Internal energy and total heat of universe

In summary: W is a positive numberdU = Q - W0 = Q - a positive numberSo Q is a positive number.So heat is being added to the universe constantly.Is this correct?In summary, the energy of the universe is not a well defined quantity and heat is being added to the universe constantly.
  • #1
CuriousBanker
190
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Hello. I am starting to learn about thermodynamics. (i'm going to use lower case "d" for delta)

Energy is neither created nor destroyed. So dU = 0 for the universe as a whole.

If the universe is constantly expanding, then it must be doing work on the vacuum around it, right? So W is a positive number

dU = Q - W
0 = Q - a positive number

So Q is a positive number.

So heat is being added to the universe constantly.

Is this correct?
 
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  • #2
CuriousBanker said:
Hello. I am starting to learn about thermodynamics. (i'm going to use lower case "d" for delta)

Energy is neither created nor destroyed. So dU = 0 for the universe as a whole.

If the universe is constantly expanding, then it must be doing work on the vacuum around it, right? So W is a positive number

dU = Q - W
0 = Q - a positive number

So Q is a positive number.

So heat is being added to the universe constantly.

Is this correct?
Energy is not conserved at cosmological scales

http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/
 
  • #3
CuriousBanker said:
Energy is neither created nor destroyed. So dU = 0 for the universe as a whole.
Unfortunately, the energy of the universe is not a well defined quantity. http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html

A globally conserved energy is only defined for a class of spacetimes that does not include the usual model of the universe.

CuriousBanker said:
If the universe is constantly expanding, then it must be doing work on the vacuum around it, right?
There is no vacuum around the universe in the usual cosmological models.
 
  • #4
CuriousBanker said:
must be doing work on the vacuum around it, right?
Dale said:
There is no vacuum around the universe in the usual cosmological models.

And if there were, the universe would not be doing work on the vacuum.
 
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Likes Dale

1. What is internal energy?

Internal energy is the total energy contained within a system, including the kinetic energy of its particles and the potential energy of its interactions. It is a measure of the system's overall energy, and can be affected by changes in temperature, pressure, and composition.

2. How is internal energy related to total heat?

Total heat is the sum of the internal energy and the external work done on the system. This means that changes in total heat can result from changes in internal energy or from work being done on or by the system.

3. How does internal energy affect the universe?

Internal energy plays a crucial role in the behavior and evolution of the universe. It is responsible for the motion and interactions of particles, and can contribute to processes such as nuclear fusion and radiation. Changes in internal energy can also affect the temperature and pressure of a system, which can have wider implications for the universe as a whole.

4. Can internal energy be measured?

Yes, internal energy can be measured through various methods such as calorimetry, which measures the heat transfer associated with a process, or by using thermodynamic equations that relate changes in internal energy to other measurable quantities such as temperature and pressure.

5. How does the concept of internal energy relate to the laws of thermodynamics?

The first and second laws of thermodynamics govern the behavior of internal energy in a system. The first law states that energy cannot be created or destroyed, only transferred or converted between different forms. The second law states that the total entropy of a closed system can never decrease, meaning that systems tend to move towards a state of higher disorder and thus their internal energy tends to increase over time.

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