Relativity Quotes - page 5

Among the problems of the known string theories, as a theory of hadrons, was the fact that the spectrum of open strings contains massless spin 1 particles, and the spectrum of closed strings contains a massless spin 2 particle (as well as other massless particles), but there are no massless hadrons. In 1974, Joël Scherk and I decided to take string theory seriously as it stood, rather than forcing it to conform to our preconceptions. ... Specifically, Scherk and Schwarz (1974) proposed trying to interpret string theory as a unified quantum theory of all forces including gravity. Neveu and Scherk (1972) had shown that string theory incorporates the correct gauge invariances to ensure agreement at low energies (compared to the scale given by the string tension) with Yang-Mills theory. Yoneya (1973,1974) and Scherk and Schwarz (1974) showed that it also contains gauge invariances that ensure agreement at low energies with general relativity. (John Henry Schwarz)
On notable classmate was Dan Friedan. Friedan stunned me, and I think everyone else, at his Ph. D. seminar, when he showed that Einstein's equation, the basic equation of general relativity, could be interpreted in terms of one of the basic objects in QFT, the β function that governs the energy scale. I did not see what this could possibly mean, but a few years later it showed up as one of the key ideas in string theory.
Joseph Polchinski
I wrote A Wrinkle in Time when we were living in a small dairy farm village in New England. I had three small children to raise, and life was not easy. We lost four of our closest friends within two years by death - that's a lot of death statistically. And I really wasn't finding the answers to my big questions in the logical places. So, at the time I discovered the world of particle physics. I discovered Einstein and relativity. I read a book of Einstein's, in which he said that anyone who's not lost in rapturous awe at the power and glory of the mind behind the universe is as good as a burnt-out candle. And I thought, "Oh, I've found my theologian, what a wonderful thing."
Madeleine L'Engle
Some of the effects predicted by the theory [of loop quantum gravity] appear to be in conflict with one of the principles of Einstein's special theory of relativity... that the speed of light is a universal constant. ...Photons of higher energy travel slightly slower than low-energy photons. ...the principle of [general] relativity is preserved but Einstein's special theory of relativity requires modification. ...A photon can have an energy-dependent speed without violating the principle of [general] relativity!
Lee Smolin
General relativity predicts that time ends inside black holes because the gravitational collapse squeezes matter to infinite density.
Lee Smolin
There certainly is a tension between the relativity of simultaneity and non-locality in quantum theory, but it's not strong enough to add up to a falsification of either side by itself.
Lee Smolin
Relativity and... quantum... remain incomplete.... the main reason each is incomplete is the existence of the other. The mind calls for a third theory to unify all of physics, and for a simple reason. Nature is... "unified." ...interconnected, in that everything interacts with everything else.
Lee Smolin
We have known since the middle of the nineteenth century that the world is not composed only of particles. ...the world is also composed of fields. ...General relativity is a theory of... the gravitational field. ...Because there are three sets of field lines, the gravitational field defines a network of relationships having to do with how the... lines link with one another. ...This is why we call relativity a relational theory.
Lee Smolin
One of the evident facts about the world is the stability of empty space-time. In classical general relativity we can explain this as a consequence of the positive energy theorem... the positive energy theorem must extend in some suitable form to any viable quantum theory of gravity.
Lee Smolin
Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is called the problem of quantum gravity.
Lee Smolin
In both quantum theory and general relativity, we encounter predictions of physically sensible quantities becoming infinite. This is likely the way that nature punishes impudent theorists who dare to break her unity. ...If infinities are signs of missing unification, a unified theory will have none. It will be what we call a finite theory. (Lee Smolin)
In string theory one studies strings moving in a fixed classical spacetime. ...what we call a background-dependent approach. ...One of the fundamental discoveries of Einstein is that there is no fixed background. The very geometry of space and time is a dynamical system that evolves in time. The experimental observations that energy leaks from binary pulsars in the form of gravitational waves-at the rate predicted by general relativity to the... accuracy of eleven decimal places-tell us that there is no more a fixed background of spacetime geometry than there are fixed crystal spheres holding the planets up.
Lee Smolin
I believe that the main lesson of relativity and quantum theory is that the world is nothing but an evolving network of relationships.
Lee Smolin
In the theory of electric fields it is assumed that points have meaning. ...Physicists using general relativity... cannot speak of a point, except by naming some features of the field lines that will uniquely distinguish that point. ...the network of relationships evolve with time... constantly changing.
Lee Smolin
While most people... were seeking to modify the principles of either relativity or quantum theory, we surprised ourselves (and many other people) by succeeding in putting them together without modifying their principles.
Lee Smolin
The suggestion was that a positive energy proof for general relativity could be gotten by restricting supergravity to its bosonic sector, which is general relativity.
Lee Smolin
Neither space nor time has any existence outside the system of evolving relationships that comprises the universe. Physicists refer to this feature of general relativity as background independence.
Lee Smolin
It is absurd in general relativity to speak of a universe in which nothing happens.
Lee Smolin
I came away from the two science surveys superficially acquainted with what was already a rather old-fashioned version of contemporary natural science. Relativity and quantum mechanics were mentioned... but not explained; the stars were still eternal; and both subatomic particles and biochemistry were discreetly omitted. ...The two courses persuaded me that, in some sense, I understood the natural world. The illusion endured, for later in life... I tagged along by reading popular accounts, believing that the natural world out there was somehow within my reach, even without the mathematics that made quantum mechanics so mysteriously plausible.
William H. McNeill
Jesus could not have imagined such an idea as Albert Einstein's theory of relativity.
John Shelby Spong
The star S0-2 orbits around Sgr A* every 16 years and will go through its closest approach in 2018. That's an opportunity to test Einstein's General Relativity theory through very precise measurements of this star's short period orbit. (Andrea M. Ghez)
I always found it satisfying that gravity was described by Einstein's geometric theory of general relativity.
Antony Garrett Lisi
And it really began with Einstein. We attended his lectures. Now the theory of relativity remained - and still remains - only a theory. It has not been proven. But it suggested a completely different picture of the physical world.
Douglas Sirk
What you can show using physics, forces this universe to continue to exist. As long as you're using general relativity and quantum mechanics you are forced to conclude that God exists.
Frank J. Tipler
General relativity has changed our understanding of space and time. ...The spacetime of general relativity ...is likely to be just a classical approximation that loses its meaning in the quantum theory, for the same reason the trajectory of a particle does.
Carlo Rovelli