News tagged with entropy
Physicist Proposes Solution to Arrow-of-Time Paradox
(PhysOrg.com) -- Entropy can decrease, according to a new proposal - but the process would destroy any evidence of its existence, and erase any memory an observer might have of it. It sounds like the plot ...
Aug 27, 2009 |
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Second Law of Thermodynamics May Explain Economic Evolution
(PhysOrg.com) -- Terms such as the "invisible hand," laissez-faire policy, and free-market principles suggest that economic growth and decline in capitalist societies seem to be somehow self-regulated. Now, ...
Nov 02, 2009 |
4.3 / 5 (34) |
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How to Measure What We Don't Know
(PhysOrg.com) -- How do we discover new things? For scientists, observation and measurement are the main ways to extract information from Nature. Based on observations, scientists build models that, in turn, are used to make ...
Sep 10, 2009 |
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Researcher finds optimal fix-free codes
(PhysOrg.com) -- More than 50 years after David Huffman developed Huffman coding, an entropy encoding algorithm used for lossless data compression in computer science and information theory, an electrical ...
Technology / Computer Sciences
Apr 03, 2009 |
4.6 / 5 (22) |
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Prediction or cause? Information theory may hold the key
(PhysOrg.com) -- "A perplexing philosophical issue in science is the question of anticipation, or prediction, versus causality," Shawn Pethel tells PhysOrg.com. "Can you tell the difference between something predicting an eve ...
Sep 30, 2011 |
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Cosmic entropy could be 100 times greater than previously thought
(PhysOrg.com) -- A new analysis of supermassive black holes has discovered the entropy of the universe is much greater than previously thought, which means it may also be very slightly closer to ultimate heat death.
Oct 06, 2009 |
4.3 / 5 (21) |
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Could Maxwell's Demon Exist in Nanoscale Systems?
(PhysOrg.com) -- Maxwell’s demon may be making a comeback. Physicists know that the demon, an imaginary creature that decreases the entropy of a system, cannot exist in macroscopic systems due to the energy ...
Jun 24, 2009 |
4.4 / 5 (19) |
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Sign language puzzle solved
(PhysOrg.com) -- Scientists have known for 40 years that even though it takes longer to use sign language to sign individual words, sentences can be signed, on average, in the same time it takes to say them, ...
Technology / Computer Sciences
Dec 15, 2009 |
4.6 / 5 (18) |
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New entropy battery pulls energy from difference in salinity between fresh water and seawater
(PhysOrg.com) -- A team of researchers, led by Dr. Yi Cui, of Stanford and Dr. Bruce Logan from Penn State University have succeeded in developing an entropy battery that pulls energy from the imbalance of ...
Nanotechnology / Nanomaterials
Mar 25, 2011 |
4.6 / 5 (18) |
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Researchers unlock mystery of how 'handedness' arises
The overwhelming majority of proteins and other functional molecules in our bodies display a striking molecular characteristic: They can exist in two distinct forms that are mirror images of each other, like ...
May 08, 2012 |
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Entropy study suggests Pictish symbols likely were part of a written language
(PhysOrg.com) -- How can you tell the difference between random pictures and an ancient, symbol-based language? A new study has shown that concepts in entropy can be used to measure the degree of repetitiveness ...
Jun 10, 2010 |
4.6 / 5 (15) |
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Holographic dark information energy
Holographic Dark Information Energy gets my vote for the best mix of arcane theoretical concepts expressed in the shortest number of words – and just to keep it interesting, it’s mostly about entropy.
May 30, 2011 |
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The perfect liquid -- now even more perfect
Ultra hot quark-gluon-plasma, generated by heavy-ion collisions in particle accelerators, is supposed to be the "most perfect fluid" in the world. Previous theories imposed a limit on how "liquid" fluids can ...
Jan 17, 2012 |
4.9 / 5 (10) |
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Quantum knowledge cools computers: New understanding of entropy
From a laptop warming a knee to a supercomputer heating a room, the idea that computers generate heat is familiar to everyone. But theoretical physicists have discovered something astonishing: not only do computational processes ...
Jun 01, 2011 |
4.9 / 5 (9) |
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Disorder is key to nanotube mystery
Scientists often find strange and unexpected things when they look at materials at the nanoscale -- the level of single atoms and molecules. This holds true even for the most common materials, such as water.
Nanotechnology / Nanomaterials
Aug 12, 2011 |
4.9 / 5 (9) |
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Entropy
Entropy is a concept applied across physics, information theory, mathematics and other branches of science and engineering. The following definition is shared across all these fields:
where S is the conventional symbol for entropy. The sum runs over all microstates consistent with the given macrostate and is the probability of the ith microstate. The constant of proportionality k depends on what units are chosen to measure S. When SI units are chosen, we have k = kB = Boltzmann's constant = 1.38066×10−23 J K−1. If units of bits are chosen, then k = 1/ln(2) so that .
Entropy is central to the second law of thermodynamics. The second law in conjunction with the fundamental thermodynamic relation places limits on a system's ability to do useful work.
The second law can also be used to predict whether a physical process will proceed spontaneously. Spontaneous changes in isolated systems occur with an increase in entropy.
The word "entropy" is derived from the Greek εντροπία "a turning towards" (εν- "in" + τροπή "a turning").
For more information about Entropy, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
