How many degrees does the earth spin through in one day? Simple question, you say! 360! Not so?

Question

Defined a day as the time it takes the Earth to spin from one sun's zeneth (highest point in the sky) to the next.

Whilst the Earth is spinning from zenneth to zeneth it is rotating round the sun. In the period of one day the earth moves through aproximately one degree of its orbit. Draw your own conclusions.

I do want some serious answers please.

Answer 1

An apparent sidereal day is the time it takes for the Earth to turn 360 degrees in its rotation; more precisely, is the time it takes a typical star to make two successive upper meridian transits. This is slightly shorter than a solar day. There are 366.2422 sidereal days in a tropical year, but 365.2422 solar days, resulting in a sidereal day of 86,164.091 seconds (or: 23 hours, 56 minutes, 4.091 seconds).

The reason there is one more sidereal day than "normal" days in a year is that the Earth's orbit around the Sun offsets one sidereal day, giving observers on Earth 365 1/4 days, even though the planet itself rotated 366 1/4 times (the Earth rotates in the same direction around its axis as it does around the Sun: seen from the northern sky, counter-clockwise).

Answer 2

If the earth turned 360 degrees in 24 hours, then if you start at noon in 6 months one should be looking out into space at noon - not towards the sun. Since the stars remained fixed in the sky - minus the earth's tilt - and in 6 months we are still looking st the sun - then the fixed stars must also be orbiting the galactic core at the same rate. You can not calculate the stars as a fixed point in space and then also say it rotates so it keeps the sun at a fixed point. The two are mutually exclusive of one another unless those fixed points are not really fixed points, or heaven forbid, we don't orbit the sun.

Think about what you are asking. You ask that in 6 months the earth is looking 90 degrees to its original position since at noon it still looks towards the sun, yet the same stars remained fixed in the sky minus the tilt of the earth?

Answer 3

The Earth turns 360 degrees in 23 hours, 56 minutes and 4 seconds with respect to the stars, which is called a sidereal day. It turns 360 degrees in 24 hours with respect to the Sun, which is called a solar day. The difference is due to the Earth's orbital motion, as you say. Another way to say it is that the Earth has to turn almost a degree more than 360 to complete a solar day.

Answer 4

Let's take your definition of day. A very important fact in this context is that looking down from the north pole, the earth rotates about its own axis in a clockwise direction while it revolves around the sun in anti-clockwise direction.
Hence, a point nearest to the sun at a particular instant rotates and after a day again comes nearest to the sun - before it completes one rotation.
Assuming earth's orbit to be circular, the centre of earth moves through approximately one degree along the orbit in one day. Hence, the angle covered by any point on the earth (with respect to the centre of earth) is 360 - 1 = 359 degree.

Answer 5

It's about 361. Without calculating more precisely, the earth does move about 1 degree around the sun in 24 hours (360 degrees / 365.25 days ~ 1 degree/day). So the earth rotates 360 degrees plus 1 more degree to get the sun back to the same spot in the sky.

Answer 6

Assume these figures to be correct:
Rotational velocity Equatorial : 465.11 m/s
Circumference: Equatorial :40,075.02 km
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so in 24 hours it rotates 40185.504 KM (in a 24 hour period)
so in a 24 hour day, the earth rotates 360.9924 Degrees.
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Differently. in 365 days the earth makes 365 rotations we can seen and 1 we do not notice, as it also travels once around the sun. We then have a total of 366 days in a year but only 365. taking a simple ration we can deduce that in a solar day we travel a little over 360 degrees (366/365) or about 360.986 degrees.

I would guess that the first value is more precise

Answer 7

It takes approx 365.25 days for the earth return to the same place in it's orbit around the sun (as measured bu the stars).

On each of those days, the earth had to spin 360 degrees to be lined up with the same stars, plus another 360/365.25 to be lined up with the sun, or just under 361.

Answer 8

Good point. I suppose it spins approximately three sixty plus three sixty five and a quarter divided by three sixty.
But it could be the other way around. I'm not sure which direction the earth orbits in relation to it's rotation.

Answer 9

Sidereal rotation period (hrs) 23.9345

rotation degrees is then 360.985 deg in 24 hours

Answer 10

365 degrees, I don't know. I'm not a math dude!

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