More than a century after Albert Einstein postulated the theory of general relativity, the astronomers, helped by the Hubble Space Telescope and the Very Large Telescope (VLT), have made it possible to accurately test Einstein’s most famous theory outside the Solar System. More specifically, the scientists focused on focused on the ESO325-G004 galaxy which is 450 million light years from Earth and is one of the nearest gravitational lenses.
This galaxy has offered a unique opportunity to test Einstein’s theory of general relativity on a galactic scale, that is, over a range of distances of about 6,000 light years or about 10,000 billion kilometers.
The ESO325-G004 galaxy acts as a lens for another galaxy behind it, more than 10 billion light-years away.
Astronomers have calculated the total mass of the galaxy in the foreground as a function of the rotation speed of its stars, something that had not been possible until now with another 200 gravitational lenses known to be much further away.
The type of Einstein Ring (see the image below) that should be formed on the basis of general relativity was then calculated.
The Einsteins’ theory of general relativity proved correct on a galactic scale
The result, published today in the journal Science, provides the value of the constant “γ” that expresses the curvature of space-time as a function of the mass of a body.
The results of the study show a value of 0.97 with a margin of error of 0.09 above or below, consistent with the value of 1 assigned by the theory of general relativity.
“It is very interesting that the theory of general relativity, which was formulated based on the motion of planets in the Solar System, describes the behavior of the Universe at much larger scales perfectly,” pointed out Thomas Collett from the University of Portsmouth, UK, and the study’s leading author.
Also, dark matter and dark energy, two components of the Universe, that are not yet fully understood, seem to have an important role for the Einstein’s theory of general relativity. However, some question the standard model precisely because of the existence of dark matter and energy and the lack of scientific knowledge on these two components.