Seven Brief Lessons on Physics summary

In 1905, a young man by the name of Albert Einstein submitted three articles to one of the world’s most prestigious scientific journals, the Annalen der Physik.

Remarkably, each of these articles is now considered worthy of a Nobel Prize, but it was the third article that became the most famous since it contained Einstein’s first theory of relativity. Today, this is known as his theory of special relativity, and it essentially describes how time is relative, depending on the conditions surrounding the person experiencing it.

For example, if you’re traveling fast enough, time slows down. So, if you leave your friend hanging around while you go for a quick rocketship ride that takes you around the world at the speed of light then, when you land, time will have passed more slowly for you than for your friend who stood still.

Einstein’s theory sent shockwaves through the scientific community, gaining him instant notoriety. However, there was one issue with which he had to deal: at the time, his theory was in direct conflict with Isaac Newton’s theory of gravity, which had been in place since the seventeenth century.

Newton’s theory stated that the force of gravity controlled how the planets and stars interacted with one another and moved through space. This was a huge step in how we understood the universe and the laws that governed it. For the first time, we had a hint that there was something unseen at work in the vast emptiness of space.

That seemingly empty space was further filled by the British physicists Michael Faraday and James Maxwell, who brought forth the concept of electromagnetic fields. Now, along with gravity, there were radio waves that could “transport” electrical forces.

It took Einstein ten years of hard work, but he eventually emerged with his theory of general relativity, a masterpiece of thinking so beautiful and elegant that some would say it’s comparable to Mozart’s Requiem or Homer’s Odyssey.

Central to Einstein’s thinking was that, if there is an electromagnetic field, there must be a gravitational field as well. Einstein’s stroke of genius lay in taking this a step further to theorize that the gravitational field doesn’t so much “fill” space as it is the space.

This means that space isn’t flat – it curves around massive objects such as planets and stars, and as it does so, the gravitational field exerts a measure of force that keeps things from flying away.

Einstein’s work offered a perfect launching pad for further theories.