What is Remote Sensing?

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Welcome to CoreFacts, where we're always short on time and big on science. I'm Jessica Robertson. Today's question is...

What is Remote Sensing?

Remote sensing is the gathering of information about the Earth from a distance. Information can be collected about the land using special cameras and instruments located just a few feet above the Earth's surface, from an airplane flying hundreds to thousands of feet above the ground or even from a satellite orbiting hundreds of miles above the Earth!

Uses include the mapping of large forest fires from space, allowing rangers to see a much larger area than from the ground. Images allow for one to watch erupting volcanoes, track clouds to help predict the weather, monitor for dust storms, view the growth of a city, and track changes in farmland over several years or even decades.

Remote sensing also allows us to gather images of and map the ocean floor without needing to travel to the bottom of the ocean. Information is collected about the seafloor using a sonar system towed on a cable behind a ship. Instead of taking a picture using light to see, sonar "sees" using sound. By measuring the amount of time it takes sound to travel from the ship to the seafloor and back to the ship, and how strong the sounds bounces back, we can make a picture of the seafloor.

These remotely sensed images are often collected as digital files. This allows us to use computers to improve and analyze the images.

And now you know. Join us again every week for a new CoreFact. For other CoreFacts or for CoreCast, our in depth science podcast, go to www.usgs.gov/podcasts. If you'd like to have questions featured on our show, give us an email at corefacts@usgs.gov or a phone call at 703-648-5600. Remember, long distance fees do apply.

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