December 2024
New research could lead to a complete overhaul of the standard model in cosmology. There might not be any ‘dark energy’ in space. The basis for the dark energy theory could be an illusion created by variations in how fast time moves, according to a study published in the journal Monthly Notices of the Royal Astronomical Society.
However, the new scientific paper suggests that the theory may be a dead end. The reason why the expansion seems to be accelerating, the paper proposes, has nothing to do with dark energy, it is simply an illusion caused by gravity slowing down time.
According to Einstein’s theory of general relativity, gravity can distort the flow of time: Within galaxies it is slow, and between galaxies it is fast. The universe may simply be expanding at different rates in different regions. The difference in ‘clock time’ could be billions of years.
The research team at the University of Canterbury, led by professor David Wiltshire, calls their alternative to the standard model timescape cosmology.
“These results provide evidence for a need to revisit the foundations of theoretical and observational cosmology”, the team writes.
No part of science is immune to paradigm shifts, not even physics. The discovery of the quantum world is a clear case in point. This goes for astrophysics, as well. If you think what you learned in school, or even at the university, about the properties of the universe is safely established knowledge, think again.
Remember dark energy? This enigmatic force was introduced decades ago to explain the accelerated expansion of the universe. And not as “a cherry on top” of the known mass; it is thought to comprise almost 70 percent of the universe’s total energy density. Dark energy has been described as an “antigravity” force.
Astrophysicists came up with this idea when observed supernovae appeared to be farther away than expected than if the universe followed a purely gravitational model.
The basic principle was not new. Einstein introduced the ‘cosmological constant’ in 1917 to counterbalance the effect of gravity. The universe was then thought to be static (and eternal). The constant is closely related to dark energy. It was abandoned when the universe was found to expand, yet reintroduced when the expansion was found to accelerate.
Even though nobody has been able to prove the existence of this dark addition to the universe, it has been a standard framework in cosmology for 25 years. And regular references in the mainstream signal it’s practically considered fact.
Not even the timing of the Big Bang is certain. A paper published last year recalculates the age of the universe and reaches the conclusion that it is not 13.8 billion years old, as we have learned for some time now, but closer to 27 billion years –- another blow to the standard cosmological model.
The 2023 study claims to resolve the ‘impossible early galaxy problem’. Galaxies that are estimated to be as young as 300 million years old appear to be as evolved as galaxies that are thought to be 10 billion years old. That doesn’t make sense within conventional astrophysics.
The re-dating of the universe provides enough time to form massive galaxies.
The author, physicist Rajendra Gupta at the University of Ottawa, also expresses scepticism towards the ideas of a cosmological constant and dark energy.
Do these new findings mean we finally have a grip on reality? Don’t hold your breath.
If acceleration is illusory, then perhaps expansion itself is illusory. Could a questioning of the Big Bang be next up?
Anders Bolling
