While we may never know if the Universe as a whole is infinite or bounded, we know that the cosmic microwave background – the distant shell of fading fire that surrounds us – is the most distant light...

The reason the Universe can be glowing all around us but still look dark comes down to the physics of light in an expanding universe. When space expands, and the distance between objects grows, the light passing between those things gets stretched out, shifting the light to lower frequencies on t...

Whether it’s more troubling to imagine that the Universe goes on forever in every direction, or that it has an edge, beyond which there is nothing, is hard to say.

Astrophysics doesn’t provide any guidance as to which flavour of existential crisis we should be having – while we can’t say wi...

Olbers’ Paradox asks: if the Universe is infinite, and if there are stars (or galaxies) throughout it, why is the sky dark? Surely, if we look in any direction in the sky, that sightline will, eventually, land on a sta...