What are Earth's and Neptune's rates of rotation?

Answer 1

One revolution in 23 hours 56 minutes, or 3.988888 degrees per minute.

Answer 2

Because Neptune is not a solid body, its atmosphere undergoes differential rotation. Thus:-

The wide equatorial zone rotates at a period of about 18 hours,

The polar regions the rotation period is about 12 hours.

Its magnetic field rotates in 16H 6 MIN 36 SEC

Its orbit around the sun (Neptunian Year) is 60,190 earth days or about 164.79 earth years.

Answer 3

About 18.5 miles per second. (mean velocity of 29.78 kilometers per second)

This is about 66,600 miles per hour.

Go figure: approximate distance to Sun = 93 million miles (to center of the Sun)

so for a circular orbit, the distance length would be 186 x pi million miles = 584,336,000 miles

Divide by 365.25 days, 24 hours a day, 3600 seconds per hour, is about 18.6 miles per second.

Since it's an ellipse, the distance of the Earth to the Sun changes, as well as it's speed around the Sun. Some months it's moving faster than others. But the average (mean) speed is 29.78 km/sec.

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* By the way, the speed of the solar system around the galactic center (rotation of the Milky Way) is much greater! One revolution in 220 million years does not seem very fast but the radius (our distance to the galactic center) is more than 30 000 light years. The solar system is orbiting at about 514,000 mph.

Answer 4

The previous answer is not quite accurate. First, the author appears to be confusing negligible with nonexistent. Just because there is negligible matter from the Sun's atmosphere does not mean there is none, nor that there is not matter in the space through which the earth travels. There is and there is. And while the effect of that matter is "negligible" over even seemingly large time scales, it it not nonexistent. Furthermore, all orbits continuously decay due to gravitational radiation, as the objects radiate gravitational energy. Neither of these contribute enough to decay the earth's orbit to the point that it would be signficant prior to the aforementiond solar expansion as the sun begins to die, which will have signficant effects on the earth's orbit long before the effects of the previous forces have signficant effects on the earth's orbital path.

Answer 5

The earth's speed around the sun depends on the Gravity Constant G, the mass of the sun M and the distance from the sun r. This gives the speed as: v=(GM/r)^.5 = squareroot(GM/r)= ((2e-10/3)x2e30/150e9))=29,814 meters/second or around 30km/s.

The earth's velocity, a vector, has a direction angle of arccos v/c = arccos 9.938e-5 giving an angle 89 59' 39.5" from the sun's radial direction. This is the redshift angle of the earth. This indicates that the earth is moving nearly perpendicular to the sun's radius.

The redshift is the ratio of v/c and increases when v increases. As you can see from the formula for speed, the closer the earth is to the sun, the faster the speed and the farther the earth is from the sun the slower the speed. It is clear here that if the earth speed was approaching the speed of light, as in expansion, it would be moving towards the sun not expanding away.

Answer 6

Reference: Chapter 13, (The Earth's Slowing Rotation) "The MIND of MANKIND" - http://wiki.answers.com/Q/Special:Booksources&isbn=0964926512, Published 1996, Suna Press. Donald L. Hamilton, author of "The MIND of Mankind" © 1996 - 2006. Based on the claims contained within the Author's article, it may be stated that the earth's rotation has more-or-less continuously slowed since the birth of the planet and the solar system some 4.5 billion years ago (I apologize if this or any other assertion herein contained does not, in some way, agree with the ideas Hamilton expresses). Hamilton further claims that "friction" is the principle phenomenon which decelerates the Earth's rotational velocity but it is not clear to this reader if there are not, in fact, other causes. It seems apparent that Hamilton might claim that the rate of rotational deceleration probably is not constant, and I postulate that relatively significant changes given rise by "single-events" might be possible. In his article, Hamilton states that "100,000,000 years ago its [the Earth's] rotation period had slowed to 23.6 hours". In the intervening time, then, I conclude that its rotation has slowed another 0.4 hours (1.69%) -- as an aside, this 0.4 hour difference in the length of the "day" (making the present day "longer" than it was 100 million years ago) could also mean that the "year" is now 6.20 days shorter than it was back then, if one were to assume (probably erroneously) that the duration of Earth's orbit about the Sun did not change in any appreciable way. On a directly proportional basis, it might be claimed that a further reduction of 0.35 hours (1.46%) could take another 85 million years, or it could happen practically overnight if one were to theorize the existence of physical phenomenon which have the energy to impact the planet's rotational momentum in extraordinary fashion (eg: a "close approach" of a super-massive black-hole?). Why "0.35 hours", you ask? If the length of the day became 24.35 hours and if the Earth's orbital periodicity remained more or less constant (8,766 hours), then the number of days in the year would equal 360. See Revelations in The Bible, wherein a certain unusual quantum of time is used repeatedly by Paul as he describes the events of the end-times: 1,260 days would equal 3-1/2 years and one year would equal "a time" if a year came to equal 360 days. Then I posit, "if the length of the day could be rapidly extended 1.46% by some unforeseeable physical event, might that event also signal the onset of the so-called "end times?"

Answer 7

Not yet. Orbits "decay" if there is some kind of friction that slows down an object and causes it to fall into the primary body.

The orbits of satellites in near Earth orbit do decay, because the Earth's exosphere extends hundreds of miles into space. So over the next hundred years or so, the Space Station will eventually fall - if no spacecraft are available to push it back into a higher orbit. But communications satellites in geosynchronous orbits are 23,000 miles up, far beyond even the outer traces of the atmosphere, and those orbits will probably never decay.

The Earth's orbit is 93 million miles from the Sun, which is far beyond the faintest traces of the Sun's atmosphere. So our orbit is stable, and not subject to decay. But in about 4 billion years, the Sun will turn into a red giant, and expand, possibly big enough to swallow Venus - and at that time, the Earth's orbit WILL begin to decay, and eventually the Earth will probably fall into the Sun.

But that's a LONG time from now.

Answer 8

Earth rotates once about its axis approximately every 24 hours, defining a day. In contrast, Neptune rotates much more slowly, spinning once about its axis roughly every 16 hours.

Answer 9

The Earth moves 30km/sec around the sun or 18.5 miles/sec.

Answer 10

One rotation every 23hours 56minutes 4seconds