Today at 17.11 (Spanish peninsular time) the launch of the Euclid space telescope of the European Space Agency (ESA) is scheduled, which can provide answers to some of the most fundamental questions about the universe. Why is it expanding? What is your final destination? What is the nature of the dark energy and matter that make up 95% of the cosmos? How does gravity work on a large scale?
Euclid will observe more than 1,500 million galaxies for six years to build a very detailed map that will allow us to see how the large structures of the universe have evolved and how the distribution of matter has varied over the last 10,000 million years.
The launch will take place from Cape Canaveral, in Florida, with a Falcon 9 rocket from the SpaceX company. Initially, the mission was to be launched on a Russian Soyuz rocket launched from French Guiana. But as a result of the war in Ukraine, the option of using the Russian rocket was ruled out, which delayed the mission by about six months.
Euclid's main goal is to understand what is and how the mysterious dark energy that is accelerating the expansion of the universe is and what is the nature of dark matter, which dominates in a ratio of 6 to 1 over the ordinary matter made of atoms. These two components, energy and dark matter, represent more than 95% of the contents of the cosmos (the remaining 5% is ordinary matter, i.e. stars, galaxies, planets and everything we see around us).
The Euclid spacecraft is not a conventional space telescope. Its main components are a 1.2 meter diameter mirror, a 600 megapixel camera capable of photographing, in a single shot and with a very high level of detail, an area of the sky larger than two full moons, and a sensor of infrared that can break down and analyze the light of very distant objects.
Euclid will repeatedly scan 36% of the firmament, which corresponds to the areas that are not obstructed by our own galaxy and by the interplanetary dust that is distributed within the solar system.
Euclid will operate from a point in space known as Lagrange L2, located 1.5 million kilometers from Earth in the opposite direction from the Sun. It is a particularly stable place thanks to the combined action of the gravity of the Earth and the Sun, and where the James Webb Space Telescope is also located.
The ship will protect its delicate instruments from sunlight by means of a large shield, as it is necessary for the infrared sensors to operate at a temperature that does not exceed -180º C.
Euclid will combine two complementary detection methods. On the one hand, it will detect the tiny deformations that light from ancient galaxies has undergone to reach us. This phenomenon, called gravitational lensing, occurs when light from distant stars is distorted by the gravity of massive objects that are closer. Since dark matter is the majority compared to ordinary matter, Euclid is expected to find dark matter structures due to its gravitational lensing effect.
On the other hand, Euclid will observe how the galaxies are grouped in the universe. For this reason, it will analyze the light of around 35 million galaxies to draw a map of their spatial distribution. Its infrared instrument will obtain the light spectrum of the objects, by means of which it is possible to know the distance at which they are.
The combination of these observation methods will allow us to know how the structure of the cosmos and the distribution of matter has evolved since the universe was 3.8 billion years old until now.
The Euclid mission will generate about 850 Gb of data per day and the first data is expected to be available to the scientific community in 2025. Data processing centers involved in the mission include the Science Information Port located on the campus of the Autonomous University (UAB). Among the twenty Spanish scientific institutions participating in the mission, the Institut de Ciències de l'Espai (IEEC-CSIC) and the Institut de Física d'Altes Energies (IFAE) stand out, which have been involved in the design of the mission since its inception in 2006 and have participated in the design, construction and testing of one of its main instruments.
