What a wonderful question! The simple answer is that they relied on centuries of previous observations. Remember, even computers have to be programmed with the right data to produce future times of ...

More than a thousand years ago, astronomers from the Maya civilization developed one of the most sophisticated time-keeping systems in the ancient world—a system that could predict solar eclipses for ...

Still in its original galaxy, a rare holdout from the second generation of stars sheds new light on the origins of the elements—and how massive supernovae reshaped the cosmos ...

Before telescopes, ancient Greek astronomers relied on naked-eye observations of the night sky to understand the universe around them. The meticulous star catalog belonging to one of the best of these ...

A piece of thousand-year-old parchment is finally giving up its secrets. In a major breakthrough this week, researchers at the SLAC National Accelerator Laboratory in Menlo Park used X-ray beams to ...

As interstellar comet 3I/ATLAS makes its closest approach to gas giant Jupiter, a team of astronomers has concluded it may be even older than we thought. By analysing its chemical composition, they ...