This past week or two (mid-February 2016) we received news of scientists having detected what they and Albert Einstein before them have called gravitational waves. NBC news anchor Lester Holt described these waves "rippling across the universe," and he added modestly that "it is a very big deal, at least that is what I've been told."
This is about humanity's ability to detect with his senses. It began with the naked eye and advanced in modern times with various devices such as the telescope, the microscope, the radio receiver and other equipment. In the last three or so centuries, electromagnetic radiation has been delivering information to us through our telescopes. Light waves are a part of the electromagnetic spectrum. Other parts of the electromagnetic spectrum are radio wave-lengths, shorter waves called microwave, ultraviolet light, gamma rays and X-rays. Now scientists are looking forward gravitational waves telling us what light waves cannot tell us.
We have been gathering a greater understanding of the physical world's complexity. In the 400s BCE, Greeks were describing physical reality as divided among four basic elements: earth, water, air, and fire. They didn't know about radiation or the many chemical elements we know of today. Fire was supposed to be the source of light and heat. The Hindus also had fire as a basic element, embodied in the god Agni, with light rays thought of as a stream of high velocity fire atoms. Today, scientists describe fire not as a basic element but as a process – a chemical process. Fire took place where there was combustible. Fire is, like everything else, movement. It's ignited by environmental change and involves rapid oxidation (oxygen one of the elements that ancients didn't know about but were close to with the concept of air.)
Today we are well aware of chemicals creating electric currents and light waves. By the early 1930s, scientists were theorizing about a duality called antiparticles and particles. According to Wikipedia:
Antiparticles are created everywhere in the universe where high-energy particle collisions take place. High-energy cosmic rays impacting Earth's atmosphere (or any other matter in the Solar System produce minute quantities of antiparticles in the resulting particle jets, which are immediately annihilated by contact with nearby matter.
Backing up a bit, the invention of the telescope in the early 1600s was followed by a deeper look into the movement of bodies in space. Then in the late 1600s, Newton came along and gave us understanding about gravity. Gravity was also about movement: an apple pulled to the ground, planet earth pulled toward the sun. The earth doesn't crash into the sun because a balance between gravity and an inertia that would otherwise take the planet away in a straight line. Gravity, in other words, as Newton observed, kept celestial bodies from flying out of orbit. Newton did his math and concluded that the force of gravity between two bodies was relative to the differences in mass of those bodies reduced by the square of the distance between those two bodies.
A foremost passion of scientists is measurement, and a physicist named Albert Einstein elaborated on mass in motion with a simple equation that measured energy: energy (E) equals mass (m) times the speed of light (c) squared (E = mc2).
There was also the issue of time. Time is a measure of matter in motion. Without matter and sequence there is nothing to measure, there is no time. With time as part of the picture, we have Einstein's theory of special relativity. He wrote that one person might see two events in space as simultaneous, and someone else somewhere else (moving on a different trajectory) would see the two events as not simultaneous. It's part of the three dimensional reality that we live in.
Challenged by language, scientists began using the expression space-time. Why they didn't use distance-time instead I can't say, but it doesn't matter. And, speaking of distance, that was expressed in light-years: the distance that light travelled in one year. Events in the cosmos would be described as happening billions of light years from earth – a distance difficult to imagine. And the billions of years that it took light to reach one of our telescopes is a time-span also difficult to imagine.
Ten years after publishing his theory of Theory of Special Relativity, Einstein in 1915, developed his theory of "General Relativity." It held that gravitation acted on light waves, that gravity bent light waves. In 1919 the moon totally eclipsed the sun and a scientist, Sir Arthur Eddington, was able to observe that light waves were indeed bent, adding credence to Einstein's claim and ma Einstein a celebrity.
In 1929 Edwin Hubble, looking through his telescope, did his math and concluded that galaxies were drifting apart. An expanding universe was hypothesized – movement from extreme density to lesser density, which fit with some of the complexities of Einstein's theory of general relativity. The Big Bang theory was born. Measurements of the redshifts of supernovae (exploding stars) indicated that expansion of the universe was accelerating.
With a telescope, dark spots were observed. Physicists detected the gravitational pull that dark spots exerted on stars and galaxies. Dark spots were eventually called "black holes." The question arose whether "black holes" were collapsed stars retaining a neutral electrical charge. It would be concluded that Black Holes had mass and was so dense that electromagnetic radiation (light, cosmic rays, et cetera) was not flying out. Black holes were described as leftover material from the big bang that passes through space and leaves no trace except through gravitational waves. .
In 2015, Stephen Hawking described a Black Hole as having gravity so strong that electromagnetic waves, including light – held at the holes outer boundary – were prevented from outward transmission.
In 2015, in Louisiana and in Washington state, antennas designed to detect gravitational waves picked up a signal from two "black holes" that collided 1.3 billion years ago. The mass of one of the black holes was measured as having the equivalent of the mass 29 times the mass of our suns. The other black hole was measured at 36 times the mass of our sun. Each black whole was measured at around 50 kilometers (30 miles) in diameter. The collision created a gravitational wave that scientists picked up on their instrument as a momentary sound – a single beep.
As of February 2016, it was being said that a new era of how we explore the universe had begun, an exploration drawing from gravitational waves – a new sense for mapping the universe.
Subatomic particles called "neutrinos" (they are neutral, in other words without electric charge) have been described as perhaps the stuff of dark matter. Scientists are looking forward to new information about the relationship between matter and antimatter and a greater understanding of the neutrino character – something they describe as of great importance.
Copyright © 2018 by Frank E. Smitha. All rights reserved.