When we look up at the night sky, we see stars, planets, and galaxies, but what if I told you there's more out there—things that we can't see or even directly detect?

This hidden universe is made up of mysterious forces called dark matter and dark energy. While they sound like science fiction, these invisible forces make up about 95% of the universe!

So, how can we explain something that we can't see, touch, or measure directly? Let's dive into the science behind dark matter and dark energy, and see how they shape our universe.

What is Dark Energy?

Video by Science Time

What is Dark Matter?

Let's start with dark matter, which is often described as the "invisible glue" that holds galaxies together. Even though we can't see it, we know it's there because of its gravitational effects. Dark matter doesn't emit, absorb, or reflect light, making it completely invisible to telescopes. Yet, we can observe its presence by noticing how it affects the movement of galaxies.

When we look at galaxies, they rotate much faster than they should, based on the visible matter we can see in them. This suggests there's something else exerting gravitational pull—something invisible but massive enough to affect how galaxies move. We can think of dark matter as a type of cosmic scaffolding, helping to shape the structure of the universe, although we have no idea what it's made of yet.

How Do We Know Dark Matter Exists?

You might be wondering, if we can't see dark matter, how can we be so sure it exists? The answer lies in its influence on the things we can see. As we study galaxies and star clusters, scientists have noticed that the visible matter alone doesn't explain how these structures behave. The gravitational effects we see—like the way galaxies bend light around them (a phenomenon called gravitational lensing)—suggest there's much more mass than what meets the eye.

Additionally, simulations of how galaxies form and evolve show that dark matter is needed to account for their structures. Without dark matter, our models would fall apart. So, while we can't detect it directly, we know dark matter must be there based on the effects it has on the visible universe.

What is Dark Energy?

If dark matter is the "glue" that holds things together, dark energy is the force that's causing things to fly apart. Dark energy is a mysterious force responsible for the accelerated expansion of the universe. You might have heard that the universe is expanding, but what you might not know is that this expansion is actually speeding up. In the past, scientists thought gravity would slow the universe's expansion, but observations from distant galaxies show the opposite—it's getting faster.

This surprising discovery was made in the late 1990s and led to the realization that dark energy makes up about 68% of the universe. Just like dark matter, dark energy is invisible and cannot be directly detected, but its effects are clear: it's driving the universe apart.

The Connection Between Dark Matter and Dark Energy

So, how do dark matter and dark energy work together, if at all? While they are very different in nature, both play crucial roles in shaping the universe. Dark matter works by exerting gravitational pull, helping to form galaxies and hold them together. On the other hand, dark energy works in the opposite way, pushing things apart and causing the universe to expand.

These two forces are like the yin and yang of the cosmos: dark matter helps to structure the universe, while dark energy accelerates its expansion. The interaction between these two forces is still a mystery, but understanding them is one of the biggest challenges in modern astrophysics.

Why Do Dark Matter and Dark Energy Matter to Us?

You might be asking, "Why should I care about dark matter and dark energy?" The answer is simple: understanding these invisible forces is key to understanding the very nature of our universe. These two forces influence everything from the formation of galaxies to the ultimate fate of the cosmos.

If we can unlock the mysteries of dark matter and dark energy, we could gain a deeper understanding of how the universe began, how it evolved, and where it's headed. Furthermore, they could help answer some of the most profound questions in science: What is the universe made of? Why is it expanding? And what will happen to it in the future?

Conclusion: The Unseen Forces of the Universe

In the end, dark matter and dark energy remind us that there's so much more to the universe than meets the eye. While we can't see them directly, their effects shape everything we know about space. These invisible forces are an essential part of the cosmic puzzle, helping to explain why the universe looks the way it does.

Lykkers, as we continue to explore the universe, who knows what other secrets are waiting to be uncovered? The mysteries of dark matter and dark energy may be just the beginning of our journey into the unknown.