Universal Limits: Are There Other Natural Boundaries?

[Sturk200]

The speed of light is the universal speed limit and absolute zero is the universal temperature limit. Are there any other universal limits like this in nature?

 

[William White]

speed of light in a vacuum is the speed limit

although it is (presently) not possible to reduce the temperature of a body to 0 K it is possible for a body to have negative temperature
other limits

Plank length - below which distance measurements are said to have no physical meaning.

 

[rootone]

Chandrasekhar limit.

The maximum mass for a white dwarf star.
If the white dwarf accumulates a greater mass through accretion or merger it will become unstable, usually producing a supernova explosion.
Other possible outcomes are a collapse into either neutron star or black hole.

 

[gianeshwar]

There are limits in filling of orbitals(Pauli exclusion principle)

 

[jfizzix]

When dealing with quantum or classical waves, there is the Heisenberg limit.
A pulse of light or any other wave cannot both have a narrow frequency spread and be of a very short duration.

For example, one cannot create a pulse of green light that is shorter than a femtosecond or so long. The pulse will necessarily be "white", containing all frequencies of the visible spectrum.

This comes into play, say, in fiber optics, where there's only a certain spectrum of colors that optical fibers can transmit well. If we transmit data as optical pulses, the Heisenberg limit shows us that we can only send data through the fiber so quickly. If we make the pulses too short, the more extreme parts of their color spectrum will get absorbed by the fiber, and the pulses will get all distorted as a result.

 

[haael]

What about the Bekenstein bound, the highest possible entropy a region of space can have?

For a given substance, this should also translate to the highest possible temperature the substance can have, trapped in a fixed volume.