“IT’S ALL RELATIVE”
RELATIVITY AND QUANTUM MECHANICS
Late 1800s, early 1900s
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| Albert Einstein during a lecture in Vienna in 1921 (age 42). Credti: Image by Ferdinand Schmutzer, courtesy of Wikipedia. |
E=mc2. Most of us have heard of this equation, and may even know that it means “energy equals mass times the speed of light squared.” But what does this really mean, and why does everyone think what Einstein discovered is so important? Basically, Einstein had realized that energy and mass are not completely different things, but different forms of the same thing, and that huge amounts of energy are contained in each atom (that’s where the “speed of light squared” comes in). Einstein’s famous papers on relativity appeared about 100 years ago (one a little more, the other a little less than 100) and ended up revolutionizing science’s ideas about the nature of space and time.
In his first big paper on the special theory of relativity in 1905, Einstein showed that time and space are not absolute and fixed, but are relative to one another – if something moves faster and faster, it actually is getting shorter and shorter, and a clock moving faster and faster will run slower and slower! It is from this ‘relative’ relationship between space and time that Einstein realized that famous equation. In his general theory of relativity in 1916, Einstein added one more big complication to the puzzle – gravity. He discovered that there was a curvature or bending in space and time. Such curvature affects how things – even light! – move through space – there was an interaction between ‘space-time’ and gravity. Einstein’s discoveries have set forth an entirely new understanding of the universe, especially the nature and behavior of solar systems and galaxies. Einstein’s ideas set forth the modern fields of cosmology (the study of the structure and evolution of the universe) and astrophysics. His ideas laid the foundation for the development of the “Big Bang” theory of the universe.
Another very important understanding was added to Einstein’s concepts, and that is quantum theory. Quantum theory, originally proposed by Max Planck in 1900, quantum theory has been developed and refined by many physicists during the earlier 1900s. It applies to the action of matter at the other end of the scale, not stars and galaxies, but on a microscopic scale looking at the behavior of atoms and subatomic particles and trying to understand the fundamental properties of matter. It deals with a complicated dual nature of both matter and radiation, that is, they behave like particles but also like waves. A number of important fields in modern physics and chemistry, including particle physics, nuclear physics, solid state physics (how its subatomic properties affect the ‘solid state’ of a material), and quantum chemistry have developed from quantum mechanics.
WHY SHOULD I CARE?
These discoveries about the nature of the physical world have revolutionized scientific understanding about the nature of the universe, the nature of space and time, and the nature of the atoms that hold us and everything else together. They have laid the foundation for the exploration of the greater universe and the probing of the inner workings of atoms. They have had major impact on our lives, ushering in nuclear energy and the benefits and hazards it provides, lasers, the electron microscope, magnetic resonance imaging, and the development of the semiconductor industry (including transistors and diodes) that underlies all of the electronics that surround us today.
WEB RESOURCES
This is a PBS review of the theory of relativity and Einstein’s life.
https://www.pbs.org/wgbh/nova/einstein/relativity/
This is a video that explains Einstein’s Special Theory of Relativity.
https://www.youtube.com/watch?v=Gg8rUHqT0LU
This is a Wikipedia page about Einstein’s Theory of Relativity.
https://en.wikipedia.org/wiki/Theory_of_relativity
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