The solutions to
the cosmological constant problems may involve modifying the very long-range
dynamics of gravity by adding new degrees of freedom. As an example of a conservative and minimal
such modification, we consider the possibility that the graviton has a very
small mass. Massive gravity has received
renewed interest due to recent advances which have resolved its traditional
problems. This kind of modification has
some peculiar and unexpected features, and it points us towards a universe
which looks quite unfamiliar.
for this colloquium is provided by The Templeton Frontiers Program.