Dark Mysteries: Energy and Matter
By Dr. Richard Hammond
This is not the first time we were caught off guard. When astronomers began measuring the speeds of galaxies in clusters, and later, when they measured the speed of individual stars in the outer regions of galaxies, they were hit with another bombshell—the outer stars were moving too fast. These scofflaws were not just a little out of line, like speeders ticketed on the freeway, they were zipping along at ten times the speed limit, ten times what the theory allowed. This precipitated an explosive program of experiment and theory, where the basic laws of gravity were put under the microscope of scrutiny, and our entire concept of what a galaxy is, and what matter is, were put on trial.
To reconcile these extraordinary observations with our theories, we have begun to believe that a galaxy is filled with another kind of matter, a new kind of matter that does not interact with light as ordinary matter does—dark matter. For decades we have been looking for this baffling new form of matter, whether it be theoretically predicted particles like axions, or remnants from string theory. For a while, some thought this to be biggest problem in all of physics and astronomy. But then came dark energy.
When we say dark matter, we are being literal: We do not see it, and perhaps we can never see it. Dark energy is a bit metaphoric, we cannot see what it is, but more, we cannot understand what it is. We understand, through the famous formula,, that energy is equivalent to mass, and from this we conclude that all forms of energy in the universe, like mass, tend to pull our myriad galaxies together.
But recent observations are telling us this is false. Something is causing the galaxies to push themselves apart like prisoners in a jailbreak. Flying apart at ever increasing rates, the galaxies reveal that the universe is expanding faster than ever before, but we cannot understand why. In desperation, we invent the concept of dark energy, an inscrutable substance that gives rise to a cosmological repulsion causing the cosmos to grow faster than ever before.
So, what can dark energy be? Many believe this is the most pressing issue in physics today, but gather up a horde of physicists in a room and ask, “What is dark matter?” and we will argue like politicians at a convention. One idea actually goes back to Einstein himself. His idea of the cosmological constant seemed superfluous when we consider an expanding universe, and Einstein even called it his biggest blunder, but “one decade’s blunder can be another decade’s salvation.” This term can act like a cosmic repulsion, but we no longer think it is really constant, and we have no other evidence of its existence.
Another idea comes from vacuum itself. According to quantum theory, vacuum is not the empty ghost town, as we used to think of it, lifeless and devoid action. The vacuum is bustling with as much energy as a boom town: Particles are created and then destroyed, and even the real estate is changing, as space and time are whipped to a foam-like frenzy at the very small scale. The “vacuum energy” may be part of the solution, but there is a long way to go before we have sufficient evidence to know.
Or, perhaps our theories are wrong. Long ruling theories of physics have been dethroned before, when they are pushed to new realms where they have never been tested. It is possible that Einstein’s theory must be modified again, or maybe a whole new theory is necessary. And perhaps it is nothing we can think of, and we will have to wait until future observations will give us the clues necessary to solve this riddle. Time will tell.
For more information or to purchase click here: The Unknown Universe: The Origin of the Universe, Quantum Gravity, Wormholes, and Other Things Science Still Can't Explain
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