Why Do Things Affect Each Other in the Universe?

[greatteamwork]

The best understanding I have got is that it is the word we use to describe flux - a fundamental state of the universe.

Maybe the question can be rephrased as 'why do things affect each other?'

 

[Drakkith]

We have a specific definition of energy:
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems.

Maybe the question can be rephrased as 'why do things affect each other?'

I'd say because there are forces that act upon objects. I don't really think energy has anything to do with this effect, it is merely how we measure change or potential change between objects.

 

[Haroldingo]

E = Mc^2 ;)

 

[Drakkith]

E = Mc^2 ;)

Care to elaborate on exactly what you mean by posting that equation?

 

[Jagella]

Care to elaborate on exactly what you mean by posting that equation?

I hope you don't mind if I butt in here.

I don't know about other people, but I've found that the relationship that Einstein discovered between mass and energy is easy to forget. I tend to think of matter and its mass (measure of inertia) as distinct from energy which is defined as the ability to do work. If we equate mass and energy, we have the following:

the tendency of a body at rest to stay at rest and a body in motion to stay in motion = the ability to do work

Although the two characteristics may seem similar in some ways, they are hardly obviously the same.

Some physicists claim that matter and energy are much the same, though. At the subatomic level, matter appears to be essentially energy. At the macro level, the differences become much more pronounced. I believe that this paradox can be reconciled by noting the old maxim: the whole is greater than the sum of its parts. It's the way energy is "put together" to make matter that makes something like hydrogen or lead so much different than light or radio waves.

So what can we make of E = mc^2? Like much of science, it may be counterintuitive. But as anybody who has studied relativity or quantum mechanics can attest, the world we live in doesn't always make sense.

Jagella

 

[Drakkith]

I don't know about other people, but I've found that the relationship that Einstein discovered between mass and energy is easy to forget. I tend to think of matter and its mass (measure of inertia) as distinct from energy which is defined as the ability to do work. If we equate mass and energy, we have the following:

the tendency of a body at rest to stay at rest and a body in motion to stay in motion = the ability to do work

Although the two characteristics may seem similar in some ways, they are hardly obviously the same.

I think too many people have a misunderstanding of what the equation means. Mass and Energy are NOT the same thing. E=MC^2 refers to the fact that you can remove mass and transfer it elsewhere to produce work. The amount of work produced can be given as "energy". Chemical and nuclear reactions remove mass from the original fuels as they react, or bind, and transfer that mass elsewhere to produce work in the form of heat or moving particles. (Both of those can be stated as "forms" of energy) This is why the splitting of Uranium causes the products to have less mass than the original nucleus.

Some physicists claim that matter and energy are much the same, though. At the subatomic level, matter appears to be essentially energy. At the macro level, the differences become much more pronounced. I believe that this paradox can be reconciled by noting the old maxim: the whole is greater than the sum of its parts. It's the way energy is "put together" to make matter that makes something like hydrogen or lead so much different than light or radio waves.

While matter is a slightly disputed term, it is not composed of energy. By definition energy isn't something physical. Matter, whatever it is composed of, has fundamental properties such as mass, charge, and spin. Energy is not one of these. The very fact that the energy of something can change means that it cannot be fundamental.

So what can we make of E = mc^2? Like much of science, it may be counterintuitive. But as anybody who has studied relativity or quantum mechanics can attest, the world we live in doesn't always make sense.

The ability to do work. How is that counter-intuitive? The fact that people try to make energy into something it isn't causes much confusion.

Energy causes things to happen around us. Look out the window.

During the day, the sun gives out light and heat energy. At night, street lamps use electrical energy to light our way.

When a car drives by, it is being powered by gasoline, a type of stored energy.

The food we eat contains energy. We use that energy to work and play.

All of this is true, but it doesn't explain what energy is.

 

[Kiril]

Hi Drakkith, I'm not yet clear how I can reduce energy to the perceptual level of cognition(directly or indirectly), which is what must be done to answer such a question - I suggest that should be the goal of those who seek to provide an answer.

However I was curious that you mentioned mass and charge as irreducible(fundamental) properties of matter. Did you intend to say that they could not be reduced to more fundamental phenomenon and/or relationships?

