WASHINGTON (Reuters) - Fresh corroboration of the perplexing observation that the universe is expanding more rapidly than expected has scientists pondering the cause - perhaps some unknown factor ...

The universe is expanding. But how fast ... who in the 1920s discovered that the light from many galaxies is red-shifted, a sign the galaxies are moving away from us. Moreover, the red shift ...

WASHINGTON (Reuters) - Fresh corroboration of the perplexing observation that the universe is expanding more rapidly than expected has scientists pondering the cause - perhaps some unknown factor ...