Image credit: Jim Maragos/U.S. Fish and Wildlife Service

If you could, what would you want to look at? Maybe to find out if a crab is about to nibble on your toe? Well, if you were really lucky, you might just see a beautiful coral reef.

What is a reef? It’s basically a big collection of rocks sitting on the floor of the ocean. Coral reefs are living reefs covered by tiny animals called corals. They make their skeletons on the outside of their bodies, like a shell, and glue it to a rock—they stay in one place for their whole life!

After corals die, their hard outer shells stay attached to the reef. After years and years of corals leaving their little skeletons behind, a reef gets bigger and bigger. A reef in Australia is so gigantic you can see it from space!

We have learned that coral reefs are very sensitive to changes in temperature and light. They don’t like it when they can’t get enough clean water because the ocean has pollution in it. And sometimes the water they are living in gets too hot for them to survive.

In 2016. NASA invented a way to study coral reefs from airplanes. Because reefs are underwater, it’s not very easy to see them clearly. That’s why NASA is going to use a special instrument (called an imaging spectrometer) to see how the reefs are doing.

Coral reefs are usually really pretty. Some animals that live on reefs are fish, crabs, eels, sharks, sea turtles, and starfish. A lot of the fish living on coral reefs are very brightly colored, which makes people want to go and look at them. Just be sure to bring a mask and snorkel so you can see and breathe under water!  And visit the Space Place web site to learn more about Earth (