Why Does Earth Spin? Exploring Heat Exchange Theory

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In summary: The short version of this hypothesis is that a Mars-sized planetesimal (called Theia) collided with the Earth, and the Moon condensed from the debris of that collision. This would give the Earth a relatively high angular momentum compared to its orbital angular momentum around the Sun, compared to the other planets. In summary, the Earth's rotation and its relatively constant speed can be explained by the conservation of angular momentum. However, the Moon's influence through tides has caused a gradual decrease in the Earth's rotation rate. The initial spin of the Earth may have been caused by eddies in the early solar system, and it may have been modified by events such as the collision that formed the Moon.
  • #1
JamiePocock
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Question: I read conflicting information on why Earth spins and has done so for millions of years with very little speed change.
Some say it’s due to cosmic spinning particles millions of years ago others say it spins due to collisions in space and some say it remains spinning from the big bag etc.

May be its just my lack of understanding but none of these seem to hold up to me or make much sense.

Could it be the Earth settled in orbit around the sun and then over millions of years began to rotate because the sun heating one surface and the dark side getting colder and colder hence eventually heat diffusing from the hot service and air to the cold service and air mixed with the orbit of the sun caused the Earth to start rotating.

If so at this time it would have spun up quickly in space terms until the temperature of both sides settled down.

Now in this day during the period the earth’s surface is exposed to the suns radiation that surface area (sea or land) and the air above it becomes warmer and warmer until it falls back into darkness (night) and begins to cool, the coldest part that has been in the dark the longest is now being attracted to the warming sun facing surface (morning).

In a vacuum such as space surely this well known heat reaction could over millions of years cause Earth to continue to rotate and remain rotating at its fairly constant speed.
If my theory is correct then someone better at maths than me could proof this by looking at the rotation speed of Earth and calculating the period the suns radiation is on the surface, mass of the Earth and distance from the sun, my maths is not good but I hope you understand what I am saying here.

So if the Earth is in fact rotated by heat diffusing from the hot air to the cold air then this would have a lot of implications such as calculating service temperatures of celestial bodies including the sun and planets, deterring what elements may exists, estimating mass, distance from the sun etc

So could it be rotation has existed for so many years due to the simple physics of heat exchange?

I don't pretend to understand astrophysics, so could someone tell me if this theory is even possible.

Thank you for your time

Jamie Pocock
 
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  • #2
JamiePocock said:
Question: I read conflicting information on why Earth spins and has done so for millions of years with very little speed change.
Some say it’s due to cosmic spinning particles millions of years ago others say it spins due to collisions in space and some say it remains spinning from the big bag etc.
None of the above.

Angular momentum is a conserved quantity. What that means is once something starts spinning, some action, a torque, is required to change that angular momentum. Without any external torques acting on a spinning body, that spinning object would maintain the same angular momentum forever.

That said, the Earth's rotation rate is not constant. The Earth was rotating considerably faster than it is now 4+ billion years ago; some estimate the length of the day was as short as four to six hours. The Moon is the primary culprit. The Moon raises tides in the oceans. Those tides don't flow freely; they interact with the land: Friction.

The friction causes a torque on the Earth, and that torque in turn makes the Earth's rotation rate decrease (rather slowly). There is also an affect on the Moon's orbit. Because the Earth is rotating faster than once per month, the Earth's rotation drags the tidal bulges slightly ahead of the line between the Earth and Moon. This makes the Moon accelerate a bit faster than it would if those tidal bulges were not present, and that in turn makes the Moon slowly recede from the Earth. End result: Angular momentum is being transferred from the Earth's rotation about its axis to the Moon's orbit about the Earth.
 
  • #3
The initial spin would probably have been from eddies in the clouds of material from which the whole solar system was formed. When you pull in matter (in this case using gravity) from a distance, any slight uneven motions in the initial distribution turn into strong rotation locally, in the same way as water draining from a basin, because angular momentum is conserved, so the rate of rotation increases as the material is pulled in.

The rotation could however have been modified by whatever events created the Moon or other interactions between planets. Although most of the bodies in the solar system are spinning generally in the same direction, some fairly major interactions must have happened at some time to explain the anomalous rotations of Venus and Uranus.
 
  • #4
Jonathan Scott said:
The rotation could however have been modified by whatever events created the Moon
One of the appeals of the giant impact hypothesis is that it explains the anomalously high angular momentum of the Earth-Moon system.
 
  • #5


I appreciate your curiosity and willingness to explore different theories about why Earth spins. While there are various theories out there, the current scientific understanding is that Earth's rotation is primarily due to the conservation of angular momentum from its formation. This is also supported by observations of other planets in our solar system and their rotational speeds.

The idea of heat exchange theory, while interesting, has not been widely accepted by the scientific community as the main reason for Earth's rotation. This is because, as you mentioned, the Earth has been spinning at a fairly constant speed for millions of years, and the heat exchange between the hot and cold sides would not likely be enough to sustain such a consistent rotation.

Additionally, the Earth's rotation is not solely dependent on the sun's radiation, as other factors such as the moon's gravitational pull and the Earth's tilt also play a role. It is a complex interaction of these factors that contribute to the Earth's rotation.

While your theory may have some implications for studying celestial bodies, it would require further research and evidence to be considered a valid explanation for Earth's rotation. As scientists, we must continue to question and explore different ideas, but ultimately it is important to base our conclusions on solid evidence and scientific principles.

I hope this helps to clarify the current understanding of Earth's rotation and the complexities involved. Keep asking questions and exploring different theories, as that is the foundation of scientific discovery.
 

Related to Why Does Earth Spin? Exploring Heat Exchange Theory

1. Why does the Earth spin?

The Earth spins because of its initial angular momentum, which was acquired during its formation. As the planet accreted from smaller particles, gravity caused it to spin faster, and this rotation has continued since then.

2. How fast does the Earth spin?

The Earth rotates at a speed of approximately 1,037 miles per hour at the equator. This speed decreases as you move towards the poles, with no rotation at all at the exact poles.

3. Does the Earth's rotation affect its climate?

Yes, the Earth's rotation plays a crucial role in shaping its climate. The spin of the Earth causes the Coriolis effect, which influences wind patterns and ocean currents, ultimately affecting global climate patterns.

4. What is the heat exchange theory?

The heat exchange theory proposes that the Earth's spin and its tilted axis are responsible for the uneven distribution of heat on the planet's surface. As the Earth rotates, different parts of the planet are exposed to varying amounts of sunlight, resulting in temperature differences that drive global circulation patterns.

5. Can the Earth's rotation change?

The Earth's rotation can change over long periods of time due to factors such as tidal forces from the Moon and Sun, changes in the planet's shape, and movements of the Earth's tectonic plates. However, these changes occur very slowly and are not noticeable in our daily lives.

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