The boundary of the stratosphere and space. At what altitude do planes, satellites and spaceships fly? No end, no end

A few years ago, another disaster occurred in the United States during the launch of a space shuttle. The spacecraft exploded within seconds of liftoff. A feature of this case is the fact that the dead employees of the American space agency were not included in the list of dead astronauts.

The thing is that, despite the decent height at which the tragedy happened, the “boundary of space” has not yet been crossed. From all this follows a completely logical question - "where does the cosmos begin?". This is what will be discussed next.

No end, no end

Talk about where exactly space begins, starting from what height it can be considered that outer space begins, has been going on for a very long time. The thing is that the very interpretation of the concept of space is very blurred. Due to differences in definitions, scientists cannot agree on the answer to the question about the beginning of the cosmos.

Many scientists, relying on various sciences, note different numbers, trying to establish the point of "the beginning of the cosmos." For example, from the point of view of climatology, experts argue that space begins at a height of 118 km. The thing is that at such a distance from our earth, scientists study the processes of climate formation. However, many note other indicators in relation to outer space. At the same time, many also rely on our atmosphere as a certain milestone. It would seem that everything is simple, our atmosphere has ended and space begins. However, there are also some nuances here. Air, even if very rarefied, has been repeatedly recorded by various instruments at a very large distance from the ground. The same distance goes far beyond our atmosphere.

Scientists studying the issues of radiation, operating on the fact that the cosmos is a radiation space, argue that the cosmos begins where radiation also begins. In turn, scientists studying gravity say that space begins where the gravitational force of the earth completely "ends", namely, at a distance of more than twenty million kilometers.

If we rely on the figures proposed by specialists studying gravity, then we can say that the lion's share of all space expeditions cannot be considered as such at all. In addition, with such a "boundary" of space, the very concept of an astronaut is invalid. After all, a distance of twenty million kilometers is a very serious indicator. For comparison, if we take into account these figures, it turns out that space begins only outside the orbit of the moon.

Specialists from the American space agency at one time proposed a mark of 122 km as a starting point. The thing is that during the descent of the spacecraft to the surface of the earth, it is at this altitude that the astronauts turn off the onboard engines and begin the aerodynamic entry. However, this figure is different for domestic cosmonauts. Today, the Americans began to consider 80 km as a "barrier". They took this figure based on the fact that it is at this distance from the earth that a meteorite entering the atmosphere begins to “glow”.

As a summary, it can be noted that, despite the fact that scientists still have not come to a compromise on the issue of the beginning of space, the figure of 100 km has been adopted by the international community as conditionally marking the beginning of space. This figure was taken as such a conditional reference point, since at such an altitude the flight of an aircraft is no longer possible due to the low air density.

The latest data, obtained through a thorough study and generalization of a large amount of information over almost two years, allowed Canadian scientists in the first half of April to declare that space begins at an altitude of 118 km ...

Andrey Kislyakov, for RIA Novosti.

It would seem that it is not so significant where the "Earth" ends and space begins. Meanwhile, disputes over the meaning of the height, beyond which boundless outer space already stretches, have not subsided for almost a century. The latest data, obtained through a thorough study and generalization of a large amount of information for almost two years, allowed Canadian scientists in the first half of April to declare that space begins at an altitude of 118 km. From the point of view of the impact of cosmic energy on the Earth, this number is very important for climatologists and geophysicists.

On the other hand, it is unlikely that it will be possible soon to finally end this dispute by establishing a single border that suits everyone by the whole world. The fact is that there are several parameters that are considered fundamental for the corresponding assessment.

A bit of history. The fact that hard cosmic radiation acts outside the earth's atmosphere has long been known. However, it was not possible to clearly define the boundaries of the atmosphere, measure the strength of electromagnetic flows and obtain their characteristics before the launch of artificial earth satellites. Meanwhile, the main space task of both the USSR and the United States in the mid-1950s was the preparation of a manned flight. This, in turn, required a clear knowledge of the conditions just outside the earth's atmosphere.

Already on the second Soviet satellite, launched in November 1957, there were sensors for measuring solar ultraviolet, X-ray and other types of cosmic radiation. Fundamentally important for the successful implementation of manned flights was the discovery in 1958 of two radiation belts around the Earth.

