Sphinx Observatory at Jungfraujoch: History, Science and the View

Perched on a rocky summit above the Jungfraujoch saddle in the Bernese Alps, the Sphinx Observatory is one of the highest observatories in the world, at 3,571 metres above sea level. Its dome and steel terrace look out over the Great Aletsch Glacier, and behind the famous viewing deck sits a working research station that has been measuring the atmosphere for decades.

Sphinx Observatory at Jungfraujoch: the facts

• Elevation: 3,571 m, on the Sphinx summit above Jungfraujoch, on the border of the cantons of Valais and Bern.
• Completed: 1937, as part of the High Altitude Research Station Jungfraujoch.
• Inside: two large and two small laboratories, a workshop, two terraces for experiments, a weather observation station and an astronomical dome with a 76 cm telescope, now retired.
• Access: a lift climbs through the tunnelled mountain top from Jungfraujoch railway station, the highest railway station in Europe at 3,454 m.
• Setting: the Jungfrau region became a UNESCO World Heritage Site in 2001.

The Jungfrau Railway: how science reached 3,454 metres

Research at Jungfraujoch exists because of the Jungfrau Railway. The industrialist Adolf Guyer-Zeller proposed the route in 1893 and construction began in 1896. The work was hard and dangerous: in 1908 an accidental explosion of 30 tonnes of dynamite set the project back, and the line finally reached Jungfraujoch on 1 August 1912, nine years late.

The rack railway runs 9.34 km from Kleine Scheidegg (2,061 m), almost entirely inside a tunnel through the Eiger and the Mönch. On the way it stops at Eismeer station, 3,158 m up inside the mountain, where windows in the Eiger's rock look out over the "sea of ice". With year-round access, scientists could finally bring people and equipment into the high mountains: the International Foundation High Alpine Research Station Jungfraujoch was established in 1930, its research station opened in 1931, and the Sphinx followed in 1937.

Discoveries made at the Sphinx

Thin, clean air and a high altitude made the Sphinx ideal for physics and astronomy:

• 1949: nuclear emulsion plates exposed at the observatory gave early evidence of the charged K-meson, a subatomic particle.
• 1950: the University of Liège began measuring the solar spectrum, producing a widely used solar atlas. The first astronomical cupola went on the roof the same year.
• 1951: a large Wilson cloud chamber built here by Blackett and Wilson was later used at CERN.
• 1962: Labs and Neckel made the first absolute measurements of the solar constant.
• 1990: Blumthaler and Ambach made the first direct measurements of rising UV intensity at the Earth's surface.

Climate research at Jungfraujoch today

Today the focus has moved from the stars to the atmosphere. Around 50 projects measure more than 100 variables, and Jungfraujoch is one of about 30 global stations in the World Meteorological Organization's Global Atmosphere Watch. Swiss research institute Empa has tracked some 100 gases here since 1972, Heidelberg has measured radiocarbon in atmospheric CO2 since 1986, and Liège's infrared spectrometers follow more than 20 gases linked to ozone depletion and the greenhouse effect. Other teams study aerosols and clouds, cosmic rays with neutron monitors, and the Great Aletsch Glacier, the longest glacier in the Alps at about 23 km.

Visiting the Sphinx terrace

The laboratories are closed to the public, but the open viewing deck beside the observatory is the highlight of a trip to Jungfraujoch. From the terrace you look down the Aletsch Glacier towards the south and across to the Jungfrau and Mönch. Trains to Jungfraujoch start from Kleine Scheidegg, which you reach by the Wengernalp Railway from Lauterbrunnen or Grindelwald. Pick a clear day, bring warm layers and sunglasses, and take it slowly at 3,500 metres: the thin air leaves many visitors breathless or with a headache.

For more high-Alpine travel, ride the Pilatus cogwheel railway or see Åreskutan’s coated lift.

Related reading

• Peak Walk by Tissot: A Bridge Between Alpine Viewpoints
• Titlis Cliff Walk: The High-Alpine Bridge and the View Around It
• Robert Bösch’s Mammut Photographs: People Giving Mountains Scale
• The Matterhorn Lit in Red: A Photograph with 150 Years of History
• The Matterhorn Through the Day: Twelve Photographs, One Remarkable Mountain
• 15 Swiss Ski Resorts: Compare the Villages, Terrain and Connected Areas
• Nine Climbers on the Jungfrau: A Mountain Turned into a Tiny Planet
• Oeschinensee: A Mountain-Lake Visit for the Right Season and Route
• Solvay Hut on the Matterhorn: A Shelter Reserved for Emergencies

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