John, Falling apart. What everything does (eventually). What you and I are doing right now (getting older, and falling apart). Austin John Smith wrote:> "Kevin Neilson" <kevin_neilson@removethiscomcast.net> wrote in message > news:ZzCob.71991$Fm2.57178@attbi_s04... > > I read an article in "Scientific American" about how much information can > be > > compressed into a certain volume, and apparently all objects have a > Shannon > > entropy in addition to the thermodynamic entropy. Also, black holes have > a > > Shannon entropy that is based on the surface area of the event horizon. I > > was totally lost. Can anybody else explain how Shannon's information > > theory applies to black holes? > > -Kevin > > > > > > For the ignorant (me): what it Entropy? > > Rich
Shannon Entropy for Black Holes
Started by ●October 31, 2003
Reply by ●November 3, 20032003-11-03
Reply by ●November 3, 20032003-11-03
"Austin Lesea" <Austin.Lesea@xilinx.com> wrote in message news:3FA3000A.45C10F96@xilinx.com...> Kevin, > > Really quite easy. > > Just read http://www.mdpi.org/entropy/papers/e3010012.pdf > > Now after you have read it, go get a stiff drink ....and then fall into a > troubled sleep. > > As you toss and turn having nightmares about information horizons, andgravity> strings, remember what the White Rabbit said: "feed your hair." >I thought it was "feed your head."
Reply by ●November 3, 20032003-11-03
John Smith wrote:> "Kevin Neilson" <kevin_neilson@removethiscomcast.net> wrote in message > news:ZzCob.71991$Fm2.57178@attbi_s04... > >>I read an article in "Scientific American" about how much information can > > be > >>compressed into a certain volume, and apparently all objects have a > > Shannon > >>entropy in addition to the thermodynamic entropy. Also, black holes have > > a > >>Shannon entropy that is based on the surface area of the event horizon. I >>was totally lost. Can anybody else explain how Shannon's information >>theory applies to black holes? >>-Kevin >> >> > > > For the ignorant (me): what it Entropy? > > Rich >http://www.2ndlaw.com/ will be a good start. Note that if S is entropy, q the amount of heat -- BTU, Calories -- and T absolute temperature, S = Integral(dQ/T). Simplifying: heat, like water, runs downhill, and unless something like a waterwheel or a heat engine extracts energy when it does, some of what had been available energy is permanently lost. The water or heat is all still there, and so is the energy -- just not available. Lost available energy shows up as increased entropy. Two Laws of Thermodynamics have been stated thus: You can't get something for nothing. Water had to be pumped up before it ran down to turn the wheel. You can't even break even. (The second law is about entropy.) Because of inevitable inefficiencies -- friction or moving heat across a temperature gradient, entropy will increase, and you won't get all of the energy out. Let's leave the Third Law for some other time. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●November 3, 20032003-11-03
santosh nath wrote:> > I am really curious to know how thermodynamic entropy differs from > Shannon'sThere is some controversy about this. The two ideas are fundamentally distinct and it is unfortunate that they have the same name. They are related, of course, but the relationship is something that has to be spelled out carefully. In my opinion the best work on this is a paper Ed Jaynes wrote for the Am. J. Phys. You'll find it here: http://bayes.wustl.edu/etj/node1.html "Gibbs vs. Boltzmann Entropies", article 21. I believe Anton Garrett wrote a lengthy paper spelling it out further based on Jaynes's argument; I think it was in *Foundations of Physics* several years ago. This isn't trivial stuff; good luck studying it! -Tom -- To respond by email, replace "somewhere" with "astro" in the return address.
Reply by ●November 3, 20032003-11-03
> > Kevin Neilson wrote: > > > Can anybody else explain how Shannon's information > > > theory applies to black holes? > > > > Sounds like just the place for a > > First In Never Out (FINO) transmit buffer. > > > > -- Mike Treseler > > I had to debug somebody else's hardware that implemented a FINO > > He had invented the wonderful new memory type... 2K by 8 WOM > > Write-Only Memory :-) > > IanIan, Signetics invented this 30 years ago! try :- http://www.ariplex.com/tina/tsignet1.htm Syms.
