For years astronomers have known
that the Universe is expanding. Gravity tends to slow expansion, so a
pressing question seems to be whether the expansion will slow all the
way to zero. Observations thought to resolve this question found instead
a startling result: instead of slowing down, the universe is actually
accelerating its expansion!
This result, first suggested by observations
of supernova explosions in distant galaxies, has been confirmed during
the past year by an entirely different set of observations of the unevenness
in the cosmic background radiation. How can we explain this result? Come
with us on a tour of cosmological thought and observation and hear Dr.
Goldsmith give his best explanation of what we currently believe, and
why, about the mighty cosmos in which we live. Dr. Goldsmith will also
show his video explanation of cosmology that will leave you dying of laughter!
Born in Washington, D.C. in 1943 where his parents were both economists for the government, he graduated from Harvard College in 1963 and then received his Ph.D. in Astronomy from U.C. Berkeley, where he later became a professor. He is the award-winning author of The Ultimate Einstein, The Hunt for Life on Mars, and The Astronomers. Dr. Goldsmith also authored the book, Voyage to the Milky Way, and he served as a consultant for the video of the same title.
Gravity can bend light. Almost all of the bright
objects in this Hubble Space Telescope image are galaxies in the cluster
known as Abell 2218. The cluster is so massive and so compact that its gravity
bends and focuses the light from galaxies that lie behind it. As a result,
multiple images of these background galaxies are distorted into faint stretched
out arcs - a simple lensing effect, similar to looking through a glass of
wine. The Abell 2218 cluster itself is about 3 billion light-years away
in the northern constellation Draco.