Modern radar was invented in the mid 1930's. It was originally created to make airplanes detectable before they were able to drop bombs during war. Physicist Robert Watson-Watt was asked by the British Air Ministry to develop a way to take down enemy planes using only radio waves, in hopes of competing with Hitler's rumored "death ray."
Watson-Watt determined that while it wasn't possible to destroy an entire aircraft with radio waves, it was possible to detect how close they were using the radio energy coming from the body of the plane. That process became known as radar and it didn't just make an impact on warfare, it significantly changed the entire future of technology.
By the 1970's, radar had become so advanced that scientists were able to bounce radio waves off of incredibly small objects, like electrons and ions in the upper atmosphere. They used this technology to study things like the beautifully colored auroras in the night sky, or what the sun does to our planet, among many other things.
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That's why EISCAT was built. The European Incoherent Scatter Facility was constructed in 1981 on Svalbard (a group of islands between Norway and the North Pole) in order to help scientists understand how the sun interacts with Earth's atmosphere. The technology that makes this possible is, of course, radar.
Trace Dominguez spoke to Assar Westman, Radar Systems Supervisor for EISCAT, about how radar works on a scale of this magnitude.
"This is a very potent radar system," he told Trace. "We have at this site two big parabolic dishes. One dish is 42 meters in diameter, and the second dish is 32 meters in diameter. The power amplifier that we are using has a peak power of 1 million watts. We need this because what we are studying is these free electrons at 100 kilometers. First, they are far away, and these are just free electrons, so they are very, very tiny."
EISCAT is powered by enormous dishes that sit atop mountains in Svalbard to measure the plasma, which is electrically charged gas moving through the upper atmosphere. Plasma comes from the sun's corona and the magnetic field of Earth pulls it down to the planet's poles. The molecules in the atmosphere then interact with these ions and electrons, which results in beautiful lights that we know as auroras.
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"The principle is almost like an old television screen, where you have the phosphorus and you have the electron beam that's impinging on the phosphorus, and it starts to glow," Westman explains.
EISCAT is powerful enough to detect all that junk up in space too, but what it's mostly used for is learning about weather patterns in space. This will come in especially handy for our next big space endeavor: going to Mars.
"Today they [scientists] are all talking about going to Mars," Westman says. "When you're going to Mars, then you need to know the space weather. Where this plasma will heat then and so on. If not then you're in big danger I should say. This is one of [these] things that actually you can use this facility for, or the data set we have accumulated for 35 years to be able to make this space weather predictions."
It's research like this that not only helps us understand the world around us, but the worlds above us as well. We wouldn't be able to continue space exploration without it.
-- Molly Fosco
EISCAT: A Brief History of EISCAT
Space.com: What Causes the Northern Lights & Where to See Them
BBC: What are the Northern Lights?