 

[Drakkith]

Hi Drakkith, I'm not yet clear how I can reduce energy to the perceptual level of cognition(directly or indirectly), which is what must be done to answer such a question - I suggest that should be the goal of those who seek to provide an answer.

However I was curious that you mentioned mass and charge as irreducible(fundamental) properties of matter. Did you intend to say that they could not be reduced to more fundamental phenomenon and/or relationships?

I don't understand the first paragraph, and I would answer Yes to the 2nd.

 

[Jagella]

Mass and Energy are NOT the same thing.

I agree. If they were the same, then we wouldn't give them different names and define them differently.

E=MC^2 refers to the fact that you can remove mass and transfer it elsewhere to produce work. The amount of work produced can be given as "energy". Chemical and nuclear reactions remove mass from the original fuels as they react, or bind, and transfer that mass elsewhere to produce work in the form of heat or moving particles.

I like to use the example of a nuclear bomb detonating: matter is no more energy than plutonium is a nuclear explosion. Einstein's famous equation doesn't claim that mass is energy—it tells us how much energy we can get from a given mass. To get that energy, we must “remove the mass” as you say. In other words, we cannot have our cake and eat it too.

E=MC^2 refers to the fact that you can remove mass and transfer it elsewhere to produce work. The amount of work produced can be given as "energy". Chemical and nuclear reactions remove mass from the original fuels as they react, or bind, and transfer that mass elsewhere to produce work in the form of heat or moving particles.

This is where I'm confused. A member at another forum tried to tell me that energy can provide a gravitational pull! I disputed that claim, and he told me that matter at the subatomic level is energy. I do know that some physicists see subatomic particles as waves. Maybe the inherent energy in any wave is the energy he's referring to.

The ability to do work. How is that counter-intuitive?

I was referring to the relationship between energy and mass. I must admit that prior to Einstein's discoveries, I would not have recognized that a given mass could be converted to energy. They just seem too different to be related in the way Einstein's Theory of Relativity tells us they are related. That's what made Einstein such a great thinker: He saw things that most people might miss.

Jagella

 

[Drakkith]

This is where I'm confused. A member at another forum tried to tell me that energy can provide a gravitational pull! I disputed that claim, and he told me that matter at the subatomic level is energy. I do know that some physicists see subatomic particles as waves. Maybe the inherent energy in any wave is the energy he's referring to.

The force of gravity is provided by the effect of mass on spacetime. (Or so GR tells us)
It is this force, along with the other 3 fundamental forces, that causes changes in objects. Hence they "cause" energy for lack of a better word at the moment. NONE of the 4 forces of nature require "energy" to function. Gravity doesn't simply switch off because we run out of energy.

Whatever it is that makes up subatomic particles, it is not energy. Labeling things as wavelike only describes how they interact. What are they actually made up of? I have no idea. My best guess is a mix of different forces.

I was referring to the relationship between energy and mass. I must admit that prior to Einstein's discoveries, I would not have recognized that a given mass could be converted to energy. They just seem too different to be related in the way Einstein's Theory of Relativity tells us they are related. That's what made Einstein such a great thinker: He saw things that most people might miss.

Ah ok.

 

[Naty1]

A member at another forum tried to tell me that energy can provide a gravitational pull!

That's true and comes from the Einstein stress ENERGY tensor...mass, energy, momentum, even pressure, have gravitational effects. Everything has gravitational effects because everything has one or more of the listed elements. This means everything curves spacetime.

 

[Jagella]

That's true and comes from the Einstein stress ENERGY tensor...mass, energy, momentum, even pressure, have gravitational effects. Everything has gravitational effects because everything has one or more of the listed elements. This means everything curves spacetime.

Is a "gravitational effect" the same as a gravitational pull? If energy can cause a gravitational pull, then is it safe to assume that the light and heat from a star contributes to the gravity that keeps its planets in their orbits? Or are you saying that the effect of energy is more indirect than that?

I thought that a celestial body's gravitational field is caused by its mass warping the fabric of space. It's analogous to a bowling ball placed on a mattress warping the surface of the mattress and causing marbles near it to fall into it.

