Yeqiao Wang is fascinated by what can be learned by studying satellite images of Earth. “We usually see our world from the bottom up, but satellites allow us to interpret our whole planet from the outside world looking in,” he said.

Terrestrial remote sensing is a discipline that Professor Wang learned about early in his career, when satellites represented the future, long before anyone imagined them playing a role in smart phones and GPS systems. He uses satellite technology to monitor changes in land use and land cover caused by such factors as urbanization, natural disasters and climate change. By studying and interpreting satellite imagery, he detects the growing human footprint across the landscape.

For instance, he just completed a five-year examination of the ecological changes along the Appalachian Trail. He said that the trail’s north-south alignment from Georgia to Maine, with its cross-section of the forests and alpine areas throughout the eastern United States, makes it an ideal setting for early detection of undesirable changes to the region’s natural resources. Right now he’s studying how the salt marsh ecosystems along the Northeast coastline were impacted and are recovering from Hurricane Sandy.

“Satellite observation is the only way to monitor many of the changes taking place on Earth, like melting of the ice caps,” Professor Wang explained. “Satellites are observing Earth day after day after day. We can’t visit all those sites ourselves nearly as often.”

But it’s not just scientists like Professor Wang who depend on satellite imagery. When a major disaster happens around the globe, the first thing many people do is search online for satellite images to see for themselves what happened.

“Because of satellite technology, the globe is getting smaller and smaller,” he said. “Now we can see any part of the world with the same precision as we see our own backyard.”