Two October Sixths: A Planet Around Another Sun, and a Rock Seen Before It Fell

Today in space history, two October sixths, thirteen years apart.

A Planet Around Another Sun

Stardate 1813.6800 (6 October 1995)

On 6 October 1995, in a conference hall in Florence, Michel Mayor and Didier Queloz told their colleagues that a Jupiter-mass companion was tugging at the star 51 Pegasi. The signal was a gentle four-day wobble, measured with the ELODIE spectrograph at Haute-Provence. It was the first planet confirmed around a star like the Sun.

The world sat impossibly close to its star, a hot Jupiter that did not fit the tidy order of our own system. Within days other observers confirmed the wobble, and a new field opened. Mayor and Queloz would share the 2019 Nobel Prize in Physics for that quiet announcement. The sky, it turned out, was full of planets we had simply not yet learned how to see.

Seen Before It Fell

Stardate 2497.5759 (6 October 2008)

Just before dawn in Arizona, on 6 October 2008, Richard Kowalski of the Catalina Sky Survey recorded a faint moving point. Within hours the orbit was clear. The object, later named 2008 TC3, would meet Earth over northern Sudan the next morning. It was the first time an asteroid had been found in space and its impact predicted before it arrived.

The rock was only a few metres across, no threat to anyone on the ground. What mattered was the warning itself. Observatories on several continents tracked it through the day, and calculations at JPL placed the entry over the Nubian Desert at 02:46 UTC on 7 October. The sky kept the appointment. For planetary defence, a small stone had become proof that the watch could work.