It was like looking for a needle in a haystack. On a quiet night last year, thousands of people reported a fireball in the sky. A battery of special cameras helped narrow down the area where fragments of the meteorite could have fallen. But it was still extremely vague - "Somewhere north of Cheltenham, over towards Stow-On-The-Wold" - and such fragments are usually the size of a sugar cube.

But this time the researchers got lucky: a man in the town of Winchcombe rang to say that he had found a pile of charred stone in his front drive. Dr Richard Greenwood of the Open University set off to investigate.

"I looked in this plastic bag he'd been told to put it in, and my legs went wobbly," says Greenwood. "It was unbelievable. This is a very special meteorite."

After hitting the Earth's atmosphere at 30,000mph, most of the fireball had vapourised within six seconds. What remained was extraordinarily precious. Greenwood recognised it as being made of carbonaceous chondrite, a stony material that retains unaltered chemistry from the formation of the Solar System 4.5 billion years ago.

Of the 65,000 meteorites in collections around the world, barely 2% have had eyewitnesses to their fall - and of those, only 51 belong to this type.

Dr Ashley King of the Natural History Museum in London describes carbonaceous chondrites as "the left-over building blocks of our solar system. Many contain simple organics and amino acids; some of them contain minerals formed by water - so all the ingredients are there for understanding how you make a habitable planet such as the Earth."

The Winchcombe meteorite was the first to be retrieved in the UK since 1991. In February, fragments were sold at auction in London. One chunk weighing 15g beat its presale estimate, fetching a price onf £22,304. This is partly due to its amazing condition, as Greenwood explains: "It must be very close to pristine... It's as good as you will ever get collected here on Earth."

Last year, videos taken by the special cameras operated by the UK Fireball Alliance made it possible to work out where the meteorite came from. "In this case, the orbit was like an asteroid's," says Dr King. "This particular piece of asteroid spent most of its orbit between Mars and Jupiter, though sometimes got closer to the Sun than Earth is."

"Basically, that's part of the Solar System we regard as like a deep freeze of material that's 4.5 billion years old," says Professor Sara Russell, also of the Natural History Museum.

"It hasn't had a chance to change at all from pre-planetary time. It will give us an insight into what our solar system was like before the planets were there."

Both NASA and Japan's space agency have sent probes to bring back similar material from asteroids. But experts say that the Winchcombe meteorite is almost as good a subject for study.

Yes: As technology becomes ever more sophisticated, there will be nothing of significance we will not be able to discover.

No: The universe is infinite and there will always be more for us to discover. We need to travel in search of it.

Or... This meteorite does reveal stunning information about the wider universe. But finding one like this is extremely rare. If we want to learn quicker, we must rely on space exploration as well as studying space rocks on Earth.