Heat death of the universe and conservation of energy

[Conny]

I am little experience of physics so please be patience with me, This is my first post of this great internet forum.

I have a friend who said that energy will never remove from the universe only transform (e.g. cogs loses energy from friction that´s turn into radiation).

But if that true how come the universe will end? What´s the name of the theory about the end of the universe?

if energy is constant universe wouldn't universe live forever?

thanks for your time best regards Conny. :)

 

[UltrafastPED]

I have a friend who said that energy will never remove from the universe only transform (e.g. cogs loses energy from friction that´s turn into radiation).

This is simply the first law of thermodynamics: energy may be transformed, but the total amount doesn't change.

But if that true how come the universe will end? What´s the name of the theory about the end of the universe?

if energy is constant universe wouldn't universe live forever?

The universe is expanding - so the energy is thinning out in each region: the density is decreasing. So if you wait long enough there won't be anything left but a thin "gas" of ever weaker photons - the cosmic background radiation plus any additions from stars, etc - and at some point you might say that "this is no longer interesting - nothing going on here!

At that point you might say "the universe has come to an end".

There are various cosmic theories; you might enjoy Stephan Hawking's "A Brief History of Time".

PS: Welcome to PF!