# Why are there 24 hours in a day?

**URL:** https://boards.straightdope.com/t/why-are-there-24-hours-in-a-day/261921
**Category:** Factual Questions
**Created:** [August 28, 2004, 6:41am UTC](https://boards.straightdope.com/t/why-are-there-24-hours-in-a-day/261921 "2004-08-28T06:41:10Z")
**Posts on this page:** 1
**Page:** 2

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### Author: ![UDS](https://avatars.discourse-cdn.com/v4/letter/u/ecae2f/32.png) [@UDS](https://boards.straightdope.com/u/UDS)
#### Post date: [August 30, 2004, 1:28am UTC](https://boards.straightdope.com/t/why-are-there-24-hours-in-a-day/261921/21 "2004-08-30T01:28:47Z")

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> [@Rubystreak](#):
>
> [There was a fascinating study done at Purdue](http://www.innovations-report.de/html/berichte/biowissenschaften_chemie/bericht-15508.html) regarding the biological basis for the 24 hour day schedule. Cells grow in 12 minute intervals, then rest for 12 minutes, and these reactions are apparently governed by a single protein. Thus, the 24 hour day is not merely a human construct; it appears to be hard-wired in most living organisms on the planet . . .

. . . because, of course, the minute is a fundamental constant of the universe, and not at all a human construct. :smack:

Cells only work on 12-minute cycles because we have _already_ divided the day into twenty-four hours of sixty minutes each. If we divided the day into 20 “hours” of 100 “minutes” each, then cells would work on approximiately 17-“minute” cycles. Would this prove anything about the number 17?

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