– The galaxies organize themselves in a web structure and in between there are enormous voids, says Martin Sahlén who is an astrophysicist at Uppsala University.
Already at the dawn of the universe, small condensations were formed in the matter which, with the help of gravity, grew and became increasingly larger. And after a few hundred million years, it was in those clumps that the first stars ignited and galaxies formed. Now Euclid will dispel the mystery surrounding how it happened.
The dark side of the universe
Most of the universe is invisible to us. All the stars and planets in the universe make up only 5 percent of the universe’s mass. There is five times more so-called dark matter that only makes itself felt through gravity.
Astrophysicists today are convinced that dark matter was a driving force when the first stars ignited in the universe. Martin Sahlén will use observational data from Euclid to better understand the interaction between dark matter and the formation of stars and galaxies.
– We want to look at how these early galaxies are distributed in time and space. How bright are they? When and how quickly did their stars light up?
The great mystery
In 1998, the surprising discovery was made that the universe is expanding at an accelerating rate. The force believed to be behind it is called dark energy, and calculations show that 70 percent of the universe’s total energy consists of precisely dark energy, which no one knows what it consists of.
– Euclid’s main mission is to make large maps of how the structures of the universe have developed over the past 10 billion years. The aim is to investigate how the dark energy has behaved during this time, says Martin Sahlén.
Euclid has been developed by the European Space Agency ESA and will be launched 1.5 million km into space and then put into an orbit that goes around the Sun together with the Earth.