[juanrga]

gib65, on 10 December 2004 - 05:15 PM, said:

I googled for "define: entropy" and came up with this:

"A measure of the disorder in a system."

I also entered "entropy" into www.dictionary.com and found, among other definitions:

"The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity."

So if I understand this correctly, entropy is the phenomenon observed when, for instance, an elastic band goes from stretched to slack or a building going from erect to rubble when demolished by means of explosives. Is this correct?

If so, what do we call the opposite phenomenon - that is, the building up of physical systems from something simple with uniformly distributed energy to something more complex and non-uniformly structured?

Those definitions appealing to "disorder" often confound the thermodynamic concept of entropy with the informational concept of entropy.

The opposite phenomenon that you report is creation of structures. It is studied with the concept of entropy as well.

[derek w]

Io the moon of Jupiter gains internal heat due to the gravitational pull of Jupiter,is this entropy in reverse?

[Bill Angel]

juanrga, on 14 April 2012 - 05:19 PM, said:

Those definitions appealing to "disorder" often confound the thermodynamic concept of entropy with the informational concept of entropy.

The opposite phenomenon that you report is creation of structures. It is studied with the concept of entropy as well.

One good example of what you mention is living organisms. We eat food and produce waste heat, but in the process synthesize highly ordered structures (DNA, enzymes, etc). Nevertheless a person's metabolism (via the waste products it produces) increases the overall entropy of the universe.

[swansont]

derek w, on 18 May 2012 - 10:28 AM, said:

Io the moon of Jupiter gains internal heat due to the gravitational pull of Jupiter,is this entropy in reverse?

It's the result of work.

[juanrga]

Bill Angel, on 18 May 2012 - 10:57 AM, said:

One good example of what you mention is living organisms. We eat food and produce waste heat, but in the process synthesize highly ordered structures (DNA, enzymes, etc). Nevertheless a person's metabolism (via the waste products it produces) increases the overall entropy of the universe.

Living organisms are a beautiful example of dissipative structures.

[PeterJ]

Is not the OP simply referring to negative entropy?

[derek w]

ok.If the big bang happened in reverse and the whole universe was to collapse back to a single point would that not be negative entropy?