Many people want to travel in space one day. But when can we actually say that we are in space? Why don’t we stay in space when we travel by plane? The answers are simple: you just have to know where the earth ends and space begins.
A boundary that lies between the layers of the Earth’s atmosphere
When you look up at the sky, the space seems endless, and it probably is. On the other hand, it should be noted that there is a clear difference between the sky and infinite space in our atmosphere. So the question is where does the earth end and where does space begin? To answer this question, one must first understand the structure of the atmosphere. First, the atmosphere is a layered structure that provides our planet with adequate temperature, density, and exposure to sunlight for life on Earth.
The atmosphere is divided into five levels: troposphere, stratosphere, mesosphere, thermosphere and exosphere. Each of these layers plays a role in making the Earth a habitable planet. Each of these layers has boundaries and is defined by four main parameters: temperature change, chemical composition, density and gas movement. And a line between the mesosphere and the thermosphere that formally serves as the boundary between the earth and space.
The boundary that marks the beginning of space is called the Karman line. According to the Hungarian physicist Theodore von Carmen, the Carmen Line is an important element of aeronautics and astronomy. In fact, the Kerman line is mandatory when determining the altitude at which an aircraft can fly. Engineers and scientists also consider the Karman line when determining how satellites and spacecraft can be placed in orbit around the Earth.
A more or less well-defined boundary between space and the earth
The Kerman line is defined as the approximate height where the kinetic forces of the orbit are more important than the aerodynamic forces. In other words, it is the altitude from which the density of air decreases so much that the atmosphere alone can no longer support the spacecraft at coastal speeds. Theodore von Carmen estimated that this famous line was about 80 kilometers above sea level. With the advancement of science, scientists have finally agreed that this boundary is about 100 kilometers above sea level.
However, the range used by space and aeronautical agencies is usually 80 kilometers, although this is a source of much controversy. If there is so much controversy about this, it is because the atmosphere does not disappear, but becomes thinner with height. This means that a part of the atmosphere is in space. Furthermore, it is estimated that the Earth’s atmosphere extends up to about 1,000 kilometers, outside the Karman Line. Thus, confusion is allowed, where space is defined as the absence of atmosphere.
This confusion is problematic because international law and treaties define space as a free zone for anyone to explore and use. On the other hand, it is not at all the case of airspace over different nations. However, international law does not provide a precise limit for the height at which this airspace will end. This lack of a universal definition of boundary between space and earth can thus lead to intrusion into sovereign airspace; An act that can be misunderstood as aggression.