German-born physicist Albert Einstein (1879–1955) had such a profound impact that brilliance has come to be associated with his name alone. At the age of 26, Einstein filed four papers to the German journal Annalen der Physik in 1905 while working as a patent clerk. These publications fundamentally altered how people understood time, gravity, and light. Even though he was only getting started, historians now refer to this year as Einstein’s annus mirabilis, or “miracle year.” Einstein’s work is renowned for being extremely thick. The general theory of relativity and other theories by Einstein are so complex that only physicists truly need to understand them, but these discoveries provide the foundation for the technology that the rest of us take for granted on a daily basis. These are five ways that Einstein’s theories have altered the course of human history and still serve as a guide for future research.
Without General Theory of Relativity, GPS Would Not Be Possible
The 31 satellites that make up the Global Positioning System (GPS) orbit Earth around 10,900 nautical miles above our heads, yet if Einstein hadn’t been born, those satellites would have remained little more than space debris. Since satellites must maintain time in order to accurately register the distance from a ground-based receiver (like your smartphone), precise timekeeping is the fundamental basis of GPS. It would be impossible to achieve the level of precision achieved by GPS satellites without Einstein’s special and general theories of relativity, whose atomic clocks are accurate to within three billionths of a second. According to the special theory of relativity, the velocity determines how time flows. In comparison to Earth-based receivers, satellites “lose” seven microseconds per day due to their 8,700 miles per hour speed. Furthermore, Einstein’s general theory of relativity, which was published in 1915 and essentially builds on his earlier theory by including gravity, asserts that the passage of time is likewise influenced by a source of mass’s distance, in this case the Earth. Because your feet are closer to the Earth than your head is, strictly speaking, your head ages more quickly than your feet (on time scales that are ultimately unimportant). These days, GPS accounts for this “time dilation,” so when you open Google Maps, satellites are constantly aware of your location.
Modern Solar Power Is Made Possible by the Understanding of the Photoelectric Effect
The fact that Einstein received the Nobel Prize in physics in 1921 should not come as a surprise, but many people are unaware that the prize was given for his innovative—and frequently disregarded—explanation of the photoelectric effect, rather than for his revolutionary general theory of relativity. German physicist Heinrich Rudolf Hertz (yes, same Hertz) made the original discovery of the photoelectric effect in 1887 when he observed that ultraviolet light caused sparks to fly when it struck a metal plate. The fact that different metals needed various frequencies to have the same action was perplexing. Eventually, in 1905, 26-year-old Einstein provided a new theory of light to resolve this puzzle, which he reported in his first work that was submitted to Annalen der Physik. He maintained that light was a stream of particles, thereafter referred to as “photons,” rather than merely a wave, as some scientists had previously proposed. Though it was mocked for years, Einstein’s theory—which proposed that these photons had a constant amount of energy based on their frequency—was able to explain the photoelectric phenomena. ever though solar cells were discovered decades before Einstein, it wasn’t until his theory that scientists understood why they functioned, which led to the development of ever more effective solar panels.
Because of Einstein's Quantum Theory of Radiation, Lasers Were Developed
The core of optical communication, self-driving cars, and grocery scanning are all made possible by lasers, which stand for “Light Amplification by Stimulated Emission of Radiation.” Yes, we can also give Einstein credit for this one. A article describing Einstein’s quantum theory of radiation was published in 1917. In essence, the idea says that when an atom is struck with a particular frequency, it can be stimulated to change its energy level. When an identically frequency photon strikes an excited atom, it will create two coherent photons that will both go in the same direction when the atom’s electron returns to its ground state. This implies that a quick burst of coherent light, sometimes referred to as “stimulated emission of radiation” (the “ser” in “laser”), may be purposefully produced as atoms explode in a series of reactions. Einstein’s finding was not put to use until the end of World War II, when researchers created the laser by amplifying light using mirrors.
The Nuclear Bomb's Scientific Foundation Was Formed by the E=MC2 Equation
The idea that energy and light are similar and that their connection can be expressed by the beautifully straightforward equation E=MC2, which states that energy is equal to mass times the speed of light squared, was the last discovery made by Einstein during his “miracle year.” Einstein’s equation, which defines mass as basically super-dense energy, demonstrates how even minute amounts of mass at the atomic level may generate enormous amounts of energy when multiplied by the square of the speed of light. You can probably guess where this is headed. This mechanism describes how a uranium atom divides into smaller atoms when a neutron launched from it releases a huge amount of energy. Nuclear energy with minimal emissions may be produced through a process known as nuclear fission when it properly managed. It may be utilized to create an atomic bomb in an uncontrolled discharge. Although Einstein did not participate in the Manhattan Project, the government’s covert effort to develop the first nuclear weapon, he gave his approval to the idea in a 1939 letter to Franklin D. Roosevelt, arguing that the United States should develop the bomb before Nazi Germany. That letter was ultimately considered by Einstein to be the “one great mistake in my life.”
The E=MC2 Equation May Hint to Energy's Future
Nuclear fission operates by splitting an element, such a heavy uranium-235 atom, into two smaller atoms (krypton and barium), as was previously explained. But something fascinating also happens: Similar to fission but in reverse, two light nuclei (i.e., hydrogen) can fuse together to generate a heavy helium-4 atom if they can overcome electrostatic repulsion. In a similar vein, this process generates an enormous quantity of heat and energy according to the E=MC2 equation. This process is called nuclear fusion, and stars generate energy using atomic physics. In theory, nuclear fusion holds the key to meeting humanity’s growing energy demands. Fusion reactors are completely carbon-free, don’t produce any radioactive material as a byproduct, don’t worry about nuclear proliferation, don’t involve enriched material, and release 4 million times more energy through atom-to-atom fusion than they do through chemical burning of coal. The only drawback is that fusion reactor construction is exceedingly difficult. However, that has never deterred anybody before. The International Thermonuclear Experimental Reactor, or ITER, is being built by a global alliance of organizations and scientists, with a target completion date of 2025
