A space observatory begins its journey

Researchers compared thousands of dated observations with modern orbital calculations to study long-term changes in Earth's rotation.

A mismatch between predicted and recorded eclipse paths reveals accumulated changes in the length of the day.

Records reaching back many centuries give modern science a time span impossible to reproduce with recent instruments alone.

Chinese textual expertise and modern celestial mechanics together create evidence neither discipline could produce independently.

The telescope lifted off aboard space shuttle Discovery for an orbit above Earth’s atmosphere.

Hubble was designed so astronauts could later repair and upgrade it.

NASA and ESA contributed to the space telescope, whose deployment occurred the next day.

Mayor and Queloz announced evidence for a planet orbiting a Sun-like star.

The team’s announced planet had a short orbit, unlike the giant planets of our solar system.

The announcement relied on changes in the host star’s measured radial velocity.