Jagella

 

[WannabeNewton]

Is a "gravitational effect" the same as a gravitational pull? If energy can cause a gravitational pull, then is it safe to assume that the light and heat from a star contributes to the gravity that keeps its planets in their orbits? Or are you saying that the effect of energy is more indirect than that?

I thought that a celestial body's gravitational field is caused by its mass warping the fabric of space. It's analogous to a bowling ball placed on a mattress warping the surface of the mattress and causing marbles near it to fall into it.

Jagella

Because of mass - energy equivalence, a distribution of energy (energy density) and/or a flux of energy can induce space - time curvature.

 

[Kiril]

I don't understand the first paragraph, and I would answer Yes to the 2nd.

Chemical and nuclear reactions remove mass from the original fuels as they react, or bind, and transfer that mass elsewhere to produce work in the form of heat or moving particles. (Both of those can be stated as "forms" of energy)

This is along_the_lines(approximately) of what I'm referring to in paragraph 1.
You are at the beginnings of showing what the measurement implies in terms of data that is available to all men, in direct perceptual experience - experiences(not inferences from it) which are not open to proof and are therefore axiomatic. This is what the term "understand" properly refers to.

So far, my attempt to do this with the concept "energy" : Is an abstract property(it is not indirectly perceived - its a way of regarding something in certain existing relationships/states). Which means that it names, without reference to their specific types or conditions, all instances of matter possessing the attribute/property of motion(and its potential). Viewed this way motion/action is a synonym of energy - where energy adds the recognition of mass and force(cause and effect).
I would like to stress that the term abstract means - finding what is in common between two or more other abstractions.
What makes me uncertain about this explanation is my inability to reduce 'work' in the same way; to figure out if it is an arbitrary mathematical construct or something specific in reality.

In regard to paragraph 2:
- Since currently we are not aware of the physical nature of gravity - AE's space-time is a useful mathematical tool much like a vector, not a physical description.(Same can be said for electric and magnetic fields).
- Since we are currently not aware what causes inertia - it is not a gravitational effect, nor is it fully explained by macroscopic resistance forces.
- Since quarks and gluons, as well as strong and weak nuclear forces, are postulates or logical amendments to account for unforeseen results - not experimentally derived.
- Since we are not aware of the physical nature of an electron - at the moment its treated, mathematically, as a point-particle - which is useful, but not a physical description
- And what we know of all of these phenomena is their effects on other entities, and the extent of these effects in terms of their motion.

I suggest, no one is in a position to claim the nature of mass, and it is infect a hindrance to do so - since it creates the false impression that we actually know all these things.
And it is also exciting to think that so much still stands undiscovered!

 

[Naty1]

Is a "gravitational effect" the same as a gravitational pull?

In simple terms yes...but Einstein's formulation (graviatational effects) inlcudes more sources (others besides Newton's mass) and describes "pull" as the curvature of spacetime...
To Einstein in GR gravity is a geometric curvature; to Netwon it was a force.

 

[Naty1]

What is energy?

nobody knows!
Nobody!

..but post #2 and Wikipedia give some operational insights...relationships to other phenomena.

Nobody knows what energy "is" any more than we know what mass, or time or gravity "is".

So we stick to operational definitions which reflect our observations...we have theories, theorems and so forth which usually provide a mathematical basis for relating phenomena, like mass, energy, time, etc to the best of our understanding.

One insight might be from string theory...that energy reflects vibrational amplitude and frequency of strings...but then nobody knows what a string "is" either...other than a theoretical two dimensionmal "particle" of energy...

 

[Jagella]

Because of mass - energy equivalence, a distribution of energy (energy density) and/or a flux of energy can induce space - time curvature.

Thanks. I'll need to investigate this topic when I get time. It's kind of hard to imagine rays of light exerting a gravitational pull, but gravity is so weak that massive objects like mountains don't cause much of a gravitational pull either.

Jagella

 

[Drakkith]

Kiril, I think you are over-thinking it lol.
I try to stick with the current definition of things by science and avoid anything beyond that as it typically serves no purpose other than for one person to argue with another over vague interpretations and beliefs.

 

[Kiril]

Drakkith, I'm disappointed that you chose to approach it in this manner.

Kiril

 

[chiro]

The best understanding I have got is that it is the word we use to describe flux - a fundamental state of the universe.

