Spiral galaxy NGC 5468


Webb Telescope Measures Universe’s Expansion

Astronomers have used the Webb telescope to observe Cepheid variable stars, ruling out one source of the prevailing "Hubble tension.”

Supernova Refsdal in widefield image of galaxies


Replay of Star’s Death Sheds Light on Universe’s Expansion

A cosmic lens magnified the light of an exploding star. Now, astronomers are using observations of that supernova to calculate the universe’s current rate of expansion.

cluster of various galaxies


The Universe Is Too Smooth By Half

Results from a complex new analysis support cosmologists’ suspicions that something is missing from our understanding of the universe.

EBOSS map of the universe


New 3D Map of the Universe — and a Growing Cosmological Debate

The Sloan Digital Sky Survey has released a new map of the universe — and the results confirm ongoing tension over the expansion rate of the universe.

Red giant stars in galaxy halos


Tension Over Hubble Constant Continues

A new measurement fuels an ongoing debate about the rate at which today’s universe is expanding.


Dark Energy Survey Releases First Three Years of Data

Results from the first data release of the Dark Energy Survey include eleven new stellar streams in the Milky Way galaxy.


Does Dark Energy Change Over Time?

Scientists are considering whether the mysterious “force” accelerating the universe’s expansion changes with time.

Gravitationally lensed quasar


H0Li COW! Is Our Universe Expanding Faster Than We Thought?

Observations of lensed quasars suggest the universe is expanding more quickly than we thought. But they contradict what we know about the young universe.


Quasars Track Expanding Universe

The most precise measurement yet of the Hubble parameter illuminates dark energy — the elusive entity that’s accelerating the universe’s expansion.