Einstein is safe
An international research team with researchers from KTH and Stockholm University have been able to establish that the speed of light through space is exactly the same at both high and low energy levels. Accordingly, that aspect of Einstein’s relativity theory is still correct. The research results can, in turn, lead to an improved understanding of the structure of the universe.
Over a long period of time, Einstein’s relativity theory and quantum mechanics have to some extent found themselves on a collision course. One of the cornerstones of relativity theory is namely that the speed of light in a vacuum is constant, irrespective of light’s energy. According to quantum mechanics, it is not certain that this is true at really high levels of energy.
In order to test this, the international research team used observations made with the slightly more than one-year-old Fermi satellite to measure the radiation from a cosmic explosion, a so-called gamma-ray flash.
The advantage of these gamma-ray flashes is that they are so bright that they can be seen at enormous distances, several billions of light years away. This makes them excellent test objects to examine whether the speed of light varies.
“The study shows that the speed of light is still constant. The research is also an important aspect of the work towards understanding the universe better, and is the first time anybody has measured radiation in gamma-ray flashes so thoroughly as we have done,” says Felix Ryde, Docent in astroparticle physics at KTH.
“Seeing as light travels such a long way we can detect very small differences in the speed between different energies,” says Magnus Axelsson, astronomer at Stockholm University.
He adds however that the observations made do not show any signs of this. So Einstein’s almost 100 year assumption still stands.
Magnus Axelsson and Felix Ryde both belong to the group of Swedish scientists that are participating in the international cooperation relating to the Fermi satellite. The latest results are regarded as extremely important and the research was published yesterday in Nature, the scientific journal.
For more information, contact Felix Ryde at felix@particle.kth.se or 08 - 55 37 85 45.
Magnus Axelsson at Stockholm University can be reached at magnus.axelsson@astro.su.se or 08 - 55 37 85 15.
Read the article on Nature´s website
Peter Larsson