Dark Energy is the most mysterious thing in the world of physical cosmology which consists of 72% of the entire mass of the universe. It is property of space, which is a form of energy which exerts a negative repulsive pressure exactly opposite of gravity. Scientists have been working on it since ages but it hasn’t been directly observed but rather inferred from observations of gravitational interaction b/w astronomical objects. Measure of the large scale wave patterns are the biggest evidence of its existence. More is unknown about it than known. We know how much dark energy is there in space because we know how it affects our universe. There are n number of explanations about the existence of dark energy in our universe, one of which states that it may be a kind of dynamical fluid, something that fills up all the space but its effect on the expansion of universe is opposite of the normal energy. Found to be very homogeneous, not dense, no interaction has been observed with any of the fundamental forces except gravity so far.
EINSTEIN’S BIGGEST BLUNDER
In 1917, he discovered something strikingly similar as an odd to his general theory of relativity when he realized that gravity would cause the universe to collapse. He added a fudge factor the COSMOLOGICAL CONSTANT, a mysterious anti-gravity force inherent to space. Later he ended up calling it as the biggest blunder.
When Hubble was studying the exploding stars to determine the expansion of universe, he was surprised to find that the expansion wasn’t slowing down, rather speeding up. This was the moment when the concept of dark matter, an anti-gravity force came into existence. Years later, it was realized that the properties of these anti-gravity force was consistent with cosmological constant. As universe expands, a normal matter gets less dense, radiations decrease but this remains constant, making it even more bizarre.
Dark energy and Negative energy, these are the two terms which are considered to be synonymous at some instances but the fact is that the dark energy and negative energy are two completely different things. Where dark energy is a sort of anti-gravity energy, negative energy is found to be the energy of an ordinary anti matter which constitutes less than 6% of the mass of the universe.
Dark energy isn’t similar to negative energy but it is similar to Vacuum energy, a part of zero point energy, a dynamic quantum vacuum energy, which describes the static vacuum energy density which is most of the time considered as the cosmological constant.
There are many possible solutions for this mystery. One of them may be that our universe is filled with exotic changing energy field ‘QUINTESSENCE’. The other may be that we are lacking in understanding the concepts of gravity.
A century has passed since the use of this term came into existence but it still lacks a proper definition or a proper identity. Only the proper understanding of quantum vacuum can solve the jigsaw of this term