Impossible Barriers and such?

[Koby]

Any thought on what other things,principles and ideas that can never be proved wrong?

 

For example:

Law of energy conservation states that energy can neither be destroyed nor created, only that it can only be transformed.

 

Perpetual Mechanical Motion

 

Perfect Vacuum and Purity in substance.

 

 

Any other things to add? and another question...why is heat the most useless kind of energy?

[zapatos]

Any thought on what other things,principles and ideas that can never be proved wrong?

 

For example:

Law of energy conservation states that energy can neither be destroyed nor created, only that it can only be transformed.

You need to be careful when saying 'never'. It is possible to falsify scientific laws.

[Greg H.]

another question...why is heat the most useless kind of energy?

 

Useless is a subjective term. I imagine someone freezing to death would find heat to be very useful indeed.

[swansont]

Any thought on what other things,principles and ideas that can never be proved wrong?

 

For example:

Law of energy conservation states that energy can neither be destroyed nor created, only that it can only be transformed.

It's not that you can never prove this wrong, it's that to do so, you would have to show that the laws of physics are changing with time. As that does not appear to be the case, we have a conservation law.

 

 

Any other things to add? and another question...why is heat the most useless kind of energy?

Because it's not? Some context would be helpful here.

[Didymus]

Energy is constantly being created. Gravity is produced by all massive bodies and will never "run out.". This energy is directly harnessable (the tides move because of gravity, wind power and hydroelectric plants are all methods of harnessing gravity).

 

So, that one's shot.

 

As for perpetual motion.... We're floating around on a big perpetually moving rock right now. An object in orbit will never stop falling because gravity will never run out (unless thé system is altered by an outside force, or imbalanced by the sun deteriorating or whatnot).

 

"impossible" is another word for "I'm too lazy to find the exception."

Or, swan, that the law was based on assumption that was nevet correct to begin with. The earth didn't start orbiting the sun when the scientific community accepted the idea. The universe is what it is, and it would be foolish to limit the universe because we're too ignorant/stubborn to understand it's infinite simplicity.

[MigL]

I beg to differ.

This big 'perpetually' moving rock is falling or orbiting about the sun because energy is conserved. Certainly not because gravity is 'creating' energy.

[Didymus]

Wrong scale. Why does steam rise? Because it be ones less dense than surrounding air that falls underneith it, pushing it up.

 

Are you just suggesting that gravity isn't energy? Or do you seriously propose that a massive body can "run out" of that energy?

 

...air circulating (due to gravity) is harvested in wind energy.

 

 

Why does rain fall? When the droplets become heavier than the air, it falls... These drops accumulate into rivers, which gravity pulls downhill.... This water rolling down hill is funneled through generators in dams.... Hydroelectricity... From gravity.

 

As to your claim that an orbit is only sustained by a conservation of enery.... The moon's gravitational pull on the tides.... Constantly exerting force on our planet, we can pull a ton of energy from tidal shifts, without the moon ever "running out of gravity."

[swansont]

Energy is constantly being created. Gravity is produced by all massive bodies and will never "run out.". This energy is directly harnessable (the tides move because of gravity, wind power and hydroelectric plants are all methods of harnessing gravity).

And the thing is, the moon is receding and the earth is slowing down as a result. Energy is conserved. Gravity is not "creating" any.

 

So, that one's shot.

 

As for perpetual motion.... We're floating around on a big perpetually moving rock right now. An object in orbit will never stop falling because gravity will never run out (unless thé system is altered by an outside force, or imbalanced by the sun deteriorating or whatnot).

 

"impossible" is another word for "I'm too lazy to find the exception."

Or, swan, that the law was based on assumption that was nevet correct to begin with. The earth didn't start orbiting the sun when the scientific community accepted the idea. The universe is what it is, and it would be foolish to limit the universe because we're too ignorant/stubborn to understand it's infinite simplicity.

I don't think anyone is claiming that the orbits only started when we noticed them and accepted the idea; that's backwards from how history played out. Conservation of energy, like orbits, is an observation of how the universe behaves.

[Didymus]

So, rather than simply a wonkey trajectory or any number of possible variables... You actually believe that an object such as the moon can eventually run out of gravity?

 

Do you believe black holes can run out of gravity as well?

