The oldest of the ancient: the Webb telescope has discovered the oldest galaxy

In July 2022, the James Webb Telescope — the largest cosmic infrared observatory ever launched — sent its data to an international team of researchers at NASA.

The telescope has detected the 13.5-billion-year-old GLASS-z13 galaxy, which may be the oldest galaxy in the universe

The galaxy in question predates the universe by a mere 250 million years. GLASS-z13 is fairly passive and has many stars whose formation process scientists estimate began about 200 million years after the Big Bang. Light from GLASS-z13 took more than 13 billion years to reach Earth, while at present, the distance from us to this galaxy is already 33 billion light years due to the continuous expansion of the universe.

It is still difficult to establish the exact age of GLASS-z13, but humanity is certainly the oldest galaxy ever detected. When rendered from the infrared to the visible spectrum, it is a red spot with a white centre, and its mass is several billion times larger than our solar system.

In addition to GLASS-z13, scientists have also found another candidate for "the oldest galaxy in history", CEERS-93316, which may help researchers determine when the Reionisation Era began, that is, when the first galaxies started to re-ionise hydrogen after the so-called "dark ages" ended. Thanks to the data obtained, the observatory can also reach new heights in galaxy evolution and star formation at different stages of the universe.

To analyse the findings, the scientists also used the Lyman Leap method. A photon with a wavelength shorter than 91.2 nanometres is absorbed by the hydrogen gas in the observed galaxy, causing the spectrum to "break down" and display redshifts through filters for different wavelengths. It has also facilitated scientists being able to confirm that the galaxies detected are not random flares or other objects. However, there is still work to do because if the ages of the oldest galaxies are confirmed, it would mean that the Webb telescope has the potential to find out even what happened at the time of the Big Bang.