Today I’ll try to explain what the dark energy and dark matter are in my opinion.
We all heard of the theory of relativity which is quite dithering.
There are two kinds of relativity, the first is the special and the second is the general.
The first one says:
1. That the speed of light is constant. It never changes, whichever speed you travel with the speed of light will be the same. For this to happen, time slows down for the one who is moving close to the speed of light. It has to be close to the speed of light or at least half the speed of light, otherwise you won’t notice a thing.
2. If somebody is travelling at a different speed or direction than you, they will disagree with you on whether certain events happened at the same time. For instance, if you’re standing on a moving staircase moving at 2 km/Ⓗ and someone is watching you standing still, this person will see you moving at 2 km/Ⓗ. Now if you start walking on this stairs, you’ll see yourself walking at 2 km/Ⓗ but this person who is watching you will conclude that you’re walking at 4 km/Ⓗ. In fact both of you are right, it is a question of relativity.
3. If something is moving very fast, it gets shorter in the direction that it is moving. If you take a ball hanged on a piece of rope, and you make it spin faster and faster you’ll notice your ball getting shrink a little in the direction it is spinning, but if it spins close to the speed of light you’ll see it shrink a lot.
Now in the general relativity we can speak of the twin paradox which had nothing to do with our topic but to give a breve description we may say that two people moving apart, the first at a normal speed and the second close to the speed of light, if they could see each other’s watch, they would see each other’s time slowing down even though only close to the speed of light that time slows down. So when this person who is traveling close to the speed of light decides to go back, he will find the other person much older than him.
Speeding Up and Slowing Down Are the Same Thing, for e.g when you take a cab you feel the acceleration when the taxi driver accelerate, you feel a “force” pushing you behind. When this driver slows down, you feel something pushing you forward. in fact this is called “inertia”: something which has mass shouldn’t be changing state – either in motion or still. This force which pushes you backwards when the cab driver accelerates is the same sensation as gravity. When he slows down, it is your seat belt which stops you from moving forward, but you still feel this gravity which pulls you. It’s the same thing if you find yourself floating in space and a spaceship accelerates beneath you, you’ll feel or see yourself falling into the spaceship and as soon as it reaches you, you’ll feel as if gravity was pulling you from beneath. This is a way to say that gravity and acceleration is the same thing. To make myself clear I’m not speaking about the famous Newton’s gravity ( the more mass an object has, the more gravity it produce), I’m speaking about the source of gravity as mentioned above when you were floating in space. Massive object floating through space, attracts space to itself, which we call curved space or curved space-time. As “time” never leaves “space” it is better to call it spacetime.
The spin of a heavy object, such as Earth, should twist and distort the space-time around it.
Now what all this has to do with dark energy and dark matter? Well it is complicated to describe but you see, the dark energy is what is expanding the universe, so this dark energy is the pillar which holds the universe from crumbling upon us. without it the universe would have crunched already. But what is wonderful is that it’s an invisible pillar. Can you imagine a big building with its walls, its doors, its windows and even its roof but with nothing visible to hold the roof? So this dark energy coming from nowhere – it’s better to say “are” – are the pillars of this spectacular huge sky which stands all around us.
Black holes is a region of space having a gravitational field so intense that no matter or radiation can escape. So black holes slow down the expansion, absorbing whatever comes by. It turns out that roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest – everything on Earth, everything ever observed with all of our instruments, all normal matter – adds up to less than 5% of the universe.
We know that space is not a completely empty space, we can find particles mainly, hydrogen and helium, or even gravitational waves which are ripples in the curvature of spacetime that propagate as waves at the speed of light, generated in certain gravitational interactions that propagate outward from their source, but I believe that space isn’t completely empty by no means. It is huge gravitational field.
Between the possibilities for the dark energy to be – a property of space, a new dynamic fluid, or a new theory of gravity – I would personally believe that it’s a property of space! It’s the pillar which holds and expands the heavens.
The dark matter is even more complicated, although it has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, its influence on the universe’s large-scale structure, and its effects in the cosmic microwave background. Dark matter is transparent to electromagnetic radiation it is so dense and small that it fails to absorb or emit enough radiation to be detectable with current imaging technology. Some galaxies are made of 99% of dark matter such as Dragonfly 44, an ultra diffuse galaxy with the mass of the Milky Way galaxy, but with nearly no discernable stars or galactic structure or even VIRGOHI21.