Decay of Matter: Will It Last Forever?

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Discussion Overview

The discussion centers around the decay of matter, specifically questioning whether a block of lead placed in a vacuum would degrade or change over infinite time. Participants explore concepts related to matter's permanence and the implications of various physical processes, including proton decay and black hole formation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that unless proton decay occurs, matter like lead should last indefinitely.
  • Another participant introduces the idea that if black holes can form from quantum fluctuations, the block of lead may eventually become a black hole rather than lasting forever.
  • A further explanation discusses the conditions under which black holes might decay and the implications for the fate of matter in relation to the universe's expansion or contraction.
  • One participant questions the clarity of the original question, noting that the decay of lead depends on the specific isotopes in question, with some being stable and others undergoing radioactive decay.
  • It is noted that while some isotopes of lead are stable, others can decay into different elements over time.

Areas of Agreement / Disagreement

Participants express differing views on whether matter can last forever, with some arguing for its permanence under certain conditions and others suggesting potential transformations into black holes or decay processes. The discussion remains unresolved regarding the ultimate fate of matter.

Contextual Notes

The discussion highlights the dependence on definitions of decay and stability, as well as the implications of cosmic phenomena on matter's longevity. There are unresolved assumptions regarding the conditions under which matter may change.

Ward
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Hi,

I have a question regarding decay of matter. Let's say I have a block of lead. Now imagine I sit it in a vacuum - given infinite time. What will happen to it - will it ever degrade or change. In another way does matter last forever?

Also what is the correct physics term for what I am describing

Thanks
Ward
 
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I believe that unless proton decay occurs, then yes, it should last forever.
 
If black holes can form by quantum fluctuations and there exists the smallest possible black hole that does not decay, then the block of lead will not last forever, it will eventually form a black hole instead.

If black holes can decay, no matter how small, then the fate of the block of lead depends on the speed of expansion of universe (lol). Basically, the stable configuration will be an evaporating black hole surrounded by Hawking radiation in thermal equilibrium. The hole radiates particles and absorbs particles at the same rate. The equilibrium state can not be achieved if the universe expands so that the temperature of Hawking radiation constantly drops - in this case the ultimate fate will be single noninteracting particles flowing through space forever. Also, equilibrium can not be reached if the universe contracts, so that temperature rises.
 
The original question is not clear. Does it apply specifically to natural lead, or to any matter?

Radioactive decay, also known as nuclear decay or radioactivity, is the process by which a nucleus of an unstable atom loses energy by emitting radiation. https://en.wikipedia.org/wiki/Radioactive_decay

Via that process some nuclei decay into other kinds of nuclei. For example, one isotope of lead, 210Pb, decays into mercury or bismuth with a half life of 22.3 years. But other isotopes of lead (204, 206, 207, 208) are called "observationally stable" which means they don't decay. The most common natural forms of lead are the stable ones. That is what Drakkith meant when he said it "should last forever".

You asked "will it ever degrade or change" The answer is sometimes yes, sometimes no, depending on what "it" refers to.
 

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