If you look up on a clear night, the moon is likely to be the brightest and largest object in the sky. And if you don’t have a proper telescope, it’s the only natural satellite you can see with your own eyes. As a result, most people have a distorted idea of what the Moon is and how common these natural satellites actually are.
In fact, there are hundreds, if not thousands, of natural satellites in our cosmic neighborhood, ranging from irregular city-sized space rocks to massive rounded bodies potentially large enough to be considered planets in their own right.
So exactly how much Solar System did we find the moon? The answer, it turns out, depends on your definition of the moon.
The International Astronomical Union (IAU) officially recognizes 288 planetary moons orbiting the eight worlds of the Solar System. NASA. But there are also another 473 “small body satellites” — moons of asteroids and dwarf planets — listed by NASA. Current drive laboratory. If we include both types, as most astronomers would, the total number of natural satellites in the solar system should be 761 (as of June 2024).
But that’s probably just the tip of the iceberg. Edward Ashton, an astronomer at the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, told Live Science in an email. Astronomers have found dozens of new planetary moons and satellites of small bodies in the past few years alone, and technological advances are likely to accelerate the rate at which they can spot more in the coming years, he added.
what is the month
“The simplest definition [of a moon] it would be an object that is in orbit around a larger, non-stellar object,” Ashton told Live Science. “But that’s not quite the complete answer.”
Currently there are e.g thousands of man-made satellites in orbit around the Earth which meet the above definition but are not considered moons because they are not natural. These spacecraft used to have a limited lifespan as well they fall back to Earth and burn up in our atmosphere.
Some natural satellites, such as quasi-moons and mini-moons, are also temporary and do not actually orbit planets.
Related: Will Earth ever lose its moon?
There is also the question of size, Brett Gladman, an astronomer at the University of British Columbia in Canada, told Live Science in an email. For example, ring particles — the tiny fragments of rock that make up the rings of planets like Saturn and Uranus — orbit their host planet on their own, but are not considered moons, Gladman said.
Objects smaller than a few hundred feet, often referred to as “ring moons” or “moons,” also have “fuzzy definitions” and are not considered true moons, Gladman added.
Even among the recognized months, there are still points of contention. For example, planetary moons can be divided into two groups: regular moons, which are usually larger and have small circular orbits close to the equator of their host planet; and irregular moons, which can be much smaller and have larger, elliptical orbits around their host planets, Ashton said.
Among the regular moons, about 20 are considered major moons—meaning they are large enough to have a rounded shape caused by their gravity. Planetary Society.
Planetary moons
We start closest to the Sun, the closest neighbors to our home star, Quicksilver and Venus, have no real moons due to their proximity to a giant ball of gas that would have long since torn any potential moons off the planets. Venus has one known quasi-moon, Zoozve, but that doesn’t count because it actually orbits the Sun, not Venus.
We’re moving on, we’re coming to Earth. Our the home planet has only one large moon. But he also has at least seven quasi-moons and occasionally gains additional mini-moons approximately a year at a time. These monthly cheats don’t count either. However, some scientists think we could use these space rocks as temporary bases help us become an interplanetary species.
Next up is Marswhich has two real moons: Phobos and Deimos. Both are only a few miles wide and orbit very close to the Red Planet. Phobos is slowly falling towards Mars and is predicted to one day hit the surface of the world – if it doesn’t tear first.
As we move to the giant planets, things start to get more interesting. The first gas giant, Jupiterhas an incredible 95 moons, including four major moons — Callisto, EuropeIo a Ganymede, the largest moon in the solar system. But Saturn has even more: There are at least 146 Saturnian moons, including six large moons such as Titan, Mimas and Enceladus.
Ice giants Uranium and Neptune they have 28 and 16 months and seven major months between them.
Related: Where does the solar system end?
However, these numbers have changed significantly in just the last few years. As of early 2023, astronomers including Ashton and Gladman have found the least 62 new irregular moons around Saturn and 12 new Jovian moonsas well as a a pair of Neptune’s moons and one moon around Uranus.
Advances in technology may explain the sudden increase in lunar discoveries. More powerful telescopes can spot smaller moons — especially irregular moons — that are abundant around giant planets, Ashton said.
As a result, the number of moons is likely to continue to rise sharply over the next few years. For example, Ashton revealed that he has already discovered some other planetary moons, but is still waiting for follow-up observations to confirm their existence before handing them over to the IAU.
The number of planetary moons may also increase if we find more planets in the solar system. One such world is elusive Planet Nine – a hypothetical giant planet that may be hiding in the far reaches of the solar system. If this planet exists, scientists already assumed it did may be surrounded by multiple moons.
Researchers have also speculated that other distant worlds captured from interstellar space by the Sun’s gravitational pull, known as rogue planetshe might as well have been months.
Small body satellites
The number of 473 small body satellites according to NASA is even more uncertain than the number of planetary moons because we are find more asteroids throughout. Some asteroids may also have multiple satellites difficult to distinguish from each otherAshton said.
The IAU also estimates that there could be “more than 100” additional dwarf planets waiting to be found in the outer solar systemall of which can be months.
“As with giant planetary satellites, most of them are yet to be discovered,” Ashton said. Overall, there are likely to be “about as many satellites of small bodies as planetary moons,” he added.
However, other astronomers, such as Gladman, are less certain about how many small satellites there might be. “So much for the ‘parent’ population [of host objects] it is still not known that this issue is difficult to solve,” he said.
How many months can there be in total?
There are more than 700 known natural satellites in the solar system. However, as we have seen, this number is likely to grow significantly in the future.
Past studies have shown that there could be hundreds, if not thousands, of small planetary moons that could be discovered with more powerful telescopes, Gladman said. And as we’ve already seen, there’s a lot of uncertainty about how many small-body satellites there really are.
However, this uncertainty does not prevent researchers from venturing to guess.
“I think there are probably about 10,000 moons in the solar system,” Ashton said.
But there’s no telling how long it might take us to find them all.