When I was a student at Trinity College, Cambridge, in the 1950s, Sir Isaac Newton's presence was still almost palpable. - John Moffat

Indeed, there is a now a minority of cosmologists who question a beginning of the universe at all; instead they favor a cyclic model with a series of expansions and contractions.

To physicists such as myself, the huge amount of invisible dark matter needed to make Einstein's theory fit the astrophysical data is reason enough for exploring modified gravity theories.

Today, like the elusive planet Vulcan in the nineteenth century, dark matter is accepted by the majority of astronomers and physicists as actually existing. Dark matter, although it has never been seen, is part of the generally accepted standard model of physics and cosmology, which also includes the big bang beginning of the universe.