RE: Nature of Energy
March 14, 2016 at 6:46 am
(This post was last modified: March 14, 2016 at 7:15 am by Alex K.)
How would you know that you have reached the fundamental level. How would we even know that any theory can describe nature exactly. I don't think it is possible to know. The history of science should be sufficient warning that nature always has more subtlety and new surprises in store.
Energy is, at the end of the day, a concept we ourselves have developed to describe certain aspects of nature. It is a number (one of many) we can assign to states of matter and radiation, which is particularly useful for describing physical processes because it 1) remains the same to good accuracy, 2) tells us how strongly an object is involved with gravitation, 4) and knowing how this number depends on the detailed configuration of particles and fields yields precise predictions about its future movements, a indispensable approach to physics pioneered by people like Hamilton and Lagrange. 5) Its flow is related to Entropy
Because total Energy stays the same and energy transfer at a certain temperature gives the change in Entropy, we can easily tell whether certain work can be accomplished by a physical system simply by looking at how much energy it contains, how much of it must be transferred to accomplish the task, and whether the entropy of the system is low enough such that this transfer will occur without clashing with the second law. Other conserved quantities such as angular Momentum and Momentum can give similar useful information, but Energy tends to be the most powerful concept.
It is a philosophical can of worms unto itself whether Energy is something that fundamentally exists in nature, or whether it is just an effective description of nature. I have given a modern and very general definition of what energy is in a different thread: it can be identified with the conserved quantity which is associated with a particular continuous symmetry in the laws of nature, namely that the laws of nature do not vary over time.
If time stops to be a continuous thing when looking closely enough because it becomes fuzzy or discrete at short enough time intervals, it will become difficult to even find a fundamental definition of what Energy is, and the concept of Energy might just be describing an emergent property of physical systems (like air pressure or temperature) that is not really a fundamental property of stuff but instead something that only appears when looking at large averages of particles or, in this case, many Planck time intervals or what have you.
Energy is, at the end of the day, a concept we ourselves have developed to describe certain aspects of nature. It is a number (one of many) we can assign to states of matter and radiation, which is particularly useful for describing physical processes because it 1) remains the same to good accuracy, 2) tells us how strongly an object is involved with gravitation, 4) and knowing how this number depends on the detailed configuration of particles and fields yields precise predictions about its future movements, a indispensable approach to physics pioneered by people like Hamilton and Lagrange. 5) Its flow is related to Entropy
Because total Energy stays the same and energy transfer at a certain temperature gives the change in Entropy, we can easily tell whether certain work can be accomplished by a physical system simply by looking at how much energy it contains, how much of it must be transferred to accomplish the task, and whether the entropy of the system is low enough such that this transfer will occur without clashing with the second law. Other conserved quantities such as angular Momentum and Momentum can give similar useful information, but Energy tends to be the most powerful concept.
It is a philosophical can of worms unto itself whether Energy is something that fundamentally exists in nature, or whether it is just an effective description of nature. I have given a modern and very general definition of what energy is in a different thread: it can be identified with the conserved quantity which is associated with a particular continuous symmetry in the laws of nature, namely that the laws of nature do not vary over time.
If time stops to be a continuous thing when looking closely enough because it becomes fuzzy or discrete at short enough time intervals, it will become difficult to even find a fundamental definition of what Energy is, and the concept of Energy might just be describing an emergent property of physical systems (like air pressure or temperature) that is not really a fundamental property of stuff but instead something that only appears when looking at large averages of particles or, in this case, many Planck time intervals or what have you.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition
