If the universe is infinite and there are an infinite number of stars then every point in the sky should be a star. However, we observe the night sky as being dark not bright.
This has been attempted to be explained a few ways, that the universe is finite (not generally accepted) or the Big Bang means a finite amount of stars are observable because the universe is expanding (microwave background radiation, invisible to the human eye, seems to prove that).
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An interstellar object that passed through our solar system in 2018. Researchers believe it to be solid chunk of hydrogen that was formed in a gas cloud 40MM years ago. However, if does not have the usual features of a comet (e.g. a coma) and it’s accelerating. An alternative explanation is that it’s extraterrestrial in origin.