What is dark energy? Explained
Matters that we know such as planets, stars, galaxies, trees, rocks, etc they are only 5% of the universe. About 27% is dark matter and 68% is d ark energy . Both dark matter and dark energy are invisible to us.
So, how do we know that dark energy exists? What research has been done about it? If all these questions come to your mind and you want to know about it, then this article is for you. Today, I am going to unlock the details of the dark energy . In this article, you will know -
1. What is dark energy?
2. What is dark matter?
What is dark energy?
Dark energy occupies about 68% of the universe. It appears to be associated with the vacuum in space. It is evenly distributed throughout the universe, not just in space but also in time. In other words, its effects do not mix with the expansion of the universe.
If we talk about its gravitational force, then the dark energy has no local gravitational effect but has a global effect on the universe as a whole. This leads to a repulsive force that helps to accelerate the expansion of the universe.
The rate of expansion and its acceleration can be measured by observing the expansion of the galaxy with the Hubble Telescope . These measurements, along with other scientific data, have confirmed the existence of dark energy which provides an estimate of how much of this mysterious substance exists.
In the early 1990s, we knew that our universe was constantly expanding. We were sure of one more thing about its expansion. It was that the energy density of this universe was so limited that at some point it will stop spreading and eventually it will merge again at one point, or its energy density is so high that it will always be expanding.
Here you might be wondering what is this energy density? Energy density is like the amount of energy that we can store in a substance or system. In simple words, if the energy density of a substance is high, it means that there is more energy stored in that substance.
Scientists had estimated that either the universe would merge in one point or it would continue to spread according to its energy density. But according to the theory, one thing was absolutely certain that the gravitational attraction will slow down the speed of expansion of the universe with the passage of time.
Scientists were believed this because they believed that the universe was made up of commonly visible substances and his gravitational attraction binds the whole universe. Due to the gravitational attraction, it was natural for the speed of its expansion to slow down.
But in 1998, Hubble Telescope took a picture of a supernova, which showed that in the past the rate of expansion of our universe was slower than it is now. This meant that the speed of its expansion was increasing rather than decreasing. Which was contrary to the...