So the wavelength of black body radiation is called Wien's Law [1]. If you look at the electromagnetic spectrum [2], the IR spectrum is 25 μm to 2.5 μm. Compar

So the wavelength of black body radiation is called Wien's Law [1]. If you look at the electromagnetic spectrum [2], the IR spectrum is 25 μm to 2.5 μm. Compare those two and you'll see pretty much any reasonable range of temperatures has a heavy IR element. Some things to consider: 1. Tungsten has probably the highest melting point at ~3700K. It seems unlikely that complex matter of any kind can realistically survive at such extreme temperatures; 2. Heat above a certain level can itself be used to generate energy in a straightforward fashion. This itself will generate waste heat, most likely at a much lower temperature. As an aside, recycling heat is often raised as an objection to the IR signature issue with Dyson Swarms but that ignores thermodynamics. Let's say heat recycling for a star like the Sun is 90% effective then that's still 10% energy lost and 10% of the Sun's output is still massively significant. If there's perfect recycling, well that ignores entropy. [1]: https://en.wikipedia.org/wiki/Wien%27s_displacement_law https://en.wikipedia.org/wiki/Wien%27s_displacement_law [2]: http://labman.phys.utk.edu/phys222core/modules/m6/The%20EM%20spectrum.html http://labman.phys.utk.edu/phys222core/modules/m6/The%20EM%2...