Finally, we are on our way to study the mysterious dark matter and dark energy that constitute most of the Universe. As of now, there are many more questions about those two than answers. Euclid is our chance to change it.

The telescope Euclid took off from Cape Canaveral, Florida, at 11:12 am local time (1512 GMT) on a SpaceX Falcon 9 rocket. Minutes later, after separating from the rocket, Euclid contacted the mission control center on the ground, and right on schedule.

“The launch was perfect,” said Carole Mundell, ESA’s science director. “Now begins that journey.”

Euclid might now be on its own in space, but soon, within four weeks it should join the already legendary James Webb Space Telescope at Lagrange point L2, around 1.5 million kilometers from Earth. From there, it will start creating the largest-ever map of the Universe, that will host even two billion galaxies spread across a third of the sky. The furthest galaxies it will be able to reach are 10 billion light years away from us, therefore we will have a chance to study most of the history of the Universe.

We don’t know anything about most of the Universe

With Euclid astronomers are urged to make up for the fact that we do not know basically anything about 95 percent ofthe mass-energy of the Universe. The matter that galaxies, stars and planets are made of add up to just 5 percent of it. In other words, we have not yet started to become familiar with the place that we live in. Euclid’s wide field of view encompasses an area equivalent to two full moons. It will therefore be able to survey large swaths of the sky.

Around 70 percent of the Universe is thought to be made of dark energy, the unknown force that is causing the universe to expand at faster and faster pace. Further 25 percent is dark matter, which binds the universe together and make up around 80 percent of its mass.

Dark Universe explorer

Euclid, which is 4.7 meters tall and 3.5 meters wide, will have just two scientific instruments to map the sky. Its visible light camera will measure the shape of galaxies and its near-infrared spectrometer will measure how far away they are.

So how will Euclid try to spot things that cannot be seen? By searching for their absence. In other words, the light coming from the farthest reaches of the Universe is slightly modified by the mass of visible and dark matter along the way. Astronomers call that phenomenon weak gravitational lensing. Subtracting the visible matter, scientists will calculate the presence and amount of the dark matter inbetween.

As for dark energy, astronomers want to try to see how fast the Universe inflates. This can reveal new information about dark energy which is thought to be responsible for expanding the Universe at an accelerated pace.

It is worth noting, that Euclid will allow astronomers to learn more about black holes, evolution of galaxies and much more. There is a lot to wait for. First images should be available to the public in October, but major releases are already planned for 2025, 2027 and 2030, so mark those years in your calendars, so that you don’t miss it.

By Rad Kos

Author of OuterSpace24. Astronomy communicator. Writing daily about space since 2015. Over 6000 news articles under the belt.