If the universe had expanded just a little slower, the material would have dribbled out like big drops of water, then collapsed back where it came from by the force of gravity.
A little too fast, and you get a meaningless spray of fine dust. A little too slow, and the whole universe collapses back into one big black hole.
The surprising thing is just how narrow the difference is. To strike the perfect balance between too fast and too slow, the force, something that physicists call “the Dark Energy Term” had to be accurate to one part in ten with 120 zeros.
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