But unlike dark energy, there are several ideas about what it might be, and one of them is the subject of a second paper, in Physical Review Letters, by Peter Biermann of the University of Bonn, in Germany, and Alexander Kusenko, of the University of California, Los Angeles.

ECONOMIST: Research from the beginning of time

When GMP moved into their new glass-fronted headquarters recently, Sir Peter asked that the principles of Sir Robert Peel be written on the windows in letters that can be read 50m away.

BBC: The police are the public and vice versa

Peter Higgs, eponymous predictor of physics's missing boson, faced similar trouble with Physics Letters.

ECONOMIST: An academic journal provides haven for rejected work

Since only three letters from Walker have been found, she comes alive through Peter and Susan's letters and their family papers, as well as through the Cameron family papers and the archives of Boston abolitionists.

WSJ: Book Review: To Free a Family