And to find out more about the dark red dot itself (whose explosion was designated GRB 250314A), see ESA's report here: www.esa.int/ESA_Multimed...

You can find out much more about the affectable universe and the ultimate limits of causality in our universe in a paper I wrote called 'The Edges of Our Universe':
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arxiv.org/pdf/2104.01191

Here's a diagram I made, showing our place in the affectable universe, and its place within even greater regions:
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So if beings from Earth and that distant galaxy set off towards each other at close to the speed of light, they could yet meet.
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Though interestingly, current events in that star's galaxy could still affect *us*. Our affectable universe doesn’t include it and its affectable universe doesn’t include the Earth. But these spheres do overlap...
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So this image shows a star which is so far away that it is outside the affectable universe. Nothing we do here and now could ever affect it, and nothing that happens there now could ever affect the Earth.
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However, when a star explodes in a supernova, it releases so much energy in such a short time that it can outshine its entire galaxy, making an individual star visible at such an immense distance.
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The observable universe is (currently) about 3 times the diameter of the affectable universe, so there are many such stars that are observable but not affectable. Though until recently, we’d only been able to see entire galaxies of them as small smudges on the best Hubble images.
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Each year the observable universe grows in diameter as there is more time for the light to have reached us.
Each year the affectable universe shrinks by the same amount as there is less time for our light to reach the distant galaxies before they drift away.
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I call everything within this distance the "affectable universe". It is the lesser-known twin to the observable universe:
The observable universe is all places we can currently observe, while the affectable universe is all places we can currently affect.
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One way to think about this is that there is a critical distance — about 16.5 billion light years — that demarcates the part of the universe we could ever affect.
(This is all according to current known physics, assuming the standard ΛCDM cosmology).
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But the new star whose supernova explosion has just been detected as a dim red dot in the blackness between distant galaxies is more than twice as far away — about 29 billion light years. This is so far away that our light can never catch up (and nor could anything else).
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But the light would be gaining on it — making up the distance faster than Icarus can drift away. In 35 billion years our light would finally catch up.
So we *can* affect Icarus.
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14.4 billion light years is a long way. Light would take light 14.4 billion years to travel that distance. But during those years the intervening space would keep expanding, so Icarus would be even further away and even 14.4 billion years from now the light still wouldn’t have reached it.
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Icarus is currently about 14.4 billion light years from Earth and its light had been travelling for 9.3 billion years before it struck the lens of the Hubble Space Telescope. Those numbers differ because the space between us has expanded while the light was in flight.
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What is going on?
Until 2022, the furthest individual star ever discovered was “MACS J1149 Lensed Star 1” — aka “Icarus”.
en.wikipedia.org/wiki/MACS_J1...
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Whether or not we will ever be able to travel to other stars, we can usually affect them (and they can affect us) through the light we each emit.
Shine a torch into the night sky and you will personally affect galaxies billions of light years away.
But not in this case.
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