# Particles loss of energy

1. Mar 29, 2015

### hagar

I do not know what area of the forum my question belongs in and I am not sure how to phrase it correctly so it will be understandable but I will do my best.

At some point in time will the energy of all particles deteriorate to nothing (assuming an expanding universe) and if so how will it affect atoms ? With the forces gone will they disintegrate.

Respectfully,
Hagar

Last edited: Mar 30, 2015
2. Mar 29, 2015

### Staff: Mentor

No. The locally measured energies of particles, and objects made of particles (like atoms), are unaffected by the expansion of the universe.

3. Mar 29, 2015

### Staff: Mentor

It's important to understand that objects bound together by the fundamental forces do not undergo expansion. Expansion works on the scales of galaxy clusters and larger because gravity's strength between most galaxy clusters is not enough to counteract expansion. At this scale gravity is the only force at work because the other fundamental forces are either too short ranged or are neutralized by an equal number of charges.

4. Mar 29, 2015

### hagar

I see my first error was referring to the expansion of the universe so I will try again. Will atoms always be created or will the universe ever run out of particles to make them.

Respectfully,
Hagar

Last edited: Mar 30, 2015
5. Mar 29, 2015

### Staff: Mentor

Unknown. If proton decay doesn't occur then the universe will have atoms forever. However, if proton decay does occur, everything will eventually decay into photons and leptons (electron-type particles). But this would occur on a timescale of about 1040 years. For comparison, the current age of the universe is only 1.37x107 years old, so we're talking about a process that would place roughly about a 1000 billion, billion, billion, billion, billion years from now. http://en.wikipedia.org/wiki/Future_of_an_expanding_universe#Nucleons_start_to_decay

6. Mar 30, 2015

### hagar

Thank you !

That is exactly the answer I was searching for !
Also, thanks to both of you for the lesson on expansion. I gained a bit of knowledge from that as well and the link you gave is quite interesting.
With a time frame like that it sounds just like tomorrow. :-)

Respectfully,
Hagar

Last edited: Mar 30, 2015
7. Mar 30, 2015

### Chalnoth

The number of atoms generally decreases over time. Stars gradually combine hydrogen and helium into heavier elements, and the hydrogen and helium are not replenished. Some atoms also fall into black holes. This is an inconsequential number to date, but after somewhere between $10^{40}$ and $10^{65}$ years (depending upon the rate of proton decay), black holes will make up most of the matter in our universe. After that, there will be essentially no atoms left.

8. Mar 30, 2015

### Chalnoth

The Wikipedia article linked by Drakkith above is well worth a read if you're interested in what the universe will look like many trillions of years from now and beyond.

9. Mar 30, 2015

### hagar

Thank you Chalnoth and yes, I will read it through. I have already read a part of it and I intend to finish. I read a good bit from Wikipedia but there is so much information I do not know where to start so it is always good to ask specific questions from those such as yourselves who can supply an exact link to the item in question.

Respectfully,
Hagar