When you're inside something, it's hard to see its shape. We're still finding out new things about the shape of our galaxy.
The shape of the universe? That's a lot harder to gauge, but years of observational data, cosmological models and physics suggest it's flat. Send a beam of photons out across the void, and it will just keep going in a straight line.
A new study argues otherwise. Based on data released last year collected by the European Space Agency's Planck satellite, astronomers have argued the case that the universe is actually curved and closed, like an inflating sphere.
Image: The oldest light in the universe, called the cosmic microwave background, as observed by the Planck space telescope is shown in an oval sky map. Planck Collaboration/ESA
