How Many Moons Does Venus Have?
Written by Fraser Cain
Venus. From the Pioneer Venus Orbiter
As you look at the beautiful moon in our sky, and then see bright Venus, do you ever wonder how many moons Venus has? Think about it. Venus is almost exactly the same size as Earth, and even tiny Pluto has moons. Well, Venus doesn't have any moons.
None. Not even an asteroid-sized moon.
Why doesn't Venus have any moons? Astronomers think that moons are formed in a few ways. You could have the moons form around the planet during the earliest times in the Solar System, when all the planets themselves were forming. You could capture a moon later with your gravity. Or you could choose the Earth's method. In our early history, a Mars-sized rock smashed into the Earth and the debris collected together into the Moon.
One of the most likely events to happen to Venus is a colossal impact. In fact, Venus has an unusual rotation; it's going backwards compared to the rest of the planets in the Solar System. It's possible that a big impact carved out a moon for Venus, but it didn't get thrown out far enough, and crashed back down to the surface.
It's also possible that Venus has had several periods of time where captured asteroids orbiting around it. But these asteroid moons don't seem to last long. Mars' moon Phobos is slowly spiraling inward towards the planet, and will crash in the next 10 million years or so. Perhaps Venus had moons but they crashed.
So, how many moons does Venus have? Zero. It might have had moons in the distant past, but it doesn't have them today.
Other planets in the Solar System have moons. For example, here's how many moons Jupiter has, and here's how many moons Saturn has.
Here's the official entry on this question from NASA. Seriously, click the link, you'll laugh.
We have recorded an episode of Astronomy Cast all about Venus. Check it out here: Episode 50: Venus.
Filed under: Astronomy
