Dark Energy

cosmology · universe · expansion · invisible

Most of the universe. Dark energy makes up about 68% of all the stuff in the universe. That is way more than stars, planets, and all the regular matter we can see, which only makes up 5%.

Pushing things apart. Dark energy acts like an invisible force that pushes galaxies away from each other. This makes the universe expand faster and faster, like a balloon being blown up.

Super spread out. Dark energy is incredibly thin and spread evenly throughout all of space. It is so dilute that you would never notice it nearby, but because it fills the entire universe, it has a huge effect overall.

Still a mystery. Even though scientists know dark energy exists and what it does, they don't know what it actually is. It is one of the biggest unsolved puzzles in physics.

Slows down clumping. Dark energy doesn't just push things apart. It also slows down how fast galaxies and clusters of galaxies form and stick together in space.