The actual length of a year is 365 1/4 days, this is the reason for the leap year every 4 years. However, why dont we notice the fact that we are 12 hours behind, 2 years after a leap year??? Shouldnt that mean that night would become day and day become night 2 years after a leap year?? If I am being an idiot I am sorry, it was my mates question and he no longer has access to yahoo answers? I will be giving best answer to the best answer. This is no joke!!
2007-06-01 02:19:12 · 9 answers · asked by Non Believer 2 in Science & Mathematics ➔ Astronomy & Space
The actual length of the year refers to the length of time required to complete one orbit of the Sun. The calendar year is measured in days, rotations of the Earth about its axis. What this does not mean, as your mate seems to think, is that between January 1st and December 31st is actually 365.25 days. What it means is that by the time December 31st comes round we have not quite completed one orbit. By the time December 31st comes round the following year we are slightly further behind in the orbit. However, the Earth has still rotated another 365 times, giving us 365 complete days.
If we take out the leap years, let's see what happens. Let's take January 1st this year as our starting point. After one calendar year Earth will be about 1/4 degree behind where it started at the beginning of the year. After four years it would be about a degree behind, roughly one whole day. After 8 years, 2 degrees. After 720 years it would be about 180 degrees away from where it began. Does this matter? Yes, because it would affect the seasons. Let's say it was winter in England when we started looking at Earth's position, as it is on January 1st every year. This is due to the tilt of the Earth's axis pointing the northern hemisphere away from the sun. Six months later, halfway round the orbit, 180 degrees, the northern hemisphere is tilted towards the sun and it is summer in England. But we've just said that after 720 calendar years with no leap years Earth would be 180 degrees away from where it started on January 1st. That means it would be summer on January 1st 2727. The summer solstice that year would be on December 21st, with the winter solstice on June 21st. Without leap years our seasons would cycle round with a period of 1440 years, and our solstices and equinoxes would move by one day every four years.
It is far easier to bung an extra day in every four years to allow Earth to catch up to its starting point than it is to have the seasons shifting around the calendar.
2007-06-01 02:46:11 · answer #1 · answered by Jason T 7 · 0⤊ 0⤋
1
2016-05-18 04:37:21 · answer #2 · answered by ? 3 · 0⤊ 0⤋
Here's how it is; the earth spins on it's axis like a top, which creates the night/day cycle. At the same time, the earth is making laps around the sun. It takes 365 1/4 days for the earth to make that lap.
Even though we don't make a full lap each year, the day/night cycle doesn't cange. By the time we get to a leap year, we need to use an extra day/night cycle to allow the earth time to complete the lap.
The day/night cycle is the reason we need leap years. We want to make sure that the time of day relative to the earth spinning remains the same. So we start the year at 12midnight on Jan 1, even though we haven't made a full lap around the sun.
It would be easier to explain with pictures, but I hope that helps
2007-06-01 02:32:25 · answer #3 · answered by wax 3 · 0⤊ 0⤋
The world rotates (spins on its axis) we call that day and night
The world revolves around the sun we call a complete circle a year the revolving earth is not completely matched with the rotating earth. hence the 1/4 day and leap every four years the man made calander must be corrected hence leap year. we do not loose any clock time at all. Your mate is a little daft by the way.
2007-06-01 02:32:19 · answer #4 · answered by mousehth72 5 · 0⤊ 0⤋
You are assuming that the extra time is distributed evenly over the length of the year. i.e. each day is slightly longer than 24 hours. This would cause a slight shift in how we measure day/night. Each day is still 24 hours (rotation of the earth). It's the length of time that the earth takes to revolve around the sun that gives us the extra six hours.
If we didn't have the extra day every leap year, you would begin to notice a shift in the seasons. i.e. after 182 years, summer and winter would be swapped. But individual day/night would be unaffected.
2007-06-01 02:29:32 · answer #5 · answered by Mark B 5 · 3⤊ 0⤋
Our 365 day year is a standard we imposed. They do not match nature. Our days are 24 hours, so we are not "thrown off". The adjustment we make each 4 years is to keep us in a match for our orbit around the sun. That is how we keep the equinox on the "correct" day.
2007-06-01 02:33:01 · answer #6 · answered by Treefrog 43 2 · 0⤊ 0⤋
one day = the time it takes the earth to rotate once around its axis.
one year = the time it takes earth to make one complete revolution around the sun.
day and night have to do with the earth's rotation on its axis and the year has to do with the rotations around the sun.
they don't happen to line up, nothing about the rules of science say they have to be.
2007-06-01 02:40:24 · answer #7 · answered by Shawn D 2 · 0⤊ 0⤋
Is that why I'm so tired today?
2007-06-01 02:27:23 · answer #8 · answered by shorty 6 · 0⤊ 1⤋
come to think of it, no
2007-06-05 00:53:10 · answer #9 · answered by robert T 2 · 0⤊ 0⤋