Skip to main content

Three tiny new moons spotted orbiting Uranus and Neptune

Our solar system has a few new entries with the recent discovery of three moons of Uranus and Neptune. These ice giant planets are so far away that it is difficult to detect small moons orbiting them, especially when one of the recently discovered moons is the faintest moon ever discovered by a ground-based telescope.

Unlike Jupiter and Saturn, which both have a plethora of moons, Uranus is known to host 28 moons and Neptune just 16. That includes Uranus’s new diminutive moon, which is just 5 miles across. Like Uranus’ other moons, it will be named after a character from a Shakespeare plays, but a new name has not yet been chosen, so for now it is S/2023 U1.

The discovery image of the new Uranian moon S/2023 U1 using the Magellan telescope on November 4, 2023. Uranus is just off the field of view in the upper left, as seen by the increased scattered light. S/2023 U1 is the faint point of light in the center of the image. (There is an arrow pointing to it in the lower version of the image). The trails are from background stars.
The discovery image of the new Uranian moon S/2023 U1 was taken using the Magellan telescope on November 4, 2023. Uranus is just off the field of view in the upper left, as seen by the increased scattered light. S/2023 U1 is the faint point of light in the center of the image. (There is an arrow pointing to it in the lower version of the image). The trails are from background stars. Scott Sheppard

The tiny moon was spotted using the Magellan telescope in Chile by Scott Sheppard of Carnegie Science. He also identified two Neptunian moons, S/2002 N5, which is around 14 miles across, and S/2021 N1, which is 9 miles across. “The three newly discovered moons are the faintest ever found around these two ice giant planets using ground-based telescopes,” said Sheppard in a statement. “It took special image processing to reveal such faint objects.”

Recommended Videos

The existence of the moons was confirmed using other telescopes, including the European Southern Observatory’s Very Large Telescope and  Gemini Observatory’s 8-meter telescope. Multiple observations were required to confirm the moon’s orbit and size.

And one of the moons turned out to be something that had been spotted before, although not identified. “Once S/2002 N5’s orbit around Neptune was determined using the 2021, 2022, and 2023 observations, it was traced back to an object that was spotted near Neptune in 2003, but lost before it could be confirmed as orbiting the planet,” Sheppard explained.

One of the interesting facts about the discovery of moons of the distant planets is that the moon systems of the giant planets seem to be similar, despite how different the planets are.

“Even Uranus, which is tipped on its side, has a similar moon population to the other giant planets orbiting our sun,” Sheppard explained. “And Neptune, which likely captured the distant Kuiper Belt object Triton — an ice rich body larger than Pluto — an event that could have disrupted its moon system, has outer moons that appear similar to its neighbors.”

Georgina Torbet
Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…
Spot the space station with this new NASA app
The International Space Station.

The International Space Station (ISS) orbits Earth 16 times a day, which means that at some point it’s likely to pass over your neighborhood.

Despite being 250 miles above our heads, it’s actually easy to spot the ISS thanks to the reflection that occurs when the sun’s rays bounce off its solar arrays. You just need to know when to look up.

Read more
Neptune has a dark spot of its own, and it has been imaged from Earth
Neptune observed with the MUSE instrument at ESO’s Very Large Telescope.

While the most famous planetary spot in the solar system would have to be Jupiter's Great Red Spot, an epic storm 10,000 miles wide that has been raging for hundreds of years, other planets are known to host spots of their own as well. That includes Neptune, which had a large dark spot that was first imaged by Voyager 2 when it passed by in the 1980s.

Neptune's spot was named the Great Dark Spot, but when the Hubble Space Telescope tried to image the spot in 1994, it had disappeared. Now, a Neptune spot has been imaged from the ground for the first time, using the European Southern Observatory's Very Large Telescope (VLT).

Read more
Clouds on Neptune might be created by the sun, strangely enough
Neptune

As distant as it is, orbiting nearly 3 million miles from the sun, we know a surprising amount about the atmosphere and weather conditions on Neptune. Dramatic storms have been observed there including by the Voyager 2 spacecraft which passed by in the 1980s, which saw dark spots surrounded by white clouds of frozen methane. However, astronomers are now faced with a puzzle about these storms and why they seem to be appearing and disappearing over time.

Researchers recently used Hubble and other telescopes to observe Neptune's clouds to investigate a mystery: why sometimes the planet had plentiful clouds in its atmosphere and at other times had barely any. In 2019, the level of clouds dropped dramatically and it wasn't clear why.

Read more