Reply by ●November 4, 20032003-11-04
"Jerry Avins" <jya@ieee.org> wrote in message news:bo69ks$a3e$1@bob.news.rcn.net...> John Smith wrote: > > > "Kevin Neilson" <kevin_neilson@removethiscomcast.net> wrote in message > > news:ZzCob.71991$Fm2.57178@attbi_s04... > > > >>I read an article in "Scientific American" about how much informationcan> > > > be > > > >>compressed into a certain volume, and apparently all objects have a > > > > Shannon > > > >>entropy in addition to the thermodynamic entropy. Also, black holeshave> > > > a > > > >>Shannon entropy that is based on the surface area of the event horizon.I> >>was totally lost. Can anybody else explain how Shannon's information > >>theory applies to black holes? > >>-Kevin > >> > >> > > > > > > For the ignorant (me): what it Entropy? > > > > Rich > > > http://www.2ndlaw.com/ will be a good start. Note that if S is entropy, q > the amount of heat -- BTU, Calories -- and T absolute temperature, > S = Integral(dQ/T). > Simplifying: heat, like water, runs downhill, and unless something like a > waterwheel or a heat engine extracts energy when it does, some of what > had been available energy is permanently lost. The water or heat is all > still there, and so is the energy -- just not available. Lost available > energy shows up as increased entropy. > > Two Laws of Thermodynamics have been stated thus: > > You can't get something for nothing. Water had to be pumped up before it > ran down to turn the wheel. > > You can't even break even. (The second law is about entropy.) Because of > inevitable inefficiencies -- friction or moving heat across a temperature > gradient, entropy will increase, and you won't get all of the energy out. > > Let's leave the Third Law for some other time. > > Jerry > -- > Engineering is the art of making what you want from things you can get. > ����������������������������������������������������������������������� >Aggghhhh.... I'm gonna be on 2ndlaw.com, and its sister, I may be a while... Thanks for the answers guys. 'Lost' energy (non-recoverable energy) is my summary. Correct? Thanks again JS
Reply by ●November 4, 20032003-11-04
John, Nope. 1st law says that energy is conserved. Can not lose it. Austin John Smith wrote:> "Jerry Avins" <jya@ieee.org> wrote in message > news:bo69ks$a3e$1@bob.news.rcn.net... > > John Smith wrote: > > > > > "Kevin Neilson" <kevin_neilson@removethiscomcast.net> wrote in message > > > news:ZzCob.71991$Fm2.57178@attbi_s04... > > > > > >>I read an article in "Scientific American" about how much information > can > > > > > > be > > > > > >>compressed into a certain volume, and apparently all objects have a > > > > > > Shannon > > > > > >>entropy in addition to the thermodynamic entropy. Also, black holes > have > > > > > > a > > > > > >>Shannon entropy that is based on the surface area of the event horizon. > I > > >>was totally lost. Can anybody else explain how Shannon's information > > >>theory applies to black holes? > > >>-Kevin > > >> > > >> > > > > > > > > > For the ignorant (me): what it Entropy? > > > > > > Rich > > > > > http://www.2ndlaw.com/ will be a good start. Note that if S is entropy, q > > the amount of heat -- BTU, Calories -- and T absolute temperature, > > S = Integral(dQ/T). > > Simplifying: heat, like water, runs downhill, and unless something like a > > waterwheel or a heat engine extracts energy when it does, some of what > > had been available energy is permanently lost. The water or heat is all > > still there, and so is the energy -- just not available. Lost available > > energy shows up as increased entropy. > > > > Two Laws of Thermodynamics have been stated thus: > > > > You can't get something for nothing. Water had to be pumped up before it > > ran down to turn the wheel. > > > > You can't even break even. (The second law is about entropy.) Because of > > inevitable inefficiencies -- friction or moving heat across a temperature > > gradient, entropy will increase, and you won't get all of the energy out. > > > > Let's leave the Third Law for some other time. > > > > Jerry > > -- > > Engineering is the art of making what you want from things you can get. > > ����������������������������������������������������������������������� > > > > Aggghhhh.... I'm gonna be on 2ndlaw.com, and its sister, I may be a while... > > Thanks for the answers guys. 'Lost' energy (non-recoverable energy) is my > summary. Correct? > > Thanks again > JS
