DECRYPTION – If the signal were confirmed, the most distant galaxy ever identified would emit surprisingly powerful ultraviolet radiation.
The Universe is extraordinarily large. So huge that the light, yet the fastest object there is, seems to propagate there at the speed of a neurasthenic snail. For example, a photon takes eight minutes to reach us from the Sun, four years to reach the nearest star (Proxima Centauri) and more than 200,000 years to cross our galaxy from side to side. When you look at the Sun, then, you actually see it as it was eight minutes ago; Proxima Centauri, as it was four years ago. Most stars visible to the naked eye in the sky take you back a few hundred to a few thousand years. And that’s nothing yet. Light from the Andromeda galaxy, our nearest neighbour, took 2.5 million years to reach us, so we see it as it was 2.5 million years ago.
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You have understood: the greater the distance that separates us from an object, the further we look into the past. It is…