Chill, a space friend

Shy, a space friend

Sled, a space friend

My sticker book

Tap a sparkling star on any page to meet a space friend and keep their sticker.

Dark star field near distant Neptune

Distant Neptune, Triton's planet

Triton, Neptune's largest moon

Page 18 · The backward moon

Triton

Far from home, a pale pink moon walks the other way around giant Neptune. Voyager 2 once flew past and saw dark streaks and icy fountains on this freezing world.

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Voyager 2 flying toward Triton

Ari steadies a field viewer while Dot samples Triton's icy surface

Dark streaks and a geyser-like fountain — what Voyager 2 photographed.

A moon that walks backward

Neptune's largest moon

Tap the diagram to replay its motion. Diagrams are explanatory and not to scale.