7 years and 5 day

The time will come when diligent research over long periods will bring to light thingswhich now lie hidden. A single lifetime, even though entirely devoted to the sky, would notbe enough for the investigation of so vast a subject . . . And so this knowledge will beunfolded only through long successive ages. There will come a time when our descendantswill be amazed that we did not know things that are so plain to them . . . Many discoveriesare reserved for ages still to come, when memory of us will have been effaced. Ouruniverse is a sorry little affair unless it has in it something for every age to investigate . . .Nature does not reveal her mysteries once and for all