Aristotle discovered the earth was round, on the heavens, eclipses, and the North Star

Copernicus came up with the sun as the center of the universe

Galileo observed jupiters moons

Kepler came up with elliptical orbits

Isaac Newton came up with gravity by an apple

The sun is 8 light minutes away from us

The ether is what makes up empty space

E=mc^2 means nothing can travel the speed of light. It would take infinite energy with an infinite mass

Spacetime is warped by the distribution of mass and energy

Geodesic is the shortest path between two nearby points

The nearest star is Proxima Centauri is 4 light years away from us

We can tell a stars temperature from the spectrum of its light

Most stars are hundreds of light years away

Our Milky Way galaxy is one of some hundred thousand million each with some hundred thousand million stars

Low frequency light is red, high frequency is blue. Doppler effect is red shifting meaning it is moving farther away since the frequencies of light are getting lower

The universe is expanding according to the Doppler effect and the farthest galaxies moving away at a faster pace