Why is the Earth a perpetual motion machine

In summary: Earth's orbit and why it keeps moving in the same spot every day...but I can't seem to find a good answer for it now :(
  • #1
eratosthenes2
4
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Seems like an odd question - but if your an astraunaut in Earth orbit and travel with it around the sun - your going different speeds around the sun but always traveling the same distance away from any two points on the sun every second (keplers #2)

the how = closer you are to sun, the faster you go around it, farther you are, slower you go
the why = (i don't know - it has to do with distance messing up the influence, but that's not why it it does it)

Now what's obvious to me is there's some sort of influence there that's invisible and sometime ago a man made up and invented a random name to call it and called it gravity - but that doesn't answer why the Earth is so obsessed with always traveling the same amount of space every hour relative to its distance away from the sun (keplers 2nd law).
For example, on Earth, when you put two items in a bowl and whirl em around.. they tend to keep coming closer and closer together .. in space they would do this because of attraction.. but I've never seen nor heard of any instance where the Earth keeps coming closer and closer to the Sun in its annual ellipse. It just keeps going like a perpetual motion machine For some reason Galaxies merge and other items tend to collide.. and meteoroids keep coming closer and closer to the Sun on each pass by.. but the Earth keeps at it's same ellipse. Why is that?

(I'm wondering if it has to do with the Sun just being a foci and not the center of the Earth's path, but why do other things keep coming closer then?)
 
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  • #2
eratosthenes2 said:
It just keeps going like a perpetual motion machine For some reason Galaxies merge and other items tend to collide.. and meteoroids keep coming closer and closer to the Sun on each pass by.. but the Earth keeps at it's same ellipse. Why is that?

Hi eratosthenes2! :smile:

The Earth keeps going because its tangential velocity balances its centripetal gravitational acceleration towards the sun.

When galaxies collide, it is because they do not have sufficient tangential velocity to balance the gravitational acceleration! :smile:
For example, on Earth, when you put two items in a bowl and whirl em around.. they tend to keep coming closer and closer together .. in space they would do this because of attraction.. but I've never seen nor heard of any instance where the Earth keeps coming closer and closer to the Sun in its annual ellipse.

The two items in a bowl come together because of various resonances, not because of any attraction between them.

In fact, though, in the early solar system, the planets did sometimes attract each other (that's how we got the Moon! :wink:), and indeed that's how the planets formed in the first place.

The orbits of the eight (nine?) planets we have today are what is left after all the resonances settled down. :smile:
 
  • #3
eratosthenes2 said:
Seems like an odd question - but if your an astraunaut in Earth orbit and travel with it around the sun - your going different speeds around the sun but always traveling the same distance away from any two points on the sun every second (keplers #2)

the how = closer you are to sun, the faster you go around it, farther you are, slower you go
the why = (i don't know - it has to do with distance messing up the influence, but that's not why it it does it)

Now what's obvious to me is there's some sort of influence there that's invisible and sometime ago a man made up and invented a random name to call it and called it gravity - but that doesn't answer why the Earth is so obsessed with always traveling the same amount of space every hour relative to its distance away from the sun (keplers 2nd law).
For example, on Earth, when you put two items in a bowl and whirl em around.. they tend to keep coming closer and closer together .. in space they would do this because of attraction.. but I've never seen nor heard of any instance where the Earth keeps coming closer and closer to the Sun in its annual ellipse. It just keeps going like a perpetual motion machine For some reason Galaxies merge and other items tend to collide.. and meteoroids keep coming closer and closer to the Sun on each pass by.. but the Earth keeps at it's same ellipse. Why is that?

(I'm wondering if it has to do with the Sun just being a foci and not the center of the Earth's path, but why do other things keep coming closer then?)

I asked a question similar to this a while ago. I'm thinking that what you're wondering is: Why are systems, such as solar systems and galaxies, the way they are? Why are they organized the way they are rather than entering a state of chaos and disorder? I still do not have much of an answer to that.

The Earth is not exactly 100% a perpetual motion machine...the reason why its relatively stable is because its at a state of energy in equilibrium. This does not necessarily imply that all systems are stable. Apparently, the universe is expanding...so at the moment we cannot imply its stability just yet.
 

1. Why is the Earth considered a perpetual motion machine?

The Earth is considered a perpetual motion machine because it is constantly moving and has been doing so since its formation. It rotates on its axis, orbits the sun, and is a part of the larger movement of the solar system within the Milky Way galaxy. This movement continues indefinitely without any external source of energy.

2. How does the Earth's rotation contribute to it being a perpetual motion machine?

The Earth's rotation on its axis creates the effect of day and night, which is a result of its constant movement. This rotation also creates the Coriolis effect, which influences global wind patterns and ocean currents. The energy required for this continuous movement comes from the Earth's original formation and is sustained by the Earth's internal heat and gravitational pull.

3. What about the Earth's orbit around the sun makes it a perpetual motion machine?

The Earth's orbit around the sun is an elliptical path, which means it is not a perfect circle. This causes the Earth to speed up and slow down at different points in its orbit. However, due to the conservation of angular momentum, the Earth's overall speed remains constant, making its orbit a perpetual motion.

4. Does the Earth's perpetual motion have any impact on its climate and weather patterns?

Yes, the Earth's perpetual motion has a significant impact on its climate and weather patterns. The tilt of the Earth's axis and its orbit around the sun create seasonal changes, while the Earth's rotation influences wind patterns and ocean currents. These movements also contribute to the formation of natural phenomena such as hurricanes and tornadoes.

5. Can the Earth's perpetual motion ever stop or change?

The Earth's perpetual motion is a result of natural forces and will continue as long as these forces remain in balance. However, external factors such as human activity and astronomical events can impact the Earth's motion and potentially alter its course. It is also possible that the Earth's perpetual motion could be disrupted in the distant future if the sun's energy supply runs out or if the Earth's orbit is affected by the gravitational pull of other celestial bodies.

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