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Editors of EarthSky

Christopher Flavin says wind power surging

Christopher Flavin said over 40 percent of the new generating capacity added in the U.S. last year is from wind power. It's surpassed a little by natural gas.

Is it a coincidence that moon keeps one face to Earth?

The moon spins once for each of its orbits around Earth - and that's why the moon always keeps a single face turned our way.

Does every animal have eyelids?

Fish and snakes don't have eyelids. Some lizards have 2! Why we need eyelids ...

Could penguins and polar bears swap habitats?

Earth's Arctic and the Antarctic are very different kinds of places - but if these polar animals switched habitats, penguins might struggle, and polar bears might thrive.

What’s so special about water?

Water is unusual in that it can occur naturally in three distinct forms - gas, liquid and solid - at the same time.

Do animals laugh, is it in animal behavior?

Do animals laugh? If you tickle a chimp, it'll make a panting noise that sounds like a handsaw cutting wood. When dogs play, they wag their tails.

Why is Jupiter called a failed star?

Jupiter is the biggest planet in our solar system, but it isn't massive enough to be a star. Stars require a certain amount of mass to spark thermonuclear fusion - in other words, to shine.

Gravity, does it have a specific speed?

Today's scientists theorize that gravity might travel in space at light speed, as a massless particle called a "graviton."

What makes the night sky dark?

On any clear evening, you can see the curved line of Earth's shadow ascending in the eastern sky. Earth's own shadow makes the night sky dark.

How do Monarch butterflies migrate?

Monarch butterflies of eastern and central North America migrate each fall, over great distances, to the same winter homes of their great-great grandparents.