# Heat & Physics Q: Is There a Cosmic Temp Limit?

• ekkotrakker
In summary, the author made a statement that there is a temperature minimum for the universe, but no maximum. He imagined an object approaching light speed while travelling through a tube and thought that it should be approaching a sort of cosmic temperature limit. This is incorrect, as there is no physical maximum for kinetic energy.
ekkotrakker
Hi, I feel a bit out of place in this forum. I am a microbiology student with about as much physics knowledge as is generally deemed necessary for my field, which means that this knowledge doesn't run particularly deep. I do have an interest in physics however, and a lot of questions concerning some of its mechanisms. This will likely be the first of many so I apologize in advance for the imposition.

I just finished reading a book on the search for absolute zero and a statement in the book got me thinking. The statement was the fairly innocuous and seemingly common sense one that there is a temperature minimum for the universe but no maximum. After reading the statement I imagined an object approaching light speed while traveling through a fitted tube. If both the object and the tube are roughened to optimal roughness for heat generation through friction, then as the object approaches it's cosmic speed limit, motion and heat being equivalent, it appeared to me that it should be approaching a sort of cosmic temperature limit as well. Is this the case, and if not, could you please point out the error in my thinking? Thank you.

Hello and welcome to Physics Forums.

there is a temperature minimum for the universe but no maximum.

Actually it is more of a maths thing than a physics one.

There is a lower bound (maths term) to temperature. There is no minimum. These terms are not the same and it is difficult to describe the difference in other than mathematical terms.

You can approach absolute zero arbitrarily closely but you can never actually reach it.

As to a maximum, no there is no physical principle that provides an upper bound, but there are definite practical ones as I'm sure you appreciate.

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I'd like to point out that while the speed of light is the maximum speed, there is NO maximum kinetic energy. What I mean is that you can accelerate forever, constantly increasing your kinetic energy without limit. You will just never reach light speed, only edge closer and closer. So your thinking that the heat should be limited based on speed is incorrect. Make sense?

That point about acceleration clears it up completely. Thank you.

I can understand your interest in physics and your curiosity about the concept of a cosmic temperature limit. However, it is important to note that the concept of a cosmic temperature limit is still a subject of debate and research in the scientific community. The idea of a minimum temperature for the universe is based on the concept of absolute zero, which is the lowest possible temperature that can be reached, according to the laws of thermodynamics. This temperature is equivalent to 0 Kelvin or -273.15 degrees Celsius, and it is believed that it represents the point at which all molecular motion stops.

On the other hand, the concept of a maximum temperature for the universe is not as well-defined. Some theories suggest that there may be a limit to the amount of energy that can exist in the universe, which would correspond to a maximum temperature. However, this is still a topic of ongoing research and there is no consensus among scientists about whether or not such a limit exists.

In regards to your example of an object approaching light speed in a fitted tube, it is important to note that the laws of thermodynamics only apply to systems in equilibrium. In this scenario, the object is constantly gaining energy from the external force of motion, which means it is not in equilibrium and the laws of thermodynamics do not necessarily apply. Additionally, the concept of motion and heat being equivalent is not entirely accurate. While there is a relationship between the two, they are not interchangeable concepts.

In conclusion, the concept of a cosmic temperature limit is still a subject of ongoing research and there is no definitive answer at this time. Your curiosity and interest in physics are commendable, and I encourage you to continue exploring and learning about this fascinating field.

## 1. What is the maximum temperature in the universe?

The maximum temperature in the universe is currently unknown. The highest recorded temperature was 1.2 trillion degrees Celsius, achieved at the Large Hadron Collider in 2012. However, it is believed that there may be regions in the universe with even higher temperatures.

## 2. Is there a limit to how hot an object can get?

Yes, there is a theoretical limit to how hot an object can get, known as the Planck temperature. This is approximately 1.4 x 10^32 Kelvin, at which point the laws of physics as we know them break down.

## 3. Can heat travel through a vacuum?

No, heat cannot travel through a vacuum. Heat is the transfer of thermal energy between particles, and a vacuum is a space devoid of particles. However, radiation, which is a form of energy, can travel through a vacuum.

## 4. What is the relationship between temperature and energy?

Temperature is a measure of the average kinetic energy of the particles in a substance. The higher the temperature, the more energy the particles have, and vice versa. However, temperature is not the only factor that determines the amount of energy in a substance.

## 5. How does heat transfer occur?

Heat transfer occurs through three main methods: conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between particles, convection is the transfer of heat through the movement of fluids, and radiation is the transfer of heat through electromagnetic waves.

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