Department of Physics
MIT
Thursday, January 18th 2018, 18:30
Stephen Leacock Building, Leacock Auditorium (room 132)
Inflationary Cosmology:
Is Our Universe Part of a
Multiverse
Inflationary cosmology gives a plausible explanation for many observed
features of the universe, including its uniformity, its mass density, and the
patterns of the ripples that are observed in the cosmic microwave background.
Beyond what we can observe, most versions of inflation imply that our universe
is not unique, but is part of a possibly infinite multiverse. I will describe
the workings of inflation, the evidence for inflation, and why I believe that
the possibility of a multiverse should be taken seriously.
Friday, January 19th 2018, 15:30
Ernest Rutherford Physics Building, Keys Auditorium (room 112)
Infinite Phase Space and the Two-Headed Arrow of Time
One of the unsolved mysteries of physics is the arrow of time: the laws
of physics make no distinction between the future and the past, but in our
experience they are entirely different. The arrow of time can be identified
with the growth of entropy, but what caused the entropy to be lower in the past?
I will describe a speculative picture which shows how an arrow of time can
develop naturally, provided that the available phase space is infinite,
even in a system with time-reversible laws of physics, and with no special
initial conditions. I will also discuss the alternative possibility that the
phase space available to the universe is finite, arguing that this assumption
leads to serious cosmological problems.
|