The adjective radiant is useful for describing anything that glows with warmth or light. When you open your eyes on a sunny summer morning and see your curtains glowing with sunlight, you can call them radiant.
Something that shines or glows is radiant, and you can also describe anything that's bright as radiant, like a smile or a powerful emotion ("a radiant sense of happiness"). In science, radiant means "transmitted by radiation," and it usually describes heat, like the radiant heat from an oven. The Latin root is radiantem, "shining," and sometime around 1500 it started being used to describe physical beauty, which Shakespeare did in "Twelfth Night": "Most radiant, exquisite, and unmatchable beauty..."