5 (number)

:This article discusses the number five. For the year 5 AD, see 5. For other uses of 5, see 5 (disambiguation)

In science

• The number of appendages on most starfish, which exhibit pentamerism.
• Almost all amphibians, reptiles, birds and mammals which have fingers or toes have five of them on each extremity.
• The maximum category on the Saffir-Simpson Hurricane Scale, the most damaging.
• The atomic number of boron.

In astronomy

• Messier object M5, a magnitude 7.0 globular cluster in the constellation Serpens.
• The New General Catalogue object NGC 5, a magnitude 13 spiral galaxy in the constellation Andromeda
• The Saros number of the solar eclipse series which began on April 4, 2720 BC and ended on May 24, 1422 BC. The duration of Saros series 5 was 1298.1 years, and it contained 73 solar eclipses.
• The Saros number of the lunar eclipse series which began on -2581 October 8 and ended on -1084 March 24. The duration of Saros series 5 was 1496.5 years, and it contained 84 lunar eclipses.