Does Venus Have Moons?

Why doesn't Venus have any moons?

Venus sits inside the Sun's gravitational reach, where the Sun's pull tends to destabilize moon orbits over time. According to NASA, Venus has no moons. The Hill sphere, or the region where a planet's gravity wins out over the Sun's, is much smaller for Venus than for outer planets. Combined with Venus's odd backwards rotation and slow spin, the conditions for keeping a long-term satellite are tough to maintain.

Did Venus ever have a moon?

Possibly. One leading theory is that Venus originally had a moon, similar to Earth's, that was either pulled in by gravity and crashed into the planet, or got flung out of orbit. Some scientists have suggested that a massive impact may have stripped Venus of its moon while also reversing its rotation, which would explain two of Venus's most unusual features at once. There's no direct evidence of an ancient moon, but the idea fits some of the data.

Why is Venus's lack of moons so unusual?

Because Venus is otherwise so Earth-like. It's almost the same size, mass, and density as Earth, with a rocky composition and an iron core. Earth has a moon that's massive relative to the planet, formed in a giant impact billions of years ago. Many planetary scientists expected Venus to have something similar. The fact that it doesn't is one of the bigger oddities of our solar system, and it's one of the reasons Venus is sometimes called Earth's broken twin.

Which other planets have no moons?

Mercury is the other moonless planet. From Earth outward, every planet has at least one moon: Earth has 1, Mars has 2, and the gas giants have dozens each. Jupiter and Saturn alone account for over 100 known moons combined. Mercury and Venus, the two innermost planets, are the only ones without natural satellites, which suggests that being close to the Sun makes long-term moons unusually hard to keep.