Einstein entertained counterintuitive notions that allowed him to pull physics from the mechanistic, clockwork universe of the eighteenth century up … - John Moffat

This is an extraordinary time in the history of science, in that we cannot only theorize about the beginning of the universe, but actually study the celestial fossils of how it happened.

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.

The eighteenth-century German philosopher Immanuel Kant had conjectured that Messier's nebulae were distant "island universes" outside our Milky Way galaxy, but many scientists in the early twentieth century disagreed.