What was the appearance of the universe like 13.8 billion years ago? The most distant "baby galaxy" tells you the answer →

The existence of JADES-GS-z14-0 is like an "early diary" in the history of the universe, recording the appearance of the universe 13.8 billion years ago (only 300 million years after the birth of the universe).

Why is it so far away?

Astronomers use a phenomenon called "redshift" to determine how far away objects in the universe are. When a galaxy is moving away from us at high speed, its light is "stretched" and becomes reddish - the greater the redshift, the greater the distance. JADES-GS-z14-0 has a redshift of 14, which means that its light took more than 13.8 billion years to reach Earth! Scientists have used giant telescopes (such as Hubble and James Webb) to barely "glimpse" its blurry figure.

What is so special about this galaxy in the universe?

1. It is a "star baby": Although this galaxy is small (the core diameter is only about 260 light years), it is creating new stars at a very fast rate. Its brightness is equivalent to the sum of billions of suns, like a "star manufacturing factory"! But strangely, it releases a large amount of invisible ultraviolet light - these ultraviolet rays can actually "escape" from the galaxy and illuminate the surrounding dark space like a lighthouse.

2. It actually has “metal”?

In the early days of the Big Bang, there were almost only hydrogen and helium, and metals (in astronomy, elements heavier than hydrogen) were the product of nuclear fusion inside stars. The metal content of this early galaxy reached 17% of that of the sun! This shows that although it was born early, it has already experienced the "reincarnation" of at least one generation of stars - star explosions throw heavy elements into interstellar space, providing materials for a new generation of stars. Scientists speculate that this may come from supernova explosions or the promotion of stellar winds.

How did it "survive" in such an early universe?

The early universe was filled with hydrogen, like a dense "dark fog". The light of stars was blocked until the first galaxies were born, and their ultraviolet light acted like a "fog breaker", gradually ionizing the surrounding gas, eventually allowing light to propagate. JADES-GS-z14-0 may be participating in this "cosmic dawn" - its escaped ultraviolet light may be helping to "blow away" the surrounding gas, paving the way for the birth of subsequent galaxies.

Conclusion

JADES-GS-z14-0 is like a puzzle piece, helping humans piece together the story of the "first billion years" after the birth of the universe. In the future, with the construction of larger telescopes (such as the Giant Magellan Telescope), we may be able to see it in more detail, and even discover its "brothers and sisters", and finally unveil the epic of the universe from chaos to stars.

Did you know?

- The universe is about 13.8 billion years old, and the light emitted by this galaxy "started" at this time, which is equivalent to us "seeing with our own eyes" what it looked like in its infancy at this moment!

- The expansion of the universe has caused its light to "run" for so long that it may have grown into a completely different appearance now, but we can only "look back" at its state when it was born.

(Reference for this article: https://doi.org/10.1051/0004-6361/202452451)