The universe is "disappearing"

The discovery of the most distant galaxy ever observed by the James Webb Space Telescope (JWST) has astonished the scientific community. By examining the distant Universe, this telescope has allowed us to observe galaxies dating back billions of years.


This achievement raises questions about the limits of our observable Universe. James Webb sees this galaxy as it was just 300 million years after the Big Bang.

The Universe is 13.8 billion years old, meaning that the most distant galaxies should be located at that distance. Yet, the galaxy JADES-GS-z14-0 is currently 33.8 billion light-years away. How is this possible? This distance seems to contradict our understanding of the Universe's age.

The expansion of the Universe offers an explanation. Although the light from JADES-GS-z14-0 has traveled for 13.5 billion years, the expanding Universe has stretched this distance to 33.8 billion light-years today.

The Universe has gone through several phases of expansion, including a rapid cosmic inflation period after the Big Bang. This phase was followed by a matter-dominated period, then by a new acceleration phase driven by dark energy, which is still active today.



Galaxies like JADES-GS-z14-0, visible today, will no longer be observable in a few billion years due to the continuous expansion of the Universe. Future observers will only be able to see local galaxies; the most distant ones will have moved beyond the cosmological horizon.

On a physical level, the expansion of the Universe will increase the distance between them and us at speeds greater than that of light. Their light will never be able to reach us again. This expansion process is ongoing. The expansion is even accelerating.

Thus, James Webb provides a unique window into cosmic history, allowing us to explore eras that will be invisible to future generations. Astronomers are fully taking advantage of this privilege to deepen our understanding of the Universe and its origins.