Maybe the question can be rephrased as 'why do things affect each other?'

With regards to the ability to do work, if you understand some calculus you can look at this:

http://en.wikipedia.org/wiki/Energy#Applications_of_the_concept_of_energy

This is a classical definition of energy though, but it implies that some force of some kind exists that is used to interact with something.

The origin of the different forces however, is not a simple question to answer (if it even has an answer). Physicists and philosophers alike are still debating what causes these forces to act like they do.

With regards to utilizing electrical and other energies, the thermodynamic theory framework is used to outline constraints on energy conversion and dissipation. This body of knowledge is usually applied to energy conversion processes that are thermodynamic such as thermonuclear processes used in nuclear power plant energy generation, or geothermal power energy generation, and conventional combustion engines found in automobiles

In terms of other processes, it is still an active part of research and many people are investigating and experimenting with ideas that are different to conventional thermodynamic processes mentioned above.

 

[Drakkith]

Drakkith, I'm disappointed that you chose to approach it in this manner.

Kiril

I'm not sure why you are disappointed. Has something in my posts offended you in some way?

 

[Naty1]

I try to stick with the current definition of things by science ...

That's likely the way to get started when learning and to understand terminology as used in science. Otherwise you will not likely arrive at the same definition as science has over perhaps 100 years and dozens and maybe hundreds of experts perspectives.

But if Einstein never thought beyond what was known about light at the time he was first exposed to it, he might never have thought about "What happens when I catch up to a
light beam and observe it.". So thinking beyond strict definitions is extremely useful too.

 

[Drakkith]

But if Einstein never thought beyond what was known about light at the time he was first exposed to it, he might never have thought about "What happens when I catch up to a
light beam and observe it.". So thinking beyond strict definitions is extremely useful too.

I agree except when the definition is simply a way to measure changes in systems. I don't know why everyone gets so uppity over energy. It's a very simply concept that gets overanalyzed and misinterpreted in my opinion. And sticking to the definitions by science is 100% applicable to this thread while trying to think "beyond" it is not.

 

[Goldstone1]

The best understanding I have got is that it is the word we use to describe flux - a fundamental state of the universe.

Maybe the question can be rephrased as 'why do things affect each other?'

Energy is a diffused matter, while matter is a concentrated energy.

 

[Drakkith]

Energy is a diffused matter, while matter is a concentrated energy.

I don't believe this is correct.

 

[Jagella]

Energy is a diffused matter, while matter is a concentrated energy.

I tend to see matter and energy in much the same way. Matter "concentrates" energy in the form of subatomic particles which may be vibrating strings if string theory is correct.

As anybody who has studied the subatomic world knows, electrons move in orbits around the atom's nucleus. The volume of the atom is then the sphere traced out by the electrons moving in their orbits. Since the electrons and nucleus are tiny compared to the radius of this sphere, most of the atom is empty space. As a result, matter is mostly empty space with an illusion of solidity created by the energy that moves the electrons in their orbits.

Jagella

 

[Goldstone1]

I don't believe this is correct.

Of course energy is a diffused matter. What do you think E=Mc^2 means? It means that matter is a concentrated form of energy, and since this is so, energy is a diffused state of matter.

 

[Drakkith]

Of course energy is a diffused matter. What do you think E=Mc^2 means? It means that matter is a concentrated form of energy, and since this is so, energy is a diffused state of matter.

No, it does not mean that. It means that all transfers and types of energy have mass and vice versa. The release of energy from all reactions also results in less mass. It does not mean that they are the same thing. Mass cannot be made of energy, just look at the basic definition of energy. It is an abstract concept, meaning that it isn't tangible and physical. Just like you and I cannot be made of "love" or "hate" as those are also abstract concepts that describe interactions between people.

 

[Goldstone1]

No, it does not mean that. It means that all transfers and types of energy have mass and vice versa. The release of energy from all reactions also results in less mass. It does not mean that they are the same thing. Mass cannot be made of energy, just look at the basic definition of energy. It is an abstract concept, meaning that it isn't tangible and physical. Just like you and I cannot be made of "love" or "hate" as those are also abstract concepts that describe interactions between people.

