Ask a Physicist

Do you think that Albert Einstein had a big influence on the way people live their lives today? Do you think German people have a different opinion of him than English?
Submitted by Rebecca from Liverpool, England

I don't know how opinions differ from one country to another, but Einstein has a lot of influence on how we live today, even if you only look at the more practical things.

GPS, the Global Positioning System, is a good example. It determines the location of your car, a missile, or whatever by comparing clock signals with several satellites. The curvature of spacetime may sound like a very abstract thing, but it has very concrete consequences. Basically, relativity predicts that the clocks up in orbit on the satellites tick faster than clocks on the ground. It's only forty microseconds per day, but if the effect weren't correctly calculated from Einstein's equations and compensated for, GPS would accumulate position errors of seven miles per day. GPS would very quickly become useless.

Einstein did much more than relativity. He predicted all sorts of properties of atoms and light. Arguably he was one of the founding fathers of quantum mechanics, though he never was very happy with it. Einstein worked out how the right sort of microscopic particles could clump up in ways that would be visible at human scales, which is basically how superconductors work. He also worked out that atoms making light could make other atoms make the same kind of light. It took decades to develop the technology to make this practical, but it has a huge influence. It's called the laser, and it's used for everything from reading prices at supermarkets to wowing the fans at Pink Floyd concerts to searching with LIGO for the gravitational waves predicted by relativity - nicely tying together what are arguably Einstein's biggest results.

And Einstein explained why rivers meander - that is, why they don't flow straight over flat land but rather grow big loops which pinch off or move downstream. I found out about that achievement of his when I was growing up in Louisiana, where that sort of thing has a big effect on the landscape. So it made a big impression on me, but it doesn't seem very widely known. It ought to be, since it shows the breadth of Einstein's achievements, and that he thought about very down-to-earth things as well as the very far out.