Reply by ●November 7, 20032003-11-07
Austin Lesea wrote:> > John, > > Nope. 1st law says that energy is conserved. Can not lose it. > > Austin > > John Smith wrote: > > > > Aggghhhh.... I'm gonna be on 2ndlaw.com, and its sister, I may be a while... > > > > Thanks for the answers guys. 'Lost' energy (non-recoverable energy) is my > > summary. Correct? > > > > Thanks again > > JSJohn, Don't let this confuse you. In reality "lost" energy is still energy. But it is lost in the sense that you can't do anything useful with it. It becomes spread out evenly as heat otherwise known as "disorder". Only "orderly" forms of energy can be used. Heat is only useful (orderly) if there is more of it here than there, then you can get some useful work from it by tapping it as it flows from here to there. But then both here and there are at the same temperature and you can do no more work with that energy. In that sense, it is "lost". -- Rick "rickman" Collins rick.collins@XYarius.com Ignore the reply address. To email me use the above address with the XY removed. Arius - A Signal Processing Solutions Company Specializing in DSP and FPGA design URL http://www.arius.com 4 King Ave 301-682-7772 Voice Frederick, MD 21701-3110 301-682-7666 FAX
Reply by ●November 7, 20032003-11-07
"rickman" <spamgoeshere4@yahoo.com> wrote in message news:3FAB4DAA.28A58C19@yahoo.com...> Austin Lesea wrote: > > > > John, > > > > Nope. 1st law says that energy is conserved. Can not lose it. > > > > Austin > > > > John Smith wrote: > > > > > > Aggghhhh.... I'm gonna be on 2ndlaw.com, and its sister, I may be awhile...> > > > > > Thanks for the answers guys. 'Lost' energy (non-recoverable energy) ismy> > > summary. Correct? > > > > > > Thanks again > > > JS > > John, > > Don't let this confuse you. In reality "lost" energy is still energy. > But it is lost in the sense that you can't do anything useful with it. > It becomes spread out evenly as heat otherwise known as "disorder". > Only "orderly" forms of energy can be used. > > Heat is only useful (orderly) if there is more of it here than there, > then you can get some useful work from it by tapping it as it flows from > here to there. But then both here and there are at the same temperature > and you can do no more work with that energy. In that sense, it is > "lost". > > -- > > Rick "rickman" Collins > > rick.collins@XYarius.com > Ignore the reply address. To email me use the above address with the XY > removed. > > Arius - A Signal Processing Solutions Company > Specializing in DSP and FPGA design URL http://www.arius.com > 4 King Ave 301-682-7772 Voice > Frederick, MD 21701-3110 301-682-7666 FAXRick I did get the drift of it, hopefully the previous poster hadn't had his morning coffee yet. Thanks JS
Reply by ●November 7, 20032003-11-07
In comp.arch.fpga rickman <spamgoeshere4@yahoo.com> wrote: : Don't let this confuse you. In reality "lost" energy is still energy. : But it is lost in the sense that you can't do anything useful with it. : It becomes spread out evenly as heat otherwise known as "disorder". : Only "orderly" forms of energy can be used. Energy: Total Exergy: Usable part of total energy Anergy: Unusable part of total energy : Heat is only useful (orderly) if there is more of it here than there, : then you can get some useful work from it by tapping it as it flows from : here to there. But then both here and there are at the same temperature : and you can do no more work with that energy. In that sense, it is : "lost". Bye -- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
