Blue and white come with universal associations, too. White suggests purity, peace, and light; blue is associated with the sky, faith, wisdom, and truth. (The expression isn’t “true blue ...

On Monday, first lady Jill Biden revealed this year’s White House holiday decorations. Among them is the focal point of the Blue Room: the floor-to-ceiling Fraser fir Christmas tree. The ...

When they look at sky brightness—what they call the sky background—they use a unit of brightness per area of the sky: how much light is spread out over a given parcel of celestial real estate.