News Astronomy

Honing the Hubble

New value supports finding that dark energy does not vary with time

By Ron Cowen

- More than 2 years ago

BALTIMORE — Astronomers are honing measurements of a familiar cosmic parameter to shed new light on dark energy, the mysterious entity that’s accelerating the universe’s rate of expansion.

MEASURING MASERS Astronomers have used the radio-emitting water molecules (illustrated here), or masers, at the heart of the galaxy NGC 4258 to find a more accurate value of the Hubble constant and shed new light on dark energy.