Has Big Bang theory been superceded by Loop Quantum Cosmology?

Answer 1

no, loop quantum gravity and string theory are the leading theories that attempt to resolve the conflicts between quantum mechanics and general relativity. neither loop quantum gravity nor string theory attempts to supersede the big bang. it is interesting because the two theories seem to complement each other. i mean that one's strengths are the other's weaknesses.

http://en.wikipedia.org/wiki/Loop_quantum_gravity
http://en.wikipedia.org/wiki/String_theory

watch "the elegant universe" on pbs here:
http://www.pbs.org/wgbh/nova/elegant/program.html

Answer 2

Don't be fooled by the theory of the day. Einstein called the cosmological constant the biggest mistake he ever made. He introduced it to give a stable universe. It turns out that his complication of his original formulas was not needed to stabilize the universe because the universe is not stable. We know today that to make his formulas consistent with today's observations requires the cosmological constant. As we add more complexity to the description of the universe there will come a time when everything will be thrown out and a new paradigm will be presented that makes it simple again. Never mix up the model with the real thing. The models we make are to help us make predictions about the real world. Models are good or bad based on the quality of the predictions they make. For many purposes newtons laws are adequate and they are comparatively easy to use. They are therefore the preferred method of estimating how to build a building or a car or even a rocket to the moon.

Answer 3

In short NO...

In length...
While there has been a recent proposal relating to observation of naked singularities,[19] and doubly special relativity, as a part of a program called loop quantum cosmology as of now, not a single experimental observation exists for which loop quantum gravity makes a prediction not made by the Standard Model or general relativity. This problem plagues all current theories of quantum gravity, excepting those which have been proved wrong.

Making predictions from the theory of LQG has been extremely difficult computationally, also a recurring problem with modern theories in physics.

Another problem is that a crucial free parameter in the theory known as the Immirzi parameter can only be computed by demanding agreement with Bekenstein and Hawking's calculation of the black hole entropy. Loop quantum gravity predicts that the entropy of a black hole is proportional to the area of the event horizon, but does not obtain the Bekenstein-Hawking formula S = A/4 unless the Immirzi parameter is chosen to give this value. A prediction directly from theory would be preferable.

Finally, LQG has gained limited support in the physics community. At present more physicists work in string theory than in LQG.