Dark Energy and the Accelerating Universe
TL;DR Summary
The expansion of the universe isnt slowing down; its speeding up. Dark energy is the mysterious force driving this acceleration.
The Shocking Discovery
In the late 1990s, astronomers measuring the distance to distant supernovas expected to find that the expansion of the universe was slowing down due to gravity. Instead, they discovered the exact opposite: the expansion is accelerating.
What is Dark Energy?
To explain this acceleration, scientists hypothesized a mysterious, repulsive force that permeates all of space, which they called Dark Energy. It makes up roughly 68% of the total energy density of the universe.
The Big Rip
If dark energy continues to accelerate the expansion of the universe, it could eventually overcome all gravitational and electromagnetic forces. In a scenario known as the "Big Rip," galaxies, stars, planets, and eventually atoms themselves would be torn apart by the accelerating expansion of space.