Planetary motion as perpetual motion?

In summary, the conversation discusses whether a planet orbiting around a sun can be considered an example of perpetual motion. It is noted that while the planet's orbit may fit the definition, scientists do not use the term in this way. The stability of the orbit is explained as a balance between gravity and velocity, with no external forces slowing it down. However, it is also mentioned that planetary orbits do eventually decay, making them not truly perpetual.
  • #1
Could a planet orbiting around a sun be considered an example of perpetual motion? I know that the planet wouldn't be doing any work, since it goes back to the same spot every year, but does an object have to be performing for it to be considered perpetual motion? The two might have nothing to do with one another, but I admittedly don't have very much experience with physics and all that.
 
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  • #2
Your instincts are correct: though Newton's first Law might fit the dictionary definition for "perpetual" motion, scientists don't use that word to describe it. They only use the word to describe motions that violate the laws of physics (thermodynamics).
 
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  • #3
Essentially, its stable orbit is a rare balance of gravity opposed by just the correct velocity of the planet, as space is a vacuum, no drag occurs to slow the planets endless orbiting.
 
  • #4
Planetary orbits eventually decay. They ultimately either escape the host star, or are consumed by it. This process can take many billions of years. So an orbit can be robust, but, not perpetual.
 
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  • #5


I can provide a response to the idea of planetary motion as perpetual motion. Perpetual motion refers to the concept of a system that can continue to move or operate indefinitely without any external source of energy. In this case, the planet orbiting around a sun may seem like a potential example of perpetual motion, as it continuously moves around the sun without any apparent external force.

However, it is important to note that in physics, perpetual motion is considered impossible. This is because all systems are subject to various forms of energy loss, such as friction and air resistance, which eventually cause the system to slow down and stop. Therefore, while the planet may appear to be in perpetual motion, it is actually subject to various forces that prevent it from truly being perpetual.

Additionally, the concept of work is also important to consider in relation to perpetual motion. Work is defined as the transfer of energy from one system to another. In the case of the planet orbiting the sun, there is no transfer of energy, as the planet is not performing any work. It is simply following the laws of gravity and inertia.

In conclusion, while the idea of a planet orbiting a sun may seem like an example of perpetual motion, it is not considered as such in the scientific community. The laws of physics and the concept of work prevent it from being a true perpetual motion system.
 

What is planetary motion as perpetual motion?

Planetary motion as perpetual motion is the idea that the movement of planets in their orbits around the sun can continue indefinitely without any external force acting upon them.

Is planetary motion considered perpetual motion?

No, planetary motion is not considered perpetual motion. While the planets in our solar system do have a constant motion around the sun, this is due to the gravitational force of the sun and not an infinite source of energy.

Why is planetary motion not perpetual motion?

Perpetual motion is defined as a hypothetical motion that continues indefinitely without any external energy source. However, planetary motion is driven by the force of gravity, which is a limited source of energy. Eventually, the planets will slow down and eventually come to a stop or fall into the sun.

Are there any examples of perpetual motion in the universe?

No, there are no known examples of perpetual motion in the universe. All known systems require an external source of energy to maintain motion.

Why is the concept of perpetual motion important in science?

The concept of perpetual motion is important in science because it challenges our understanding of the laws of thermodynamics and conservation of energy. While it has been proven to be impossible, the pursuit of perpetual motion has led to important discoveries in physics and engineering.

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