Is there anything that could restart the universe expansion?
Basically a black whole or something else entirely different? It seems to me that, once the Universe stops expanding, the human life would be non-existent.
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The expansion (nor contraction) of the universe has no effect on humanity. The effect is so small on our scale that it's unnoticeable. The local gravitational attraction of our galaxy and Sun negate any local effect of expansion or contraction; space will expand, but gravity will still hold our galaxy and nearby galaxies together for quite some time.
Eventually expansion will be happening so fast that all other galaxies will be moving away from us, even in our local group. In about 2,000,000,000,000 years all other galaxies will be accelerating away so quickly we will no longer be able to see them, they will be moving away at the speed of light. Even then the only effect on what counts as humanity 2 trillion years from now is they will have no evidence of a universe outside their galaxy.