Well-defined Numbers That Are Not Precisely Known
Sagan's number is the number of stars in the observable universe. It is named in honor of Carl Sagan. This number is reasonably well defined, since we know what stars are and what the observable universe is, but its value is not known with any certainty (it is presently estimated to be approximately 70 sextillion (short scale)).
Sagan's number is unrelated to the bogus sagan unit or the humorous use of the term "sagan" to denote any large quantity.
Read more about this topic: Indefinite And Fictitious Numbers
Famous quotes containing the words numbers and/or precisely:
“I had but three chairs in my house; one for solitude, two for friendship; three for society. When visitors came in larger and unexpected numbers there was but the third chair for them all, but they generally economized the room by standing up.”
—Henry David Thoreau (1817–1862)
“People without imagination are beginning to tire of the importance attached to comfort, to culture, to leisure, to all that destroys imagination. This means that people are not really tired of comfort, culture and leisure, but of the use to which they are put, which is precisely what stops us enjoying them.”
—Raoul Vaneigem (b. 1934)