"I am using the word theory as a scientist means it: a set of ideas so well established by observations and physical models that it is essentially indistinguishable from fact. That is different from the colloquial use that means "guess."To a scientist, you can bet your life on a theory. Remember, gravity is "just a theory"too."
PH
Philip Plait, Death from the Skies!: These Are the Ways the World Will End...
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