Enigmatic dark energy, thought to make up 68% of the universe, may not exist at all, according to a Hungarian-American team. The researchers believe that standard models of the universe fail to take account of its changing structure, but that once this is done the need for dark energy disappears.
According to experts, 68 percent of the universe we think is out there may not exist at all. According to simulations, new models proposed by scientists show accelerated expansion CAN exist without energy.
Is it time to rewrite everything we thought we knew about the cosmos?
The mysterious force thought to be the number one reason why our universe is expanding and that which accounts for approximately 68 percent of the contents of the universe may not exist. Simulations have shown that dark matter—an unidentified type of matter distinct from dark energy, baryonic matter (ordinary matter), and neutrinos—may not exist after all.
New studies have driven researchers to suggest that ‘accelerated expansion’ of our cosmos can be explained without the need for dark matter. This, as reported by experts, is somewhat consistent with present observations and general relativity.
The new study—which was published in Monthly Notices of the Royal Astronomical Society—argues that mainstream models of the universe fail to understand and unravel the mysteries behind the changing structure of the cosmos.
Instead—experts argue—these models rely on approximations, assuming that matter must have a uniform density.
As explained by the co-author of the study Dr. László Dobos of Eötvös Loránd University: “Einstein’s equations of general relativity that describe the expansion of the universe are so complex mathematically, that for a hundred years no solutions accounting for the effect of cosmic structures have been found.”
“We know from very precise supernova observations that the universe is accelerating, but at the same time we rely on coarse approximations to Einstein’s equations which may introduce serious side-effects, such as the need for dark energy, in the models designed to fit the observational data.”
Using new computer simulations to recreate the effect of gravity on particles of dark matter across the universe, experts found out surprising results.
As explained by Science Daily, dark matter is now thought to make up 27% of the content of universe in contrast ‘ordinary’ matter amounts to only 5%.
To come to this conclusion, experts reconstructed the evolution of our universe. They took into account everything they thought existed when the universe came into existence, like the early clumping of matter and the formation of a large-scale structure. They found that unlike previous simulations which show a smooth expansion of the cosmos, the addition of this structure resulted in a model of the universe where different parts of it expand at a different pace.
The new Avera model that considers the structure of the universe and eliminates the need for dark energy and the Einstein-de Sitter cosmology, the original model without dark energy.
Interestingly, as noted by experts, the expansion rate of the universe remained the same with present observations, meaning that the universe is in fact accelerating.
Scientists concluded that DARK MATTER does not need to exist in order to explain the accelerated expansion of the universe. The universe can accelerate without it.
Dr. Dobos writes: “The theory of general relativity is fundamental in understanding the way the universe evolves. We do not question its validity; we question the validity of the approximate solutions. Our findings rely on a mathematical conjecture which permits the differential expansion of space, consistent with general relativity, and they show how the formation of complex structures of matter affects the expansion. These issues were previously swept under the rug but taking them into account can explain the acceleration without the need for dark energy.”
Above: A short animation that shows the expansion of the universe in the standard ‘Lambda Cold Dark Matter’ cosmology, which includes dark energy (top left panel red), the new Avera model, that considers the structure of the universe and eliminates the need for dark energy (top middle panel, blue), and the Einstein-de Sitter cosmology, the original model without dark energy (top right, green). The panel at the bottom shows the increase of the ‘scale factor’ (an indication of the size) as a function of time. The growth of structure can also be seen in the top panels. One dot roughly represents an entire galaxy cluster. Units of scale are in Megaparsecs (Mpc), where 1 Mpc is around 3 million million million km. Credit: István Csabai et al.
Source and reference: Explaining the accelerating expansion of the universe without dark energy
Featured Image: An image of the Milky Way Galaxy. Image Credit NASA