A new model of the universe suggests dark energy doesn’t exist.
A team of American and Hungarian scientists believe that current models of the expanding universe fail to take into account its changing structure, and that once you do, the need for “dark energy” in the expansion model disappears. Dark energy is the mysterious energy thought to make up some 68% of the universe. The researchers have published their findings in a paper in Monthly Notices of the Royal Astronomical Society.
The universe was formed some 13.8 billion years ago during the Big Bang, and since then, it has been expanding at an ever increasing rate. Scientists model this expansion after something called Hubble’s law, which is based on observations of galaxies in different places around the universe. On average, the speed at which galaxies are moving away from us is proportional to their distance from us. This speed can be measured in something called “red shift”. Red shift is a phenomenon in which light shifts to a more reddish hue the faster it’s moving away from us. This is essentially a visual version of the doppler effect, the phenomenon which is responsible for why sirens sound different as they’re approaching or moving away from you.
Since the 1920’s, scientists have used red shift to determine that the universe is continually expanding, faster and faster, and that the expansion can be traced back to an origin in a single point. During the 20th century, our understanding of the universe expanded as well, and we concluded that matter only makes up about 5% of the universe’s composition, with dark matter accounting for some 27%, and dark energy taking up the remaining 68%. Almost nothing is known about dark energy, and it has been theorized in order to explain why the universe’s expansion is speeding up.
Phd student Gábor Rácz of Eötvös Loránd University in Hungary claims that the current models of the expanding universe relies heavily on approximations, and assuming that matter is distributed uniformly, which in’t the case in reality. He questions if dark energy even exists, and that modelling the universe with structures in mind, removes the need for dark energy.
“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.” explains Dr László Dobos, co-author of the paper, also at Eötvös Loránd University.
The research team created a new model of the universe which does take structure into account, and achieved results which differ a lot from the conventional expansion model. The universe expanded at different rates in different regions, based on the density of matter, but the overall expansion rate is consistent with observations. If the findings are upheld, it could mean significant changes in cosmology and how we see the universe.