Look, the equation states you can get a large amount of energy from a small bit of matter. If energy and matter are the same thing, as we are told (just different phases), then matter is a concentrated form of energy. This is how the Atom Bomb works.

 

[Drakkith]

Look, the equation states you can get a large amount of energy from a small bit of matter. If energy and matter are the same thing, as we are told (just different phases), then matter is a concentrated form of energy. This is how the Atom Bomb works.

That is correct, you do lots of energy from the conversion of mass. However energy and mass are NOT the same thing. It is actually much more accurate to say that energy and work are different versions of the same thing. Work being the transfer of energy and energy being the capability to do work. Both describe the interaction and changes between systems and both use the same units of measurement. Moving mass from one location to another via work is measured using energy. Changing a property such as velocity or direction in an object is also measured by energy. In the case of particle-antiparticle annihilation the particles are converted to photons and other particles, with the amount of combined mass equal to the original mass of the two particles. Any work you can get is measured in energy!

 

[khemist]

As anybody who has studied the subatomic world knows, electrons move in orbits around the atom's nucleus. The volume of the atom is then the sphere traced out by the electrons moving in their orbits. Since the electrons and nucleus are tiny compared to the radius of this sphere, most of the atom is empty space. As a result, matter is mostly empty space with an illusion of solidity created by the energy that moves the electrons in their orbits.

Um no...

http://en.wikipedia.org/wiki/Atomic_orbital

 

[Dale]

Look, the equation states you can get a large amount of energy from a small bit of matter.

No, the m stands for mass, not matter. You can get a large amount of energy from a small amount of mass.

Mass and matter are different things. Matter refers to fermions or things composed of fermions, but there are massive bosons also and other non-matter fields with mass.

Re: the OP. Energy is the capacity to do work. There is no mystery to the question "what is energy". We know exactly what it is because that is how we defined it.

 

[Goldstone1]

No, the m stands for mass, not matter. You can get a large amount of energy from a small amount of mass.

Mass and matter are different things. Matter refers to fermions or things composed of fermions, but there are massive bosons also and other non-matter fields with mass.

Re: the OP. Energy is the capacity to do work. There is no mystery to the question "what is energy". We know exactly what it is because that is how we defined it.

Don't try and be pedantic. My statement was very true. M is for the mass, or matter of a particle. Why be pedantic on such terminologies? The answer I gave was not dangerous, nor was it incorrect. Your explanation is not incorrect either, but I'd argue it's not as elegant as mine. For instance:

''energy is the capacity to do work''

Saying energy is more of a fundamental fluctuation which is a diffused matter, while matter is a concentrated form of energy is absolutely correct within the framework of Einstein's energy-mass equation.

 

[Naty1]

And sticking to the definitions by science is 100% applicable to this thread while trying to think "beyond" it is not.

not at all: in fact you have it backwards. Science can't answer such fundamental questions as "What is energy?" or "What is mass?"

You can define energy, but you cannot determine "what energy IS" without going waaaaaaaaaaaaaaaaaaaaaaay beyond existing definitions. You CAN explain via scientific definitions and formulas and such what we observe about energy...but, alas, not what it IS.

 

[Dale]

My statement was very true. M is for the mass, or matter of a particle. Why be pedantic on such terminologies?

There are other things beside matter or particles that have mass. E.g. fields or thermal energy.

 

[Joncon]

The http://en.wikipedia.org/wiki/Energy" on energy mentions this: -

For example, a compressed spring will be slightly more massive than before it was compressed. Likewise, whenever energy is transferred between systems by any mechanism, an associated mass is transferred with it.

Doesn't this contradict the view that energy is just an abstract concept? Or is this just plain wrong?

 

[WannabeNewton]

Don't try and be pedantic. My statement was very true. M is for the mass, or matter of a particle. Why be pedantic on such terminologies? The answer I gave was not dangerous, nor was it incorrect. Your explanation is not incorrect either, but I'd argue it's not as elegant as mine. For instance:

''energy is the capacity to do work''

Saying energy is more of a fundamental fluctuation which is a diffused matter, while matter is a concentrated form of energy is absolutely correct within the framework of Einstein's energy-mass equation.

https://www.physicsforums.com/showthread.php?t=509191 It's their word against yours. I think "absolutely correct" is a rather strong classification of your statement.

