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Health, Science, Environment

Studying flames in space could help clean up the air on Earth

A comparison of what flames look like on Earth versus in zero gravity.
NASA video screenshot
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Despite how long ago humans began using fire, the substance is still a mystery to scientists. Researchers at Washington University are hoping to answer some fundamental questions about it by studying flames in space. Earlier this month, they launched an experiment to do this to the International Space Station.

When a flame burns on Earth, gravity pulls cold, dense air to the base of it, causing hot air to rise. The upward flow of air is what gives flames the familiar teardrop shape. However, a flame acts differently in space.

“It doesn’t go up like a normal flame would,” said Richard Axelbaum, environmental engineering professor at Wash U. “It would just expand out.”

In the years 2019 and 2020, astronauts aboard the International Space Station will help Axelbaum observe how flames behave in zero gravity. Studying combustion in such an environment, he said, could help researchers figure out how to reduce air pollution, such as the soot that comes out of buses and other large vehicles.

The flame experiment on the ISS could also settle a disagreement that Axelbaum and other researchers are having about eliminating the formation of soot. Some researchers, he said, believe that removing soot is related to the flow of air in the flame that’s influenced by gravity. Axelbaum argued that it’s more related to something in the fundamental structure of a flame, independent of gravity’s influence.

“What we found from other experiments is space has all sorts of surprises,” Axelbaum said. “The exciting thing is not so much to prove your point as it is to discover something new.”

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