Jupiter and Saturn: New Moons Transform the Solar System Race

Around the two gas giants, Jupiter and Saturn, a full dozen previously unknown moons have been identified. The objects are so small and faint that only some of Earth’s most powerful telescopes can detect them at all. Even so, they substantially alter Solar System statistics – and allow Saturn to pull decisively ahead in the race for moons.

Tiny points of light at the edge of visibility

The discoveries are split between the two gas giants: four of the moons orbit Jupiter, while eleven orbit Saturn. None of these celestial bodies is remotely large – quite the opposite. Each is only about three kilometres across, roughly the distance many people drive to work each day.

These moons are beyond the reach of amateur astronomers. Their brightness ranges from magnitude 25 to 27. By comparison, good binoculars can reveal stars down to around magnitude 9, while smaller amateur telescopes may reach magnitude 12 or 13. Anything in the magnitude-25 range presents a genuine challenge even for professionals.

“The new moons are so faint that, even in high-resolution images, they initially look like tiny image defects – until it becomes clear that they are moving.”

Turning a suspicious point of light into a confirmed moon requires patience and precision. Astronomers repeatedly photograph the same region of sky over weeks and months, compare the images, and look for points that shift very slowly against the background stars. A discovery is considered secure only when its orbit can be clearly linked to a planet.

Giant telescopes in Chile and Hawaii do the hard work

Some of the new moons around Jupiter were detected using two of the world’s most significant large telescopes: the 6.5-metre Magellan Baade Telescope in Chile and the 8-metre Subaru Telescope in Hawaii. Both observatories are located at exceptionally dark, dry sites where the air is highly stable – ideal conditions for imaging objects at the limit of visibility.

In raw images, the moons initially resemble noise. Only with specialised software, long exposures, and repeated observations do the faint points begin to emerge. Researchers must then track their positions over an extended period. If an object moves regularly and remains close to a planet, that is strong evidence that it is a moon.

Saturn extends its lead in known moons

With the eleven additions, Saturn now has an impressive 285 known moons. Jupiter is far behind with 101. The gap between the two giants is widening.

“Saturn is no longer merely the planet with the most beautiful rings – it is also the undisputed moon king of the Solar System.”

The Minor Planet Center maintains the official register of new moons. After thorough examination, discoveries are published there in notices known as circulars. For the latest discoveries, Saturn’s moons appear, for example, in notice MPEC 2026-F14, while several MPECs numbered F09 to F12 list new moons of Jupiter.

Saturn’s advantage is not a new development. In 2025, a team led by astronomer Edward Ashton had already reported 128 new Saturnian moons. That flood of discoveries had propelled the planet well ahead of Jupiter at the time. The eleven now announced reinforce its lead further.

The number of moons orbiting the most important planets

• Saturn: 285 known moons
• Jupiter: 101 known moons
• Uranus: 28 moons
• Neptune: 16 moons
• Earth: 1 moon
• Mars: 2 small moons (Phobos and Deimos)

This extreme distribution illustrates how greatly planetary systems differ in the outer Solar System. The gas giants act like enormous vacuum cleaners, capturing asteroids and chunks of ice over billions of years.

A small group of researchers produces hundreds of discoveries

One remarkable aspect is that a large proportion of the new moons can be attributed to the work of just a few specialist teams. According to specialist outlets such as Space.com, Scott Sheppard and Edward Ashton have each co-discovered more than 200 moons.

Their formula for success is to search systematically far beyond the already known major moons. This is where the orbits of so-called irregular moons lie, often highly inclined, strongly elliptical, or even retrograde – meaning they travel in the direction opposite to the planet’s rotation.

To establish whether a point of light is genuinely a moon, researchers have to calculate its orbit precisely. If the object remains gravitationally bound to a planet for months and years, it is officially recognised as a satellite and receives a provisional designation.

What these tiny moons reveal about the Solar System’s past

Although the new moons appear inconspicuous, they are regarded as time capsules. Many are likely fragments of larger celestial bodies that collided in the distant past or broke apart during close encounters. Others may originally have been asteroids travelling freely through space before later being captured by Saturn or Jupiter.

“Each of these moons tells a small chapter of the chaotic early history of the Solar System – together, they create an ever more complete picture.”

The distribution of their orbits can reveal which catastrophes occurred during the first hundred million years after the planets formed. Groups of moons with similar orbits suggest that they were once a single body that was broken into several pieces.

Why new moons are being found all the time

The rapidly rising number of known moons is not because more objects have formed recently – they have always been there. What is new is chiefly the available technology:

• larger mirror telescopes with greater light-gathering power
• digital cameras with extremely sensitive sensors
• improved image-processing software that filters faint signals from noise
• faster computers capable of analysing huge volumes of data

As a result, the boundary of what can be achieved is moving ever further outwards. In the past, only major moons such as Titan, Ganymede, or Europa stood out, whereas today images reveal miniature bodies only a few kilometres in diameter.

How many moons are still missing?

The current total of 442 known moons in the Solar System is likely to be only an interim figure. In the outer regions of planetary orbits, far from bright rings and large satellites, researchers suspect there are dozens, if not hundreds, of additional tiny moons.

Every new instrument brings these objects closer to the detection limit. In future, space telescopes fitted with specially optimised cameras could also be used, including successors to Hubble and James Webb. They observe above Earth’s atmosphere, avoiding the disruptive atmospheric shimmer that affects even the finest ground-based sites.

Terms worth knowing

Many reports about new moons use technical expressions that can easily be confusing. Three key terms help put them into context:

Term	Meaning
Magnitude	A measure of an object’s brightness; the higher the number, the fainter its light.
Irregular moon	A satellite with an unusual orbit, often distant, steeply inclined, or retrograde.
Minor Planet Center	The international body that registers and catalogues small bodies such as asteroids and moons.

Anyone reading reports about new moons can use these terms to judge more effectively how remarkable a discovery really is and how much work lies behind it.

For planetary science, the latest discoveries primarily provide one thing: more data. Every newly charted orbit, newly determined diameter, and brightness measurement helps refine models of the Solar System’s formation and development. The tiny moons around Saturn and Jupiter are therefore far more than figures on a record list – they form a mosaic of clues that becomes denser year after year.