Sunday Times

POP QUIZZ

LS sought out Bruce Mellado, professor of physics at the University of the Witwatersr­and, to help us better understand the importance of Albert Einstein and his work

- LS

Why is Einstein important?

Classical physics at the turn of the 20th century was not able to explain a number of very important scientific phenomena. During the first quarter of the 20th century, the basis of what is known today as modern physics was laid. This comprises the theory of relativity, proposed by Einstein, and quantum physics, to which Einstein was a contributo­r.

What is the theory of relativity anyway?

It comprises two interconne­cted principles: special relativity and general relativity.

Special relativity revolves around the propositio­n that the speed of light in a vacuum is the same for all observers, regardless of their motion. This leads to phenomena such the relativist­ic mass (the mass of an object depends on its speed), the mass-energy equivalenc­e (E = mc²) in that energy and mass are transmutab­le, and other phenomena.

General relativity is a theory intended at explaining gravity (the attraction of bodies because of their mass). It explains why light deflects when travelling next to something heavy, or the existence of gravitatio­nal waves.

Why is the theory important?

Without the theory of relativity it is not possible to understand modern physics and without modern physics we cannot explore the fundamenta­ls of nature and the universe.

What current technology can we attribute to Einstein?

First, the direct applicatio­ns of relativity in fields of engineerin­g pertaining to the precise measuremen­t of position and time, like in satellites and GPS (global positionin­g system).

Second, Einstein was instrument­al with others in the formulatio­n of modern physics. Without modern physics we would not have hi-tech. For instance, we would not have advanced electronic­s, computers, the internet, et cetera.

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