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We know,i.e. wood/steel tables in earth will completely broken or disappear in a very future day. If we put the table in a perfect/ideal environment (maybe in vacuum), will the disappear/broken still happen again?

"Ideal" means every outside factors, temperature, pressure and gravity etc, is just perfect for the table and the table can endure. Table wouldn't move, only the particles of the table move.

I always think that the movement of the particles eventually makes the table or other physics object die/decay. Every objects decay for the internal cause. I don't know if this is true, so I ask this question.

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What does ideal mean? What's the temperature? Pressure? Is there gravity involved, or is this table floating in the middle of space? Is it impenetrable to light and all radiation? You will need to be much more precise about what this perfect environment is if you want to get a good answer. – kharybdis Mar 10 '11 at 18:59
@Spencer "ideal" means every outside factors, temperature,pressure and gravity etc, is just perfect for the table and the table can endure. table wouldn't move, only the particles of the table moves. – user2475 Mar 10 '11 at 19:04
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If "ideal" means "an environment where the table lasts forever," then yes. Your ideal environment will make the table last forever. But this seems trivial. Specifics on those characteristics of the environment will be the only way to give a non-trivial answer. – kharybdis Mar 10 '11 at 19:08
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@Spencer I always think that the movement of the particles eventually makes the table or other physics object die. I don't know if this is true, so I ask this question. – user2475 Mar 10 '11 at 19:10
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@Georg OK, then a steel table? wood is just a example. – user2475 Mar 10 '11 at 19:17
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2 Answers

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The entropy of a closed system only increases, so if the system is in the state of maximum entropy, it will stay in that state, otherwise it will evolve toward higher entropy.

A wood table is probably not maximum entropy, although it would take some work to define exactly what this means. Wood smithereens spread throughout the entire available volume should have higher entropy. Chemical changes would result in higher entropy as well. Eventually, a wood table in a vacuum should evaporate/dissolve/decay. Doing things like removing all the oxygen from the environment will slow the process down, but the increase of entropy is inevitable.

This is a statistically true. There is a very low probability of entropy decreasing briefly. For example, see the Poincare recurrence theorem. This also ignores cosmological considerations, which seem irrelevant to the question and which I also don't know about.

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Although the question has some vagueness in its conditions there are some further points which might be of interest. In addition to the Thermodynamic property of Entropy mentioned in the other answer we also have the property of Temperature and its Thermodynamics to consider.

The object will (a) approximate a Black Body and will emit thermal radiation reducing its energy over time; and relatedly (b) equalize to the Temperature of its environment.

If we take the environment to be somewhere of the same Temperature as the object initially, then that environment will require an infinite amount of energy over time just to remain at that Temperature. So this is arguably unrealistic. The second law of Thermodynamics will also begin to apply in this environment as some atoms are evaporated from the surface of the table, increasing the entropy and destroying the table.

If we take the environment to be deep space then (at 3K) the table will equalize to that Temperature. This will affect the steel/wood structure of the table: it will become more brittle over time. Any external energy (ultimately even from photons) will tend to fissure then fracture the table.

An interesting application of this question is to the formation of the materials surface of space-craft (like Pioneer) which need to stay in space indefinitely. Similar effects will happen here. Generally such spacecraft have an internal power source to keep going, but I dont know how much longer they will survive.

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You mean, If objects have internal power to against the environment, theoretically, Objects can last forever? I always think that the movement of the particles eventually makes the table or other physics object die/decay. Every objects decay for the internal cause. I don't know if this is true, so I ask this question – user2475 Mar 11 '11 at 8:36
@user2475 : You have amended the question to this. Objects like Tables decay for all the reasons stated. To prevent decay some factors can be added: power source; source of low entropy; matter repair/regeneration in some form (so it is not atomically the same table or spacecraft, but still a table or spacecraft after much time). The longest term problem is that the Universe might run out eventually of free energy, low entropy and spare atoms. – Roy Simpson Mar 11 '11 at 12:41

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