Star light, star bright, is there a green star out tonight? According to a new NASA Astronomy Picture of the Day entry, the answer is a heavily qualified "sort of, but no." The featured illustration depicts WD J1330+6435, a white dwarf star wrapped in an accretion disk of gas and rocks orbiting around it - a cosmic ring toss rendered in the name of science.

Here's the thing about stars: apart from the Sun, they're all so absurdly far from Earth that they register as mere points in the sky. Mostly they look white, occasionally noticeably red or blue, and that color generally tracks temperature - blue stars run hotter than red ones. Simple enough. But astronomers have recently found that some white dwarf stars, despite the name, would actually appear yellow, green, cyan, pink, or purple. The culprit: trace elements accreted onto these stars interact with the stellar atmosphere and shift its normally white hue. So the universe does have a green star. It's just not the emerald beacon of nursery-rhyme fame.

White dwarfs themselves are small, faint leftovers - the smoldering remains of stars like the Sun once they exhaust their nuclear fuel. Which brings us to the APOD entry's gloriously resigned kicker: "But, alas! I wish I may, I wish I might, but they are too faint to see tonight..." A green star you cannot observe, described in verse. Somewhere, a wish-granting star is refusing to take the call.

Tomorrow's picture: eye in the sky. Presumably also faint, but at least the puns will keep coming.