Look up into the night sky and everything looks so calm. So still. And yet, the truth of the matter is everything, every star you see, every galaxy is hurtling away from you at incredible speeds. The expansion of the Universe was proved by Hubble in 1925. In the early 90s, the scientists were fairly certain that even though the Universe was expanding, it should have enough energy density to stop its expansion and recollapse. If not that, gravity would cause the expansion to slow down. So as time goes on, the rate of expansion would decrease. But Mother Nature threw another curveball at us. From the data collected by the Hubble Space Telescope, scientists found out that the rate of expansion of the Universe was actually increasing.
Now hold on a bit and think about how interesting this discovery is. Think about it this way. You throw a ball up in the air. You’d expect that it would reach a certain height and then fall back down. But imagine that the ball continues to go up and its speed increases the higher it goes. Crazy, right?
To explain this weird behavior, theorists came up with “Dark Energy”. Don’t worry, it’s nothing evil. (Or maybe it is. Vashta Nerada, anyone?)
Dark Energy makes up about 68% of our Universe. Though we’re still not really sure what it actually is. We know it’s evenly distributed throughout the Universe. We know it’s gravitationally repulsive in nature, to account for the increased rate of expansion. But the exact nature of this energy is still unknown.
Until then, we can continue to attribute intrigue and killer microscopic swarming aliens to the Dark.
That’s all for today! I’m keeping the A-Z posts short. If you have any questions, comment below! Or just say “Run!” and leave a link to your blog! See you tomorrow.