Euclid, the European space probe, has taken off on a mission to explore the composition and evolution of the dark universe.

Euclid’s space telescope “will create a great map of the large-scale structure of the universe across space and time by observing billions of galaxies out to 10 billion light-years, across more than a third of the sky,” according to the European Space Agency (ESA).

Euclid aims to explore how the universe has expanded and how structure has formed over cosmic history, to reveal more about the role of gravity and the nature of dark energy and dark matter, ESA said ahead of the launch.

The spacecraft took off from US spaceport Cape Canaveral in Florida, aboard a Falcon 9 rocket from US company SpaceX, live images showed.

Tweet from @SpaceX

Euclid is set to fly about 1.5 million kilometres into space on a journey expected to take about a month.

After a few tests, the mission, which is costing 1.4 billion euro ($2.3 billion), will begin in earnest in October.

The probe is to be in operation for six years.

Space researchers hope Euclid will shed light on the expansion of the universe and help deepen understanding of the way individual structures have formed.

“I expect Euclid to flood the scientific community with an unprecedented, huge amount of data,” said Giuseppe Racca, who is responsible for the mission at ESA.

“The Euclid mission aims to uncover the mysteries of the ‘dark’ universe… the invisible part of the cosmos makes up more than 95 per cent of the mass and energy in our universe,” ESA said ahead of the launch.

— AAP