How do we know the universe is ever expanding?
In: Physics
When a source is moving away from a viewer the light emitted gets a slightly reddish color due to light red light moving slightly slower. If a source is moving toward a viewer, the light gets a bluish tint. We have observed a general redshift in light from other celestial bodies. There is other evidence too in quantum mechanics that has further support for this, but it’s quite complicated and I don’t fully understand it myself.
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