Particles' Energy Loss: Atom's Fate in an Expanding Universe

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Discussion Overview

The discussion centers on the fate of particles and atoms in an expanding universe, specifically addressing whether the energy of particles will eventually diminish and how that might affect the existence of atoms over time. The scope includes theoretical considerations about particle decay, atomic formation, and the implications of cosmic expansion.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Hagar questions whether the energy of all particles will deteriorate to nothing in an expanding universe and how this would affect atoms.
  • Some participants assert that the locally measured energies of particles are unaffected by the universe's expansion.
  • It is noted that objects bound by fundamental forces do not undergo expansion, which primarily affects larger scales like galaxy clusters.
  • Hagar later asks if atoms will always be created or if the universe will eventually run out of particles, leading to a discussion on proton decay and its implications for the future of atomic existence.
  • One participant suggests that if proton decay does not occur, atoms could exist indefinitely, while if it does, they would eventually decay into photons and leptons over an extremely long timescale.
  • Another participant mentions that the number of atoms generally decreases over time due to processes like star formation and black hole accumulation, suggesting that after a significant timescale, there may be essentially no atoms left.
  • Participants reference external resources, such as a Wikipedia article, for further exploration of the universe's future.

Areas of Agreement / Disagreement

Participants express differing views on the permanence of atoms and the implications of proton decay, indicating that multiple competing perspectives remain unresolved regarding the long-term fate of atomic matter in the universe.

Contextual Notes

The discussion includes assumptions about the nature of particle decay and the timescales involved, which are not fully resolved. The implications of cosmic expansion on smaller scales and the specifics of atomic formation and decay are also not definitively established.

hagar
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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:
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hagar said:
At some point in time will the energy of all particles deteriorate to nothing

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

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
 
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hagar said:
Will atoms always be created or will the universe ever run out of particles to make them.

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
 
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
 
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hagar said:
Thank you for the answers.

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
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.
 
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.
 
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
 

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