Physics Questions People Ask Fermilab
Concept of ether in explaining forces
Will there be any research carried out in the near or distant future to find a physical relationship between gravity, mass, light, matter/antimatter through something like the idea of ether hundred years ago?
The concept of ether surfaced decades before scientists knew of quantum mechanics and some very fundamental symmetry principles of the microscopic world. Because of the huge change in knowledge, the historic word ether is not used anymore since it is a historical concept based on classical, not quantum physics.
Today's equivalent of the ether is the vacuum!
Physicists have come to realize that vacuum is not just empty space and the absence of things. The laws of quantum physics and experimental observations clearly show that many physical phenomena are explained by the fact that the vacuum has certain physical properties, including vacuum energy and quantum fluctuations: particles and antiparticles can appear and then disappear after a short period of time.
Understanding the properties of the vacuum is the basics for physics topics like superconductivity, the origin of mass, creation of antimatter, and many more. Past, present and future research has been and will be devoted to understand more about the vacuum and its implications to matter, space and time.
The properties of the vacuum are not immediately apparent in our daily life. They, however, become important when studying the microcosm, also called the quantum world.
Physicists have developed quantum theories that can explain many interactions of matter and antimatter, including the creation and exchange of light. So far, physicists have not been successful in integrating gravity into those quantum theories. Though all other microscopic interactions can be described by quantum theories, a consistent theory of quantum gravity has not been formulated. Experimental information about this aspect is absent since the gravitational force, at the microscopic level, is much weaker than all other forces. The gravitational attraction of two protons or two quarks is much, much weaker than the electric force between protons or the strong force (also called color force) between quarks.
Improving our knowledge of the established quantum theories will hopefully lead to the right theoretical concepts with regard to gravity. Three very fundamental forces (electromagnetic, weak and strong) can be described by quantum theories with surprisingly similar concepts and the same properties of vacuum.
Physicists are optimistic that the fourth fundamental force, gravity, will be explained in terms of a consistent quantum theory some day in the future. The vacuum may hold the key to the solution.
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