The universe is constantly expanding, but how do scientists think about what it’s expanding into?

The origin of our Universe remains one of the greatest enigmas of science, a question that seems to defy the limits of our ...

So what does the edge of the universe look like? At first, I thought it might be like Earth’s atmosphere, where outside is ...

(via Sabine Hossenfelder) Is the universe really infinite? Or could it close back on itself like a sphere? If it’s infinite, how can it expand? And is it true that there might be copies of you in it?

The fabric of space-time itself is what is expanding, so we cannot truly say that the universe is expanding “into” anything else.

But if the universe consists of all regions, there can't be an edge. This means the universe might be infinitely big, and it's impossible to point to the center of an infinite space.

Is the universe flat and infinite, or something more complex? We can’t say for sure, but a new search strategy is mapping out the subtle signals that would reveal if the universe had a shape.

This idea leads to a problem, though: if the universe is infinite in space, with stars evenly distributed throughout, then the sky should be bright —very bright, based on its geometry.

Heat death, big rip, big crunch? Here are five ways the universe could come to an end.

Whenever we look out at the Universe, no matter how powerful our tools or how clever our techniques, there’s always a limit to what we’re capable of observing. No photons, or quanta of lig ...