The blue-green planet with 27 satellites is Uranus. It is the seventh planet from the sun in our solar system and has 27 known moons or satellites.
Moons are the heavenly bodies that revolve around a planet. Moons are natural satellites that orbit a planet in a regular and predictable manner, influenced by the planet's gravity. The Earth's moon is an example of a natural satellite that orbits our planet.
Jupiter is thought to have the most moons, a total of 63 have been confirmed so far.
The largest planet with no moons is Mercury. It is the smallest planet in our solar system and does not have any natural satellites orbiting around it.
I don't know of any planet with exactly 21 known moons. The best answer is probably "Uranus" with 27 moons (natural satellites).
Jupiter
You probably mean to ask about natural satellites as opposed to artificial satellites. In terms of neutrality, all satellites are neutral. In any event, the planet Jupiter has the most natural satellites, of any planet in our solar system. The planet Earth has the most artificial satellites.
Jupiter has the most moons or satellites in our solar system with a total of 79 known moons.
Boy, have you got the wrong planet. I believe you are thinking of Saturn.
Eclipse
There are no known satellites of Mercury.
The blue-green planet with 27 satellites is Uranus. It is the seventh planet from the sun in our solar system and has 27 known moons or satellites.
Mercury & Venus have no natural satellites.
Moons are the heavenly bodies that revolve around a planet. Moons are natural satellites that orbit a planet in a regular and predictable manner, influenced by the planet's gravity. The Earth's moon is an example of a natural satellite that orbits our planet.
Objects such as moons or satellites that revolve around a planet are typically referred to as "natural satellites" or "moons." Artificial satellites placed in orbit around a planet are simply called "satellites."
Venus has no known natural satellites (moons).
No natural satellites of Mercury have been discovered.