# Earth Rotation – Two Questions?

(1)

If the Earth were not a body that spins around its axis would the force that keep objects, such as people, on the planet be the same as it is now that the Earth does spin? I think I’m talking about gravity.

(2)

Does Earth’s spin around its axis have any effect upon its rotation around the sun, and for that matter, upon its pull of our Moon while keeping it in orbit?

I guess I am asking if the Earth’s spin around its axis has any influence upon gravitational forces.

Relevance
• 2 weeks ago

1. The Earth spins - but not very fast.  That spin *does* create a slight force *away* from the Earth's center of gravity, which reduces the weight you feel due to gravity.  As you'd expect, that slight force is greatest at the equator, diminishing as you approach the poles.   And - since Earth spins only once in 24 hours, it's not truly noticeable - but it *does* exist.  So, you weigh slightly less due to Earth's rotation.

2. And no... the Earth's period of orbit about the sun has nothing to do with our spin, nor does it have much to do with the Moon's orbit about the Earth. If our day was only 6 hours long, or 600 - we'd orbit the sun in the same amount of time as we do now.

The moon is sort of a special case... we owe the length of our day to the moon, sort of. The moon was formed by an impact early in Earth's history - it was a glancing blow, that ejected tons of material into space, which later collected to form the moon. The impact imparted a spin on the Earth - about 6 hours long - which the gravitational/tidal effects of the moon have slowed over time... The moon has moved further away from Earth, while our day slows - and, the effect continues today. So... our spin does affect the moon, a tiny bit - it's moving away from Earth at a rate of about 1 1/3 inches per year.

• 2 weeks ago

We don't live on a magical, tilting, spinning, shooting, watery, space ball travelling through the galaxy at over a million mph.

Gravity that allegedly holds large biddies of water  round a ball is preposterous and something you were programmed to believe as an infant.

This cannot be scientifically proven, measured, or demonstrated. All you have a belief, the only thing thats been to space is your imagination.

Do you actually believe that passenger airliners can fly level completely around a ball????

• D g
Lv 7
2 weeks agoReport

you are so stupid  you can  easily  show water forms to shape of a sphere

and yes   PASSENGER AIRLINES FLY   circular routes to  the destinations you  MORON ..   a two year old should  notbe allowed to type answers on here   its  annoying to see the utter  idiocy that comes from your  brain..

• 2 weeks ago

If the earth stopped spinning then the gravitational forces would remain unchanged , however the centripetal force acting on someone at the equator would also stop and the person would feel like gravity had increased. A person at the poles would not notice any difference.

• goring
Lv 6
2 weeks ago

Basically the Earth spin time follows the orbit time around the Sun. And the sun orbit  rotates relative to the center of the Galaxy estimated as 10^5 years.

Gravitational field increase as the earth comes closer to the Sun.by the same token time becomes shorter and the orbital speed of the earth increases increases also.That means the days are shorter.

• 2 weeks ago

Your weight at the equator would be 1% greater if earth did not rotate.

Earth's rotation does not affect its gravitational field.

• Jon
Lv 6
2 weeks ago

According to Newton's theory of gravity, there would be no effect apart from the apparent centrifugal force that others have already mentioned.

But according to Einstein's theory of gravity, also known as general relativity, there would be a slight difference in the real gravitational field, since in general relativity the gravitational field is coupled to energy, momentum, and stress, not simply mass.

• 2 weeks ago

Gravitational force is slightly "reduced" by the centrifugal force that acts on objects at the equator, but the difference is less than 1%.

The earth's spin on its axis has no effect on its rotation around the sun, nor on its pull of the moon.

• oyubir
Lv 6
2 weeks ago

1) Yes, very slightly.

Centrifugal forces (the same that try to put you out of a merry go round) oppose to gravity.

Gravity is around 9.82 m/s².

Centrifugal forces varies from 0,03 m/s² at the equator, to 0 at the pole.

Which leads to an average 9.81 m/s².

Without the rotation, apparent gravity would be 9.82 instead of 9.81.

Nobody would notice of course (The end of Earth spin would be noticed. Everyone would die. But not because of gravity change)

2) No.

Note that even for 1, strictly speaking there is no infuence of spin on gravity. Only on apparent gravity.

It is only because inhabitants are spining with Earth that they feal that apparent modification of the gravity. Moon and Sun are not spinning (at least not with Earth spin). So they don't care.

It is like when you are on the said merry go round. Or in a turning car. Or an accelerating or decelerating elevator: you have a feeling that gravity changes. On the merry go round, or the turning car, gravity is increased and not vertical,  In an elevator accelerating upward (at the beginning of a lift upward. Or at the end of a descent), apparent gravity is higher. In an elevator accelerating downward (beginning of a travel down or end of a travel up) apparent gravity is lower. But obviously, that modification of apparent gravity only impacts those who are in motion. Watcher of the merry go round, pedestrian next to the turning car, other people in the building where an elevator is moving are not impacted at all by that apparent gravity.

Because it is only apparent. It is because the vehicle in which you are is not traveling at a constant linear speed that you have this feeling (passenger of the car would be traveling in straight line, with his/her inertia when the car is turning. But the seat on which he/she is seated is not, and exert a force on the one seated. So he/she feels a force from that seat, as if he/she would feel if the gravity was oriented in the other direction.

So everything, from the point of view of the passenger is as if gravity was modified. But in reality it is not.

Inhabitant of the Earth are like passenger of a vehicle, turning around a huge roundabout of 8000 miles of diameter, at a speed of 1 turn every 24 hours. So they feel a gravity pulling them outside (so, upward, opposing real gravity). But that is only apparent gravity, and it impacts only passenger of that vehicle, that is those who are on the surface of the Earth.

• 2 weeks ago

1, Earth's Gravity is caused by Earth's Mass

Weight is Mass x Gravity

The Moon has less Gravity because it has 1/6th of Earth's Mass , you would be 1/6th of your actual weight there yet your Mass hasn't changed

This Gravity overcomes the Centrifugal Force of the Earth's spin and Gives us Weight

Our Mass and Spin has a negligible effect on the Sun

The Sun's Mass keeps us in our slightly eccentric orbit

On January 3rd we are at Perihelion, our closest to the Sun, while on 3rd June we are at Apehelion, the farthest from the Sun in our orbit

This difference is barely just over a Million Miles

Meanwhile the Moon has enough Mass to Cause Tides on Earth

It is actually slowing Earth's spin down very Gradually by Tidal Friction

And the Same is Causing the Moon to Speed up in its Orbit

The Moon too has a Perigee and Apogee

When it is between the Sun and the Earth It gets Pulled away from us slightly

With the Gravity of the Earth and the Sun pulling on it it gets pulled towards its Perigee

Eventually, over probably Millions of years, Earth will have slowed its spin to coincide with the Moons Orbit

Giving rise to Tidal locking with both objects showing the same face to each other

The Moon has already reached there

With the Moon accelerating it will increase its altitude until Complete Tidal locking occurs

Just like Pluto and Charon

Source(s): New Horizons, Pluto and Charon
• Henry
Lv 5
2 weeks ago

Earth is probably stationary and flat with an angel at each corner.

• Demiurge42
Lv 7
2 weeks agoReport

The Moon has about 1.2% of the mass of the Earth.  Not 1/6