Einstein’s Extraordinary Year
IN 1905, a 26-year-old patent clerk named Albert Einstein published four scientific papers that altered the way we view our universe—from its tiniest building blocks to its most massive galaxies. Some of these papers also became springboards launching many of the life-altering inventions produced during the past 100 years.
“There is scarcely any important fundamental idea in modern physics,” says Nobel laureate in physics Isidor Rabi, “whose origin does not trace back at least in part to Einstein.” What exactly did Einstein discover a century ago?
Unlocking the Secrets of Light
Einstein’s paper published in March 1905 uncovered some secrets about the nature of light. Scientists had already discovered that as light travels through space, it seems to behave much like waves of water rippling across a pond. However, the wave theory could not explain why dim blue light generates an electric current when it strikes certain metals, whereas bright red light fails to do so. Einstein’s paper helped to explain this so-called photoelectric effect.
Einstein argued that light can at times be considered to consist of small packets of energy, later called photons. When these photons are of the right energy level, or color, they can dislodge electrons from the atoms of some metals. (Photons of red light are too weak to do the job.) This interaction causes an electric current to flow in the material. Modern inventions such as television camera tubes, solar power cells, and photographic light meters all relate to Einstein’s description of the photoelectric effect.
Einstein won the 1921 Nobel Prize for Physics for his way of explaining light. His paper helped lead the way to a new field of science called quantum theory. In turn, quantum theory laid the foundation for a host of applications including nuclear science, electronics, and nanotechnology.
Why the Pollen Dances
In 1905, Einstein also turned his attention to atoms and molecules. He provided a theoretical explanation of their effect on tiny pollen grains suspended in water. In 1827, a biologist named Robert Brown had peered through a microscope and noticed that pollen grains immersed in water jiggle about. He called the dance of the pollen Brownian motion, but he was unable to explain why it happened.
In his May 1905 paper, Einstein suggested how vibrating water molecules caused this Brownian motion. He not only calculated the size of the water molecules but also predicted the specific properties of their atoms. Other scientists built on these predictions, removing doubts concerning the existence of atoms. Modern physics is founded on the idea that matter is made of atoms.
Time Is Relative
Einstein’s special theory of relativity, published in June 1905, disagreed with a fundamental belief of scientists such as Isaac Newton—that the measurement of time is a constant throughout the universe. The implications of Einstein’s now generally accepted theory seem quite bizarre.
For example, imagine that you and a friend perfectly synchronize your watches. Your friend then flies around the world, while you stay at home. When he returns, the time displayed by his watch will lag a fraction behind the time shown on your watch. From your perspective, time slowed down for your traveling friend. The difference is, of course, infinitesimal at human speeds. However, when approaching the speed of light, not only does time slow down significantly but objects also become smaller and their mass increases. Einstein’s theory maintained that the speed of light, not time, is constant across the universe.
A Formula That Changed the World
In September 1905, Einstein published another paper, considered to be a mathematical footnote to his special theory of relativity. It contained the formula now synonymous with his work, E=mc2. This equation says that the amount of energy released when an atom is split equals the loss of its mass times the speed of light squared.
As a result of the efforts of scientists like Einstein, mankind has learned much about the nature of the universe. Even so, man’s present state of knowledge is still similar to that described by ancient Job. Speaking of the Creator’s works, he humbly acknowledged: “Look! These are the fringes of his ways, and what a whisper of a matter has been heard of him!”—Job 26:14.
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Light behaves both as waves and as particles. Understanding this has made possible solar-powered calculators and light sensors in digital cameras
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The jiggle of Brownian motion helped prove the existence of atoms
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c2 times speed of light squared
c2 means c times c, or 186,282 miles per second times 186,282 miles per second
Because c2 is a fantastically large number (34,701,000,000 mi2/sec2), a small amount of mass can be converted into an enormous amount of energy. When an atom of uranium is split, it quickly forms two smaller atoms but also loses about 0.1 percent of its mass; that tiny amount converts into a vast release of energy
Just one pound [450 g] of any substance completely converted into energy equals:
▪ 11 billion kilowatt hours
▪ the power needed to drive a car around the earth 180,000 times
▪ the power required to propel the largest oil tanker around the world 400 times
▪ the electric power needs of the United States for one day
The reverse is also true. It takes a tremendous amount of energy to “materialize” just one atom
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The faster you travel, the slower time moves
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Clocks aboard satellites of the Global Positioning System (GPS) do not tick at the same speed as clocks on earth. Without correcting for this effect of relativity, the GPS signal would be rendered useless
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Einstein: Photo by Topical Press Agency/Getty Images; background: CERN photo, Geneva