LAP1-B, the primordial galaxy that can explain fossil galaxies

The James Webb Space Telescope has observed LAP1-B, a very faint and ancient galaxy that was born about 800 million years after the Big Bang. The data indicates that it contains very little oxygen and resembles a "primordial" galaxy, meaning it is one of the closest objects to the first galaxies ever studied so far.

This discovery comes from a study published in Nature. Astronomers observed LAP1-B thanks to a kind of natural magnification created by the gravity of a large cluster of galaxies, which bends the light from the background object and makes it easier to study.

LAP1-B has an oxygen amount equal to about 1/240 of that of the Sun, an extremely low value. For this reason, it is considered a chemically almost primitive galaxy, with a composition very similar to what is expected in the early life stages of the Universe.

This is where the reference to fossil galaxies comes into play: these are small galaxies close to the Milky Way that retain very ancient traces of their formation because they have undergone few transformations over time. LAP1-B could be a sort of ancestor, observed when the Universe was still very young.

Why it matters

The discovery is interesting because it may help understand how the first cosmic structures were born and how the first stars formed. In essence, it is like observing a very ancient fragment of the history of the Universe, still little changed from the era when the cosmos was very young.

Furthermore, the authors of the study also point out that LAP1-B is extremely small: its stellar mass remains below 3,300 solar masses, making it much lighter than a galaxy like the Milky Way. The data also highlights how it is dominated by dark matter, the invisible component that influences the behavior of galaxies.

Therefore, it is not a "normal" galaxy, but a very rare, very faint, and ancient object, observed thanks to the sensitivity of the James Webb Space Telescope and the lensing effect produced by another cosmic mass. For this reason, LAP1-B is useful to understand what the first galaxies of the Universe were like and how they have evolved up to today.