Observations of the universe are limited by the physical properties of light. Terrestrial observations are limited by the fact that light propagates in straight lines, while the surface of Earth is curved. The distance one can see can be increased by...

In physical cosmology, a cosmological horizon marks a limit to observability, and marks the boundary of a region that an observer cannot see into directly due to cosmological effects. The existence, properties, and significance of a cosmological...

Scientists can learn more about the possibility of life on other universes by studying our own. Questions raised by theologists about the nature of the universe and the existence of a creator are discussed, along with reality and ethics. What is conventionally called...

Byline: Jerry Adler The more the universe seems comprehensible," the physicist Steven Weinberg once wrote, "the more it seems pointless." It is said that many of his colleagues were dismayed, not by the assertion that the universe was pointless, but over the...