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A comment on Frontier AI has broken the open CTF format. Parent comment

Re:Frontier AI has broken the open CTF format by tardedmeme on Saturday May 16, 2026 @09:01AM (#48159893)
There actually is a law of conservation of mass (it's the same law, because mass is energy) and it only appears violated if you forget about the particles that are zooming away at the speed of light. Of course the mass of a system changes if mass can flow in and out.
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Re:Frontier AI has broken the open CTF format by mr_mitm on Saturday May 16, 2026 @09:28AM (#48160102)
Mass is not the same as energy. Mass can be converted to energy or has energy, but a photon, for example, is massless while carrying energy.
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Re:Frontier AI has broken the open CTF format by tardedmeme on Saturday May 16, 2026 @04:33PM (#48163545)
That is incorrect. Photons have mass. They have no rest mass. They also cannot rest, so you might wonder how relevant that is.
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Re:Frontier AI has broken the open CTF format by mr_mitm on Saturday May 16, 2026 @04:41PM (#48163595)
The concepts of rest mass and relativistic mass are considered outdated. In modern physics, "mass" means what they meant by "rest mass".

Here some indication I'm not making this up: https://hsm.stackexchange.com/questions/2465/when-and-why-di...

In any case, I never use those concepts, and I know no professional particle physicist that does. By "mass", I mean rest mass.

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Re:Frontier AI has broken the open CTF format by tardedmeme on Sunday May 17, 2026 @04:39PM (#48172995)
When you put a photon in a stationary box, the "relativistic mass" of the photon becomes part of the "rest mass" of the photon-box system. You can't ignore it.
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