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It weighs as much as 780 million suns and helped to cast off the cosmic Dark Ages. But now that astronomers have found the earliest known black hole, they wonder: How could this giant have grown so big, so fast?
A number of high-energy anomalies raised hopes that astrophysicists had seen their first direct glimpses of dark matter. New studies suggest a different source may be responsible.
Astronomers are mystified by a strange star explosion in a distant galaxy that might be a relic from an earlier cosmological era.
The Zoomable Universe, a new book by the astrobiologist Caleb Scharf, the illustrator Ron Miller and 5W Infographics, tours the universe’s 62 orders of magnitude.
The core of a neutron star is such an extreme environment that physicists can’t agree on what happens inside. But a new space-based experiment — and a few more colliding neutron stars — should reveal whether neutrons themselves break down.
Newly discovered “standard sirens” provide an independent, clean way to measure how fast the universe is expanding.