 

.... I mean.... Sure, perhaps you've stubled across what big bangers have been looking for since the theory came around: if the universe were in a state of singularity, with the combined masses of all black holes in the universe (and all other matter), infinitely dense.... How could it have exploded with no outside source of energy? Without time or space even existing outside of that singularity.... Maybe the collective universe ran out of gravity once.... Long enough for the big bang, then it got it back real quick so that galexies could start forming!

 

.... That would require some pretty fancy evidence, though.

[Delta1212]

Gravity isn't constantly generated energy. It does not, therefore, need to run out for energy to be conserved.

[Didymus]

Are you just disagreeing because of the term used?

 

How would you phrase it if I had a radioactive material that continually gave off a force that could be used to generate electricity? And when this material applies force to the generator, nothing is lost from that material... I.e. it has no finite limit and could continue to generate electricity until the mechanism degraded.

 

Would you call this possible?

[swansont]

Are you just disagreeing because of the term used?

 

How would you phrase it if I had a radioactive material that continually gave off a force that could be used to generate electricity? And when this material applies force to the generator, nothing is lost from that material... I.e. it has no finite limit and could continue to generate electricity until the mechanism degraded.

 

Would you call this possible?

No, not possible. You aren't describing a radioactive material; if you were, the mass would decrease and it would be untrue that "nothing is lost" from the material and would also decrease in energy release over time.

[doG]

Law of energy conservation states that energy can neither be destroyed nor created, only that it can only be transformed.

 

Actually:

In physics, the law of conservation of energy states that the total energy of an isolated system cannot change—it is said to be conserved over time. Energy cannot be created or destroyed, but can change form; for instance, chemical energy can beconverted to kinetic energy.

 

 

 

An object in orbit will never stop falling because gravity will never run out (unless thé system is altered by an outside force, or imbalanced by the sun deteriorating or whatnot).

 

Ummmmmmmm......NO!

 

As an example:

 

 

 

The Moon is gradually receding from the Earth into a higher orbit, and calculations^[9][10] suggest that this would continue for about fifty billion years.

Edited August 17, 2013 by doG

[MigL]

According to Didymus "an object in orbit will never stop falling because gravity will never run out". I don;t think he understands gravity too well because the object will stop falling once it hits the ground and the gravitational potential energy which transformed into kinetic energy will finally become heat. He forgets that work had to be done originally to raise the object to the height from which it fell. Energy IS conserved.

According to our best theory of gravity an orbiting object has no work done or force applied to it, it simply goes about its business in uniform motion along a 'straight' line defined by the curved space-time of the gravitator.

[Didymus]

I've heard the theory that the moon's receding before. Possible... but do you believe it's more likely a matter of trajectory, or do you honestly believe that the effect of the gravity between the earth and moon is actually causing both to recede from each other? (Or do you actually suggest that a loss of energy is restricted to the moon? It's gravitational effect on our planet is causing it to lose energy, while our own planet does not?)

Honest question here, because I haven't been too interested in planetary orbits... Are all moons receding from their planets? Are all planets receding from the sun? Because, although we're a bit farther away from the sun, and the earth is a bit less massive compared to the sun than the moon is compared to the earth... but, you realize all of our planets do affect the sun to an extent. So, if the suggestion that the moon's gravity producing a measurable force on the earth is causing it to recede has any merit... all objects in orbit should be receding from what they're orbiting...

Is that the case? Or, is your theory completely shot?

According to Didymus "an object in orbit will never stop falling because gravity will never run out". I don;t think he understands gravity too well because the object will stop falling once it hits the ground and the gravitational potential energy which transformed into kinetic energy will finally become heat. He forgets that work had to be done originally to raise the object to the height from which it fell. Energy IS conserved.

 

According to our best theory of gravity an orbiting object has no work done or force applied to it, it simply goes about its business in uniform motion along a 'straight' line defined by the curved space-time of the gravitator.

 

 

psst... even when an object is on the ground... gravity's still applying a constant force. It's not just an altered trajectory due to curved "spacetime."

For a pretty quick example... try being on the surface of the planet. Notice you still have a weight. Even when sitting still. Your body is being compressed. Your body has to resist this force in order not to flatten. For example, a tower of legos. If gravity's pull becomes greater than the structure's ability to resist gravity's pull... the structure falls down under it's own weight... even though it's still touching the ground.

[doG]

I've heard the theory that the moon's receding before. Possible... but do you believe it's more likely a matter of trajectory, or do you honestly believe that the effect of the gravity between the earth and moon is actually causing both to recede from each other? (Or do you actually suggest that a loss of energy is restricted to the moon? It's gravitational effect on our planet is causing it to lose energy, while our own planet does not?)

