A group of NASA astronomers has published new information about comet 3I/ATLAS – it turns out that this was one of the oldest cosmic objects humanity has encountered. This was evident even during the measurement of the comet's speed and trajectory, but now scientists are confident they have come across a truly ancient piece of rock. It is approximately 12 billion years old, which is very close to the age of the universe as we know it. Establishing the age was a byproduct of analyzing the chemical composition of the comet, which was measured using the James Webb Space Telescope.  In particular, scientists were interested in the isotopes of hydrogen and carbon – the deuterium content in the matter of 3I/ATLAS turned out to be anomalously high. Unfortunately, it is not possible to verify the results: the visitor from the depths of space was moving through the Solar System too quickly, and the scientists had only one opportunity to take measurements. No other objects in the Solar System have as much deuterium as 3I/ATLAS – it is also absent in young neighboring planetary systems and clusters of interstellar gas. This further indicates the venerable age of the visitor and signs of its formation. At that time, there was a lot of radiation around, but very few metals – these were precisely the conditions for the formation of the first large cosmic objects about a billion years after the Big Bang. For comparison, the age of the Solar System is only about 4.5 billion years, while 3I/ATLAS is nearly three times older than our planet.