There’s something strange happening in the universe.

Scientists have discovered mysterious forces that seem to be pushing the universe apart and pulling things together in surprising ways, but we can’t see or touch these forces.

They call these forces dark energy and dark matter.

Scientists have found that many galaxy behaviors wouldn’t make sense without a large amount of invisible matter, or dark matter.

This dark matter has an extra gravitational pull.

Without it, some galaxies would break apart, and others wouldn't even exist.

Dark matter can also bend light from faraway galaxies, making their images look distorted when they reach our telescopes.

This effect is called gravitational lensing, and it helps scientists know dark matter is there, even though we can’t see it directly.

We call it "dark" because it doesn’t emit or absorb light, and it only interacts with regular matter through gravity.

At the same time, something else is making the universe expand faster and faster. Since the universe began 13.8 billion years ago, it has been getting bigger.

Scientists thought this expansion would slow down over time, but instead, it has sped up since about five billion years ago. This mysterious force is called dark energy.

Visible matter, which includes everything we can see like stars and planets, makes up only about 5% of the universe. Dark matter and dark energy are believed to make up the other 27% and 68%, respectively.

This means that what we can see doesn’t even begin to explain most of the universe.

Scientists have proposed several theories about the ultimate fate of the universe.

The Big Rip suggests that the universe's expansion will continue to accelerate, eventually tearing apart galaxies, stars, and even atoms.

The Big Freeze hypothesizes that the universe will keep expanding, leading to a gradual cooling and dimming as stars burn out, resulting in a dark, empty cosmos.

The Big Crunch presents a different scenario where the expansion of the universe slows down and reverses, causing everything to collapse back into a singularity, much like the conditions at the universe's beginning.

Lastly, the Big Bounce theory proposes that after the Big Crunch, the universe might not end but instead rebound, leading to a new cycle of expansion and contraction.