On May 1, 2023, the Euclid (Euclid) space telescope of the European Space Agency (ESA) arrived in Florida, USA by boat from Italy to complete the stage of space travel. It is expected to launch on a SpaceX-built Falcon 9 rocket from Cape Canaveral in early July.
The space telescope is named after Euclid, the Greek mathematician who lived around 300 BC and founded geometry. Since the density of matter and energy is related to the geometry of the universe, it is named after him.
It is equipped with a 1.2-meter-diameter telescope and two scientific instruments, including a visible wavelength camera and a near-infrared camera and spectrometer.
After launch, it will orbit a region known as the Sun-Earth Lagrangian point L2, at an average distance of about 1.5 million kilometers from Earth, with an expected mission lifetime of six years.
Since L2 is where the gravitational balance of the Sun and Earth are in balance, Euclid can keep pace with Earth, providing a stable vantage point for observing the universe and joining the ranks of the Webb Space Telescope, which is also on L2.
The main mission of Euclid is to explore the evolution of the dark universe. By observing billions of galaxies within 10 billion light-years, spanning more than one-third of the sky, and drawing a 3D map of the universe (taking time as the second three dimensions).
Although dark energy accelerates the expansion of the universe and dark matter controls the growth of the universe’s structure, scientists are still not sure what dark energy and dark matter actually are.
Unlike the normal matter we see on Earth, dark matter neither reflects nor emits light. It holds galaxies together and is believed to make up 80% of the total mass of the universe. We’ve known about it for a century, but its true nature has remained a mystery.
Dark energy is equally puzzling, and astronomers have shown that the universe has expanded faster than expected over the past 5 billion years. Many believe this acceleration is driven by an invisible force known as dark energy, which accounts for 70 percent of the energy in the universe.
Euclid will observe the evolution of the universe over the past 10 billion years to reveal how the universe expanded and how the structure of the universe was formed. From this, astronomers can infer the properties of dark energy, dark matter and gravity, thereby reveal more about their precise nature.