A geographer with the Smithsonian National Air and Space Museum visited several Tyler campuses last week.
Dr. Andrew K. Johnston shared information about the different types of satellites and uses for their images during a presentation to middle school students Wednesday at Bishop T.K. Gorman Regional Catholic School. Johnston also visited a Tyler ISD Moore Middle School science class during his multiday visit.
Johnston, a Washington, D.C.-based scientist, author and exhibit curator, curated the “Earth From Space” exhibit, which is on display at the Discovery Science Place in Tyler until March.
Johnston’s research focuses on the use of remote sensing techniques to understand environmental and land cover dynamics, according to the Air and Space Museum’s website.
He told students about how scientists and others use satellite images to learn about the Earth and its processes.
There are views that cover large sections of the Earth, and those that focus in more closely so people can see individual buildings and cars on streets.
Johnston showed students a variety of images taken or produced from satellite pictures including some of Tyler.
He said scientists are trying to use satellite data to understand the Earth as a system.
Some of the satellite images are like snapshots showing a moment in time, while others are products made from images.
Different satellites are capable of capturing different sizes of objects on the Earth. For example, one satellite can pick up the image of anything about 1 1/2 times the size of a standard projection screen, while another might only be able to pick up something the size of a football field, and another something about 2 miles wide.
The uses for satellite images vary, Johnston said. Companies considering construction projects want to determine where to build can use satellite images.
Other images can be used to determine where certain plant and animal life live on the Earth.
The global view helps people to understand how the planet functions. The images also can be used to see things such as smoke from forest fires, geological formations such as the Grand Canyon, and damage from natural disasters such as volcanoes, tsunamis and more.
The movement of ice and water on the Earth can be seen as well as the presence of humans. For example, satellite images have captured manmade art on the ground and streetlights.
Most satellites except for those designed to pickup weather phenomenon pass over an area once every two weeks, Johnston said.
Students had a variety of questions for Johnston.
Eighth-grader Kevin Scott, 13, was curious about the power in the rockets that propel the satellites into space.
Johnston said after the rockets separate from the satellite and the satellite gets into orbit, there are tiny thrusters that can be used to keep it on track while it’s moving around the Earth.
Seventh-grader Sasha Goggans asked if someone is always watching people because these satellites are in space.
Johnston said not always, although a lot of people do ask questions about privacy and there are occasionally court cases about the issue.
He said existing laws allow for satellites to take any kind of pictures from space. However, he said, he couldn’t give a definitive answer as to what is right or wrong when it comes to satellite images.
“We’re all still figuring it out right now,” he said.
Sixth-grader Delaney Douglas asked how likely it is that a satellite would fall into the ocean on re-entry.
Johnston said there’s a 75 percent chance that will happen because the ocean makes up three-fourths of the Earth. Some of the satellites aren’t big enough to survive re-entry though and burn up on the way in.
Middle school director and sixth-grader science teacher Mary Schick said the great part about the program is that it builds on what some of the students are learning about in their classes, and it can show them career options.