Physicist Richard Lieu first explored the idea that gravity could exist without mass—now he’s got a new cosmological model that eschews the need for dark energy.

Ranging from the unimaginably small to the unimaginably big, the scale of the universe is mind-boggling. Watch to try to wrap your head around it. Produced by Alex Kuzoian. Follow BI Video ...

A long-simmering disagreement over the universe’s present-day expansion rate shows no signs of resolution, leaving experts ...

The first key, the period-luminosity scale discovered by Henrietta Leavitt ... In other words, the universe must be expanding. He announced his finding in 1929. The ratio of distance to redshift ...