Was Einstein Right?
Tonight I attended a lecture sponsored by the Perimeter Institute, the Canadian Association of Physicists and the University of Toronto: Was Einstein Right? with Professor Clifford M. Will of Washington University. Will is a theoretical physicist, who was born in Hamilton, Ontario, and got his math and physics undergrad degree from McMaster. He's held posts at various universities in the US, and is also a recognized "expert" on Albert Einstein. I have no idea what that means, but that's the claim his brief bio made on tonight's programme.
Will is a pretty good speaker, who managed to bring the last one hundred years of Astronomy, from the perspective of Einstein's theories of general and special relativity, down the general audience level, without alienating too many of the science buffs in his audience. He cracked some real yawns, and had a wit that would only make a physicist laugh. His lecture didn't seek to answer the title's question -- rather, it served to educate the general audience, and as he put it, that was the job of a scientist -- to present what is known, and leave everyone to make up their own minds on whether Einstein got it right or not.
Will looked at the early years of Einstein's theories -- before the 1950s -- and asked why the theory never took off? -- never developed further? His answer was a two-parter. 1) It was thought that Einstein's theory, steeped in mathematics, was way too complex for many to understand. Even fellow scientists stayed away from it. 2) Einstein's theory was just that -- a theory. There was no experimental counterbalance to validate the theory, and for a long time, the interplay between experiment and theory didn't happen. Yes, there were early proofs of Einstein's theory, but there wasn't a drive to validate his theories with experiment.
In the 1960s, according to Will, the world witnessed a revolution in Astronomy. There were observations of some rather bizarre cosmic objects that didn't have a ready explanation. In general relativity however, theories could be found to explain what was being seen. Specifically, astronomers observed the first quasars; discovered the cosmic background radiation; observed the first pulsars; and found evidence for the existence of blackholes. Traditional Newtonian physics could not explain what was being seen, however Einstein's general relativity offered possibilities. This, with the explosion of technological advancements in the 1970s and university curricula that started emphasizing general relativity in graduate and undergraduate classes, set the stage for greater intellectual investment in general relativity.
So, was Einstein right? I already mentioned that Will didn't answer the question. What he did however, was elaborated on tantalising tests for general relativity.
According to Will, that Einstein was motivated to develop his theories not to solve some fundamental problem in physics, but to find a solution that was simple, beautiful and elegant is not that remarkable -- what is remarkable is how well his theories have held up to tests and scrutiny by science. With that, I have to agree. That's truly remarkable.
Related links:
Will is a pretty good speaker, who managed to bring the last one hundred years of Astronomy, from the perspective of Einstein's theories of general and special relativity, down the general audience level, without alienating too many of the science buffs in his audience. He cracked some real yawns, and had a wit that would only make a physicist laugh. His lecture didn't seek to answer the title's question -- rather, it served to educate the general audience, and as he put it, that was the job of a scientist -- to present what is known, and leave everyone to make up their own minds on whether Einstein got it right or not.
Will looked at the early years of Einstein's theories -- before the 1950s -- and asked why the theory never took off? -- never developed further? His answer was a two-parter. 1) It was thought that Einstein's theory, steeped in mathematics, was way too complex for many to understand. Even fellow scientists stayed away from it. 2) Einstein's theory was just that -- a theory. There was no experimental counterbalance to validate the theory, and for a long time, the interplay between experiment and theory didn't happen. Yes, there were early proofs of Einstein's theory, but there wasn't a drive to validate his theories with experiment.
In the 1960s, according to Will, the world witnessed a revolution in Astronomy. There were observations of some rather bizarre cosmic objects that didn't have a ready explanation. In general relativity however, theories could be found to explain what was being seen. Specifically, astronomers observed the first quasars; discovered the cosmic background radiation; observed the first pulsars; and found evidence for the existence of blackholes. Traditional Newtonian physics could not explain what was being seen, however Einstein's general relativity offered possibilities. This, with the explosion of technological advancements in the 1970s and university curricula that started emphasizing general relativity in graduate and undergraduate classes, set the stage for greater intellectual investment in general relativity.
So, was Einstein right? I already mentioned that Will didn't answer the question. What he did however, was elaborated on tantalising tests for general relativity.
- General relativity postulates that space and time are one -- space-time -- a four-dimensional structure which is made malleable by matter, energy and their motion. Space-time deforms in four dimensions around energy and matter. In 1919, Frank Dyson, Charles Davidson and Arthur Eddington, obtained observational proof that space-time curves around matter by observing starlight being bent around the Sun during a solar eclipse.
- Space-time curvature also allows for lenses to occur, when space-time is deformed by high concentrations of mass, such a galaxy clusters. These gravitational lenses causes light from distant sources to warp, or form cosmic mirages.
- For sometime in the early 20th century, observations confirmed that Mercury's orbit was wobbling around the Sun -- known as Mercury's perihelion advance. This could not be accounted for by the gravitational influence of the Sun and other planets using Newtonian physics -- however, general relativity accurately predicted the observations.
- Frame-Dragging is another prediction of general relativity that was realized by Joseph Lense and Hans Thirring in 1918. Lense and Thirring prediction that rotating matter could also have an impact on space-time -- specifically, a rotating object could cause space-time to twist. NASA's Gravity Probe B is a test for this prediction. Observations were completed last month, and data is now being crunched.
- Just like the interaction of electricity and magnetism can generate electromagnetic waves, so too can the interaction of matter and energy generate gravitational waves, as predicted by general relativity. There is indirect evidence that gravitational waves exist via the binary pulsar system observed by Russell Hulse and Joseph Taylor -- however, there is no direct observations. Interferometer observatories around the world are now looking for the elusive waves. (LIGO, VIRGO, GEO, TAMA and LISA.)
- Finally, general relativity predicts that time would be impacted by gravity directly. Gravity probe A tested this postulate and proved it in 1976.
According to Will, that Einstein was motivated to develop his theories not to solve some fundamental problem in physics, but to find a solution that was simple, beautiful and elegant is not that remarkable -- what is remarkable is how well his theories have held up to tests and scrutiny by science. With that, I have to agree. That's truly remarkable.
Related links:
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