Historical astronomy becomes geophysical evidence

The second Voyager launch used a trajectory that overtook Voyager 2 on the way to Jupiter.

Voyager 1 began a mission designed to return images and measurements of distant giant planets.

Its record presented sounds and images from Earth to any future finders of the spacecraft.

The 5 September launch completed the pair’s departure for outer-planet exploration.

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

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’s launch created a platform for observing the universe without most atmospheric distortion.

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