A EUROPEAN spaceship is to show scientists the inner workings of Earth, from the movements of ocean currents to the location of oil deposits.

Its data will enable them to detect the flows of molten rock that underlie the movements of tectonic plates and cause earthquakes.

The Goce probe, launched last week, will measure tiny anomalies in Earth’s gravity, caused by anything from mountain ranges to subterranean lava flows or ocean trenches.

Rune Floberghagen, Goce mission manager, said: “Imagine a snowflake, which weighs a fraction of a gram, falling onto the deck of a supertanker. The impact the supertanker experiences from that snowflake is comparable to the sensitivity of our instrument.”

Scientists have long known that the Earth’s gravity varies all over its surface — and that measuring those changes could give insights into the planet’s inner workings.

However, designing an instrument capable of measuring them, which would also survive the rigours of blast-off, has until now proved impossible.

This weekend, Goce, short for Gravity field and steady-state Ocean Circulation Explorer, was declared operational.

“Goce will yield details of the Earth’s gravity field to an accuracy and resolution that is simply unobtainable by existing terrestrial and space techniques,” said Professor Philip Moore of Newcastle University, who specialises in gravity research.

At school, children are taught that Earth’s gravity makes falling bodies accelerate at a standard 9.8m per second per second.

In reality this figure varies slightly depending on where you are. The shape of the Earth, mountains, ocean trenches, and the density of the ground beneath your feet all affect Earth’s pulling power.

Goce will map those variations, showing how gravity diverges from the average in different parts of the world. This will provide a benchmark against which changes in ocean currents, the melting of ice-caps, or volcanic processes can be clearly shown.

Mark Drinkwater, Goce mission scientist at the European Space Agency (ESA), said it was necessary to measure changes in ocean circulation to understand climate change. “Currents carry large quantities of heat from the equator to the poles. The system in the north Atlantic, for example, helps to keep Europe’s climate relatively mild,” he said.

For geologists, perhaps the most exciting prospect is of being able to “peer” deep below the Earth’s crust. It will exploit the fact that minerals in the crust vary in density and hence in the amount of gravity they generate.

It means that oil and mineral deposits or ground-water reservoirs will all leave their own subtle signature on the Earth’s gravitational field.

Two other ESA probes, Herschel and Planck, are due to follow Goce into space this spring.

Herschel will be the most powerful space telescope built. Its 11ft mirror is the biggest to be put into space and will make it far more powerful than Nasa’s Hubble space telescope, whose mirror has a 8ft diameter. However, it will detect infrared radiation, which is invisible to the human eye, whereas Hubble collects mainly visible light.

Herschel is intended to solve the mystery of the formation of galaxies. Typically they contain several hundred billion stars, but astronomers do not know how these huge structures formed.

One idea is that stars arose first and then drew together to form galaxies, but other theories suggest the reverse, with huge clouds of gas accumulating and then condensing into stars.

The Planck probe will collect microwave radiation left over from the Big Bang, the event thought to have triggered the birth of the universe 13.7 billion years ago.

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