UK astronomers have solved one of the greatest riddles of the universe by identifying invisible dark matter.
Astronomers knew that visible stars, planets and galaxies must make up only four per cent of material in the cosmos.
Now a team from Cambridge have discovered that dark matter exists in blocks at least 1,000 light-years wide and 30million times heavier than the sun.
They are the major building bricks that make up 85 per cent of the universe and they are moving at 5.6 miles a second through space.
Their existence prevents fast-moving stars like the sun from flying out of their home galaxies.
The remaining substance in the universe is an invisible force called dark energy.
A team led by Professor Gerry Gilmore made the breakthrough using giant telescopes at Paranal, a European mountaintop observatory in Chile.
He said: “Dark matter is essential in keeping the universe ordered and, without it, the galaxies would quickly fall apart.”
The team’s observations of dwarf galaxies in our cosmic neighbourhood threw up another discovery – that our Milky Way is the biggest galaxy in the so-called local group.
The Andromeda galaxy, M31, had been thought to be the local champion but has now been relegated into second place.