The Moon slides through a bright triangle this evening — the planets Jupiter and Saturn and the star Fomalhaut.

Jupiter is the triangle’s brightest point, to the upper left of the Moon. It’s the largest planet in the solar system — about 11 times the diameter of Earth. It’s a ball of hydrogen and helium gas with a dense, fuzzy core of heavier elements. It’s attended by about 80 known moons, four of which are easy to see with binoculars. The Moon will stand closer to Jupiter tomorrow night; more about that tomorrow.

Saturn is farther to the lower right of the Moon. It isn’t nearly as bright as Jupiter, but still looks like a bright star. It’s the second-largest planet, and it’s put together a lot like Jupiter. It also has a large entourage of moons, including the only one in the solar system with a dense atmosphere. And it’s best known for its bright, beautiful rings.

The final point of the triangle is Fomalhaut, the brightest star in Piscis Austrinus, the southern fish, below the Moon. It’s one of our closer stellar neighbors — just 25 light-years away. In other words, the light we see from the star tonight actually began its journey through space in 1997.

Fomalhaut is about twice the size and mass of the Sun. And its surface is thousands of degrees hotter. Its core is also hotter than the Sun’s. Because of that, Fomalhaut will live billions of years less than the Sun — a short life for a bright star.

Script by Damond Benningfield

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