We know the universe is expanding at an ever increasing speed. This is due to a type of energy known as dark energy.
Raising the Bar
By measuring the distribution of hydrogen in our galaxy, we know that our galaxy is a barred spiral.
Hubble’s Constant
Hubble’s constant shows a relationship between the distance of a galaxy and the speed at which it moves away from us. Its discovery was the first evidence that the universe is expanding.
Gravitational Lensing
Einstein said space was curved, but how to we know it really is? It turns out we can observe that curvature by watching light bend around a large mass such as a galaxy.
Dark Matters
The first evidence of dark matter came from observing the motion of stars in our own galaxy. It turns out stars were moving far more quickly than they should. Ever since then astronomers have tried to determine just what dark matter is.