Planck Temperature: Is It The Upper Limit?

In summary, the Planck temperature is the theoretical lower limit on temperature. There is no theoretical upper limit on temperature.
  • #1
flotsam
29
0
Is there an upper limit on temperature? Is the 'Planck temperature' the upper limt?
 
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  • #2
I don't think so. You can keep piling more and more energy into a system and it will raise its temperature further and further.

There is a theoretical lower limit on temperature though. That is absolute zero, when no particles move at all.

I was going to mention phonons here too, but are they strictly more to do with vibration than temperature, considering vibration and temperature are fairly interchangeable concepts?
 
  • #3
Temperature is not a measure of energy in general. It is a measure of the average kinetic energy of particles in a given location.

So you're really asking whether there is an upper limit on kinetic energy, and whether this is called the Planck temperature.

The answer is yes, and yes.

Here is the Wikipedia entry, which covers it pretty neatly:

===

The Planck temperature, named after German physicist Max Planck, is the natural unit of temperature, denoted by Tp. The Planck units, in general, represent limits of quantum mechanics. Talking about anything being "hotter" than the Planck temperature doesn't make a lot of sense; it is the temperature at which black holes are theorized to evaporate and the temperature at which the Universe "started" and cooled down from there, according to current cosmology. It is difficult to imagine anything being hotter than the Big Bang.

Tp = Mp/k = square root of (hc^5/Gk^2) = 1.41679 × 10^32 K

where:

Mp is the Planck mass

c is the speed of light in a vacuum

h is the Reduced Planck constant (or Dirac's constant)

k is the Boltzmann constant

G is the gravitational constant
 
  • #4
Hooloovoo said:
Temperature is not a measure of energy in general. It is a measure of the average kinetic energy of particles in a given location.
So you're really asking whether there is an upper limit on kinetic energy, and whether this is called the Planck temperature.
The answer is yes, and yes.
Here is the Wikipedia entry, which covers it pretty neatly:
===
The Planck temperature, named after German physicist Max Planck, is the natural unit of temperature, denoted by Tp. The Planck units, in general, represent limits of quantum mechanics. Talking about anything being "hotter" than the Planck temperature doesn't make a lot of sense; it is the temperature at which black holes are theorized to evaporate and the temperature at which the Universe "started" and cooled down from there, according to current cosmology. It is difficult to imagine anything being hotter than the Big Bang.
Tp = Mp/k = square root of (hc^5/Gk^2) = 1.41679 × 10^32 K
where:
Mp is the Planck mass
c is the speed of light in a vacuum
h is the Reduced Planck constant (or Dirac's constant)
k is the Boltzmann constant
G is the gravitational constant


Thanks for the reply.
What I now wonder is; how near to this temperature do the 4 forces (gravitation, electro-magnetism, weak and strong nuclear) combine to manifest themselves as one force? Is there any actual theoretical temperature at which this occurs? Is it the Planck temperature? Do you think there could be anywhere so hostile (theoretical or not) in the universe that in that place there is only one force?
 

1. What is the Planck temperature?

The Planck temperature is the highest possible temperature in the universe, also known as the absolute hot. It is named after the physicist Max Planck and is calculated to be approximately 1.416 x 10^32 Kelvin.

2. Why is the Planck temperature considered the upper limit?

According to the laws of physics, the Planck temperature is the point at which the fundamental constants of nature break down. At this temperature, the energy density of a system would be so high that it would create a black hole, making it impossible for any further heat or energy to escape.

3. Is it possible to reach the Planck temperature?

No, it is currently not possible to reach the Planck temperature. It is estimated to be trillions of times hotter than the core of the sun and is beyond the capabilities of any known technology. It is also believed that the Planck temperature could not have existed in the early universe due to the rapid expansion and cooling of the universe after the Big Bang.

4. What are some potential implications of the Planck temperature?

The Planck temperature has significant implications for our understanding of the laws of physics. It is believed that at this temperature, the four fundamental forces of nature (gravity, electromagnetism, strong nuclear force, and weak nuclear force) would merge into one unified force. It could also provide insights into the nature of black holes and the beginning of the universe.

5. Can the Planck temperature change?

No, the Planck temperature is considered a fundamental constant and is believed to be a fixed value in the universe. However, our understanding of the universe is constantly evolving, so it is possible that our understanding of the Planck temperature may change as well in the future.

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