 

It's called tidal acceleration...

[swansont]

I've heard the theory that the moon's receding before.

Not just theory. Experiment. measured. http://eclipse.gsfc.nasa.gov/SEhelp/ApolloLaser.html

 

psst... even when an object is on the ground... gravity's still applying a constant force. It's not just an altered trajectory due to curved "spacetime."

 

For a pretty quick example... try being on the surface of the planet. Notice you still have a weight. Even when sitting still. Your body is being compressed. Your body has to resist this force in order not to flatten. For example, a tower of legos. If gravity's pull becomes greater than the structure's ability to resist gravity's pull... the structure falls down under it's own weight... even though it's still touching the ground.

And if you're just sitting there, no work is being done, so there is no change in energy. No energy is being added to the system by gravity.

[Didymus]

Then you get into the questions about the experiment... So light took an extra... what? 4(10^-11) seconds on average? This assumes the 3.8 centimeter measurement is accurate considering the margin of error is listed at 3 centimeters... which very well could indicate a fraction of a centimeter change, which could be friggin thermal expansion. Could be unaccounted for changes in the atmosphere (light only travels at C through a vacuum). Could be tectonic movements on either the earth or moon... or perhaps an underestimated margin of error.

Even assuming all variables have been accounted for and the experiment accurate... how was tidal acceleration definitively identified as the cause?


(I'd be most interested to see if there were a red shift/blue shift at the moment of the measurement. But that's an entirely different topic)

[swansont]

Then you get into the questions about the experiment... So light took an extra... what? 4(10^-11) seconds on average? This assumes the 3.8 centimeter measurement is accurate considering the margin of error is listed at 3 centimeters... which very well could indicate a fraction of a centimeter change, which could be friggin thermal expansion. Could be unaccounted for changes in the atmosphere (light only travels at C through a vacuum). Could be tectonic movements on either the earth or moon... or perhaps an underestimated margin of error.

 

 

Margin of error for the distance and margin of error for the recession rate are separate errors. Each distance measurement has an error of ~3 cm, but measurements made over a decade (and they've been doing them since 1969) will have a difference of 38 cm, so no, there is not a "fraction of a cm change"

[Didymus]

Sure. Assuming that to be accurate, what leads people to believe the moon's recession is caused by gravity lessening?

 

If the moon's effect on us were to be reducing its gravitational capacity.... Surely the earth is expending its gravity even faster as the earth is effecting the moon far more than the moon effects the earth. In addition the earth must be reseeding from its orbit due to all other massive bodies affected by earth's gravity.... Such as the sun.

Edited August 20, 2013 by Didymus

[doG]

Like I said, assuming this is correct... What leads us to believe the only probable explanation is that the moon's gravitational effect is making it run out of gravity?

It has nothing to do with running out of gravity. The moon's mass is constant and so is it's mass. Over time tidal forces between rotating bodies dissipate their rotational kinetic energy eventually leading to tidal locking. As this occurs the smaller of the two bodies recedes from the larger. Maybe you should try reading some physics....

[Didymus]

Maybe you came in late in the convo....

 

The topic is barriers that can't be broken... First example was the conservation of energy... Energy can't be created or destroyed. This lead to the idea that gravity is a constant force that can be harnessed quite a few ways to generate energy (such as electromotive force) without reducing the force of gravity.... Thus new energy.

 

The dissent said that energy pulled from falling water really came from the sun's heat (even though without gravity pulling cooler gasses down, the steam would not rise so that it could fall later). Ditto for wind power.

 

They said that geothermal energy doesn't count as they believe the heat of earth's core has nothing to do with the pressure down there... But instead comes from radiation that will eventually run out. (Similar story for solar energy. Apparently a stars mass doesn't contribute to its heat at all)

 

The current conversation regards tidal energy. Not too widely utilized, but no way to get around the work the moon does pulling the oceans around. I don't give a hoot about the moon's rotational speed, so long as it's gravitational field effects us to pull water around for us to use. They respond that this process is the cause of the moon losing energy and thus receding. I buy that there is torque on the moon that could put its rotation in synch with us.... Maybe even reverse it, perhaps. I even buy that it could be receding... But to use this to insinuate that gravity holds to the concept that energy can't be created and that all of the work the moon's gravity has done since the moon has been around.... Is somehow a finite amount that will eventually run out.... That's just silly.

