When you do post a ball into the air, it slows down gradually, stops somewhere in mid air, and then starts falling and eventually to the ground. Suppose you throw the same ball to the air, and instead of it falling to the ground, it accelerates to the sky. This is what scientists are investigating with vigor; a phenomena that happens to the entire universe. It is believed that dark energy can accelerate the expanding rate of the universe.
What Is Dark Energy?
The term dark energy refers to an entity (a strange entity), that makes up the majority of the mass-energy density of the universe. Dark energy is studied under astronomy and physical cosmology. However, one should note that dark energy is still a mysterious concept and it is still under investigation. In fact, the main reason why it is known as dark energy is because there is little information and consensus about its nature and functionality.
Evidence for Dark Energy
The following shows the evidence for dark energy:
– Measuring the shape of the universe through the radiation of the cosmic microwave background (the density of the mass energy is 27 per cent. So what is the missing 73 per cent? It could be dark energy).
– Supernovae observation (a strong explosion that takes place when a massive star gets to the end of its life).
– The cosmological constant, otherwise known as the vacuum energy, has explained observations through the vacuum energy density.
How Does It Work?
Whereas “normal” matter slows down the rate of acceleration, dark energy does the direct opposite of that; acceleration. This is attributed to its negative pressure. One of the day to day examples of negative pressure is an inflated tire or even a balloon that pushes out to the membrane that encloses it.
Einstein relativity states that both energy and pressure have a significant contribution to gravity. Dark energy possesses a strong negative pressure that the ultimate effect is not a push but a pull.
The universe’s rate of expansion is a timescale, and not speed. Similarly, velocity of galaxies is proportional to its distance, and therefore its not a constant figure.
In 1998, scientists realized that stars were actually dimmer than typical and previous results. The only explanation to this theory is that the stars were at a further distance than previously thought. Another deduction states that in normal gravity applies in small scale, but in large-scale, the repulsive force of gravity applies, in other words, dark energy.
Another thing to note about dark energy is that it was small in size 13.7 billion years ago. However, today, the dark energy takes a significant portion in the universe. It will be interesting to see what cosmology will come up with regarding the future of dark energy.
Albert Einstein observed that the concept of an empty space is not nothing after all. In addition to that, astronomers believe that the empty space has the ability to possess energy of its own. However, scientists are facing a number of challenges in the study of dark energy. For example, it is very difficult to carry out lab tests on the same due to the problem of isolating it. Despite that, scientists are hopeful that they are going to have more comprehensive findings on dark energy.