The Scale of the Universe Flashcards
Who were the 2 men who debated about the size and structure of the Universe?
Harlow Shapley and Heber Curtis
What was Shapley’s argument?
That the universe was just one galaxy and that the nebulae were huge clouds of gas and dust
What was Curtis’ argument?
That the universe was made up of many galaxies with the sun at the centre of ours. He said that the spiral nebulae were other distant galaxies
What parts of both of their explanations were correct?
Shapley was correct in saying that the Solar System is far from the centre of our galaxy
Curtis was right is saying that there are many other galaxies in the universe. He was also right about the spiral nebulae being other galaxies
What scale do astronomers use when talking abuot objects outside of the milky way?
Megaparsecs
How do we know when a galaxy is moving away from us?
The wavelength of the light from it changes; it becomes redder. This is called red shift
What is the pattern that Hubble found involving the speed and distances of galaxies?
The more distant the galaxy, the faster it moves away from us
What is Hubble’s formula to work out the speed of a galaxy’s recession?
Speed of recession = Hubble constant x distance
