Introduction

Have you ever wondered how big the universe really is, and how small we might be in comparison? Let's travel beyond our own moon and dive into the fascinating world of Hydra, one of the moons of the distant dwarf planet, Pluto. Hydra, named after a mythical nine-headed serpent, is a natural satellite that orbits Pluto and is packed with intriguing facts. ## The Size of Hydra For starters, let's get an idea of how big Hydra is. The diameter of Hydra across its longest dimension is approximately 51 kilometers or 32 miles. To put that into perspective:

• Hydra is about half the size of Rhode Island, one of the smallest states in the United States.
• It's almost four times longer than Manhattan, the heart of New York City. - Imagine stacking 16,800 football fields, end to end. That's how long Hydra is. - If you could drive across Hydra at a speed of 60 miles per hour, you would complete your journey in just over half an hour! So, it's not exactly what you'd call big, especially when compared to our own moon, which is about 3,474 kilometers in diameter. However, for a moon of a dwarf planet, Hydra is not too small either. It's actually the second-largest moon of Pluto, just slightly larger than another moon named Nix. ## The Surface of Hydra Now that we have an idea of how big Hydra is, let's learn a bit about what it's made of. The surface of Hydra is highly reflective, which means it shines very brightly in the darkness of space. This shininess isn't because of any magical fairy dust; it's due to the presence of water ice on the moon's surface. To give you a comparison, Hydra's reflectivity is intermediate, lying somewhere between the brightness of Pluto and Charon, another of Pluto's moons. So, if you ever got a chance to see Hydra from a spaceship window, it would be like looking at a shiny, icy, and quite small world glimmering in the distance. ## The Discovery of Hydra Hydra was first spotted by astronomers using the Hubble Space Telescope on 15 May 2005. It's interesting to note that Hydra is the fifth and outermost moon of Pluto, meaning it orbits Pluto further out than any of the other moons. So there you have it, a quick trip to Hydra, an icy moon of Pluto that's half the size of Rhode Island and shines like a bright star in the far reaches of our solar system. It's a small part of our enormous universe, but it's definitely not lacking in fascinating details! ## Key Points to Remember:
• Hydra is a moon of Pluto with a diameter of approximately 51 km (32 mi). - It is the second-largest moon of Pluto, slightly larger than Nix. - Hydra has a highly reflective surface due to the presence of water ice. - It was discovered by astronomers using the Hubble Space Telescope in May 2005.