But back to the 118 km established by Canadian scientists from the University of Calgary. And why, in fact, such a height? After all, the so-called "Karman Line", unofficially recognized as the boundary between the atmosphere and space, "passes" along the 100-kilometer mark. It is there that the air density is already so low that the aircraft must move at the first space velocity (about 7.9 km / s) to prevent falling to Earth. But in this case, he no longer needs aerodynamic surfaces (wing, stabilizers). Based on this, the World Aeronautics Association has adopted an altitude of 100 km as the watershed between aeronautics and astronautics.

But the degree of rarefaction of the atmosphere is far from the only parameter that determines the boundary of space. Moreover, the “terrestrial air” does not end at an altitude of 100 km. And how, say, does the state of a substance change with increasing height? Maybe this is the main thing that determines the beginning of the cosmos? Americans, in turn, consider anyone who has been at an altitude of 80 km, a true astronaut.

In Canada, they decided to identify the value of a parameter that seems to matter for our entire planet. They decided to find out at what height the influence of atmospheric winds ends and the influence of cosmic particle flows begins.

For this purpose, a special device STII (Super - Thermal Ion Imager) was developed in Canada, which was launched into orbit from a cosmodrome in Alaska two years ago. With its help, it was found that the boundary between the atmosphere and space is located at an altitude of 118 kilometers above sea level.

At the same time, data collection lasted only five minutes, while the satellite carrying it rose to its assigned altitude of 200 km. This is the only way to collect information, since this mark is too high for stratospheric probes and too low for satellite research. For the first time, the study took into account all the components, including the movement of air in the uppermost layers of the atmosphere.

Instruments like the STII will be used to continue exploration of the frontier regions of space and the atmosphere as a payload on the satellites of the European Space Agency, the active life of which will be four years. This is important because Continued research on the border regions will make it possible to learn many new facts about the impact of cosmic radiation on the Earth's climate, about the impact that ion energy has on our environment.

The change in the intensity of solar radiation, directly related to the appearance of spots on our star, somehow affects the temperature of the atmosphere, and the followers of the STII apparatus can be used to detect this influence. Already today, 12 different analyzing devices have been developed in Calgary, designed to study various parameters of the near space.

But it is not necessary to say that the beginning of space was limited to 118 km. Indeed, for their part, those who consider a height of 21 million kilometers to be real space are right! It is there that the influence of the Earth's gravitational field practically disappears. What awaits researchers at such a cosmic depth? After all, we did not climb further than the Moon (384,000 km).

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How far from Earth does space begin?

What is space, probably, many people know. But, few people thought about where the cosmos actually begins. Indeed, at what height from the Earth can we say that the object is already (or still) in space?

This question, it must be said, is not idle. Many people remember the tragic launch of the American shuttle Challenger in 1985, when after a few minutes of flight the reusable spacecraft exploded. After this accident, the question arose - should the dead crew members be considered astronauts? The dead were not included in the number of astronauts, although the explosion occurred at a very high altitude.

There is no consensus among scientists at what height space begins. For the "reference point" various options are offered. Thus, Canadian experts propose to consider the height of 118 kilometers as the beginning of space, since this is the “standard” height from which climatologists and geophysicists “look” at our planet. Some scientists suggest relying on gravity indicators. In this case, space will begin at a distance of about 21 million kilometers, this is where the earth's gravity completely disappears. But, in this case, all current cosmonauts and astronauts will not be such. Then only flights beyond the orbit of the Moon will remain space.

NASA experts believe that space begins at a height of 122 kilometers, it is this mark adopted by the MCC when the onboard engines of the descent vehicle are turned off and the aerodynamic descent from orbit begins. However, Soviet cosmonauts also perform ballistic entry into the Earth's atmosphere from other heights.

If we take the "burning" of meteorites falling into the earth's atmosphere as the beginning of space, then this will be a distance of 80 km from the Earth.

As you can see, there are many options. In order to somehow "legitimize" the initial boundary of space, scientists compromised and proposed to consider the space altitude at which planes can no longer fly due to the very low air density - 100 kilometers from the Earth's surface.

