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How big is Phobos?

Phobos is 23 kilometers

Phobos: The Fearful Moon of Mars

Have you ever wondered what’s orbiting the Red Planet, Mars? You might be surprised to discover that Mars has two moons, the larger of which is named Phobos. Its name comes from Greek mythology, where Phobos was the son of Ares (the Greek equivalent of the Roman god Mars) and represented fear and panic. But don’t worry, there’s nothing to fear about this fascinating moon!

Size Comparison of Phobos

Let’s talk about the size of Phobos. Imagine a spherical object with a radius of 11 km or 7 miles. That’s about the distance you might travel in a car in about 10 minutes on a highway. That’s roughly the size of Phobos! Compared to our own moon, it’s quite small. In fact, if you lined up 170 Phobos moons side by side, they would equal the diameter of Earth’s moon. Now, let’s compare it to something more familiar. The city of New York, for example. The length of Phobos is roughly equivalent to the distance from the southern tip of Staten Island to the northern end of the Bronx. Or think of it this way: it’s about half the size of the Grand Canyon, which is about 446 km long.

  • Phobos is 1/170th the size of Earth’s moon - Phobos is roughly equivalent to the length of New York City - Phobos is about half the size of the Grand Canyon

The Fast-Moving Moon

Another interesting fact about Phobos is its speed. It orbits Mars at a distance of 6,000 km (3,700 miles) from the Martian surface, which is closer to its primary body than any other known planetary moon. This close proximity means it moves across the sky very quickly. Phobos completes an orbit around Mars in just 7 hours and 39 minutes. That’s faster than Mars rotates, which takes about 24.6 hours. This results in a peculiar phenomenon: from the surface of Mars, Phobos appears to rise in the west and set in the east, contrary to most other celestial bodies.

A Closer Look at Phobos

Unlike our spherical moon, Phobos has an irregular shape. It resembles a lumpy potato more than a perfect sphere. This is because Phobos isn’t large enough to have enough gravity to pull itself into a spherical shape. Despite being the larger of Mars’ two moons, Phobos is still quite small compared to other moons in our solar system. But that doesn’t make it any less interesting. The mysteries and peculiarities of Phobos continue to captivate scientists and space enthusiasts alike. After all, size isn’t everything in the vast expanse of space! Remember, the universe is filled with amazing and unexpected things. So, the next time you look up at the sky and see Mars, remember the speedy, lumpy moon named Phobos orbiting around it. Who knows what other fascinating facts you might discover about our solar system.

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