Dark side of the universe: The first piece of the unique map revealed

The European Space Agency's (ESA) powerful Euclid telescope has created a stunning mosaic revealing millions of stars and galaxies in the universe. Launched in July 2023, the Euclid mission aims to construct the largest and most accurate 3D map of the universe to answer enduring questions about its "dark side."

Scientists have assembled the first part of a 208-gigapixel map from 260 observations made between March 25 and April 8. This is only a small fraction of the comprehensive sky survey Euclid will conduct in the future.

The mosaic includes approximately 100 million stars and galaxies visible from the southern hemisphere and was presented on October 15 at the International Astronautical Congress in Milan, Italy.

According to ESA's Euclid project scientist Valeria Pettorino, this remarkable image is the first piece of a map that will reveal over a third of the sky within six years. Despite representing only 1% of the map, it contains numerous resources that will help scientists explore new ways to describe the universe.

One of Euclid's primary goals is to observe dark matter and dark energy. Although dark matter has never been detected, it is believed to constitute 85% of the total matter in the universe. Dark energy is a mysterious force thought to contribute to the universe's accelerated expansion.

Astronomers hope the telescope's observations of millions of galaxies will unveil hidden forces that shape the structure of the universe and drive its mysterious acceleration.

Euclid's wide field can capture data from an area 100 times larger than that covered by NASA's James Webb Space Telescope, while its precise cameras provide detailed information about many celestial objects.

For example, the fine structure of a spiral galaxy in the Abell 3381 cluster, located 470 million light-years away, and the bright blue clouds among stars in our Milky Way can be seen in the mosaic.

Euclid's first images were released in November 2023, but the telescope began regular observations in February. Currently, the observatory has completed 12% of its scan.

Jason Rhodes, a research expert in observational cosmology at NASA's Jet Propulsion Laboratory, stated, "We have seen beautiful, high-resolution images of individual objects and groups from Euclid. This new image gives us the first hints about the vast area of the sky that Euclid will cover, allowing us to make detailed measurements of billions of galaxies."

In the 1920s, astronomers Georges Lemaître and Edwin Hubble discovered that the universe has been expanding since its birth. However, research that began in the 1990s showed that the expansion accelerated about 6 billion years ago; the cause of this acceleration remains a mystery.

Understanding the true nature of dark energy and dark matter could help astronomers uncover what the universe is made of, how its expansion has changed over time, and whether there is more to understand about gravity.

Dark matter and dark energy are also thought to play a role in the distribution and movement of objects like galaxies and stars in the universe.

Euclid is designed to observe billions of galaxies up to 10 billion light-years away and aims to reveal how dark energy has pulled and separated matter over time. These observations will allow Euclid to see how the universe has evolved over the last ten billion years.

During its observations, the telescope will catalog 1.5 billion galaxies and their stars, gathering valuable data such as each galaxy's mass and star formation rate for astronomers.

Euclid's first images provide a promising preview of the broader map it will unveil in the future.