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Distances in space. Stars and objects closest to us

Everyone has ever traveled, spending a specific time on overcoming the path. How endless the road seemed when it was measured in days. From the capital of Russia to the Far East - seven days by train! And if on this transport to overcome distances in space? It takes only 20 million years to get to Alpha Centauri by train. No, it's better by plane - it's five times faster. And this is up to the star that is nearby. Of course, nearby - this is by stellar standards.

Distance to the Sun

Aristarchus of Samos Aristarchus of Samos Astronomer, mathematician and philosopher, lived in the III century BC. e. He was the first to guess that the earth revolves around the sun and proposed a scientific method for determining the distances to it. 200 years before our era, he tried to determine the distance to the Sun. But his calculations were not very correct - he was wrong by 20 times. More accurate values were obtained by the Cassini spacecraft in 1672. The positions of Mars during its opposition were measured from two different points on the Earth. The calculated distance to the Sun turned out to be 140 million km. In the middle of the 20th century, with the help of Venus radar, the true parameters of the distances to the planets and the Sun were found out.

Now we know that the distance from the earth to the Sun is 149,597,870,691 meters. This value is called the astronomical unit, and it is the foundation for determining cosmic distances using the stellar parallax method.

Long-term observations have also shown that the Earth moves away from the Sun by about 15 meters in 100 years.

Distances to nearest objects

We don't think much about distance when we watch live broadcasts from far corners of the globe. The TV signal comes to us almost instantly. Even from our satellite, the Moon, radio waves reach the Earth in a second and a tail. But it is worth talking about objects more distant, and surprise immediately comes. Does it really take 8.3 minutes for light to travel to such a close Sun, and 5.5 hours to icy Pluto? And this, flying almost 300,000 km in a second! And in order to get to the same Alpha in the constellation Centaurus, a beam of light will take 4.25 years.

Even for near space, our usual units of measurement are not quite suitable. Of course, you can measure in kilometers, but then the numbers will not cause respect, but some fear of their size. For our solar system, it is customary to measure in astronomical units.

Now space distances to planets and other objects of near space will not look so scary. From our star to Mercury is only 0.387 AU, and to Jupiter - 5.203 AU. Even to the most distant planet - Pluto - only 39.518 AU.

The distance to the Moon is determined to the nearest kilometer. This was done by placing corner reflectors on its surface and using the laser location method. The average value of the distance to the Moon turned out to be 384,403 km. But the solar system extends much beyond the orbit of the last planet. To the border of the system as much as 150,000 AU. e. Even these units begin to be expressed in grandiose quantities. Other measurement standards are appropriate here, because the distances in space and the size of our Universe are beyond the boundaries of reasonable ideas.

Medium space

There is nothing faster than light in nature (until such sources are known), therefore, it was its speed that was taken as the basis. For objects closest to our planetary system, and for those far from it, the path traveled by light in one year is taken as a unit. Light flies to the edge of the solar system for about two years, and to the nearest star in Centaurus 4.25 sv. of the year. The well-known Polar Star is located at a distance of 460 St. from us. years.

Each of us dreamed of going to the past or the future. Traveling into the past is entirely possible. You just need to look into the night starry sky - this is the past, distant and infinitely distant.

Everything space objects we observe in their distant past, and the further the observed object, the further into the past we look. While the light flies from a distant star to us, so much time passes that perhaps at the moment this star no longer exists!

The brightest star in our sky - Sirius - will go out for us only 9 years after his death, and the red giant Betelgeuse - only after 650 years.

Our galaxy is 100,000 light across. years, and a thickness of about 1,000 sv. years. It is incredibly difficult to imagine such distances, and it is almost impossible to estimate them. Our Earth, together with its luminary and other objects of the solar system, revolves around the center of the galaxy in 225 million years, and makes one revolution in 150,000 light years. years.

deep space

Distances in space to distant objects are measured using the parallax (displacement) method. Another unit of measurement emerged from it - the parsec. Parsec (pc) - from parallactic second This is the distance from which the radius of the earth's orbit is observed at an angle of 1 ″ .. The value of one parsec was 3.26 sv. year or 206 265 a. e. Accordingly, there are both thousands of parsecs (Kpc) and millions (Mpc). And the farthest objects in the universe will be expressed in terms of distances of a billion parsecs (Gpc). The parallax method can be used to determine the distances to objects that are no further than 100 pc, b O Larger distances will have very significant measurement errors. The photometric method is used to study distant cosmic bodies. This method is based on the properties of Cepheids - variable stars.

