Proof of parallel universes radically different from our own may still lie beyond the domain of science
The sun was born in a family of stars. What became of them?
A shadow cosmos, woven silently into our own, may have its own rich inner life
Total energy must be conserved. Every student of physics learns this fundamental law. The trouble is, it does not apply to the universe as a whole
By the latest estimate, the observable universe contains 200 billion galaxies. Astronomers wonder: Why so few?
All stars are born in groups but then slowly disperse into space. A new theory seeks to explain how these groups form and fall apart or, in rare cases, persist for hundreds of millions of years
Dark energy does more than hurry along the expansion of the universe. It also has a stranglehold on the shape and spacing of galaxies
Is the theory at the heart of modern cosmology deeply flawed?
Deep down, the particles and forces of the universe are a manifestation of exquisite geometry
Our universe may have started not with a big bang but with a big bounce—an implosion that triggered an explosion, all driven by exotic quantum-gravitational effects
To learn how the universe evolved over time, a space telescope gazes back to the earliest galaxies ever observed
Some say its glory days are long gone, but the universe has life in it yet. Brand-new types of celestial phenomena will unfold over the coming billions and trillions of years
Tipping the scales at less than about a million suns in mass, middleweight black holes may hold clues to how their much larger siblings, and galaxies, first formed