Researchers at Leider University in the Netherlands have analysed incoming light from over 33,000 galaxies to produce the first piece of evidence supporting a new theory of gravity. If fully validated, this theory would completely change our understanding of the nature of gravity and the wider universe.
When light passes near an object which exerts a large gravitational force, such as a galaxy, its path is bent and the light is distorted. This gravitational lensing effect was the main subject of the study. Astronomers viewed how light from distant galaxies was distorted by the gravity of closer galaxies, and created a ‘lens profile’ of the different galaxies which could then be compared with the profiles predicted by the two competing theories: the dark matter (DM) explanation (the currently accepted theory) and the entropic gravity (EG) theory (the new, alternative theory). The research concluded that both models give good approximations to the experimental results. This is the first time that experiments have tested this new EG theory, and it seems to have passed the test.
EG was first proposed in 2009 by Erik Verlinde, a Dutch theoretical physicist. The theory postulates that, in contrast with currently standing scientific theory, gravity is not a fundamental force but an emergent one – it can be explained by other forces. EG claims that gravity and spacetime are macroscopic consequences of the huge number of interactions between atomic and subatomic particles in large objects. This distinction predicts a much stronger gravitational force than currently accepted, but one that dies away much more quickly. This stronger gravity removes the need for dark matter, the mysterious, undetectable substance used to explain why galaxies hold together despite current models suggesting gravity as not strong enough to do this with visible matter alone. Indeed, the lens profiles EG predicted closely matched those recorded by the astronomers without the need to add in this dark matter.
Entropic gravity remains divisive among the scientific community. Whilst this new study shows the first signs of EG being consistent with reality, it by no means shows any inconsistencies with the currently held dark matter interpretation. A wide range of phenomena still need to be explored and experimented upon to determine if EG could be a serious contender for providing a more accurate theory of gravitation.
(featured image courtesy of ESA/Hubble & NASA, Public Domain)