Einstein's equations may explain cosmic expansion without dark energy
Mathematicians at UC Davis suggest the universe's accelerating expansion could be explained by existing gravitational theories rather than dark energy.
A team of mathematicians at the University of California, Davis, is challenging the standard theory that dark energy causes the universe to expand at an accelerating rate, according to a report by the Times of India.
The researchers, whose findings are published in the journal Proceedings of the Royal Society A, argue that Einstein's original equations of gravity might already account for this expansion.
Blake Temple, a professor emeritus of mathematics at UC Davis and the study's corresponding author, stated that the mathematical structures at the core of the standard model, known as Friedmann spacetimes, are unstable.
Temple compared the situation to a pencil balanced on its tip, noting that while such a state is a mathematical solution, it is too fragile to be observed in nature.
The team used the Einstein-Euler equations to test the Lambda-cold dark matter model and found that disturbances during the period of matter dominance grow rather than fade.
Temple said this instability suggests that the Lambda-cold dark matter model may not be a stable solution for the Einstein equations of general relativity, regardless of whether dark energy is included.