Can a region of space contain less than nothing?
Negative energy is a concept of physics used to explain the nature of specific fields, including the gravitational field and various quantum field effects. Negative energy is so strange that one might think it must violate some law of physics.
Gravitational force is a Negative Energy??
The total energy in the universe, the gravitational potential energy which keeps two pieces of matter into contact with one another must be negative since it takes positive energy to pull them apart. When two objects move towards each other, the motion accelerates under gravity causing an increase in the positive kinetic energy of the system and hence energy. But, according to the law of energy conservation, the net energy of the system does not change. Considering the universe to be approximately uniform one can show that the total negative gravitational energy would cancel out the total positive energy represented by matter hence the universe has zero total energy in it. In the zero-energy universe model (“flat” or “Euclidean”), the total amount of energy in the universe is exactly zero: its amount of positive energy in the form of matter is exactly canceled out by its negative energy in the form of gravity. Albert Einstein said that how could the world around us be so random that even with physics it is impossible to make any prediction about it with certainty. Negative energy is one of them. Real as life itself.
The conception of Negative Energy in Dirac Sea in 1928, British physicist Paul Dirac formulated an equation for describing the dynamics of the electron, but it put forth that electron can have positive or negative kinetic energy. It was the first-time physics had indicated towards the existence of Negative Energy.
But the million dollar Question was –
How could energy be negative and if negative energy exists why doesn’t one see its presence?
Dirac explained that energy is exactly balanced out by the quantum states of Negative Energy as such the net effect remains zero and, so we are unable to see or feel the effects of Negative Energy. However, he proposed that if an ideal vacuum can be created where all the effects of positive energy can be eliminated, then the presence of the Dirac Sea and therefore Negative Energy could be verified. Creation of vacuum is impossible at the time, so the existence of Negative Energy could not be proven. Thus, Dirac was unable to verify its existence experimentally, and Negative Energy remained a theory until 1948.
In 1948, Hendrik Casimir did an experiment and was able to show that the negative energy was real and very much present. Casimir proposed an experiment which could display the effect produced by negative energy. He said that if the effect of gravity and electromagnetic effects has been nullified, and a nearly pure vacuum would be created within which the effect of negative energy can be seen in an observable manner in the form of something known as the ‘Casimir effect.’ He proved this theory by performing an experiment in which two plates were kept at a certain distance in a perfect vacuum chamber without any presence of external forces. It was found that without the presence of any external force, the plates move closer until they touch each other.
Example of the importance of Negative Energy:
Black Holes– Hawking radiation is contradicting statement because of negative energy. If a particle with Negative Energy falls into the black hole, it will decrease the mass of the black holes which will lead to evaporate the black holes after some time.
Warm Holes– Warmholes is a theoretical passage between space-time, the curvature of space-time. Hypo tunnel that connects one region of space from another. Negative Energy can help us to create wormholes for time travel by holding the wormhole open so that matter can continue through it and exit at the other end (otherwise the matter would “converge” inside the wormhole). It is much difficult to create big wormholes because the amount of negative energy should be greater than the positive energy to hold the wormhole open.
The concept of Negative Energy touches on many areas of physics: gravitation, quantum theory, and thermodynamics. The linking of so many different parts of physics shows the tight logical structure of the laws of nature. Negative Energy seems to be required to reconcile black holes with thermodynamics, but on the other hand, quantum physics prevents the unrestricted production of negative energy, which would violate the second law of thermodynamics.
Nature, no doubt has more amazements in store.
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