Scientists were able to prove Albert Einstein's theory of general relativity on an astronomical scale for the first time. By being able to prove the existence of general relativity scientists were able to prove our current understanding of gravity is correct and more evidence for the existence of dark matter and dark energy.
Einstein published his theory of general relativity in 1916.
Proving Einstein's General Relativity
A research team led by Thomas Collett of the University of Portsmouth published the results of the study in the journal Science. Researchers were able to use the MUSE instrument on the European Southern Observatory's Very Large Telescope. They were able to calculate the mass of ESO 325-G004 by measuring the movement of the stars that were inside of a nearby galaxy.
They used the VLT to see the speed of the movement of the stars with ESO 325-G004. By using this data they were able to determine the amount of mass needed to hold these stars inside the orbit of the galaxy. Researchers were also able to observe how much spacetime is being distorted by the mass of the galaxy.
They were able to observe an Einstein ring made by the light of a different galaxy that was being distorted by ESO 325-G004. This is proof of Einstein's theory of general relativity, the theory states that objects are able to bend spacetime which causes light that passes to be deflected. This is also the cause of gravitational lensing, this is the closest instance of gravitational lensing found in space. It is 450 million light-years away from Earth.
General relativity has been tested in other instance but this is the largest tests that have taken place so far. Scientists performed this tests by knowing the mass of ESO 325-G004 from previous observations and then measuring the gravitational lensing that was being caused by using the Hubble Space Telescope.
Alternative Theories To General Relativity
Other theories have been proposed for the expansion of the Universe. These other theories would do away with dark matter and dark energy altogether. The other theories predict that the effects of gravity on the curvature of spacetime are scale dependent. This would suggest that gravity behaves differently depending on the scale of the object that it is affecting.
Other theories such as the nonsymmetric gravitational theory also do away with dark matter. Collett says that even though they can prove general relativity researchers are not able to prove the existence of dark matter and dark energy. He goes on to say that the study adds additional evidence to their existence.