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Cosmologists have concluded that the universe doesn’t appear to clump as much as it should. Could both of cosmology’s big puzzles share a single fix?
Astronomers are discovering that magnetic fields permeate much of the cosmos. If these fields date back to the Big Bang, they could solve a major cosmological mystery.
Physicists have proposed extra cosmic ingredients that could explain the faster-than-expected expansion of space.
New measurements could upend the standard theory of the cosmos that has reigned since the discovery of dark energy 21 years ago.
Two ways of measuring the universe’s expansion rate yield two conflicting answers. Many point to the possibility of new physics at work, but a new analysis argues that unseen errors could be to blame.
Newly discovered “standard sirens” provide an independent, clean way to measure how fast the universe is expanding.