FEB 20, 2019 4:39 PM PST

Astronomers Discover Another Moon Orbiting Neptune

WRITTEN BY: Anthony Bouchard

Our home planet of Earth only sports a single natural satellite that we subtly refer to as the ‘Moon.’ On the other hand, it’s evident that most of the other planets in our stellar neighborhood have a multitude – sometimes dozens – of moons. 

Unsurprisingly, the solar system’s largest gas giants (Jupiter and Saturn) exhibit the highest number of confirmed moons at 79 and 62 respectively. With that in mind, it shouldn’t come off as too astonishing that Neptune has a somewhat stout lunar roster of its own.

An artist's impression of all the known inner moons of Neptune to date.

Image Credit: Mark R. Showalter, SETI Institute

Previously cited to have 13 natural satellites, Neptune’s count has been formally increased to 14 this week after astronomers confirmed the existence of another inner moon orbiting the distant, chilly world; they’ve since named the new moon Hippocamp and their findings have been published this week in the journal Nature.

Related: Astronomers find 12 more moons orbiting Jupiter

Astronomer Mark Showalter of the SETI Institute happened upon Hippocamp entirely by accident while studying Neptune’s rings with the Hubble Space Telescope back in 2013; unfortunately, not enough was known about the body at the time, so Showalter and colleagues continued their observations under the radar to learn more about it. Fast-forward to today, and it would now seem that Showalter and his team have successfully identified Hippocamp’s orbital path around Neptune and uncovered potential clues regarding where it came from.

This is what Hippocamp looked like when Mark Showalter observed it with the Hubble Space Telescope in 2013.

Image Credit: Mark R. Showalter, SETI Institute

Hippocamp measures just 21 miles in diameter, making it incredibly small when compared with Neptune’s other inner moons. In fact, it’s almost a miracle that Showalter could even discern such a tiny object given just how far away Neptune is from Earth. The peculiar circumstances drove the astronomers to dig deeper, and that’s when it struck them.

Hippocamp’s orbit around Neptune closely follows that of Proteus – the planet’s largest and outermost inner moon – which measures approximately 130 miles in diameter. The two moons orbit Neptune at just 7,500 miles apart, and the astronomers note that their obvious size difference and proximity to one another have implications for Hippocamp’s origins:

“Our results suggest that Hippocamp is probably an ancient fragment of Proteus, providing further support for the hypothesis that the inner Neptune system has been shaped by numerous impacts,” the astronomers wrote.

As it would seem, the most likely explanation for Hippocamp’s existence is that something slammed into Proteus’ surface, sending space rock fragments into space that later clumped together to form the tiny object we see today. Of course, this is only a theory, and there's certainly a lot of wiggle room for interpretation.

Related: Here's why it's a good thing that Earth only has one moon

Showalter and colleagues believe that there could be other small moons just like Hippocamp in orbit around Neptune that have not yet been discovered. Unfortunately, Neptune’s distance from Earth makes it challenging to study with observatories like the Hubble Space Telescope, and Neptune isn’t teeming with space missions like other planets are, so our understanding of the distant world is indeed limited.

With a little luck, perhaps NASA will recognize that Neptune has long slipped under the radar and consider sending a spacecraft there to study the planet up close. Only then, the researchers say, will we get a better idea of the number of objects that orbit the planet and their distinctive properties.

Source: Phys.org, The Verge, Nature

About the Author
  • Fascinated by scientific discoveries and media, Anthony found his way here at LabRoots, where he would be able to dabble in the two. Anthony is a technology junkie that has vast experience in computer systems and automobile mechanics, as opposite as those sound.
You May Also Like
JUN 25, 2020
Chemistry & Physics
Fast Radio Bursts: The Mysterious Cosmic Signals Just Got More Mysterious
JUN 25, 2020
Fast Radio Bursts: The Mysterious Cosmic Signals Just Got More Mysterious
Since the first discovery thirteen years ago, fast radio bursts (FRBs), a type of short radio pulses, have been fascinat ...
SEP 07, 2020
Space & Astronomy
Earth's Atmosphere Causes Moon to Rust
SEP 07, 2020
Earth's Atmosphere Causes Moon to Rust
Researchers from the University of Hawaii have noticed that the Moon is turning slightly red or 'rusty'- and tha ...
OCT 07, 2020
Space & Astronomy
Earth-Sized Rogue Planet Found Drifting Through Our Galaxy
OCT 07, 2020
Earth-Sized Rogue Planet Found Drifting Through Our Galaxy
A team of astronomers has found a lone planet the size of Earth drifting through the Milky Way. Known as a ‘rogue ...
OCT 22, 2020
Space & Astronomy
NASA Touches Down on the Surface of an Asteroid for a Sample
OCT 22, 2020
NASA Touches Down on the Surface of an Asteroid for a Sample
There was a time when scientists had to wait for an asteroid to fall to Earth before they could study one.
NOV 06, 2020
Space & Astronomy
300 Million Planets in the Milky Way May Be Habitable
NOV 06, 2020
300 Million Planets in the Milky Way May Be Habitable
Researchers have found that there could be at least 300 million habitable worlds in the Milky Way galaxy. This could mea ...
NOV 14, 2020
Chemistry & Physics
STEVE, what is it?
NOV 14, 2020
STEVE, what is it?
STEVE is in the sky! STEVE, as is Strong Thermal Emission Velocity Enhancement, the purple and green streaks that have b ...
Loading Comments...