  Solar seismology has allowed precision measurements of both the static and
dynamic structure of our local star, the Sun. In the near future, seismology of
solar-like stars of different ages and masses, necessarily restricted by
angular resolution to low l-modes, will allow studies of the internal structure
of stars at various stages of evolution. Such studies will test not only the
theory of stellar evolution, but also allow the determination of ages of stars
from the helium content in their cores. Such observations can be made
photometrically from space, but also spectroscopically from the ground. We
outline ground-based schemes. By correlating the external properties of nearby
stars with their internal properties, it will be possible to extend local
studies to distant open and globular clusters, and thereby to obtain an age of
the Universe, based on many stars. The combination of the age, the density
parameter Omega and Hubble's constant will allow strong limits to be placed on
the cosmological constant.
