Gravity, with Marcus Chown
Instant Genius
00:00
Why Is Gravity Only Attractive?
The universe began in a big bang about 13 point eight million years ago. The galaxies the building blocks of the university. We assumed that the only force operating was gravity and attractive force between all the galaxies. In 19 98, contrary to all expectations, we found that the expansion is actually speeding up. And we've had to postulate the existence of stuff called dark energy,. which invisible, fills all space and has repulsive gravity. It accounts for two thirds of the mass energy of the universe.
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