Recently, scientists from Cornell University in the United States discovered in photos taken by the James Webb Space Telescope that although it was born only 1.4 billion years ago, the stars inside it have replaced multiple generations of abnormally “mature” strange galaxies. In the process of studying another distant galaxy magnified by gravitational lensing, the researchers discovered that this star “crossed” from modern times to ancient galaxies. Another galaxy, called SPT0418-47, is a dusty, star-forming galaxy that existed in the early universe. The image of this galaxy has been gravitationally pulled by the foreground galaxy into a ring — the “Einstein ring.” That galaxy is hidden within the ring, but it’s just noise in pictures taken by other telescopes.
After analyzing the spectral data, the researchers determined that two previously undiscovered points of light were hidden within the “Einstein ring”, which came from the same background galaxy. While the gravitational lensing effect of the foreground galaxy forms the “Einstein ring”, it also magnifies and brightens the image of the background galaxy and makes “duplicate”, but even after the image of the galaxy is enhanced, its brightness is only as bright as 1/16 of the “Einstein Ring”. The researchers confirmed that its hydrogen, nitrogen and sulfur, and ionic carbon emission lines have the same redshift of about 4.2 as the background galaxies that form the “Einstein ring”. It shows that the distance between these two galaxies and the earth is the same, they are both in the early universe whose age is only 10% of the modern universe, and they should be “partners” for each other.
The researchers numbered the faint companion galaxy SPT0418-SE, and it is only 5 kiloparsecs away from SPT0418-47, which forms the “Einstein Ring”, only 1/10 of the distance between the Milky Way and the Milky Way’s satellites, the “Large and Small Magellanic Clouds” . This means that the two galaxies are gravitationally bound to each other and are likely in the process of merging. Both galaxies are of medium mass, and SPT0418-SE may be smaller and less dusty, appearing bluer than the dusty Einstein ring. According to the analysis of the characteristics of nearby galaxies, the researchers may be surrounded by a huge halo of dark matter, and there may be other undiscovered galaxies in the halo.
Surprisingly, the smaller companion galaxy is very high in “metallic elements” such as carbon, oxygen and nitrogen, in proportions almost equal to those of the Sun. But the sun has a lifespan of more than 4 billion years, and its body contains “metallic elements” made by generations of stars. To reach the abundance of “metal elements” in the sun, it takes nearly 8 billion years of accumulation; and this galaxy was born only 1.4 billion years ago! This means that this galaxy has experienced the replacement of multiple generations of stars in just a billion years after the birth of the universe, which is incredible. The researchers said that all of this is currently unknown. One possible explanation is that there may be some unknown force in the universe that can quickly form these weird galaxies.
