April 12, 1991 • 54m
Astronomers believe the universe contains at least ten times as much mass as can be seen and accounted for. How are they able to d...Read more
April 15, 1991 • 57m
At the center of galaxy NGC 1275, some 200 million light years from Earth, there might be a supermassive black hole. In a attempt ...Read more
April 16, 1991 • 57m
American and Japanese astronomers are followed as they seek to measure cosmic background radiation, the heat remaining from the Bi...Read more
April 17, 1991 • 57m
Gravity waves, as yet undetected but predicted by Albert Einstein, may contain the answers to many questions about the universe. S...Read more
April 18, 1991 • 55m
The deaths of stars allow human lives to come into being. This episode explains how and looks at the complete life cycle of the st...Read more
April 19, 1991 • 57m
Efforts to discover other planetary systems and to learn more about the planets of our own solar system are examined. Images are s...Read more