Our universe never stops surprising us, and it’s all a gift from the James Webb Space Telescope (JWST), which, if you didn’t know, is the most incredible telescope ever created, but we’ll tell you about that now. This telescope has once again surprised astronomers by discovering the JADES-GS-z14-0 galaxy, the most distant galaxy observed to date. That’s right! Its light has taken 13.4 billion years to reach us, which means we’re seeing it as it was when the universe was just 2% of its current age, almost as if we were looking at the first photo our great-grandparents ever took.
The discovery is incredible, but what has truly baffled scientists is its chemical composition. Against all odds, oxygen has been detected in its light spectrum, an element that, according to current theories, shouldn’t be present in such a young galaxy. Is the scientific community wondering how stars form and how galaxies evolve? Yes.
What is the James Webb Telescope?
NASA, along with the European and Canadian scientific community, had a telescope called Hubble. This telescope observed visible and ultraviolet light, but they soon developed a new version called the James Webb Space Telescope (JWST), and it’s here to stay, as it’s the most advanced space telescope ever built. It was launched in December 2021 and its main objective is to study the universe in the infrared to detect the oldest galaxies, analyse the atmospheres of exoplanets, and delve deeper into the origins of the cosmos.
It is located at the L2 Lagrange point, 1.5 million kilometres from Earth, and is equipped with a 6.5-meter diameter primary mirror, making it much more powerful than its predecessor.
How did JWST detect this galaxy?
Using infrared light, in the case of JADES-GS-z14-0, astronomers used the Mid-Infrared Instrument (MIRI), which captured a strong emission at the wavelength of 7.7 micrometres (a clear sign of the presence of ionized oxygen).
The problem is that according to cosmological models, oxygen only forms inside massive stars and is released into the interstellar medium when they explode as supernovae. For this element to be present in JADES-GS-z14-0, there must have been several generations of stars before their light reached us. This implies that the star formation process occurred much faster than we thought.
“The fact that we found this galaxy in a tiny region of the sky means there should be many more out there,” explained Jakob Helton, lead author of the study.
JADES-GS-z14-0: the most distant galaxy
JADES-GS-z14-0 stands out for its remoteness. With a confirmed redshift of z = 14.3, it is the most distant galaxy ever observed. The light we see today came from it when the universe was just 2% of its current age. Its stellar content is estimated to be 500 million times the mass of the Sun, which is why it shines so brightly.
Another surprising fact is its size. Rather than being a simple point of light, its structure is more extended than expected for such a young galaxy. According to Hainline, co-author of the study, it is not just a small point of light, but is of considerable size considering the age of the universe at the time we observed it.
Key questions for astronomers
The discovery of JADES-GS-z14-0 raises three fundamental questions about the formation of the first galaxies: whether similar galaxies exist in the early Universe, whether our theories of galaxy formation are correct, and, above all, whether there was another process that drove the evolution of these structures that we still don’t understand.
We knew that the universe and galaxies still hold thousands of secrets, but did you expect it all to be so complex?