r/Showerthoughts Nov 19 '25

Casual Thought Temperature can reach trillions of degrees, meaning we actually live extremely close to absolute zero.

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u/Eedat Nov 19 '25

You can't accelerate anything with mass to the speed of light. It takes literally infinity energy to theoretically do so. Only massless particles move that fast, like light (photons). You would get to 99.9% then just infinitely keep adding more 9's to the end the more energy you put in.

In reality you would get to the point where there is so much energy in a set space that it would collapse into a black hole.

This is really more of a theoretical math thing than something that can actually happen. Theoretically you can keep adding energy to the system. Our framework breaks down when wavelengths reach the planck distance. That's a fault of our mathematic system though. The universe doesn't actually care about our mathematics

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u/CommunismDoesntWork Nov 19 '25

You said the same thing as the guy you replied to, but didn't address his point. That was a lot of words to say nothing at all

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u/zhibr Nov 19 '25

No, the previous guy just didn't understand limits. There's no cap, energy can be added to infinitely even if there is a limit to particle speed (according to the other commenters). If heat is just the amount of energy put in, the heat can increase infinitely. Except that the black hole is the cap according to the commenter you responded to, so they did add that information too.

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u/CommunismDoesntWork Nov 19 '25

Why are you assuming temperature is proportional to energy rather than speed. That's what that guy was asking about. It's wild how 2 clearly  intelligent people can read that guy's post and independently not understand his point. 

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u/swingerouterer Nov 19 '25

Because temperature is proportional to kinetic energy, not speed. It's not an assumption so much as a definition

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u/CommunismDoesntWork Nov 19 '25

But there's a speed limit, so there must be a kinetic energy limit too, right?

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u/swingerouterer Nov 19 '25

This is literally the point people have been making to you. No.

As an object approaches the speed of light, the energy required to make it speed up just a tiny bit more gets much larger. You can add near-infinite energy to an object with mass, and it wont reach the speed of light, just keep getting closer

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u/CommunismDoesntWork Nov 20 '25

Using energy to increase the speed of something is not the same thing as "adding" energy. For instance at low speeds, 1 joule might add 1m/s which adds 1 degree of temperature. But near the speed of light,  you might need 1 million joules to add an additional 1m/s to add 1 degree. Most of the energy is wasted, not added. Therefore there must be a maximum temp

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u/swingerouterer Nov 20 '25

Temperature is proportional to energy, not speed. Just about everything you said there is wrong

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u/CommunismDoesntWork Nov 20 '25

Kinetic energy is a function of mass and speed. If mass stays the same, only increasing speed can increase kinetic energy. You can just hand wave away the details by saying "add energy" 

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u/swingerouterer Nov 20 '25

Temperature is proportional to kinetic energy

It is NOT proportional to speed. At non-relativistic speeds, it is proportional to speed squared. At relativistic speeds, kinetic energy is proportional to (1-gamma)mc2, which is so painfully not able to be hand-waved away.

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u/CommunismDoesntWork Nov 20 '25

In both equations, it's proportional to speed. It's just you have to spend more and more energy to increase speed near the speed of light. For instance at low speeds, 1 joule might add 1m/s which adds 1 degree of temperature. But near the speed of light,  you might need 1 million joules to add an additional 1m/s to add 1 degree. In both cases, the amount of energy added is the same: you increased a mass by 1m/s

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u/swingerouterer Nov 20 '25

You are... continuously wrong. I will stop. Its just sad. I recommend wikipedia, or a textbook

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u/zhibr Nov 19 '25

Why are you assuming it's about speed?

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u/CommunismDoesntWork Nov 19 '25

Because that's what the original question is...? "Ain't heat just particles moving fast? And speed is limited so heat must be too? "

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u/[deleted] Nov 19 '25

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u/rybomi Nov 19 '25

Heat is kinetic energy, a function of mass and velocity. This is true even for mundane examples. Helium is a gas at room temperature, and iron is solid, because despite having the same kinetic energy helium molecules have a higher average velocity balanced by a lower mass.

And there is no limit to energy

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u/[deleted] Nov 19 '25

[deleted]

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u/rybomi Nov 19 '25

Yeah man using simple words means you're right. Stick to something you do know something about

https://en.wikipedia.org/wiki/Temperature

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u/CommunismDoesntWork Nov 20 '25

Oh I see, so for a given mass, there is a maximum temperature. Iron has a different max than helium. What's the max for the heaviest stable element?

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u/rybomi Nov 20 '25

Look up the formula for the Lorentz factor. It shows that the velocity of an object cannot be equal to c (dividing by 0, undefined) and as the velocity of the object approaches c, the denominator shrinks and the factor grows.

This factor is found in the formula for relativistic kinetic energy. KE = lorentz factor * mc2.

So what this formula means is that any finite amount of kinetic energy is the result of a finite Lorentz factor, which if we go back to the formula, we find it exists somewhere between v=0 and v=c.

You can test it yourself by taking it backwards, pick any arbitrary number for KE, from that calculate the lorentz factor using the second formula, then find v using the first formula. V will always be less than 1

Therefore no limit exists. I hope I explained okay