If I am not mistaken, one year is one full orbit by the earth around the sun. One year is also when the earth has gone through a full cycle of the seasons (summer winter spring etc) depending on your location on the Earth.
Is it just by coincidence that these two factors have the same time period? I mean, by the time the Earth has orbited the sun and come back to where it started, the seasons or tilting of the earth have finished their cycle at exactly that point. Is this just a coincidence or are these two factors somehow linked to each other in some way?
The middle of say, summer in a particular place is not exactly new years day, but the fact that the actual cycle lasts 365 and whatever days is my point. The season of summer starts a roughly the same time every year.
When was one year in our calender worked out and by who? Did they base it on the tilting of the Earth or the orbit? Also, given this information, what is today's definition of one year based on?
2007-09-21 23:59:55 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
the romans created our calander
it is 31557600 seconds = 365 1/4 days
it is designed to follow the seasons exactly.
it is so that we can predict the seasons.
that simple.
2007-09-22 02:33:15 · answer #1 · answered by Mercury 2010 7 · 0⤊ 3⤋
Yes, it is just a coincidence, because the two years you mentioned are not the same. Let me explain:
One full orbit by the earth around the sun takes 365 days, 6 hours, 9 minutes, and 9.54 seconds. Astronomers call this one sidereal year.
One full cycle of the seasons, on the other hand, takes 365 days, 5 hours, 48 minutes, and 45.22 seconds. Astronomers call this one tropical year.
What accounts for this difference? The answer is the precession of the earth's axis. Precession causes the vernal equinox to occur slightly earlier within its orbit each year.
I say this is a coincidence because if precession happened to have a much higher rate than what we have now, then the difference would be greater. Then we laymen would have to distinguish between the sidereal and tropical year instead of lumping both under the generic term "year".
(Btw, astronomically, you always have to specify what kind of year you are referring to. Simply saying "year" is meaningless because there are many are other kinds of years such as the anomalistic, draconic, heliacal, and eclipse years aside from the two I previously mentioned.)
2007-09-22 01:43:59 · answer #2 · answered by Bamm 2 · 3⤊ 1⤋
Yes. The Earths orbital period and the seasons have a very simple relationship due to the fact that the rotational axis of the Earth and the orbital axis of the Earth are not the same. The Earths rotational axis is 'tilted' at about 23 degrees to its orbital axis. This means that for half of its orbital period the Northern Hemisphere has a longer period of exposure to the Sun and the average temperature(s) are higher. For the other half of the orbital period the Northern Hemisphere has a shorter period of exposure to the Sun and the average temperature(s) are lower. The Southern Hemisphere is exactly the same only the 'Summer' and 'Winter' seasons are reversed with respect to the Northern Hemisphere.
Doug
2007-09-22 00:10:31 · answer #3 · answered by doug_donaghue 7 · 3⤊ 2⤋
Lets see if I can keep it simple (everyone else has tried)
It takes one year for earth to complete its journey around the sun. Marked by our position in relation to the stars at the beginning and end of the trip. Technically this came first.
The calender is a measure of time. Time is relevant. Man had to come up with a way to measure this trip around the sun, when to plant, when to harvest etc.
In doing so he noticed that this time could be broken down to measure between sun rises (or sunsets or high noon)
(a note here that the bible does mention the evening and morning were a day but I am not getting into definition of that here)
Then he noticed that it could be possible to divide the times between sunrises into smaller times.
All these ways of measuring time is based upon how you measure it. We today use clocks, calenders, counting of seasons etc. In days gone by it was water, sun shadow. moon phases. Men noticed that a certain number of moon phases took place between how the stars were and when they returned. Our tilt affects only our seasons but does not affect our year. In the time it has taken me to type this, the earth has moved thru space farther than the mind can count without scientific equipment.
2007-09-22 05:25:33 · answer #4 · answered by orion_1812@yahoo.com 6 · 0⤊ 0⤋
NO, the year was not based on the tilt of the Earth, or the orbit -- people long ago did not have those concepts.
People 20,000 years ago were able to count up to 365
days a year, if they had any smarts at all. At least the priests were able to count that high. And they could and did make note of where the sun rose on the horizon each day. In the summer it rises further north, and in the winter further south (if you're in the northern hemisphere).
The tricky part is that some years, it takes 366 days to go from northernmost dawn to northernmost dawn. Predicting those years was the basis for a lot of nature religion/ magic.
2007-09-22 03:02:28 · answer #5 · answered by morningfoxnorth 6 · 0⤊ 3⤋
where The hell did you get that idea!!
simply put seasons are cased due to rotation and revolution of the earth so seasons depend on the revolution of the earth not to mention the tilt in the axis
if the earth was say to stop at a single point we would have experienced the same season it wouldn't pass which rules any possibility of it being a coincidence I'm not sure about The answers of the 4th paragraph but i would say by studying the change in seasons as months passed people finally determined when a particular season would occur and your definition in the first paragraph is right.
2007-09-22 00:23:37 · answer #6 · answered by Anonymous · 1⤊ 2⤋
It is a coincidence in the sense that they always happen together but it's not a coincidence in the sense you mean (luck) because it is earths orbit of the sun that directly causes the seasons (as a result of earth being tilted on it's axis)
2007-09-22 00:55:03 · answer #7 · answered by Anonymous · 1⤊ 2⤋
The calender has been slowly improved over thousands of years. The first attempt was the building of stone circles to map the equinoxes and solstices. until they were fixed no one new exactly how long the year was.
The present day calender was adopted on the Julian /Gregorian changeover. These were the names of Popes who presided over the adoptions of updated calenders and on the last changeover 16 days were lost to bring the right number of days / month/year.
The tear is almost exactly 365.25 days and this is why we have a Leap year every four years to bring the calendar back into step.
2007-09-22 01:47:32 · answer #8 · answered by Anonymous · 1⤊ 2⤋
365 days
2007-09-24 02:59:36 · answer #9 · answered by Anonymous · 0⤊ 0⤋
Let's make it easy. 365 days?
2007-09-22 02:13:45 · answer #10 · answered by Anonymous · 0⤊ 2⤋