In a universe with lambda = 0 and where H is about 70 Km/sec/Mpc, or about 10 ^ -19 /sec, these accelerations (and the correspondingcompressivestresses they generate in, say, solids bound by electromagnetic interactions) would be entirely imperceptible.

In the inflating early universe, where expansion is exponential, these accelerations are bigger. Much bigger. If one estimates H roughly, from the postulated inflation of the universe by a factor of about 10 ^ 43 in 10 ^ -34 sec,(see Liddle,Intoduction to Modern Cosmology, p. 106), H turns out to be about 10 ^ 77 /sec. The acceleration per unit separation of any bound elements is then very large, about 10 ^ 154 m/sec ^2. The accelerations are due to the speeding up of expansion and would cause dilation pull-apart stresses in any bound entity.

There may notbeany bound entities in an inflating universe, which I understand is postulated to be a universe where all the forces of nature are the same and where all the force carriers are massless and travel at c. I don't know whether in such a situation the FRW model is even thought to apply.

But does anyone know if such extreme internal accelerations are thought to have any consequences for the inflationary scenario? Say to disrupt even Higgs particles? Or to prevent them forming?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Tidal stresses during inflation

**Physics Forums | Science Articles, Homework Help, Discussion**