Dear stupid: how many times does the earth rotate in a year?

[Foxaèr]

You're being really silly now. If a piece of science is described in a novel, that doesn't make it a fiction. You might just as well call Laundromats ficticious because they appear in some movies.

Then by all means, provide a scientific link that supports the theory purported by the work of fiction.

[Alex K]

You're being really silly now. If a piece of science is described in a novel, that doesn't make it a fiction. You might just as well call Laundromats ficticious because they appear in some movies.

Then by all means, provide a scientific link that supports the theory purported by the work of fiction.

Maybe later, I don't want to spoil Aractus' poll. In the meantime, I'll just annoy everyone with obscure references and a knowing smile.

[ignoramus]

I hate tricky questions! But I learn from them.

[I_am_not_mafia]

This poll needed more silly answers. I chose 'depends how you define a year' but it wasn't particularly satisfying in terms of silliness.

[Aractus]

The correct answer for an orbital year is 366.242. There are two further correct answers that so far no one has picked: 366 times in a calendar year, and 367 times in a leap year. Of course those are not exact, but they are correct if rounded. Below I will give you the exact amounts.

First I'll explain how the orbital year is calculated. The earth rotates in the same direction as its orbit. The moon actually does this as well, and it takes 27 days to complete an orbit of the earth. Thus the length of a day on the moon is 27 Earth days. However if the Moon was a planet and the Earth was a star, then it would have daylight shining permanently on the one half of the planet that faces the Earth-star (the near-side of the moon), and the far side of the moon would experience permanent darkness. If it were to rotate twice per orbit, then it would experience one day per orbit. If it rotated three times, it would have two days, and so on. If it rotated 366.242 times it would have 365.242 days.

Next we can calculate how many times the earth rotates in a calendar year. The answer I've provided is 366, but of course it's not quite 366 because we know the earth has to rotate an extra 1/365.242th to experience each day (3 minutes and 56.555 seconds). The calendar year is 0.242 days short of a full year, meaning the total rotation is 366 minus 0.242 * 1/365.242. So the exact answer is 365.9993374... The final correct answer is the number of times the earth rotates in a leap year. Again, a leap year is defined as 366 days, but it is 0.758 days longer than an orbital year, and therefore the the Earth rotates a total of 367 + 0.758 * 1/365.242 times in a leap year, giving an exact answer of 367.002075...

[madog]

The correct answer for an orbital year is 366.242.  

I am not trying to be clever as I am asking from ignorance but I thought the earths rotation was inertia and wondered if the earth was actually Physically rotating? ...  

[Alex K]

Short answer: While we see 365.x days on earth during one revolution of earth around the sun, the earth actually did one more rotation in that time, 366.x, but the additional full rotation wasn't visible as another sunset and sunrise on earth because we went round the sun in the same direction once, and hence it isn't counted as an additional day.

In Verne's "Around the World in 80 days", the protagonists think they lost their bet because they counted 80 sunsets and sunrises during their travels and thought that therefore, 81 days had passed. They forgot that, by going around the earth once in the direction of its rotation, they saw one more sunset and sunrise than observers in London, and thus had in reality only spent 80 days on their travels and the bet was won. In the present question, the opposite happens.

[Alex K]

The correct answer for an orbital year is 366.242.  

I am not trying to be clever as I am asking from ignorance but I thought the earths rotation was inertia and wondered if the earth was actually Physically rotating? ...  

I don't know what you mean by "earth's rotation being inertia". Can you elaborate?

[madog]

I am not trying to be clever as I am asking from ignorance but I thought the earths rotation was inertia and wondered if the earth was actually Physically rotating? ...  

I don't know what you mean by "earth's rotation being inertia". Can you elaborate?

This was taken from Universe Today ... link below ....

"Without any unbalanced forces acting on them, the inertia of the Sun and the planets have kept them spinning for billions of years.

And they’ll continue to do so until they collide with some object, billions or even trillions of years in the future."

http://www.universetoday.com/14491/why-does-the-earth-rotate/

The way I always understood it was that things just kept going after their initial evolution through inertia (a tendency to do nothing or to remain unchanged.) and nothing was actually physically acting upon them? 

I just brought it up as I thought it might have been a trick question ...

[Alex K]

I don't know what you mean by "earth's rotation being inertia". Can you elaborate?

This was taken from Universe Today ... link below ....

"Without any unbalanced forces acting on them, the inertia of the Sun and the planets have kept them spinning for billions of years.

And they’ll continue to do so until they collide with some object, billions or even trillions of years in the future."

http://www.universetoday.com/14491/why-does-the-earth-rotate/

The way I always understood it was that things just kept going after their initial evolution through inertia (a tendency to do nothing or to remain unchanged.) and nothing was actually physically acting upon them? 

I just brought it up as I thought it might have been a trick question ...

It depends on how far down the Rabbit Hole one wants go to. In Newtonian physics, the earth rotates about its axis and its parts are kept from flying away in a straight line by the forces holding together the matter, and the gravitational attraction. In Einsteinian terms, things are very complicated because gravitation is not a force and there is not much that clearly separates rotating observers from non-rotating observers. But keeping with Newtonian Physics, there are the forces binding Earth together as a Rock, and those act on its parts and let it spin about its axis as a solid body. The fact that this rotation keeps going is indeed attributable to inertia, but that still makes the resulting rotation a physical change of the body.