Discoveries: firsts that started near the lake

21989: the World Wide Web

Tim Berners-Lee, a British scientist working at CERN, wrote the first proposal for the World Wide Web in March 1989. Together with the Belgian engineer Robert Cailliau he turned it into a formal project proposal in November 1990, and by the end of that year the first web server and browser were running at CERN. The web was developed so that scientists in universities and institutes around the world could share information automatically.

The first website, about the web project itself, ran on Berners-Lee’s NeXT computer. On 30 April 1993 CERN released the web software into the public domain, and later offered a release under an open licence, which helped the web grow. The full story is in our article The web was born at CERN.

31995: a planet around a sun-like star

On 6 October 1995 Michel Mayor and Didier Queloz of the University of Geneva announced the discovery of 51 Pegasi b, a planet that orbits its star in 4.2 days. They found it with the ELODIE spectrograph at the Haute-Provence Observatory in France, which measured the motion of stars with an accuracy of about 13 metres per second. Their paper in Nature described it as a Jupiter-mass companion to a solar-type star, with a minimum mass of about half that of Jupiter, orbiting very close to its star.

It was not the first planet found outside the Solar System. In 1992 Aleksander Wolszczan and Dale Frail reported planets orbiting the pulsar PSR B1257+12, the collapsed remnant of a massive star. 51 Pegasi b was the first planet found around an ordinary star like the Sun, and it opened the systematic search for such worlds.

The 2019 Nobel Prize in Physics recognised exactly that: Mayor and Queloz shared half of it for the discovery of an exoplanet orbiting a solar-type star.

4How a planet makes its star wobble

51 Pegasi b was not seen directly. It was found with the radial velocity method. A planet and its star both orbit their common centre of mass, so the planet’s gravity makes the star move slightly towards us and away from us, again and again.

That motion shows in the star’s light. When the star moves towards the observer, its light appears slightly bluer; when it moves away, slightly redder – much as the pitch of an ambulance siren changes as it passes. A spectrograph such as ELODIE measures those tiny shifts. For 51 Pegasi b the pattern repeated every 4.2 days: the length of the planet’s year.

The method has a built-in limit. It sees only the part of the star’s motion directed along our line of sight, and we usually do not know how the orbit is tilted. That is why the method gives a planet’s minimum mass: the true mass can only be the same or larger.

5Units for electricity

A less famous first is closer to everyday life. In the 1930s the International Electrotechnical Commission, which moved to Geneva in 1948, gave names to units such as the hertz and the weber, and helped extend the practical electrical units into a complete system that later became the International System of Units, the SI. How the SI is looked after today is explained on our sister site Sevres.science.

6Since 1818: a tree that announces spring

Not all of Geneva’s science happens in laboratories. Every spring the sautier, a senior official of the canton’s government and parliament, records the day on which the first leaf unfolds on the official chestnut tree of the Treille and announces the start of spring. The Grand Council’s series of dates goes back to 1818. The tree itself has been replaced several times; the present one has announced spring since 2016.

The record belongs to a botanical tradition more than 300 years old. In 1817 the authorities created a permanent botanical garden, led by the botanist Augustin-Pyramus de Candolle; today the Conservatory and Botanical Garden of Geneva holds a herbarium of more than six million specimens. The Treille chestnut and Geneva’s botanical tradition are on Switzerland’s list of living traditions.