What is Dark Matter? Can we See it?

What is Dark Matter? Can we See it?

Several signs indicate that our universe is filled with dark matter but humanity is just not good enough to view the unknown form of matter, at least until now.

The material that makes up 85% of the universe is called the Dark Matter. It is believed that the dark matter is made up of materials and/or particles that are still unknown to us. Dark matter is taken into account in the majority of astrophysical observations. However, much about it is unknown because scientists need to view more of it before coming up with a definitive answer. It has never been observed directly. This is partially due to the fact that dark matter is likely made up of an unknown type of particle(s). Simply put, all the unidentified matter in space is classified as the dark matter.

We know that this form of matter exists because the galaxies rotate instead of moving apart. This would only be possible if there was a significantly large amount of unseen matter present in the galaxies. Dark matter is not present in the entire electromagnetic spectrum and this makes it extremely hard to view it using our astronomical equipment.

It can be classified into three types depending on its velocity. The lower velocity matter is called the ‘cold’ dark matter. As its velocity increases, the matter can be said to be ‘warm’ or ‘hot’. Every galaxy has a dense luminous matter at its center, and this suggests that there must be some unknown particles in there.

There is something mysterious pulling everything towards itself. This unseen ‘mass’ goes along with the general relativity theory and if the dark matter did not exist, the theory would not hold its own. A popular theory on the dark matter suggests that it may be composed of ‘Weakly Interacting Massive Particles’ aka WIMPs. Commonly, it shows its force through gravity and scientists need to develop new instruments that can pinpoint dark matter in one way or another.

If we look at its presence from a more scientific point of view, it can be viewed as a bowling ball and the fabric of space-time as a trampoline. If we drop the ball onto the trampoline, the trampoline stretches downwards. Similarly, light doesn’t go in a straight line when it encounters a curve. It follows the curve instead, bending around an invisible body. That shift in a different direction is known as ‘Gravitational Lensing’. Moreover, further evidence can be found about the dark matter if we view the ‘Cosmic Microwave Background’ left over by light as old as the universe itself. Katie Mack, an Astrophysicist at the North Carolina State University, expressed her ideas about the dark matter by saying,

“People ask this question a lot. You know, maybe dark matter is just a fudge factor or something. We see patterns in that that show there had to have been something at early times that brought matter together in a way that can’t work with just regular matter. It’s kind of like if you were walking down the street and you see a plastic bag sort of move across the street in front of you. And then you see some trees lean over, and then you hear this kind of rustling sound, and then you feel a little bit of cold coming from one direction, and then you see a street sign swing, and you’re like ‘That’s wind!’ You can’t see the wind, but there are all of these different pieces of evidence that air is moving.”

All signs say that dark matter exists. However, it may be the case that our technology is not advanced enough to actually view this matter at all. Also, there is limited data to work on when it comes to this unknown form of matter. Conventional methods do not work with it as light rays pass through the matter. Hence, there is no reflection to observe the constituting particles. Having said that, scientists can use gravitational force to calculate the amount of dark matter. All in all, it can be considered that it is a ‘perfect glass’, which is there but is invisible to us.

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