Learn about the fate of the universe, with this pair of videos from NOVA Wonders: What’s the Universe Made Of? The universe is expanding; however, the gravitational effects of dark matter could potentially slow its expansion until the universe collapses back on itself in a “big crunch.” In the 1990s, astronomers studied the redshift of light from supernovae to measure the rate of expansion of the universe. To their surprise, their observations indicated that the universe has actually been accelerating in its rate of expansion. This resource is part of the NOVA Wonders Collection.