Others have mentioned color for visibility, but to the other part of your question: Absorption and emissivity are related such that things that absorb a wide range of light (e.g. dark clothing) tend to also radiate heat better than a highly-reflective material. This is part of why radiators and heatsinks tend to be coated black rather than left as bare shiny metal; the black finish radiates heat away. The night/dark is generally colder, so it’s more important to prioritize nighttime insulation.
Tl;dr if anything, the antarctic gear should be silvered to minimize its thermal radiation at night, rather than black to maximize daytime heat absorption.
It’s for visibility. If you actually **read** about what life is like in Antarctica, especially wintering in Antarctica…it’s terrifyingly easy to lose your way, even very close to home. And you don’t have long before staying out becomes dangerous.
Bright colours serve as guidance to find safety – whether it’s a teammate, a piece of equipment like a skidoo or some form of shelter, colours like that don’t occur naturally in the environment. If you see bright red, bright orange, bright green, you will know it for what it is.
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