Categories: HubbleNeptune

Researcher Finds a New Moon Around Neptune in Hubble Data

It took sharp and patient eyes, but researcher Mark Showalter of the SETI Institute has found a tiny moon orbiting Neptune that’s never been seen before. Showalter used archival data from the Hubble Space Telescope to find the moon, designated S/2004 N 1, which is estimated to be no more than 19 km (12 miles) across, making it the smallest known moon in the Neptunian system. This is the 14th known moon of Neptune.

S/2004 N 1 is so small and dim that it is roughly 100 million times fainter than the faintest star that can be seen with the naked eye, NASA said. Even Voyager 2 –which flew past Neptune in 1989 to survey planet’s system of moons and rings – didn’t catch a view of this moon, even though data from Voyager 2 revealed several other moons.

Neptune photographed by Voyager 2. Image credit: NASA/JPL

Showalter was studying the faint arcs, or segments of rings, around Neptune earlier this month.

“The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system,” he said. “It’s the same reason a sports photographer tracks a running athlete — the athlete stays in focus, but the background blurs.”

The method involved tracking the movement of a white dot that appears over and over again in more than 150 archival Neptune photographs taken by Hubble from 2004 to 2009.

Showalter noticed the white dot about 100,000 km (65,400 miles) from Neptune, located between the orbits of the Neptunian moons Larissa and Proteus. Showalter plotted a circular orbit for the moon, which completes one revolution around Neptune every 23 hours.

Showalter should get the “Eagle Eyes” award for 2013!

Source: HubbleSite

Nancy Atkinson

Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond. Follow Nancy on Twitter at and and Instagram at and

Recent Posts

The Solar Wind is Stripping Oxygen and Carbon Away From Venus

The BepiColombo mission, a joint effort between JAXA and the ESA, was only the second…

1 hour ago

The Solar Eclipse Like We’ve Never Seen it Before

You had to be in the right part of North America to get a great…

5 hours ago

The Milky Way’s Most Massive Stellar Black Hole is Only 2,000 Light Years Away

Astronomers have found the largest stellar mass black hole in the Milky Way so far.…

8 hours ago

Amazing Amateur Images of April 8th’s Total Solar Eclipse

The last total solar eclipse across the Mexico, the U.S. and Canada for a generation…

11 hours ago

Organic Chemistry: Why study it? What can it teach us about finding life beyond Earth?

Universe Today has recently had the privilege of investigating a myriad of scientific disciplines, including impact…

19 hours ago

The Milky Way’s History is Written in Streams of Stars

The Milky Way is ancient and massive, a collection of hundreds of billions of stars,…

1 day ago