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Intro music.

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NASA's Hubble Space Telescope recently caught an extraordinary planetary show that takes place only once a decade.

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With giant Jupiter taking center stage, the telescope witnessed a rare alignment of three moons around the enormous planet.

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The largest object in the Hubble image is the moon named Ganymede.

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Ganymede is more than 3,000 miles across and would be big enough to be called a planet if it orbited the Sun.

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Joining Ganymede is Io - Jupiter's most unsettled moon.

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Slightly larger than our own moon, Io is the most volcanically active body in our Solar System.

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Io's elliptical orbit around Jupiter produces an irregular gravitational pull on the moon.

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This uneven tug of gravity causes Io's surface to swell and recede more than 300 feet and remain violently unstable.

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Hidden in the wings was the third moon, Callisto.

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Only detectable by its shadow, Callisto is a battered world devoid of any atmosphere or surface activity.

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From a front row seat the Hubble Space Telescope captured this orchestrated planetary performance.

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It was a show for the ages, 10 years in the making.

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