Skip to main content
Physics

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

5
  • 123
    $\begingroup$ This reminds me of a joke : Some tourists visit the great pyramids in Giza. The guide tells them that the pyramids are 4504.5 years old. Tourists are impressed by this precision, and ask the guide how it was calculated : "That's very simple, I've been working for 4 and a half years here, and the pyramids were 4500 years old when I started". $\endgroup$ Commented Apr 24, 2018 at 7:07
  • 7
    $\begingroup$ How big is your error? $\endgroup$ Commented Apr 24, 2018 at 7:46
  • $\begingroup$ For most of the cases the error in determining the halflife on big year scales is bigger than the one you introduce by using "the wrong" year length to calculate it back. $\endgroup$ Commented Apr 24, 2018 at 9:09
  • 2
    $\begingroup$ Your question switched from years to days. The difference between sidereal and solar days is about 1/365.25, but the difference between sidereal and tropical years is about 4e-5, or 1/26000, and the reason for the difference is unrelated. $\endgroup$ Commented Apr 24, 2018 at 12:35
  • 3
    $\begingroup$ I recall, back around 1966, a college prof who liked to approximate it as pi * 10**7. $\endgroup$ Commented Apr 26, 2018 at 1:59