 

(note, typing on cell phone on a quick lunch break, so try to forgive the typos)

[zapatos]

The topic is barriers that can't be broken... First example was the conservation of energy... Energy can't be created or destroyed. This lead to the idea that gravity is a constant force that can be harnessed quite a few ways to generate energy (such as electromotive force) without reducing the force of gravity.... Thus new energy.

Perhaps I am misunderstanding, but how do you utilize gravity for generating energy without adding energy to the system? For example, it takes energy to raise water, a rock, whatever, so that thing can then be pulled down by gravity.

Without ever adding energy to raise something, how do you get to utilize gravity to harness energy?

 

It sounds like you are not reducing the force of gravity, but gravity cannot be used to generate energy (say, via a dam), unless the energy from the sun is put into the system.

 

Cut off the sun and water will quickly stop running downhill.

 

This really sounds no different than my Honda generator. It can generate electricity, but only if a source of energy (fuel) enters the system (gas tank). I wouldn't say my generator is a source of new energy. It is just the tool used to convert energy from one form to another.

Edited August 20, 2013 by zapatos

[Didymus]

That's why tidal energy is the most solid example. Moon pulls water, water pushes turbine, electricity.

 

As for the sun.. yes, it helps heat water.... But not as Mich as you would think. Imagine a lake at the bottom of a mountain. The sun hits both equally, yet the mountain's snow may not be close to melting even while the water in the lake at the bottom is evaporating. Same energy from the sun.... Vastly different results.

 

Part of this is because higher altitudes have less atmosphere insulating them. True. But also, the mountain top is farther from the warmth of the earth's core.

 

The combined heat turns some water into gas... But that's not where the majority of the energy comes from... If you vaporize water, then let it condense back into water... You won't gain squat.

 

Rivers can be tapped for energy because of gravity. Gravity pulls dense air down, which flows under the vapor, displacing it, and raising it hundreds or thousands of feet up. Also, consider that rivers aren't limited to a single dam. If you didn't care about fish, you could have generators and mills back to back, as long as it remained the path of least resistance, the same drop going down a river could power thousands of dams and water mills on a long enough river.

 

Yes... The sun helps a bit.... But gravity is the muscle behind hydro electricity.

 

.... And I believe gravity is the power behind the sun as well. There is definitely a chemical component as well... But look at all the stars out there with the same elements.... Producing different amounts of energy based on their mass. I suspect that the chemical reactions are just dominos falling... That the power behind stars are primarily their mass.

 

How often do you see stars orbiting non-stars?

[zapatos]

That's why tidal energy is the most solid example. Moon pulls water, water pushes turbine, electricity.

But the earth and moon will eventually experience tidal lock. Every time we have a tide, some of the rotation energy is transferred to the tides from which you propose to generate energy. Unless you add energy, eventually you will no longer have tides an you will not be able to harness them. Unless you are saying that tidal locking does not occur...

 

As for the sun.. yes, it helps heat water.... But not as Mich as you would think. Imagine a lake at the bottom of a mountain. The sun hits both equally, yet the mountain's snow may not be close to melting even while the water in the lake at the bottom is evaporating. Same energy from the sun.... Vastly different results. Part of this is because higher altitudes have less atmosphere insulating them. True. But also, the mountain top is farther from the warmth of the earth's core.

I don't understand your point. Different environments respond differently to sunlight. Why is that significant?

 

Rivers can be tapped for energy because of gravity. Gravity pulls dense air down, which flows under the vapor, displacing it, and raising it hundreds or thousands of feet up. Also, consider that rivers aren't limited to a single dam. If you didn't care about fish, you could have generators and mills back to back, as long as it remained the path of least resistance, the same drop going down a river could power thousands of dams and water mills on a long enough river.

 

Yes... The sun helps a bit.... But gravity is the muscle behind hydro electricity.

Are you suggesting that in the absence of the sun it will keep raining on earth and rivers will keep flowing?

 

.... And I believe gravity is the power behind the sun as well. There is definitely a chemical component as well... But look at all the stars out there with the same elements.... Producing different amounts of energy based on their mass. I suspect that the chemical reactions are just dominos falling... That the power behind stars are primarily their mass.

Are you suggesting that stars will 'burn' indefinitely?

 

How often do you see stars orbiting non-stars?

I'm not sure what you mean by that. But to be pedantic, orbiting stars are orbiting the system's center of mass. The stars in the Milky Way are orbiting the center of mass of the galaxy and the sub-system they are a part of.