Can all matter be potentially annhilated?

[Ritzycat]

I understand that every chemical reaction has a mass defect - albeit it is very, very, very, very small, to the point we simply assume Law of Conservation of Mass. Nuclear reactions have a more sizable mass defect, hence the very high amounts of energy released. However, suppose some astronomically high time. It is possible that all of the matter in the universe could be converted to energy somewhere incredibly distant in the future? Are there any ways in which new matter is introduced into the universe, and would that amount be greater than the amount lost by general physical phenomenon?

We've only briefly touched on this concept in my chemistry class but since we have to move on our teacher doesn't have much time for much theory questions. I'm very curious but my knowledge doesn't extend very far.

 

[Dale]

The universe is going the other direction. In the distant past it was radiation dominated. As it has expanded and cooled it has transitioned from radiation dominated to matter dominated. As far as I know there is no known effect which would cause it to revert to radiation dominated without a "big crunch".

 

[Ritzycat]

What are the reasons why radiation transforms into matter, especially on a universal level?

 

[mathman]

What are the reasons why radiation transforms into matter, especially on a universal level?

Right after the big bang photon-photon interactions were common resulting in matter antimatter pairs (Open question: what happened to the antimatter?). These days pair production is extremely rare.

 

[Ritzycat]

So essentially, at this point in time, there is not much conversion going on between energy and matter?

 

[phinds]

So essentially, at this point in time, there is not much conversion going on between energy and matter?

No, there's a fair amount of it going on, almost all in the direction of matter to energy, but that's in the center of stars and when there are no more stars, there won't be any more such conversion, and as Dale said, that's the direction the universe is going ... fewer stars ... fewer stars ... fewer stars ... no more stars.

Here's a thread you might find interesting:

https://www.physicsforums.com/threads/future-of-the-universe.778346/