Recent content by Peter J Carroll

Hi Nugatory, for me, GR does explain ‘Why does matter curve spacetime? Why are the paths of massive objects not subject to external forces spacetime geodesics? If it means that Matter Is Curved Spacetime, and that Geodesics Are the true shape of Spacetime in which matter moves. I can...

Well as you ask PeroK, I speak for myself but perhaps also for a lot of people who wonder what the maths implies in terms of concepts. For example, does the intrinsic angular momentum ‘spin’ of a fermion involve the concept of anything moving or storing energy in circular motion, or is it just...

Indeed, mathematics remains invaluable, but if science depends on a dialogue between mathematics and concepts, then quantum physics becomes particularly tricky when we have difficulties finding concepts to fit the maths. Thanks for your responses, no further questions at present. Regards, Pete.

PeroK, your example of Newton’s laws nicely illustrates the difference between a description and an explanation. F = ma acts as both. It works as a tautology that fits, (for moderate velocities) by defining each term in terms of the others. However, Newton’s formula for gravity works only as a...

Thank you for your replies and the links from vanhees71 which I will seek out. As Peter Donis notes “you can have different particles with the same spin but different wavelength (momentum) and frequency (energy).” Indeed, and this simple formula ##h/4\pi = \lambda mc = vmc/f## applies only...

Greetings, I'm new here, I have an interest in the nature of reality, and a question. Does the quantum spin of a particle (its intrinsic angular momentum) have anything to do with its wavelength and frequency? One of the experts on Quora said no, and I cannot find anything about it on the web...

Greetings members, I've been out of academia for decades since taking a degree at London Uni, but I have maintained a keen interest in all matters cosmological and quantum ever since. Now in retirement from business, I have devoted an increasing amount of time to bringing myself up to speed with...