Hello bloggers! How are you all doing this fine day? Well I’m doing wonderfully. You know why? Because in my cosmology class we will actually start talking about cosmology and not just gravitation! (I will warn you now, some of this stuff we’ve already gone over in the background section of this blog). So first we’ve started off with Olber’s paradox. People before the 20th century believed that the universe was infinite and static. And a consequence of an infinite universe was that if you looked out into the night sky any were you look you would see a star. So instead of being black and blotchy the night sky would be a uniform brightness. Like in the picture. But this is obviously not true. Why not? Well there are 3 main reasons quoted. Firstly is the finite speed of light. Secondly is the finite age of universe. Third is the fact that space expands. The first and second ones go together. If the universe was created a certain finite time ago then the light from the far away stars hasn’t reached us yet. The third one only adds to this effect because as the universe expands the light from really far away objects gets red-shifted into a wavelength we can’t see. So from all this we can concluded that the universe isn’t static or infinite.
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