Thursday, July 11, 2013

Quasars, homogeneity and Einstein

from Blank On The Map

People following the reporting of physics in the popular press might remember having come across a paper earlier this year that claimed to have detected the "largest structure in the Universe" in the distribution of quasars, that "challenged the Cosmological Principle". This was work done by Roger Clowes of the University of Central Lancashire and collaborators, and their paper was published in the Monthly Notices of the Royal Astronomical Society back in March (though it was available online from late last year).

The reason I suspect people might have come across it is that it was accompanied by a pretty extraordinary amount of publicity, starting from this press release on the Royal Astronomical Society website. This was then taken up by Reuters, and featured on various popular science websites and news outlets, including The AtlanticNational GeographicSpace.comThe Daily GalaxyPhys.orgGizmodo, and many more. The structure they claimed to have found even has its own Wikipedia entry.

The reason this paper got so much publicity is because of the claim that this structure violates the assumption of homogeneity. Is this true? Does the existence of such a large structure mean that the Universe is not homogeneous, the cosmological principle is wrong, and the foundation on which all of modern cosmology is based is shaky?