Thread: Are there any closed systems?

Three questions

Is there a such thing as a closed system considering even an atom is not a closed system?

I can't think of any but if there were wouldn't the average entropy always stay the same?

How can they be so sure that the 2nd law of thermodynamics should even be called a law?

The only closed system so far as Im aware is the universe.

Originally Posted by TheObserver

The only closed system so far as Im aware is the universe.

I thought about that too but we have no way of knowing. Based on the way eveything else is I would guess that its not closed.

Well when I say universe, I mean to include everything, not just the visible universe but anything else that might be out there as well. The universe to me has always meant THE closed system, whatever all that may include.

TheObserver - It depends on whether black holes eventually release all that information they're busy consuming. Or maybe they're transporting it to another dimension? (Like Hawking's suggestion.)

Also insofar as the universe is continually expanding new space is basically appearing out of nowhere, which is not a lot different from the system expanding into an empty system. And also parts of it are continually leaving the Hubble Sphere with respect to one another, which is basically the same as if they were disappearing forever.

i too think the Universe is a closed system. there is no external input of energy and as far as we can tell entropy is only going one way. black holes would just be returning the information they got from this universe.

I think that the idea of a closed system has a similar status to that of a weightless string or a frictionless pulley. These notions are useful in enabling an approximate solution to a problem to be found.

Originally Posted by Chrispen Evan

i too think the Universe is a closed system. there is no external input of energy and as far as we can tell entropy is only going one way. black holes would just be returning the information they got from this universe.

So the only closed system anyone can think of is the whole universe and we don't even know how that system works. I have read that entropy can be redused locally through randum actions creating order out of certain processes such as randum stacking. If the universe like everything else is not a closed system couldn't its entropy also be reduced?

I have read that entropy can be redused locally through randum actions creating order out of certain processes such as randum stacking. If the universe like everything else is not a closed system couldn't its entropy also be reduced?

all the stars in the universe reduce entropy locally. unfortunately they will die in the future so globally entropy goes on.

Originally Posted by Chrispen Evan

I have read that entropy can be redused locally through randum actions creating order out of certain processes such as randum stacking. If the universe like everything else is not a closed system couldn't its entropy also be reduced?

all the stars in the universe reduce entropy locally. unfortunately they will die in the future so globally entropy goes on.

Yes they do and galaxies are doing the same thing with all the stars. It appears local reduced entropy is growing.

Locally entropy can be, and often is reduced. But the star, which is a highly organized low-entropy object, also radiates away energy into space, generally increasing entropy.

Originally Posted by AlexG

Locally entropy can be, and often is reduced. But the star, which is a highly organized low-entropy object, also radiates away energy into space, generally increasing entropy.

So do galaxies and black holes on their north and south axis when there is to much matter being pushed in at one time. But they are still organizing and locally reducing entropy as they grow. I bet a mature and well formed galaxy with perfectly spaced arms would slow and steadily feed the matter into the central black hole without to much being rejected. On the other hand a young or merging galaxies would have far more gamma ray burst as the unorganized matter would sometimes bottlenecks as it was getting pushed into the center.

Originally Posted by TheObserver

The only closed system so far as Im aware is the universe.

but how many dimension ?

Originally Posted by bill alsept

So do galaxies and black holes on their north and south axis when there is to much matter being pushed in at one time. But they are still organizing and locally reducing entropy as they grow. I bet a mature and well formed galaxy with perfectly spaced arms would slow and steadily feed the matter into the central black hole without to much being rejected. On the other hand a young or merging galaxies would have far more gamma ray burst as the unorganized matter would sometimes bottlenecks as it was getting pushed into the center.

Black holes also radiate energy via Hawking radiation, just at a much slower rate. As the black hole's surface area decreases over time, it's temperature increases, accelerating the process. In the end, after a very long time if it was a massive black hole, it just evaporates. The end result is a net increase in the universe's entropy, just as the 2nd law of thermodynamics predicts.

Originally Posted by Markus Hanke

Originally Posted by bill alsept

So do galaxies and black holes on their north and south axis when there is to much matter being pushed in at one time. But they are still organizing and locally reducing entropy as they grow. I bet a mature and well formed galaxy with perfectly spaced arms would slow and steadily feed the matter into the central black hole without to much being rejected. On the other hand a young or merging galaxies would have far more gamma ray burst as the unorganized matter would sometimes bottlenecks as it was getting pushed into the center.

Black holes also radiate energy via Hawking radiation, just at a much slower rate. As the black hole's surface area decreases over time, it's temperature increases, accelerating the process. In the end, after a very long time if it was a massive black hole, it just evaporates. The end result is a net increase in the universe's entropy, just as the 2nd law of thermodynamics predicts.

I believe that all matter whatever its size is always accumulating and can never stop. Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

I believe that all matter whatever its size is always accumulating and can never stop. Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

we are talking trillions of years here for a BH to evaporate, and when that eventually happens there probably wont have been any matter for them to "gulp" for a very long time.

Originally Posted by Chrispen Evan

I believe that all matter whatever its size is always accumulating and can never stop. Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

we are talking trillions of years here for a BH to evaporate, and when that eventually happens there probably wont have been any matter for them to "gulp" for a very long time.

Like I said above I believe matter is always accumulating. Even when it looks like it is not.

Like I said above I believe matter is always accumulating.

or decaying. blackholes will still be around when there is only energy in the universe as all the "matter" particles will have decayed. assuming proton decay happens.

Originally Posted by bill alsept

Originally Posted by Chrispen Evan

I believe that all matter whatever its size is always accumulating and can never stop. Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

we are talking trillions of years here for a BH to evaporate, and when that eventually happens there probably wont have been any matter for them to "gulp" for a very long time.

Like I said above I believe matter is always accumulating. Even when it looks like it is not.

What is the basis for your belief?

Originally Posted by AlexG

Originally Posted by bill alsept

Originally Posted by Chrispen Evan

I believe that all matter whatever its size is always accumulating and can never stop. Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

we are talking trillions of years here for a BH to evaporate, and when that eventually happens there probably wont have been any matter for them to "gulp" for a very long time.

Like I said above I believe matter is always accumulating. Even when it looks like it is not.

What is the basis for your belief?

I have a few ideas but like Markus I'm not ready to lay the whole thing out yet. I do like to discuss possibilities or other ways of looking at things. It helps

Originally Posted by bill alsept

Black holes probably radiate a number of ways but I would think the amount of radiation is far far less than the constant accumulation of matter and an occasional big gulp.

Hawking radiation is the only form of energy loss that has any bearing on the total mass of a black hole. The BH's temperature is inversely proportional to the surface area of its event horizon, i.e. the smaller the BH the hotter it appears.