Each Cepheid has its own luminosity, the intensity and nature of which can be used to estimate the distance of an object located nearby.

Also, supernovae, nebulae, or very large stars of the supergiant and giant classes are used to determine brightness distances. Using this method, it is realistic to calculate the cosmic distances to objects located no further than 1000 Mpc. For example, to the galaxies closest to the Milky Way - the Large and Small Magellanic Clouds, it turns out 46 and 55 Kpc, respectively. And the nearest galaxy, the Andromeda Nebula, will be at a distance of 660 Kpc. The group of galaxies in the constellation Ursa Major is 2.64 Mpc away from us. And the size of the visible universe is 46 billion light years, or 14 Gpc!

Measurements from space

To improve the accuracy of measurements, the Hipparchus satellite was launched in 1989. The task of the satellite was to determine the parallaxes of more than 100 thousand stars with millisecond accuracy. As a result of observations, the distances for 118,218 stars were calculated. They included more than 200 Cepheids. For some objects, previously known parameters have changed. For example, the Pleiades open star cluster approached - instead of 135 pc of the previous distance, only 118 pc were obtained.

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Distances in space

The distance between the Earth and the Moon is huge, but it seems tiny compared to the scale of space.

Outer spaces, as you know, are quite large-scale, and therefore astronomers do not use the metric system that is familiar to us to measure them. In the case of the distance to the Moon (384,000 km), kilometers can still be applied, but if we express the distance to Pluto in these units, we get 4,250,000,000 km, which is already less convenient for recording and calculations. For this reason, astronomers use other distance units, which you can read about below.

astronomical unit

The smallest of these units is the astronomical unit (AU). Historically, one astronomical unit is equal to the radius of the Earth's orbit around the Sun, otherwise - the average distance from the surface of our planet to the Sun. This method of measurement was most suitable for studying the structure of the solar system in the 17th century. Its exact value is 149,597,870,700 meters. Today, the astronomical unit is used in calculations with relatively short lengths. That is, when studying distances within the solar system or other planetary systems.

Light year

A slightly larger unit of length in astronomy is the light year. It is equal to the distance that light travels in vacuum in one Earth, Julian year. The zero influence of gravitational forces on its trajectory is also implied. One light year is about 9,460,730,472,580 km or 63,241 AU. This unit of length is used only in popular science literature for the reason that the light year allows the reader to get a rough idea of distances on a galactic scale. However, due to its inaccuracy and inconvenience, the light year is practically not used in scientific work.

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Parsec

The most practical and convenient for astronomical calculations is such a unit of distance measurement as a parsec. To understand its physical meaning, one should consider such a phenomenon as parallax. Its essence lies in the fact that when the observer moves relative to two bodies distant from each other, the apparent distance between these bodies also changes. In the case of stars, the following happens. When the Earth moves in its orbit around the Sun, the visual position of the stars close to us changes somewhat, while the distant stars, acting as a background, remain in the same places. The change in the position of a star when the Earth shifts by one radius of its orbit is called the annual parallax, which is measured in arc seconds.

Then one parsec is equal to the distance to the star, the annual parallax of which is equal to one arc second - the unit of angle in astronomy. Hence the name "parsec", combined from two words: "parallax" and "second". The exact value of a parsec is 3.0856776 10 16 meters or 3.2616 light years. 1 parsec is equal to approximately 206,264.8 AU. e.

Method of laser location and radar

These two modern methods are used to determine the exact distance to an object within the solar system. It is produced in the following way. With the help of a powerful radio transmitter, a directed radio signal is sent towards the object of observation. After that, the body beats off the received signal and returns to Earth. The time it takes the signal to complete the path determines the distance to the object. Radar accuracy is only a few kilometers. In the case of laser location, instead of a radio signal, a light beam is sent by the laser, which allows you to determine the distance to the object by similar calculations. The accuracy of laser location is achieved down to fractions of a centimeter.

