Question

Which specific line is recognized as the boundary between the Earth's atmosphere and outer space?

• A. The Ozone Layer
• B. The Keeling Line
• C. The Karman Line
• D. The Stratopause

Answer 1

Answer:

C. The Karman Line

The Karman Line

The Karman Line is an internationally recognized boundary that demarcates the Earth's atmosphere from outer space. It is defined as the altitude where the atmosphere becomes too thin to support aerodynamic flight.

Key Details about the Karman Line:

• Altitude: The Karman Line is generally accepted to be at an altitude of 100 kilometers (62 miles) above mean sea level.

• Origin of the Name: It is named after Theodore von Kármán, a Hungarian-American physicist and aerospace engineer, who was the first to determine this altitude.

• Significance:

  • Aerospace Engineering: It serves as a crucial benchmark for defining the threshold for spaceflight. Any vehicle that crosses this line is considered to have entered space.

  • International Recognition: While not a formal treaty, it is widely accepted by organizations like the Fédération Aéronautique Internationale (FAI), the international air sports federation.

  • Astronaut Qualification: The U.S. Air Force, NASA, and the FAA often award astronaut wings to pilots who fly above 80 kilometers (50 miles), but the 100 km mark is the more globally accepted standard for space.

• Scientific Basis: The line is based on the concept that at this altitude, the atmosphere is so tenuous that a craft would need to travel at orbital speed to generate enough lift to stay airborne, effectively transitioning from aerodynamic flight to **ballistic flight**.