The Scale of the Universe Flashcards
What was Shapley’s & Curtis’ beliefs about how many galaxyies there were?
Shaply - the Universe was just one gigantic galaxy
Curtis- there are many galaxies making up the Universe
What was Shapley’s & Curtis’ beliefs about where in the galaxy the solar system was?
Shaply- We were far from the centre of the galaxy
Curtis- The sun was very near, or at the centre of the galaxy.
What was Shapley’s & Curtis’ beliefs about what nebulae were?
Shaply- Nebulae were huge clouds of dust that were nearby or part of the Milky Way.
Curtis- Nebulae were other distant galaxies, completely seperate from the Milky Way.
What was Shaply correct about?
The solar system is far from the centre of the galaxy.
What was Curtis correct about?
There are many more galaxies.
Nebulae
What is Red Shift?
When a galaxy is moving away the wavelength of the lights from it changes. The light becomes redder.
What can you work out by seeing how much light has been red-shifted?
How fast the galaxy is moving away. (Recession of velocity)
The greater the red shift, the greater the velocity.
What pattern did Hubble find when he compared the speed & distances of many distant galaxies?
The more distant a glazy is, the faster it moves away from us.
What is Hubble’s law?
Speed of recession (km/s) = Hubble constant (s^-1) x Distance (km)
What is Hubble’s law used for?
Finding the distance to a distant galaxy
