The significance of what’s unknown …
It’s very common to see people preach that “seeing is believing”, but that phrase in the cosmological context would be dangerously close to “ invalid ”. The reason behind this is quite simple , everything seen and perceived in this universe since the dawn of humanity accounts to only 5% of the matter , the rest 95 % is composed of mysterious substances called Dark Matter and Dark energy .
Let’s attempt to understand this :
Before we jump in, let’s get a hold of the two most important conclusions in physics :
Gravity is not a force , but rather a consequence of the curvature of spacetime caused by the uneven distribution of mass.
To make it more understandable, let's assume that the entire frame of the universe is a large trampoline. Now the diaphragm of this trampoline in cosmological terms is called “Space-time”.
Now let's place two objects of different weights on this diaphragm. We observe that the heavier object will create a deeper dent onto which the lighter object would eventually fall. This is exactly the idea behind gravity. Large objects like our Sun creates a dent in space-time while the surrounding planets appear to fall towards it. They don't get sucked up into the centre because of centripetal forces that keep them intact in their orbits.
When there is change in energy , there is a corresponding change in mass (E=mc²)
This is, by default, the most popular law in physics. It simply states that energy and mass are different forms of the same thing. In other words, it can be interchanged. Furthermore, it was Einstein's theory of relativity that introduced us to the concept of Spacetime.
But the universe does not like obeying rules!
Unfortunately, the universe is not really concerned or sympathetic towards the toiling efforts of scientists who have sacrificed their lives to understand it. From time to time, it proves that certain ideas are fundamentally wrong, which eventually allows us to understand and figure out something more intriguing.
Here are 2 instances of why it’s true …
In this case, we will try to understand how the concept of Dark Matter and Dark energy came into play.
- When scientists tried to measure the mass of distant galaxies, they found that the visible mass was very little for the amount of energy it possessed. This was violating the laws of physics, and this invisible mass was called “Dark matter”.
- Another important conclusion in science is that the universe is constantly expanding (Entropy increases). But according to gravity, when all objects are attracting each other, they have to slow down; eventually, surprisingly, experimental calculations prove otherwise and state that the universe is in a real hurry and is accelerating. So this shows that there is another stronger influence that repels gravity; this influence is called “Dark energy”.
So what is the significance of these unseen forces?
So far, we only know that the possible collision of dark matter can annihilate entire galaxy systems. This is well beyond our comprehension, but clearly, it's not a good sign.
But unfortunately even with all the advancements there is no concrete explanation so far as to what dark matter or dark energy comprises , or why they even exist in the first place.
So it is understandable that this is still a subject of pioneering research, and we can hope that someday all of this would eventually make some sense.
But anyway, if you happen to look at the night sky, it’s an eerie feeling that there is overwhelming darkness around us. Still, on the brighter side, we can feel fortunate that we exist in a time when real mysteries are out there and answers to which eludes our understanding!
If you feel that dark matter and dark energy are intriguing enough…then you may be disappointed when you read about Black holes.
Check this article to know why.