Scientists Propose Expanding Physical Reality into Extra Dimensions
One major conundrum in physics is the inconsistency between Einstein’s General Theory of Relativity and the quantum world. While some physicists work within existing frameworks to find a Grand Unified Theory, others suggest adjustments or complete changes to these theories.
One significant rethink is Modified Newtonian Dynamics (MOND), which aims to eliminate the need for hypothetical dark matter, although it has its own set of problems. Other theories make incremental changes to general relativity to harmonize it more with quantum mechanics; 'fuzzy gravity' is a prime example.
A paper published in Progress of Physics by scientists from the National Technical University of Athens proposes a refined approach to Einstein’s theory. It suggests that spacetime might be discrete rather than continuous, echoing the idea of spacetime as a tapestry of points like atoms. However, current technology cannot test this at Planck lengths.
Adding further nuance, the paper argues that spacetime could be non-commutative. Normally, variables that can be rearranged without changing the outcome are commutative. However, in fuzzy gravity, the order in which spatial coordinates are multiplied matters, which deviates from traditional geometry.
The paper states, "From the beginning, the quantum theory challenged classical notions of commutativity." It links noncommutative geometry with potential quantum structures at extremely small distances (Planck scale).
‘Fuzzy gravity’ does have limitations; it describes quantum gravity but doesn’t cover other fundamental forces like electromagnetism or nuclear forces. To address this, the authors propose using higher-dimensional spacetime to attempt unification. If extra, discrete, and noncommutative dimensions are considered, interactions with our usual four-dimensional spacetime could resemble observed elementary particle interactions.
The theory estimates deviations from general relativity would only become noticeable at Planck lengths, a scale too small for even our most advanced particle accelerators to explore. However, moving forward, merging quantum mechanics with classical physics keeps scientists exploring these intricate dimensions.
Earlier, SSP wrote about the oldest evidence of Earth's atmosphere may reside in lunar rocks.