Atoms in motion - Existence of permanent objects How to reconcile the existence of permanent objects such as fossils, with the fact that the atoms are in constant motion?
 A: Nothing is "permanent" but some things are more durable than others.
Materials exist because of (chemical) bonds between atoms, and physical bonds between molecules. Until an atom gets sufficient energy to break the bond, the material remains intact. This can happen by several mechanisms:


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*thermal motion of the atom: the hotter the material, the greater the motion. Eventually the motion is sufficient to break the bonds - the material melts or sublimates. This can happen at a very low rate at temperatures below the melting / sublimation point.

*chemical action: a chemical compound may attack the bond by offering an energetically more favorable arrangement of the electrons. Think oxidation, acids, etc. 

*radiation: UV light or other forms of radiation may attack / degrade the bonds (ionization)

*mechanical action of the environment (erosion by wind and water, being hit with a hammer, the repeated action of freezing and thawing, ...) can result in mechanical stresses that break bonds


If you take a "hard" material and protect it from the factors above, there is no reason why it would change its composition / form by much. It can stay intact for a very, very long time. But if you take the example of diamonds - they may have been formed millions of years ago and just sat there until someone found them - then they were cut and polished (mechanical action) to be more "beautiful" by human standards - but destroying the state they had been in for a very, very long time. "Diamonds are forever" - until humans get their hands on them!
