We don't usually think in terms of a "volume of light." We tend to speak of brightness. But the amount of anything available in a given space is called a volume. "Please pass a quart of light" sounds ...

New research by the Atacama Cosmology Telescope (ACT) collaboration has produced the clearest images yet of the universe's infancy—the earliest cosmic time yet accessible to humans. Measuring light ...

An international collaboration of researchers developed two new complementary approaches for versatile but precise light intensity measurements in fluorescence imaging systems. Accurate measurements ...

The great Galileo Galilei (1564-1642) tried to measure the velocity of light by means of lantern signals between mountain tops. Naturally he failed. Light travels about 186,270 miles (more than seven ...