Dark matter is a mysterious substance that makes up about 85% of the universe, but it has never been directly detected. Now scientists think they have found evidence for dark matter in our solar system.
The idea behind the dark matter is simple: It’s invisible and so can’t be seen by telescopes.
But even if you don’t believe in dark matter, you might still want to know what it looks like, and you might be wondering if it can be found here on earth.
We look at this in closer detail and analyze whether dark matter can be found on Earth, and go into further detail about what scientists have already discovered.
What Is Dark Matter?
Dark matter has long been considered a mysterious substance that makes up roughly 85% of the universe. Scientists believe that dark matter exists because they cannot see or detect its presence directly.
Dark matter particles are made up of particles called WIMPs (weakly interacting massive particles).
These particles are thought to be elementary, meaning they do not interact with other known forms of matter in any way.
The existence of these particles was first theorized by American physicist and Nobel laureate Leon Lederman in 1983. Since then, scientists have come up with several theories about what dark matter might be.
One theory suggests that dark matter consists of “cold” neutrinos, which are extremely small particles that travel at near light speed.
Another theory suggests that dark matter could be composed of axions, which are hypothetical subatomic particles that can only be detected indirectly through their effects on other particles.
Despite all this speculation, there is no direct evidence for dark matter’s existence. Dark matter remains one of the biggest mysteries in science today.
Can Dark Matter Be Found Here On Earth?
There was once a DAMA experiment that took place in a lab that lies under 1.4 kilometers of rock, inside the Gran Sasso, an Italian mountain. The experiment looked for flashes of light using a sodium iodide detector.
The flashes came from background noise, which included neutrons from radioactivity in the surrounding rocks.
However, some could have come from dark matter and if this was the case, scientists think they will witness seasonal alterations in the signal as the Earth’s speed through our galaxy changes according to its direction of motion.
This theory asserts that planet Earth should weather plentiful dark matter particles in the summer when it is moving in tandem with the Sun and fewer particles in the winter when it is moving in a different direction to the sun.
The results of this experiment were met with skepticism, as no other experiment searching for dark matter had been successful.
This encouraged DAMA to renew their search with a bigger 250-kilogram detector and results again showed an annual discrepancy in the amount of particles engaging their sensor.
After this, scientists remain skeptical, as no other experiment has witnessed dark matter.
On the other hand, evidence has shown that when particles of dark matter pass through the core of the Earth, they focus at the “root” of a hair, where the density of the particles is a billion times higher than average.
The root should be around 600,000 miles from the surface and the particles that contact Earth’s surface will form the tip of the hair, about twice as far from Earth as the hair’s root.
This means if scientists could locate the root of these hairs, they could maybe send a probe and retrieve a collection of data around dark matter on Earth.
Are There Any Other Examples Of Dark Matter?
There are many examples of dark matter throughout the universe. For example, astronomers have observed that galaxies rotate much faster than expected given how far away they are from us.
This means that there must be some kind of unseen mass between them and us that is causing them to spin.
Another example is the Bullet Cluster, an enormous cluster of galaxies that collided together about 3 billion years ago. Astronomers noticed something strange about the collision:
The two clusters of galaxies were moving apart at high speeds, yet they had very little energy left over after the collision. They concluded that most of the energy came from a huge amount of dark matter.
Another example is the gravitational lensing effect. When we observe distant objects, such as stars, nebulae, or galaxies, we notice that they appear distorted.
This distortion is caused by gravity, and it tells us that there is another object nearby.
However, when astronomers calculate the distance to the object based on the size of the distortion, they find that the object appears too close to be real.
They conclude that there must be a large amount of dark matter present.
How Is Dark Matter Detected?
Scientists use three different methods to detect dark matter.
The first method of detecting dark matter interactions involves looking for the indirect effects of the invisible particles.
To explain how this works, let’s start by imagining that you’re standing next to a friend who is holding a bowling ball.
You don’t know if your friend has a bowling ball or just a bunch of air inside his hand. If you try to push him, he won’t budge because he is holding a bowling ball inside his fist.
Now imagine that instead of trying to push him, you grab hold of his wrist and pull it back toward you. He will immediately feel the force exerted on his arm and move out of your grasp.
This is exactly how scientists think that dark matter interacts with normal matter. It exerts a force on the normal matter without being seen directly.
Astronomers use telescopes to see the effects of this interaction. They look for the distortions caused by the unseen mass. These distortions range from tiny ripples in space-time to giant black holes.
The second way to detect dark matter is to look for the particles themselves. Scientists can do this using particle accelerator.
Particle accelerators accelerate electrons and protons up to extremely high energies. At these incredibly high energies, the particles become unstable and decay into other subatomic particles.
Scientists can then study the properties of those new particles to learn more about what they might be made of.
Dark Matter Collides With Normal Matter
The third way to detect dark matter involves studying its interactions with normal matter. To understand how this works, let’s go back to our example of the bowling ball.
Imagine that your friend throws the bowling ball away. Because it was held within his fist, it wasn’t visible. But now that it is gone, you can see that there are no visible traces of it left behind.
Now imagine that your friend throws the same bowling ball straight at you. As soon as it hits you, you will feel an impact. The bowling ball didn’t disappear; it just changed direction.
That change in direction is because the bowling ball was moving through space while you were stationary.
Since the bowling ball doesn’t interact with anything else, it leaves no trace of itself behind. However, when it collides with something else, like you, it causes an effect called gravity.
We hope after reading this article you have learned all you need to know about dark matter and whether it can be found on Earth.
Although dark matter is invisible, scientists are working on its detection and evidence shows it should interact with the ordinary matter here on Earth and in our universe.
Dark matter is a mysterious substance and is associated with the acceleration of our universe, which we must keep studying and exploring as much as we can!
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