It’s time to add one more tiny moon to Neptune’s icy family tree. Astronomers using the Hubble Space Telescope have spied a previously undetected satellite around the solar system’s eighth planet, bringing its total number to 14.

The discovery, formally reported Wednesday in Nature, is a stark reminder that there is much more to be found in our own backyard, with implications for our understanding of worlds around other stars in our galaxy.

“I think people have the impression that we know everything there is to know about the moons of Jupiter, the moons of Saturn, the moons of Uranus and the moons of Neptune — but we don’t really,” said Anne Verbiscer, a planetary scientist at the University of Virginia, who was not involved in the recent discovery. “We haven’t found everything.”

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That’s especially true for Uranus and Neptune, which are known as the ice giants. While every other planet in our solar system has been poked and prodded by multiple spacecraft, these two remain largely unexplored. Voyager 2 did swing past Neptune 30 years ago — shooting images that revealed rings, six new moons and its dynamic blue globe. But the spacecraft was moving too fast and was limited by technology designed in the 1970s.