Biggest predictions in the field of physics
Theoretical physicists perform computations, make predictions, and squint at blackboards. Equipment is built, observations are made, and data sets are analyzed by experimental physicists. (At least, that’s how things work when things are going well.) Predictions made by the scientists sometimes turn out to be a discoveries.
The two groups depend on one another because experimenters can be looking to show that a theory is true (or false), while theorists might be looking to explain experimental findings. Experimentalists will be shocked to hear that we won’t accept any evidence that isn’t supported by theory, as the British theoretical physicist Arthur Eddington memorably said.
The three laws of kepler, by Isaac Newton (by 1687): predictions
Early proponents of prediction using mathematical calculation were British physicist and mathematician Issac Newton. He made it feasible to forecast the motion of objects across space and time in 1665 by developing his “fluxions,” or what is now known as calculus.
In order to do this, Newton incorporated concepts from Johannes Kepler’s three laws of planetary motion, Galileo Galilei’s theories on force and acceleration, Robert Hooke’s theories on how a planet’s tangential velocity relates to the radial force it experiences, and Galileo Galilei’s theories on how the gravitational force is an inverse square law directed towards the Sun. All of these ideas were combined by Newton, who also contributed some of his own concepts, to create the three laws of motion and the universal rule of gravity.
Siméon-Denis Poisson’s “The Arago Spot” (1818): predictions
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Siméon-Denis Poisson, a French mathematician and physicist, once made a forecast that he was certain was incorrect. Instead, his prediction regarding the forecast turned out to be false, and he unintentionally contributed to the proof that light is a wave.
Poisson was one of several scientists who suggested in 1818 that the French Academy of Science’s annual competition focus on the characteristics of light, hoping that the submissions would corroborate Newton’s corpuscular theory—that light was composed of “corpuscles”—in this way (little particles). Yet, a French engineer and physicist named Augustin-Jean Fresnel put forth a notion that expanded upon Christiaan Huygen’s theory that light was a wave, with each point on its wavefront serving as the source of secondary wavelets. All of these wavelets, according to Fresnal’s theory, interfered with one another.
James Clerk Maxwell’s Speed of Light (1865): predictions
The Scottish physicist James Clerk Maxwell began to make significant strides in the sciences of electricity and magnetism in 1860 at King’s College London in the United Kingdom by putting Michael Faraday’s experimental discoveries into mathematical form.
The 1865 work “A dynamical theory of the electromagnetic field” was the culmination of a number of publications. In this case, Maxwell generated six wave equations and a set of 20 partial differential equations, three for each spatial element of the electric field, E, and the magnetic field, B. In his conclusion, Maxwell stated that it was “scarcely avoidable” that “light consists in the transverse undulations of the same medium” (i.e., the same medium that causes electric and magnetic phenomena)
Albert Einstein’s Anomalous Perihelion Precession of Mercury (1915): predictions
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Urbain Le Verrier, a French astronomer, meticulously examined Mercury’s orbit in the 1840s. He discovered that the planet’s elliptical orbit’s perihelion, or closest point to the Sun, is moving around the Sun rather than forming a precise ellipse as Newton’s rules would have predicted. The rate of change is extremely slow, only 575 arcseconds per century, but at the time, astronomers could only explain 532 arcseconds of that shift as a result of interactions with other planets in the solar system, leaving 43 arcseconds unexplained.
Even still, astronomers were troubled by the disparity. A variety of explanations were put out, including an undiscovered planet, an almost microscopic adjustment to the exponent of 2 in Newton’s gravitational equation, and an oblate Sun, but each one appeared improvised. The German scientist Albert Einstein was then able to calculate how curved space affected Mercury’s orbit in 1915 while he was finishing up his general theory of relativity, resulting in an additional shift of the perihelion precession.
Second series of rare-earth elements, by Maria Goeppert Mayer (1941)
The periodic table is hardly something that is added to every day, but German physicist Maria Goeppert Mayer went a step farther and added a full row.
Enrico Fermi and Harold Urey were people Mayer met while attending Columbia University in the US. As element 93, neptunium, had just been found by Edwin McMillian and Philip Abelson, Fermi was attempting to decipher the decay products of uranium and elements that could lie beyond it. In order to approximate the distribution of electrons in high-Z atoms, Llewellyn Thomas and Fermi independently created the Thomas-Fermi model for the potential energy in 1927, and Fermi asked Goeppert Mayer to calculate the eigenfunctions of Erwin Schrödinger’s equation for the 5f electron orbitals of atoms close to uranium using this model.
Anomalous magnetic moment of the electron, by Julian Schwinger (1949)
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Julian Schwinger, an American theoretical physicist, developed techniques based on Green’s functions while working on military radar and waveguide technology during World War II. These techniques involve solving a simpler differential equation to obtain the Green’s function, which can then be integrated to produce the answer to the original problem. It’s difficult to achieve in practice and frequently requires perturbation, but Schwinger was a master at it.
Following the war, Schwinger used his expertise with Green’s functions to advance the field of quantum electrodynamics (QED), which studies the interactions between electrons and light. Theorists needed to take into account the self-interactions of the quantum, relativistic electron, and photon fields after the work of Schrödinger and Paul Dirac in order to fully understand their behavior. Yet, computations for measurable quantities like mass and charge produced unpleasant infinities. Schwinger published his findings for the so-called first-order radiative correction to the electron’s magnetic moment in a 1947 publication. He was the first to use Green’s functions to navigate at least some of the mathematical minefields.