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Start with the full category, then apply the exact boundary: The three standard physical mechanisms. Enter the mechanism, not a material or an energy source. You only need one qualifying answer. A longer name is not automatically rarer.
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Shortest accepted input at 65+ points
RadiationRadiation · 65 points · 9 characters
Thermal radiation transfers energy by electromagnetic waves and can cross a vacuum.
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Radiation65 points · Shortest accepted spelling: Radiation
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- Apply the complete question boundary: The three standard physical mechanisms. Enter the mechanism, not a material or an energy source.
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Each entry belongs to the bounded set defined by the prompt. The named source supports the underlying facts; our editorial scoring is a separate layer.
Source: NASA · Heat transfer ↗
Reference version: 2026-10-21. See our answer policy for how we handle aliases and omissions.