Do'es The Sun Rise Quicker Than it Sets. As the Earth Rotates and Orbit's the Sun, Hence a Leap Year ?

Question

I really want to know which it is, Morning or Evening. If we lose 4 mins every day It either must "Rise qicker" or "Set quicker"
And Remember the Earth rotates on it's Axis and it Orbits the Sun.
Paradox.

Answer 1

You are quite correct in advising us to remember that the earth rotates on its axis and around the sun. Exactly here lies your own answer to the question.

They are each separate issues.

TO CLARIFY :
Let me refer to daily spin as "rotation", and yearly movement round the sun as "orbit."

Movement relative to the stars is not involved in the current question. Nor is the shape of the orbit.

Day/night and sunrise/sunset are governed solely by the speed of rotation of the earth about its own axis, relative to the visible position of the sun. This is precisely 24hours, give or take the leap-second which is occasionaly needed.

Summer/Winter and height of the sun's apparent course across the sky is governed solely by the orbiting of of the earth around the sun. Specifically it relates to the fact that the axis of the daily rotation is tilted relative to the axis of the yearly orbit,and this tilt does not change in space as the earth orbits round the sun.
The result of this is that in June the Nothern half of the earth is tilted toward the sun, causing the daytime sun to be high in the sky, more warmth and "Summer".
In December the opposite ...."Winter".

The orbit round the sun takes approximately 365 1/4 times as long as the 24 hour rotation.

If there was an exact whole number of 24-hour days in the time of the orbit round the sun, then the leap-year would not arise. Imagine before the era of digital wristwatches, a farmer planting the crops on a particular day each 365-day year. When he was 80 years old he would end up planting them three weeks earlier relative to the growing seasons than when he was a child. He could starve.

IN SHORT :
The leap year is a practical real-life necessity to make the daily calendar fit real life.
The rate of rotation and time to orbit do not change.
The leap year is simply a way of managing the fact that 365 solar days is not quite a whole solar year, but 366 days would be too long.
No time is ever actually lost, gained, nor needs made up. The solar day (defined for example by the highest point of the sun at noon) remains constant at 24 hours. The sun never needs to rise and set early nor late, faster nor slower.


BUT :
Of course nothing is ever quite black and white. The speed of rotation varies with the moon. The axis of rotation does move in space (but takes thousands of years). I think I recall that solar flares/solar wind have their effects, as does gravity from the other planets.

However for all day to day purposes all the above is as true as it need be.
If you became an astronomer etc, where such miniscule variations counted, then you wouldn't need my input.

HOWEVER :
If your question is not intended as I and everyone else have read it, look for explanations from http://csep10.phys.utk.edu/astr161/lect/time/timekeeping.html
or http://www.sun.rhbnc.ac.uk/~uhap045/290/290note3/290note3.html
or any other site produced by searching for "sidereal day"

IN FACT :
I MAY HAVE JUST UNDERSTOOD YOUR QUESTION!
Quoted from the second of these references -

"NB. The Solar Day is longer than the Sidereal day since the orbit motion requires further rotation of the Earth for the former.
Orbital motion is 360 degrees in 365.25 days ~1 degree /day. Therefore rotation by ~361 degrees is needed for a solar day. Since 1 degree ~4 min so a Sidereal Day ~23 hr 56 min of solar time."

So the apparent motion of the sun is slower than that of the stars, so it BOTH rises AND sets slower than the stars do.
So both rising and setting are AT THE SAME SPEED AS EACH OTHER.

None of this, as explained above, has anything to do with the Leap Year. We see 365 1/4 apparent revolutions of the sun per year, we see 366 1/4 apparent revolutions of the stars per year.

If this is still wrong, I give up.

Answer 2

ok,,,, i'm not sure what you mean exactly by having a sun rise or set quickly or slowly. a sunrise is not an actual occurrence. it's only something that looks a certain way from earth. --- uhm,,,, i really don't know how to go about answering your question other than by saying that's just not the way things work.

leap year has nothing to do with sunrises or sunsets (or daylight saving). the earth takes a specific amount of time to make a complete revolution around the sun, and that amount of time is roughly 365 days and 6 hours.

but it would be kinda weird if we had a december 32nd that only lasted 6 hours long, and then everybody yelled "happy new year" just as the sun was coming up. then, for that whole year, midnight would always be right around when the sun would be rising, and new year's would come when the sun was directly above of us. you follow??? ---- this would be a silly way to do things.

similarly though,,,, we can't just ignore the extra 6 hours. otherwise, after 730 years, we'd be celebrating the 4th of july in the snow and christmas in the warm sun.

so,,,, how we fix it is,,,,, we ignore the extra 6 hours for three years straight. (and this means were 18 hours behind), then on the fourth year, we go ahead and observe the 6 hours along with the 18 hours we already missed. (that's 24 hours total.,, a complete day)

since it's only ROUGHLY 6 extra hours per year though, it's a little more complicated than that.

we observe leap year on any year that is divisible by 4 (i.e. - 1980, 1984, 1988, 1992, 1996, etc)

UNLESS that number is divisible by 100 (i.e. - the 1700, 1800, 1900, etc). and on these years we DO NOT observe leap year,,,

UNLESS the number is also divisible by 400 (i.e. - the year 1600 and 2000, etc) in which case we DO observe leap year.

