Nuclear fusion usually brings to mind sprawling facilities, blistering temperatures, and machines built on a scale that can swallow budgets whole. This device does something stranger.

A Skoltech scientist has raised the world's only isotope-labeled guinea pig. For 156 days, the animal, named Khryun, was given only heavy water to drink. Such water is non-radioactive and has long ...

More than 70% of the Earth is covered with water—H 2 O. An almost negligible proportion of a few per million consists of "heavy water," in which the hydrogen atoms (H) are replaced by deuterium atoms ...