Stardust that dates from before the Sun was born, and which was collected from a comet’s tail, has the scientific world in a state of ferment.

After 4.57 billion years drifting through space, a thousand grains of stardust are forcing scientists to reassess their theories on how the solar system was created.

They were captured from the tail of the Wild 2 comet in 2004 by a Nasa space probe, which landed on Earth with its unique payload in January, after a journey of 2.88 billion miles.

The probe was equiped with 132 ice cube-sized cells of aerogel — a porous, silcon-based solid — to catch the dust.

Among the particles formed when the Sun had only just been formed was a single fragment that predates the solar system. It is oxygen rich and is one of the ingredients of the cloud of dust and gas that contained the building blocks for the Sun and the planets.

At one one-hundred-thousandth of an inch (one micrometer) wide, it was too small to reveal its mineral content, but the remainder of the captured stardust, the first extra-terrestrial material collected by Man from space since the Moon landings, has been giving up its secrets to researchers.

The range of minerals and organic materials has led scientists to conclude that the early solar system was much more volatile than thought. Until now the mainstream theory as to why planets have different make-ups has been because they were formed in different parts of the solar system, which contained different materials.

Stardust from the comet now suggests that there was a far greater mixing of the solar system’s building blocks, which raises new questions about how planets formed.

Studies by hundreds of scientists around the world have shown that the formation of the comet overturns current assumptions. Rather than coalescing from fragments of interstellar dust in the frozen far reaches of the solar system, its chemistry shows that it is likely to have formed in stages.

Compounds that are created only when heat is available were present, showing that 10 per cent of the comet’s make-up formed much closer to the sun than previously realised.

The findings, reported in the journal Science, resulted from the first analysis of the stardust and further tests and experiments are expected to cast light on the likelihood of finding life elsewhere in the universe.

Wild 2 was regarded as the perfect comet to investigate because it had effectively been kept in quarantine from the rest of the solar system for most of its existence.

It had been racing round the periphery of the solar system beyond Neptune, in deep freeze conditions, until the gravitational pull of Jupiter took it closer to the Sun.

Having been in isolation for so long, its make-up had not been changed by solar heat, nor by space debris from the giant planets or the asteroid belt.

It is believed to have been created during the first 10 million years of the creation of the solar system, which began 4.57 billion years ago.

Having kept these primitive planetary and stellar building blocks in isolation, the chemical content is giving scientists a glimpse of the solar system as it was being made.

Among the discoveries are organic compounds and water elements, which were essential for life to begin.

Among the British scientists involved in the project was Phil Bland, of Imperial College London, who said: “The composition of minerals is all over the place, which tells us that the components that built this comet weren’t formed in one place at one time by one event.

“Fundamentally we still don’t know how you make planets from a cloud of dust and gas. Hopefully the Wild 2 samples will help us towards an answer.”

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