The sun isn't about just heat and fire. It's also about texture, variegated colors and occasional violent outbursts. Here, a whip-like filament extends over half a million miles in a long arc above the sun’s surface. Filaments are exceedingly hot ionized gasses that are magnetically anchored to the sun's photosphere. Viewed against the blackness of space, they're very bright and are known as prominences. Viewed with the sun itself as a backdrop, they appear darker since they're cooler than the overall solar mass. That more-modest appearance also earns them a more modest name.