Answer 3

The sun rises and sets because the earth is rotating at a steady rate. It does not speed up or slow down at a sunrise or sunset. (That is an absurdity. If it rose quicker in New York, that means it would have to be setting quicker half-way around the globe.)

The reason we have a leap year is because the earth actually takes approximately 365 and 1/4 days to revolve around the sun. Rather than start a new year 1/4 day later each year, the 1/4ths accumulate until there are 4/4ths which equals 1. (Imagine starting the New Year at 6:00 a.m., then noon, then 6 p.m., and so on. . . .) Thus, one day is added to the calendar every four years. Not to do so would mean that the seasons and the New Year would get really screwed up after a while on our calendar. It's a practical solution to the inconvenient amount of time a complete revolution around the sun takes.

Answer 4

Neither. The sun rises and sets at the same speed, which is determined by the rate at which the earth rotates (spins on its axis). The earth rotates once every 23 hours 56 minutes, so the stars return to the same position in the sky in that length of time.

But while the earth is rotating, it is also moving around the sun. This orbital motion means the sun has appeared to shift its position against the distant stars. The earth must rotate an additional 4 minutes to bring the sun back to the same position in the sky (relative to the horizons). We use this time, 24 hours, to measure a day.

Leap years occur because it takes the earth about 365.25 days to orbit the sun. After a "year" of 365 days, the earth has not quite completed an orbit. Every four years, we a one day short of completing four orbits, so we add a leap day to let the earth "catch up with the calendar."

No paradox!

Answer 5

Neither. Or both. Here's what I mean:

The reason for a leap year is that during a solar year (the amout of time for the earth to make one complete revolution about the sun), the earth rotates about 365 1/4 times (365 1/4 days). So, every 4 years, we add in an extra day to keep the calendar in line with the earth's revolution.

The exception is that when the 4th year ends in a zero (such as the year 2000) we do not have a leap year. That's because adding one day every 4 years would be just a bit too much. And actually, that doesn't quite do it. With this system, we're still off by 1 day in 8000 years, and people are trying to figure out how to deal with that.

So we need leap years because there is not a whole number of rotations that occur during a revolution. The leap year helps us deal with this inconvenient fraction in our calendars.

Answer 6

The apparent rising and setting of the sun are the same speeds through out the year. The solar day is 4 minutes shorter than the sidereal day. (because we have moved further along in the orbit around the sun as we spin.) Our orbit around the sun is not a circle but an ellipse. In july we are actually farther away from the sun. We are closer in January. Due to the laws of moving bodies in an ellipse orbit, when we are closer to the sun we move faster around the sun so the (gets technical here) area covering vector covers the same amount of area all the time. But sunrise and sunset do not change speeds.

Answer 7

The earth rotates at a constant rate and therefore the sun raises at the same rate as it sets. The leap year is the same as a rounding issue in mathematics. Somehow you need a way to handle the fraction extra. There is just a bit more than an even rotation but not enough to make a significant difference in a year.

Answer 8

The rotation of the earth and the orbit around the sun are constant. They don't speed up or slow down. The lenth of time for the earth to orbit the sun is 365.25 days. It is impractical to keep up with a quarter day each year. So, we just add the extra day every 4 years.

Answer 9

Whoa, go back to school The sun does not move, we do, it is called revolution. We don't lose 4 minutes every day. This time of the year we start losing daylight and that is because of the tilt of the earth and it's relationship to the sun.

The earth moves at a constant speed.

Answer 10

no, leap year makes up for the fact that each year is EXACTLY 365.25 days long. but.. since no one wants to mark a fourth of a day on their calender, they wait four years, and add an extra day.

the sun goes the same. considering it doesnt set until its halfway done cuz before then it would be rising so theres really no question of it being faster or slower.

Answer 11

The earth and the sun do what they do perfectly. I think that the problem you have raised only exists because we can't subdivide the four year cycle exactly, so we have to fine tune every four years. It represents the correction of an accumulation of miniscule errors. Remember, we humans can't even measure the area of a circle exactly.