Have Our Neighbors to the North Finally Determined Our Northern Boundary in the Sky?

May 2009 National Scene Magazine Space Article:

http://www.nationalscenemagazine.com/html/space.html

Have Our Neighbors to the North Finally Determined Our Northern Boundary in the Sky?

Canadian Scientists Believe they Have Found Boundary Between Earth’s Atmosphere and Outer Space


Written by: Karen Benardello


Much debate over where exactly the boundary between Earth’s atmosphere and outer space lies has surfaced over recent years, but researchers at the University of Calgary in Canada have announced they finally know the answer. With the data they collected from the Supra-Thermal Ion Imager, scientists at the university confirmed that space begins 73 miles above Earth’s surface.

During the new study, which is detailed in the April 7th edition of the Journal of Geophysical Research, the Ion Imager detected the boundary by tracking the winds of Earth’s atmosphere and charged particles in space. The discovery is important because the ability to gather in the area is difficult, since it’s too high for balloons and too low for satellites.

The data also “allows us to calculate energy flows into the Earth’s atmosphere that ultimately may be able to help us understand the interaction between space and our environment,” David Knudsen, a project scientist at the university, said. “That could mean a greater understanding of the link between sunspots and the warming and cooling of the Earth’s climate as well as how space weather impacts satellites, communications, navigation, and power systems.”

However, this announcement has not been made official yet, as there are many conflicting opinions over where outer space exactly starts. While some astronauts say space begins 50 miles above Earth’s surface, the Federation Aeronautique Internationale (FAI), which sets aeronautical standards and is the world governing body for aeronautics and astronautics world records, recognizes scientist Theodore von Kármán’s calculation of 62 miles.

The National Aeronautics and Space Administration (NASA) said the U.S. government doesn’t even have a set boundary standard because it feels it would complicate the issue of overflight rights of satellites and other orbiting bodies. But NASA unofficially has set the 76 mile-mile mark as their re-entry altitude because that’s where shuttles switch from steering with thrusters to maneuvering with air surfaces.

While this discovery doesn’t directly affect the lives of many people, it is helpful for astronauts and scientists. Knowing exactly where the Earth’s atmosphere ends and where outer space begins can help them determine how to continue to sustain and protect human, animal and plant life.