 

[Kahlua]

I like to think of energy in relation to Noether's theorem. Her theorem states that any differentiable symmetry of the action has a corresponding conservation law (or conserved current). Symmetries of space and time correspond to conservation of linear momentum and conservation of energy. This gives a geometric understanding of energy, and relates it to the least action variational principle, which I find particularly attractive because it works fine as a universal principle of nature even without us having to chose a coordinate system, and therefore "space and time" can sort of emerge from such a theory (which is generally not the case of certain very popular unification theories...).
To me Emmy Noether did one of the most important insights of all in physics for this reason, but obviously the above discussion also need to be extended to general relativity and quantum physics where we find additional, but consistent insights into what energy is (or rather "how" it is...). The last word about energy has certainly not been said since energy is an integral part of the quest for a grand unified theory...

Anyway, a more common everyday description of energy is to say that "energy is the ability of a system to do work on another system". I can probably come up with 10 other descriptions of energy that shed light to the physics of light, quantum fluctuations, nuclear physics, reaction chemistry, and so on. And they are all same, same but different ;-)

 

[Drakkith]

I really really don't understand why this is even an issue. Looking at the basic definition of energy and understanding the effects of energy conversions will immediately show you that the term energy only describes the interaction between objects. Mass, momentum, velocity, and pretty much every other physical property can be converted into a type of energy. Why? Because all of these things determine how objects interact. Without these fundamental properties energy has no meaning.

In contrast, you cannot convert mass to charge, or velocity to momentum. These are properties used to find energy. Energy is a "catch all" term to easily describe interactions.

 

[Kiril]

I really really don't understand why this is even an issue. Looking at the basic definition of energy and understanding the effects of energy conversions will immediately show you that the term energy only describes the interaction between objects. Mass, momentum, velocity, and pretty much every other physical property can be converted into a type of energy. Why? Because all of these things determine how objects interact. Without these fundamental properties energy has no meaning.

In contrast, you cannot convert mass to charge, or velocity to momentum. These are properties used to find energy. Energy is a "catch all" term to easily describe interactions.

Its not an issue only if you convince yourself that your right or that you have a complete answer - and that you understand the terms your using - and if you understand what is required for understanding - and if you know the proper method of forming definitions - and you are sure you understand the connection between concepts(universals) and concretes; between mathematics and reality.

Its really no problem otherwise - and its really really not a problem if you accept that the multiplication of two numbers is an immediate description of things in reality.

 

[Drakkith]

Its not an issue only if you convince yourself that your right or that you have a complete answer - and that you understand the terms your using - and if you understand what is required for understanding - and if you know the proper method of forming definitions - and you are sure you understand the connection between concepts(universals) and concretes; between mathematics and reality.

Its really no problem otherwise - and its really really not a problem if you accept that the multiplication of two numbers is an immediate description of things in reality.

Hrmm. This seems like a complicated way of saying "You don't know what you are talking about". Is that what you were getting at?

 

[Kiril]

Hrmm. This seems like a complicated way of saying "You don't know what you are talking about". Is that what you were getting at?

That depends on what you mean. That's what I mean; are the requirements for 'knowing what one is talking about'.

What part of it is superfluous, that you decided to call it "...[over] complicated"?

 

[Drakkith]

That depends on what you mean. That's what I mean; are the requirements for 'knowing what one is talking about'.

What part of it is superfluous, that you decided to call it "...[over] complicated"?

You will start making sense NOW or I WILL get the hose out!

 

[Dale]

Kiril, I agree with Drakkith, I have no idea what you are trying to say. Try to express yourself clearly and directly.

 

[Dale]

Science can't answer such fundamental questions as "What is energy?"

This is incorrect. The answer to any question of the form "What is X" is the definition of X. So "What is energy?" is completely and fully answered by the definition "Energy is the capacity to do work."

It also doesn't matter if you put if you put the word "is" in capitals or not. For example: Energy IS the capacity to do work.

 

[Claude Bile]

not at all: in fact you have it backwards. Science can't answer such fundamental questions as "What is energy?" or "What is mass?"

I regard this as a false tautology. Science can't explain what energy (for example) is in more fundamental terms yet, but surely has the capacity to in the future.

