What is on the edge of the universe? The question may seem strange when we today accept the idea that the universe is finite. And yet the idea of boundaries has a meaning, because one has to go back in time even to see the distance (p. 24). Therefore the horizon cannot exceed the Big Bang. Or rather the first light that was emitted after the Big Bang, 380,000 years later. Because earlier, the universe belonged only to him (p. 26). So far, astronomers do not have enough eyes to see. But they were able to rely on one precious ally: the Hubble Space Telescope.
The human has never seen so far, never has he gone so far, and therefore never had such an accurate vision of boundaries.
For more than thirty years, from its orbit at an altitude of 600 km, it has been bathing scientists and enthusiasts with stunning images of space. Some of which contain treasures, such as the galaxy GN-z11 whose distance from Earth has just been established with precision: 13.4 billion light years. The galaxy was never seen so far. And this is not the only record that has just fallen. In March, another space telescope, Chandra, discovered the signature of the farthest black hole it has been given to identify. Located 12.7 billion light years away, it may actually be older than the GN-z11. This is not without provoking intense debate: through what means can black holes be formed before the stars that give rise to them? New hypotheses are emerging. Among them: a type of fusion of black holes that we have also discovered for the first time this spring (p. 8)!
What is on the edge of the universe? The question is timeless but – as we can see – hot topical as well. It continues to inspire both science fiction writers (p. 32) and astrophysicists. And gives us an opportunity to invite them to explore the universe at a distance that the human mind struggles to imagine. Judge for yourself: The Sailor probe, which survived a little over forty years ago and which for its part explore the boundaries of the solar system, is only “only” 0.0024 light years away! Nevertheless, at the moment, these machines are sending us the first measurements taken from interstellar space (p. 30). Already, we have to modify the shape of the Sun’s sphere of influence. The human has never seen so far, never has he gone so far, and therefore never has he got such an accurate vision of the outskirts. When you return from this journey to find them, you can immediately reestablish Everest (p. 50) or towards the first American colonies (p. 82). Even limited, let’s continue to escape.