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Depiction of Neptune and its moon Hippocamp

Photo: L. CALCADA / various sources / AFP

Astronomers have discovered three previously unknown moons in our solar system.

Two other moons orbiting Neptune and one orbiting Uranus.

The distant, tiny moons were discovered using powerful telescopes located in Hawaii and Chile and announced Friday by the International Astronomical Union's Minor Planet Center.

According to the latest count, Neptune has 16 known moons and Uranus has 28. One of Neptune's new moons has the longest known orbit to date.

It takes the small outer moon about 27 years to complete one orbit around Neptune, the giant ice planet farthest from the sun, said astronomer Scott Sheppard.

The scientist from the Carnegie Institution for Science in Washington was involved in the discovery.

The new moon orbiting Uranus is likely the smallest of the planet's moons, with an estimated diameter of just 8 kilometers.

But it won't stay that way for long: "We suspect that there are many more smaller moons that have yet to be discovered," said Sheppard.