Consider all the quantities that were once regarded as fundamental, that have since been shown to be not so fundamental.

Claude.

 

[simpatico]

The answer to any question of the form "What is X" is the definition of X. .

This remark introduces us to the hearth of the issue.

you may see 'definition' at wikipedia (...)

As you see, it is a thorny issue because besides linguistics (semantics), epistemology we need to turn to ontology (bad word!)
because what is x is asking for the essence of x.

To make a long story short:
(we must avoid circular definition, that is begging the question.
We cannot reply
energy is mc^2 ( the sign = substitutes IS)
because mass itself is defined on energy (mass is a-form-of /trapped energy))

In the case of an object there is a shortcut.
ostensive definition
what is a mango? , and I produce a mango

but often this is not enough and we turn to:
functional definition,
when x does not carry in itself a functional definition
(dishwasher)
...
Now, coming to our issue

WHAT IS ENERGY ?
can be answered in several ways,
it is rather easy, as, even it is not an object, it is a
universally known concept

if it is a baby asking you can give him practical definition
lift that chair !

If you want a technical definition
you must list its qualities, properties, characteristics
physics can help, but not a lot, as it has never really tackled the problem as such
and , as you well know, physics has seven basic units but
there is no one specific unit of energy

If you are at all interested to know how would I answer the question,
I'd say something at the same time (technical) physical and metaphysical

Energy is just POWER to change the world

 

[Drakkith]

Again, as has been stated multiple times, MASS IS NOT ENERGY. IT IS MASS.
Mass is not made of energy, it is not a form of energy, it is a fundamental property that has certain observable features.

Is there something with the basic definitions of science that just don't sit right with people?

because what is x is asking for the essence of x.

What is the essence of x? What is it asking for? The only answer, as Dalespam said, is to give the definition of x. Not enough? Describe its properties, functions, and forms. Still not enough? Then you aren't asking What is x. You are saying "I don't believe that the definition of X is correct, and I would like something else."

Lets see what happens with a practical example.

"What is eating?"

"Eating is the process of getting food, preparing that food for digestion by putting it into your mouth, chewing it, and then swallowing it. AKA it is the process of ingesting food."

"I don't like that definition. There has to be more to it at a fundamental perceptual emotional physical universal spiritual level."

"What? We have defined eating just as that."

"I think we are all made out of eating. Because if it wasn't for that then nothing could happen. In fact, Hamstein's equation Eating = Hamburger x Swallowing^3 shows that Hamburgers and Eating are the same. So hamburgers are also made out of eating."

"No, that just shows that putting Hamburgers into your mouth and swallowing them equates to eating."

I agree with BlueTextGuy! Understanding Eating is beyond the comprehension of mortal minds, our only way to figure it out is to avoid backing ourselves into a definition corner!

You guys have completely ruined my lunch...and no, you cannot have my Hamburger. I'm going to eat it later.

 

[simpatico]

The only answer, as Dalespam said, is to give the definition of x. Not enough? Describe its properties, functions, and forms.]

You are quite right so far, but...

...I tried to explain in synthesis that definition is a very complex exercise, issue
I said thorny
If my exposition is not clear or convincing, check with academic essays.

There are several levels you are trying to demostrate, well that was agreed and settled
what is a mango?
...This is a mango defines the looks of x, tells: how to recognize it
...mango is a tropical fruit tells...
...mango contains vitamins, antocyanins tells...
...mango is moderately laxative and so on...
Then you are forgetting another fundamental disctinction between an object a concept

what is a mango ? requires different attention from
what is love ?,

but I won't go through that.

as far as mass is concerned, I am not an expert, I am a linguist but I reckon it was
Einstein himself who spoke of mass as a form of energy.
If you sure of the contrary, please offer a link

 

[Drakkith]

I agree 100% with what you just said Simpatico. I wasn't trying to infer that the definition of something wasn't a complex issue. But when we speak of concepts in science, one MUST be aware of the basic definitions of its terms or there isn't any point in defining them! Take a quick look at the E=MC2 article on Wikipedia, it explains that the equation doesn't mean that energy is equal to mass, but that energy carries with it mass, as in the case of missing mass after a nuclear or chemical reaction.