In 1905, a Swiss patent clerk shook the seemingly well-established foundations of physics with four groundbreaking papers – one proving the existence of atoms, another proving mass-energy equivalence, another proposing ‘energy quanta’ and a final one on relativity. This patent clerk was Albert Einstein, and he had just disproved the several century-old papers of Isaac Newton; proving time was not absolute, but relative, and that Newton’s law of universal gravitation was incorrect. Einstein had effectively paved the way for modern physics to progress, but could he have been wrong?
Newton
In the 17th century, Isaac Newton devised the law of universal gravitation; put any masses anywhere in the Universe, a fixed distance apart, and you will know the gravitational force between them. At the time this explained everything from the terrestrial motion of cannonballs to the celestial motion of comets, and stars, as well as objects on planet Earth, and this law’s predictions matched every observation or measurement that had ever been made for almost two centuries until physicists noticed a flaw they could not explain – Mercury’s orbit, which was completely different to the other planets’ orbits in our solar system, as the orbits of planets shifted over time, and Mercury’s orbit shifted so much faster than Newton predicted. This was a flaw that no physicist at the time would dare challenge, as Newton’s ideas had been well established for centuries, and he was considered to be absolutely correct. Newton also devised that time was absolute, claiming time exists independently and progresses at a consistent pace throughout the universe. Despite both of these ideas being flawed and disproved several centuries later, we still use them for certain calculations, such as for rocket launches.
Einstein
In the early 20th century, however, the young Albert Einstein devised several new ideas which contradicted the ideas of Isaac Newton and also provided an explanation for Mercury’s pesky orbit around the sun. Instead of exerting an attractive force like Newton, he argued that each object in our universe curves the fabric of space and time around them, forming a sort of well that other objects (and even beams of light) fall into. A great way of understanding this is through picturing the sun as a bowling ball on a mattress. It creates a depression that draws the planets close. This effectively had solved the Mercury problem - the sun curves space so it distorts the orbits of nearby bodies, including Mercury. This claim was verified through the observational Eddington experiment in 1919, whereby physicists measured the gravitational deflection of starlight passing near the Sun and saw that the values obtained from this experiment matched Einstein’s values in 1905.
Einstein also successfully proved the existence of the atom through the usage of the kinetic theory of gases, as well as receiving help from Jean Perrin’s Brownian motion experiments which verified Einstein’s claims. Using Max Planck’s work, he also successfully devised the photoelectric effect, which proposed that there is an emission of electrons when electromagnetic radiation, such as light, hits a material. And perhaps his most famous proof of all – mass-energy equivalence, which brought about the famous equation E = mc^2 (where E = energy, m = mass, and c = speed of light) – since mass and energy are equivalent, we can use this equation to calculate the amount of energy, as Einstein states that “all objects having mass, called massive objects, also have corresponding intrinsic energy, even when they are stationary”.
Thanks to all of these, we have been able to predict how much energy will be released or consumed by nuclear reactions, have been able to create the atomic bomb, GPS and other modern electronics as well as the age of stars, the distance to the stars. Einstein’s contributions to science, as well as to our society, have been astronomical.
Now, what if Einstein was wrong? Centuries before Einstein, we believed that time was absolute; that there was an audible tick-tock throughout the universe, but just over a century ago we learnt that time was relative – surely we can apply the logic that in a couple centuries, Einstein too, would be incorrect about much of his work just like Newton was?
We, physicists, have already started to notice errors in Einstein’s work, although general relativity is still a very well confirmed theory. General relativity, as stated earlier, predicts that light bends around massive objects, and predicts that the universe should be expanding; that black holes exist, that time runs more slowly in certain gravitational potentials, and so on, all of which we have observed and know are facts.
However, it does not fit well with another well-confirmed theory – quantum mechanics. Particles obey Heisenberg’s Uncertainty Principle, and so can be in two places at the same time. If we have two slits and shoot a particle towards it, quantum mechanics tells us that the particle will go through both slits. But thanks to Einstein, we are unsure as to which direction this particle will subsequently go after travelling through both slits at the same time due to the gravitational pull.
Aside from the double-slit problem, there are several other issues. One is with singularities in general relativity – a singularity is a place where both the energy-density of matter and curvature become infinitely large, such as with black holes and the beginning of our universe. It has been quite well established that this is flawed and that there is a more fundamental theory to replace it – quantum gravity. Another reason is that if we combine quantum theory with general relativity without quantizing gravity, we find that black holes will slowly shrink by emitting radiation (known as Hawking radiation thanks to the discovery of Hawking), suggesting that black holes can entirely vanish by emitting such radiation. This radiation emits only temperature and no other information, so we cannot possibly know what formed the black hole, ergo general relativity cannot fit with quantum theory.
If we are indeed incorrect, then we would have to ‘recalibrate’ everything we have come to know thanks to Einstein, such as GPS and the age of stars, as well as the other discoveries stated earlier.
We are constantly progressing in science and as a society at an incredible rate, and much of what we believe today will most certainly be disproved in several centuries, if not decades; religion, cancer, blindness, death, violence; all may become things of the past thanks to our work in physics.
