In Science
- The atomic number of protactinium, an actinide.
- McCarthy 91 function, a recursive function in discrete mathematics
In astronomy,
- Messier object M91, a magnitude 11.5 spiral galaxy in the constellation Coma Berenices
- The New General Catalogue object NGC 91, a single star in the constellation Andromeda
- The Saros number of the solar eclipse series which began on August 6, 159 BC and ended on 1175 October. The duration of Saros series 91 was 1334.2 years, and it contained 75 solar eclipses.
- The Saros number of the lunar eclipse series which began on 161 May and ended on 1459 July. The duration of Saros series 91 was 1298.1 years, and it contained 73 lunar eclipses.
Read more about this topic: 91 (number)
Famous quotes containing the word science:
“But don’t despise error. When touched by genius, when led by chance, the most superior truth can come into being from even the most foolish error. The important inventions which have been brought about in every realm of science from false hypotheses number in the hundreds, indeed in the thousands.”
—Stefan Zweig (18811942)
“Political liberty, the peace of a nation, and science itself are gifts for which Fate demands a heavy tax in blood!”
—Honoré De Balzac (1799–1850)