Cosmology

The most powerful cosmic rays in the universe currently have no explanation. New research suggests that exotic, self-annihilating particles in our own galaxy may hold the answer.

Einstein predicted the existence of gravitationally-warped rings of light in 1915. Now, a new one has been discovered just a cosmic stone's throw from our own planet.

"This process is like a cosmic CT scan, where we can look through different slices of cosmic history and track how matter clumped together at different epochs."

Because we haven't found anything yet, we've started to wonder if dark matter might be lighter or heavier than we thought.

A new study suggests that the explosive deaths of the universe's earliest stars created surprising quantities of water that may have sparked extraterrestrial life in the very first galaxies.

"As yet, nobody has managed to understand what gives rise to this strange phenomenon, and explaining dark energy remains one of the most formidable challenges of modern science."

New research suggests that dark energy isn't needed to explain the acceleration in the expansion of the universe — instead suggesting giant voids in space are creating an illusion.

The new composite image, which combines hundreds of photos from the Hubble Space Telescope, shows the Andromeda Galaxy with more than 200 million individually resolved stars.

Astronomers have been confounded by recent evidence that the universe expanded at different rates throughout its life. New findings risk turning the tension into a crisis, scientists say.

A rare group of aligned, star-birthing dwarf galaxies resemble a cosmic string of pearls.