The unexpectedly rapid local expansion of the Universe could be due to us residing in a large void. However, a void wide and deep enough to explain this discrepancy—often called the “Hubble tension”—is not possible in standard cosmology, which is built on Einstein’s theory of gravity, General Relativity.
Astronomers have discovered that there are two different types of galaxies in the Universe: elliptical galaxies and spiral galaxies. Elliptical galaxies are dead galaxies full of very old, red stars that move on chaotic random orbits around the centre of their galaxy in such a way that makes their shape look like fluffy footballs. On […]
Our Galaxy—the Milky Way—is a vast rotating disk containing billions of stars along with huge amounts of gas and dust. Its diameter is around 100,000 light years.