We all make mistakes but sometimes they have colossal implications. In science too, mistakes happen a few of which were thought to be minor but turned out to be momentous for which there’s no better example than mistakes made by Albert Einstein.

On the positive side of the ledger, his achievements were considerable. Counter to prevailing thought in the early 1900s, he showed that the speed of light was fixed but time was not — time varied with mass and speed.

He also established the fundamental relationship between energy and mass expressed in his most famous equation. Energy (E) is equal to mass (m) multiplied by the speed of light squared (c2) or E = mc2.

Such a simple equation to express the equivalence of energy and mass: Each can be converted into the other and a tiny bit of mass, can create an enormous amount of energy (the c2). The relationship has been tested many times and, even at the quantum level, holds true.

He showed that light was quantal in nature. And by inference, so also was all energy quantal in nature.

It was an insight his more reluctant colleague Max Planck was forced to adopt as the only practical solution to his study of nature of black box energy — a concept the bolder and more creative Einstein had no hesitation imagining and adopting.

Other triumphs for Einstein included the then-theoretical possibilities that collisions of massive stellar objects could create ripples in space-time and that the mass of galaxies could bend light, forming stellar lenses, with which otherwise hidden galaxies could be seen.

Both were products of his masterpiece theory of general relativity, and in more recent times were shown to not only be true, but useful tools for studying the universe.

Einstein may have won his one Nobel Prize for his study of the quantal nature of light, but it was his theory of general relativity which related mass to space-time — most simply expressed as mass bends space-time and space-time tells mass where to go — that was his greatest triumph.

This magnum opus was 10 years in the making but worth the wait because of the implications of its equations, which surprised and stunned Einstein as much as others who studied general relativity.

The most important implication of this was identified by Belgian priest Georges Lemaitre and a physicist who, after analyzing Einstein’s equations, realized they pointed to an expanding universe — not the static universe without an apparent beginning or ending imagined by Isaac Newton and Einstein.

Einstein not only told Lemaitre that he was wrong but introduced his infamous cosmological constant into his equations to restore stability to the universe.

He thus compounded his mistake by not accepting Lemaitre’s analysis and adding what he considered a convenient fix.

Einstein would lament both mistakes when Edwin Hubble’s observatory studies revealed that galaxies were moving away from one another and the farther away they were, the faster they were moving.

This was solid evidence Einstein could not ignore and he relented publicly and withdrew his constant.

Einstein’s theory of general relativity and Hubble’s observations led directly to the Big Bang hypothesis for the origin of the universe — now a well-established model even if the timing and course of events need work and clarification of the elusive nature of dark matter.

Adding a wrinkle to the story is the fact that the cosmological constant describes the very force (dark energy) responsible for the universe’s expansion, which makes sense given that the constant was created to equal what Einstein needed to correct the expansion predicted by his equations.

Thus, was made the third mistake: Failing to realize that his constant described what later became known as dark energy, the force expanding the universe.

To complete the litany of mistakes by Einstein was the realization by Karl Schwarzschild, a master mathematician and physicist, who pointed out to Einstein that his equations suggested that large enough masses might collapse space-time into what he called a singularity. Einstein agreed but thought the prospect unlikely.

Unfortunately for Einstein, Schwarzschild’s insight later became the basis for black holes or, on the scale of the universe, could have produced the tiny singularity of incredibly dense energy that gave birth to the universe 13.8 billion years ago.

But for his stubborn nature wedded to his notion of a constant universe, Einstein might have become the father of both black holes and the Big Bang hypothesis.

Einstein was also relentless in his assault on quantum physics because of its lack of causality and the uncertainty, which philosophically, he was so opposed to.

The long debate between Niels Bohr and Einstein came to a head when Einstein argued that particles at great distances could not behave as one (entangled) as quantum rules allowed.

The great debate went on beyond Einstein’s and Bohr’s lifetimes but was finally solved by experiments that supported entanglement at a distance — the subject of a Nobel Prize in 2022.

Einstein was a brilliant theorist, bold in his thinking, relentless and determined when he thought he was right and gracious when he was shown to be wrong.

But he could be stubborn to the point of failing to recognize inconvenient facts derived from his own studies.

He was human and for that and his many virtues and accomplishments, he remains my favourite physicist.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.