Where does space begin?

When are you actually out in space? At first glance, it seems simple. Outer space appears as something fundamentally different from our familiar surroundings.

While we are surrounded by air, heat, and gravity, space is empty, desolate, and cold.

Because outer space is fundamentally different from what we experience here, right?

But is there a limit? Is there a place above our heads where you clearly transition into being in space?

Read also

This is a type of galaxy that galaxy scientists have never seen before

This is a question that has been debated for many decades and there is still no good answer to it, according to the United Nations Office of Outer Space Affairs (UNOSA).

– There is no internationally agreed limit to outer space, Alla Pozdnakova tells forskning.no. She is a professor of law and has specialized in, among other things, space law and maritime law.

But why is this question so difficult to understand?

We’re also in the room

This question has two different meanings. One is political and says something about what kind of influence different countries have in the air above them and how high that influence is.

This is a complex political area, but it has nothing to do with the physical world. We’ll come back to why this is so complicated.

The second meaning is the quite physical difference between the space below and the space up there. But what is the difference, and is it possible to indicate a transition?

Soon it will be empty

The earth revolves around the sun, and it takes one year for the earth to go around the sun. The Earth’s orbit is very long – about 150 million km.

This means that the Earth, and whatever is held by Earth’s gravity, has an astronomical velocity around the Sun. It’s 108,000 kilometers per hour faster than the sun, according to NASA.

This means that both the atmosphere, you and I are also moving at such astronomical speeds even though we don’t feel like we’re moving at all.

This means that the entire globe is constantly moving towards new parts of space. If you imagine a grid, the Earth will constantly move into new areas of space. The only difference is that we, the atmosphere and everything else on the globe, move along with the globe – everything is held in place by the Earth’s gravity.

Imagine a place in space that is in Earth’s orbit. Where there used to be empty space, there is now an atmosphere, people and animals. In a brief moment, the room is empty again.

But this is a theoretical exercise. Humans need to put an end to where space begins. So what about the ground we stand on?

Where does the air end up?

Our atmosphere consists of different layers, but these layers also do not show clear boundaries of space. The second, uppermost layer is called the thermosphere, which extends from about 70 to 700 kilometers, according to NASA.

In this layer we find, among other things, the International Space Station, which orbits about 400 kilometers above our heads.

Intuitively, this looks like outer space, but there is still some air here. Here, there is a much longer distance between the air molecules than there is in the atmosphere, but it is enough for the space station to be slowed down a bit by the air.

Occasionally, you have to get a boost from the spacecraft that visit the space station. If not, it could lose so much velocity in the atmosphere that it would fall to the ground and partially burn up in the atmosphere. When he retires, this will be the way he leaves at death, According to Space.com.

The atmosphere continues far beyond the space station. The outermost part of the atmosphere is called the exosphere, and it continues to about 10,000 kilometers above the Earth’s surface. The atmosphere is getting thinner and thinner until it is almost impossible to distinguish what is called “outer space”.

There are no obvious natural boundaries to space, but there are suggestions as to where we might put imaginary boundaries, according to Astronomy magazine.

100 km straight?

The most famous proposed limit is called the Karmann limit, named after the Hungarian engineer Theodor von Karmann.

He noted that there is a limit of about 100 km above the Earth’s surface. But what is so special about this height?

His idea is based on a kind of theoretical aerodynamic limit, where the atmosphere becomes so thin that planes have to reach very high speeds to stay on their wings. Eventually, there is so little air that the plane just needs high speed to stay aloft and it will eventually start circling the Earth.

Read also

The researcher said that James Webb’s new discovery could change science. – My first thought was that we made a mistake

This limit has been calculated to be about 100 kilometers above the Earth’s surface. The Fédération Aéronautique Internationale (FAI) keeps track of who can call themselves astronauts, and they use this Karman line as the boundary for space, According to the organization itself.

That’s too high for an aircraft, and it’s virtually impossible to get that high without a rocket. The U2 spy plane was specially designed to be able to fly very high, usually about 21 kilometers in the air.

But there’s nothing special about that altitude, other than the idea that there’s some kind of theoretical aerodynamic limit.

But why should there be a room limit at all? This is a political question, and it is about what is happening in the air over a country.

Everyone must have access to the room

All countries have airspace over them, but there are no clear agreements or guidelines stating where that airspace ends.

But countries can decide their own airspace.

– Other countries must require approval or have their own agreements to be able to use the airspace over a country, Alla Pozdnakova explains.

But space is different. All nations should have free access to outer space. This is stated in the Outer Space Treaty, which most of the world’s countries signed in the 1960s.

Thus, there is a big difference between something happening in airspace or in outer space over a country. It is not clear where one ends and the other begins.

– At the international level, it has been proposed to develop a new “zone” between airspace and outer space, where the core country has jurisdiction, but not sovereignty, says Pozdnakova.

Thus, it will function somewhat like the so-called economic zone in the Law of the Sea. Any area off the coast where the country to which the area belongs can still exploit natural resources, but cannot deny other countries freedom of movement in this area.

Pozdnakova isn’t sure if there is interest among many countries in creating such a zone, but in this case it’s about 18 and 160 kilometers in the air. If it is less than 18 kilometers, Pozdnakova explains, civil aviation control applies.

– But there are many other things happening at higher altitudes that a vassal state cannot effectively control.

This could be, for example, research rockets, weather balloons or satellites traveling a few hundred kilometers above the Earth.

Swedish missile fall in Norway

Pozdnakova says that no international cap on airspace has been adopted for different countries. Remember that the first satellite, Sputnik, reached an altitude of 900 km above the Earth, and no country objected to its movement over its territory.

So it’s now agreed that it’s OK to send things into space that pass over other people’s territory at a certain altitude. But much remains unclear.

For example, launch trajectories from one country can pass through the territory of other countries, even if they are far from the Earth’s surface. But when something goes wrong, it can cause problems.

On Monday, April 24, a rocket launched from the Esrange Space Center in Kiruna, Sweden, went wrong. The missile derailed and fell 15 kilometers inside Norway, in the municipality of Malselv, although it should have already landed in Sweden, According to NRK.

The rocket had to rise to an altitude of about 250 kilometers to carry out its scientific mission.

The Foreign Ministry says it takes so-called unauthorized activity on the Norwegian side of the border seriously and that such an incident could cause significant damage, NRK writes.

The Swedish Space Center notified the Norwegian Defense Forces of both the launch and landing anomalies.

What could happen in the future?

This is an example of potential blurred borders across the country.

It gets even more difficult with drones and other things that could be seen as an infringement of the country’s basic sovereignty and a security threat.

– Satellites can take pictures of the Earth, without necessarily the affected state being able to say anything, Pozdnakova points out as an example.

But she believes it is difficult to adopt an individual country’s limit to airspace without it contradicting the goals and principles of the Outer Space Treaty, which aims to ensure all nations have access to space.

The question is whether there will be a greater need for clarification of boundaries in the future, when there may be more launches and launch sites.

Read also

A powerful solar storm is likely to give more northern lights in the future