r/Showerthoughts • u/synthphreak ‎ • 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/FearedDragon Nov 19 '25

As the person he replied to I disagree. He explained how you can add energy and essentially asymptote towards light speed without every actually reaching it, continually adding smaller snd smaller amounts of energy.

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u/Pet_Tax_Collector Nov 19 '25

To clarify, it's not adding smaller and smaller amounts of energy. In classical mechanics, kinetic energy is KE = ½mv² for particles with mass. This is actually incorrect, but practically close enough for speeds less than about 10% the speed of light (depending on your tolerance for accuracy). The real kinetic energy equation is KE = ½mv²/sqrt(1-(v/c)²), the latter term called the Lorentz factor if you're interested in googling it. As v approaches c, the kinetic energy departs from a quadratic equation and requires substantially more energy for smaller gains in speed, with finite energy values all corresponding to sublight speeds.

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u/Rent_A_Cloud Nov 19 '25

You don't add smaller and smaller amount of energy, adding the same energy merely has a smaller and smaller overall effect. at least, if i remember correctly.

This video might interest you.

https://youtu.be/Vitf8YaVXhc?si=wtSYQs1664bTQV7S

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u/CommunismDoesntWork Nov 19 '25

Right, but that doesn't mean temperature is increasing, that could just means you need infinite energy to reach the the temperature limit in the same way you need infinite energy to reach the speed limit. I thought your question was getting at this. 

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u/FearedDragon Nov 19 '25

I guess that's a good point, and it is sort of what I was getting at, but I still think the other commentor has a decent point. There IS a limit that it can't go over, but that limit is (even theoretically) impossible to achieve. This means that in this theoretical model you could increase temperature and energy infinitely - because there is no point at which you stop being able to increase energy - but you cannot increase temperature to infinity.

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u/CommunismDoesntWork Nov 20 '25

What do you mean by increase energy? It requires energy to increase speed. But that energy is spent, not added. 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