The Origin and the Fate of the Universe

Abstract:

For a long time cosmologists believed that our universe was born as an expanding spherically symmetric ball of fire. If the universe expands fast enough, it would expand forever, whereas if its expansion is slow, it would eventually collapse and disappear. This scenario dramatically changed during the last 25 years. Now we think that initially the universe was rapidly inflating, being in an unstable energetic vacuum-like state. It became hot only later, when the vacuum-like state decayed. It is quite possible that the new-born inflationary universe looked not like a sphere but like a bagel, i.e. it could be topologically nontrivial. Its subsequent evolution transformed the universe into a huge fractal consisting of many exponentially large parts in different vacuum states, with different laws of low-energy physics operating in each of them. According to string theory, the total number of different vacuum states can be extremely large, perhaps 10100 or even 101000. Our part of the universe may eventually collapse into a huge black hole, or become 10 dimensional. However, the universe as a whole is immortal.

Short biography:

Professor Andrei Linde, born in Moscow in 1948, studied physics at the Moscow State University from 1966 to 1971 and obtained his PhD in 1975 from the Lebedev Institute in Moscow. He became professor of physics at the Lebedev institute in 1985, spent two years (1989-1990) at CERN, Switzerland, and joined Stanford University (USA) as full professor of physics in 1990.

Andrei Linde is one of the inventors of the theory of cosmological phase transitions and inflationary cosmology. Both play a central role in modern cosmology and have led to a new understanding of the evolution of the universe. His achievements have earned him numerous prestigious awards, including the Oskar Klein Medal for Physics (2001) and the Dirac-Medal (2002).