The critical point of expansion is the rate of expansion ideal for a stable chemical interaction in the universe. if ever it goes way under or above the critical point the universe may just collapse or undergo on big crunch because of the gravity made by the chemical reactions.
so the fate of universe is still uncertain as for the modern studies, we can look back at the past but we don't know what the future will bring. : ))
We are surrounded by infrared every moment of every day. warm objects, such as the human body, produce large amounts of infrared, and heat-sensitive cctv cameras work by detecting these infrared waves. half of the energy produced by the sun is infrared, so we are being bombarded by it constantly.