The James Webb Space Telescope (JWST) has made another groundbreaking discovery, finding the most distant galaxy ever seen: JADES-GS-z14-0. This ancient galaxy is a mere 300 million years old, and its light has taken 13.5 billion years to reach Earth.
This remarkable find pushes back the boundaries of what we know about the universe’s earliest moments, when the first stars and galaxies began to form. The discovery was announced in a paper published in the Astrophysical Journal Letters.
The JWST is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). It’s designed to study the formation of the first galaxies and stars, as well as the origins of life itself.
**The Big Bang and Cosmic Expansion**
To understand how we can see JADES-GS-z14-0 from 13.5 billion light-years away, it helps to grasp the concept of cosmic expansion. The universe began with an initial period of rapid inflation, often referred to as the “Big Bang.” This inflationary epoch saw the volume of the cosmos increase by a factor of 10^26 (10 followed by 25 zeroes). That is equivalent to your fingernail growing from a rate of 1 nanometer per second to suddenly growing 10.6 light-years (62 trillion miles) long.
This was followed by a matter-dominated epoch beginning 47,000 years after the Big Bang. Eventually, universal expansion allowed the cosmos to cool enough for protons to form from quarks and gluons, and then protons to bond with electrons to form the first atoms of hydrogen, which formed the first stars and galaxies.
**The Dark-Energy-Dominated Epoch**
The matter-dominated epoch came to an end when the universe was just under 10 billion years old. At this time, the universe suddenly began to expand rapidly once again. This third significant period of the universe is called the dark-energy-dominated epoch. It’s the epoch we’re currently in.
**JADES-GS-z14-0: A Galaxy from the Dawn of Time**
The James Webb Space Telescope (JWST) has detected JADES-GS-z14-0, a galaxy that existed only 300 million years after the Big Bang. This ancient galaxy is the most distant ever observed and challenges our understanding of when life could have emerged.
**A Lucky Era to Have the James Webb Space Telescope**
The fact that the JWST can see JADES-GS-z14-0 means it was once “causally connected” to Earth and our local universe. In other words, it was possible for a signal from JADES-GS-z14-0 to reach us in the Milky Way, thus a “cause” in this galaxy that existed at the dawn of time could have an “effect” in our galaxy in this modern epoch of the cosmos.
**A Galaxy Beyond Our Cosmic Horizon**
This isn’t the case anymore, however. Galaxies like JADES-GS-z14-0 and other JADES-discovered galaxies are now so distant and are driven away from us so rapidly, thanks to dark energy, that no signal from them sent today could ever reach us. That’s because the photon horizon moves away from us at the speed of light, but for really distant objects, the space between the Milky Way and those galaxies is expanding faster than the speed of light.
**A Unique Point in the History of the Universe**
In around 2 trillion years after Earth and humanity are long gone, the expansion of the universe means that, whatever intelligent species replaces us in the Milky Way (if one ever does), will be unable to see any galaxies that exist beyond our local group — which has a diameter of around 10 million light-years.
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Source: https://www.livescience.com/space/cosmology/can-the-james-webb-space-telescope-see-galaxies-over-the-universes-horizon