The Universe is loaded with galaxies, and this is not something that astronomers always knew. Until the ’20s, it was believed that our Milky Way is the only existing galaxy. But the American astronomer Edwin Hubble discovered a century ago that our galaxy is just one of the billions of other galaxies out there.
Today, astronomers are certain that the total amount of galaxies in the Universe is of several trillions (at least!). Just imagining what mysteries and maybe even life forms can those other galaxies harbor is both exciting and frightening at the same time. Furthermore, the ultimate question arises: which one of those countless galaxies is the oldest from the Universe?
The galaxy cluster XLSSC 122 might hold the answer
The answer to the question may be held by the galaxy cluster XLSSC 122, which is so far away that its light needed 10.4 billion years to reach us. Considering that the speed of light is almost 300,000 km/s, we can figure out with some simple calculation that the XLSSC 122 galaxy cluster is 10.4 billion years old. Considering that the Universe is 13.7 billion years old, the cluster was around when the Universe was only 3.3 billion years old. Therefore, the chances are high that the oldest galaxy is right in the XLSSC 122 cluster.
The cluster was first discovered using the European Space Agency’s X-ray Multi-Mirror space observatory. It only looked like a collection of photons on an X-ray image of the sky. Meanwhile, astronomers could get a better understanding of the cluster, but there’s always room for more. NASA wants to launch the James Webb Space Telescope during Q1 of 2021, and the XLSSC 122 cluster will be greater analyzed.
Hopefully, one-day humanity will have the technology to visit another galaxy, something that for the moment is absolutely impossible. Most stars from a galaxy should have exoplanets orbiting around them, so there’s no telling what wonderful things we would find there.