I Big Freeze and Law of convervation of energy

[Rodrigo Olivera]

(Kurzgesagt- In a Nutshell) says that in the Big Freeze scenario all the matter will decay in the end, how is this possible without breaking the law of convervation of energy?

 

[phinds]

(Kurzgesagt- In a Nutshell) says that in the Big Freeze scenario all the matter will decay in the end, how is this possible without breaking the law of convervation of energy?

There IS no "conservation of energy" on cosmological scales.

 

[Rodrigo Olivera]

There IS no "conservation of energy" on cosmological scales.

Why?
By the way, why convervation of energy have an important rol in inflation if there is no convervation of energy in cosmological scales?. https://en.wikipedia.org/wiki/Zero-energy_universe

 

[phinds]

Why?

http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/

 

[TJGilb]

(Kurzgesagt- In a Nutshell) says that in the Big Freeze scenario all the matter will decay in the end, how is this possible without breaking the law of convervation of energy?

phinds or someone else more advanced in the Standard Model may be able to confirm or refute this, but I believe the only thing actually required to be conserved in particle decay is the particle's charges (spin, Baryon/Lepton number, strange, electric, etc.).

 

[Rodrigo Olivera]

http://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/

Okay, so when does the law of convervation is valid?

 

[TJGilb]

Okay, so when does the law of convervation is valid?

The laws of thermodynamics assume a closed system.

 

[Khashishi]

Okay, so when does the law of convervation is valid?

It is valid in situations where you can neglect gravity, or in situations where you treat gravitation potential energy as a valid kind of energy. As Sean Carroll stated, there's nothing wrong with thinking of gravitational fields having gravitational energy. The drawback is that it behaves very differently from other forms of energy.

I think it is advantageous to use the concept of gravitational energy because it makes it clear that you can't make a (cyclic) perpetual motion machine based on gravity. The total non-gravitational energy might be different at different points of the gravitational cycle, but it should return to what it was at a previous cycle.