GN-z11 is an extraordinarily distant galaxy whose light has travelled through space for about 13.4 billion years before finally reaching us. We therefore see this galaxy as it existed when the Universe was only around 400 million years old, less than three percent of its present age. Every photon captured from GN-z11 began its journey billions of years before the Sun, Earth or the Milky Way in its modern form existed.
During that immense journey, the Universe itself continued expanding. The expansion stretched GN-z11’s light toward much longer wavelengths, a phenomenon known as cosmological redshift. This is why astronomers can use distant galaxies like GN-z11 as windows into the early cosmos: looking farther into space also means looking farther backward in time. We are not seeing the galaxy as it is today, but an ancient snapshot carried across most of cosmic history.
The scale is difficult to comprehend. Human civilization occupies only a tiny fraction of those 13.4 billion years, while the light from GN-z11 has been travelling almost since the beginning of the Universe itself. Observing objects this distant allows astronomers to study some of the earliest generations of galaxies and understand how quickly stars and cosmic structures began forming after the Big Bang. 
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