The Euclid space telescope has unveiled breathtaking images of more than 1,500 billion orphan stars dispersed throughout the Perseus cluster of galaxies, situated 240 million light-years away from Earth. These orphan stars, characterized by their distinctive bluish hue and clustered formations, appear to have been stripped from the outskirts of larger galaxies or from the complete disintegration of smaller galaxies, known as dwarf galaxies.
One of the most surprising findings was the discovery that these orphan stars are not orbiting the largest galaxy in the cluster, as initially expected. Instead, they are circling a point between the two brightest galaxies in the cluster. This unexpected pattern has led astronomers to theorize that the Perseus cluster may have recently experienced a merger with another galaxy group. Such a merger could have caused significant gravitational disruptions, altering the orbits of the most massive galaxy or the orphan stars themselves.
These orphan stars, although incredibly faint—over 100,000 times dimmer than the darkest night sky on Earth—contribute about 20% of the total luminosity of the Perseus cluster. This remarkable discovery was made possible by Euclid's extraordinary sensitivity and precision, which rivals that of the Hubble Space Telescope while covering a much larger area of the sky.