Expert: Jayendra Upadhye - 12/20/2005

Question
Is the universe's expansion rate accelerating or decelerating?

Answer
Hi,
I am no expert on relativity!
But from my readings, i am aware that einstein had proposed a cosmological constant to account for observations of astronomers that suggested an expanding universe. einstein believed in steady state universe (like fred hoyle who believed in a static universe expanding and being replenished by his theory of continous creation of matter).
einstein later profoundly regretted the inclusion of this constant in his theory of relativity and even called it a mistake, after hubble and humason detected cepheid variable stars in distant galaxies and proposed a universe where space itself was expanding. iam enclosing some useful urls for u on the subject.
           current thinking points to an accelarating universe or a universe where the speed of light is slowing down over cosmological distances.
    hope this suffices.
jayen

url-1
http://www.jupiterscientific.org/sciinfo/cosmology/cosmologicalconstant.html
url-2
http://map.gsfc.nasa.gov/m_uni/uni_101accel.html