Leap years

[ducey99]

Is 2006 a leap year?

[stevie21]

only if you can divide 2006 by 4 and not get any remainders or fraction in your answer.

In brief, that's a "no".

[Gef]

In other words the next leap year is 2008.

[KebabMeister]

Easy way to remember that the end (or beginning as others may say) of each century, i.e. 1900, 2000 etc. is always a leap year. Simply add 4 onto it to find the next leap year.

[Loosehead]

No Kebab, a century is not a leap year unless it is divisable by 400 so 1900 was not a leap year 2000 was.

[KebabMeister]

Show's how good my astronomy professor is! doh!

[stevie21]

If a year (as defined by the earth's movement) lasts 365 and a quarter days (I'm sure I've read this somewhere) then I'm not sure I understand why 1900 isn't a leap year.
I mean, I know that it wasn't as I've read it but I don't get the logic behind it. Wouldn't that mean that 1896 was and 1904 was and that there was an 8 year gap?

Anyone?

[mibn2cweus]

The year last ~365.2422 days and getting longer!

[mibn2cweus]

http://en.wikipedia.org/wiki/Leap_year

[Loosehead]

As pointed out by mibn2cweus the year is slightly less that 356 and a quarter so by having an extra day every leap year we are slightly over correcting. This is rectified by not having a leap year on centuries but this too over corrected the other way so by having them on centuries that are divisible by 400 the current system is effective at preventing season drag/appreciation. The excelllent book "The Calendar" by David Ewing Duncun charts the history of this process.

[Loosehead]

That's 365 doh!

[mimififi]

er.... I thought,

1900/4=475.

Don't see any remainder there. Pointed out adequately by stevie, but I thought I'd labour the point. Jump to the defence of an astronomy prof. Go prof!

[Gef]

mimififi a century year has to be divisible by 400 to give an integer. 1900 / 400 = 4.75, so it is not a leap year.

[stevie21]

OK, so in summary, a planetary year isn't actually (and exactly) 365.25 days.

Have we established this so far? It's very slightly out so that every gawd knows how long, they have to adjust it by a millimetre!

[mibn2cweus]

. . . . .1596, 1600, 1604, 1608, 1612, 1616, 1620, 1624, 1628, 1632, 1636, 1640, 1644, 1648, 1652, 1656, 1660, 1664, 1668, 1672, 1676, 1680, 1684, 1688, 1692, 1696, 1704, 1708, 1712, 1716, 1720, 1724, 1728, 1732, 1736, 1740, 1744, 1748, 1752, 1756, 1760, 1764, 1768, 1772, 1776, 1780, 1784, 1788, 1792, 1796, 1804, 1808, 1812, 1816, 1820, 1824, 1828, 1832, 1836, 1840, 1844, 1848, 1852, 1856, 1860, 1864, 1868, 1872, 1876, 1880, 1884, 1888, 1892, 1896, 1904, 1908, 1912, 1916, 1920, 1924, 1928, 1932, 1936, 1940, 1944, 1948, 1952, 1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052, 2056, 2060, 2064, 2068, 2072, 2076, 2080, 2084, 2088, 2092, 2096, 2104, 2108, 2112, 2116, 2120, 2124, 2128, 2132, 2136, 2140, 2144, 2148, 2152, 2156, 2160, 2164, 2168, 2172, 2176, 2180, 2184, 2188, 2192, 2196, 2204, 2208, 2212, 2216, 2220, 2224, 2228, 2232, 2236, 2240, 2244, 2248, 2252, 2256, 2260, 2264, 2268, 2272, 2276, 2280, 2284, 2288, 2292, 2296, 2304, 2308, 2312, 2316, 2320, 2324, 2328, 2332, 2336, 2340, 2344, 2348, 2352, 2356, 2360, 2364, 2368, 2372, 2376, 2380, 2384, 2388, 2392, 2396, 2400, 2404, 2406, 2408, 2412, 2426,2420, . . . Any more questions?

[mibn2cweus]

Yeah, Who messed with the bottom line?

[mimififi]

fairynuffsky. I'm not an actual mathematician, so I'll humbly take your word for it Gef!

Sorry.

[MarkyP05]

yeah Loosehead is got it spot on, 'year' as defined by a complete orbit of the sun is actually slightly less than 365 and 1/4 days and so to recorrect our calender to co-inside with the earths (so that everything doesn go out of sync) we made every century not a leap year unless iits divisable by 400.

[makinsonc]

no ficko 2006 is not a leap year