Telescope TG-1 of the laser locator LE-1, Sary-Shagan test site

Trigonometric parallax method

The simplest method for measuring the distance to distant space objects is the trigonometric parallax method. It is based on school geometry and consists of the following. Let's draw a segment (basis) between two points on the earth's surface. Let's select an object in the sky, the distance to which we intend to measure, and define it as the top of the resulting triangle. Next, we measure the angles between the basis and the straight lines drawn from the selected points to the body in the sky. And knowing the side and two corners of a triangle adjacent to it, you can find all its other elements.

Trigonometric parallax

The value of the selected basis determines the accuracy of the measurement. After all, if the star is located at a very large distance from us, then the measured angles will be almost perpendicular to the basis and the error in their measurement can significantly affect the accuracy of the calculated distance to the object. Therefore, the most remote points on Earth should be chosen as a basis. Initially, the radius of the Earth acted as a basis. That is, the observers were located at different points of the globe and measured the mentioned angles, and the angle located opposite the basis was called the horizontal parallax. However, later, as a basis, they began to take a greater distance - the average radius of the Earth's orbit (astronomical unit), which made it possible to measure the distance to more distant objects. In this case, the angle opposite the basis is called the annual parallax.

This method is not very practical for studies from the Earth, for the reason that due to the interference of the Earth's atmosphere, it is not possible to determine the annual parallax of objects located more than 100 parsecs away.

However, in 1989, the Hipparcos Space Telescope was launched by the European Space Agency, which made it possible to identify stars at a distance of up to 1000 parsecs. As a result of the data obtained, scientists were able to compile a three-dimensional map of the distribution of these stars around the Sun. In 2013, ESA launched the next satellite, Gaia, which is 100 times more accurate, allowing all the stars in the Milky Way to be observed. If human eyes had the accuracy of the Gaia telescope, then we would be able to see the diameter of a human hair from a distance of 2,000 km.

Method of standard candles

To determine the distances to stars in other galaxies and the distances to these galaxies themselves, the standard candle method is used. As you know, the farther the light source is from the observer, the dimmer it seems to the observer. Those. the illumination of a light bulb at a distance of 2 m will be 4 times less than at a distance of 1 meter. This is the principle by which the distance to objects is measured using the standard candle method. Thus, drawing an analogy between a light bulb and a star, one can compare the distances to light sources with known powers.

The scale of the universe explored by existing methods is impressive. View infographic in full size.

The standard candles in astronomy are objects whose luminosity (analogous to the power of the source) is known. It can be any kind of star. To determine its luminosity, astronomers measure the surface temperature based on the frequency of its electromagnetic radiation. Then, knowing the temperature, which makes it possible to determine the spectral type of a star, its luminosity is determined using the Hertzsprung-Russell diagram. Then, having the values of luminosity and measuring the brightness (apparent value) of the star, you can calculate the distance to it. Such a standard candle allows you to get a general idea of the distance to the galaxy in which it is located.

However, this method is quite laborious and not very accurate. Therefore, it is more convenient for astronomers to use cosmic bodies with unique features as standard candles, for which the luminosity is known initially.

Unique standard candles

Cepheid PTC Puppis

Cepheids are the most commonly used standard candles, which are variable pulsating stars. By studying the physical features of these objects, astronomers have learned that Cepheids have an additional characteristic - a pulsation period that can be easily measured and which corresponds to a certain luminosity.

As a result of observations, scientists are able to measure the brightness and period of pulsation of such variable stars, and hence the luminosity, which makes it possible to calculate the distance to them. Finding a Cepheid in another galaxy makes it possible to relatively accurately and simply determine the distance to the galaxy itself. Therefore, this type of star is often referred to as the "beacons of the universe."

Despite the fact that the Cepheid method is most accurate at distances up to 10,000,000 pc, its error can reach 30%. To improve accuracy, as many Cepheids as possible in one galaxy will be required, but even in this case, the error is reduced to at least 10%. The reason for this is the inaccuracy of the period-luminosity dependence.

Cepheids are the "beacons of the universe".

In addition to Cepheids, other variable stars with known period-luminosity relationships can also be used as standard candles, as well as supernovae with known luminosity for the greatest distances. Close in accuracy to the Cepheid method is the method with red giants as standard candles. As it turned out, the brightest red giants have an absolute magnitude in a fairly narrow range, which allows you to calculate the luminosity.

Distances in numbers

Distances in the solar system:

1 a.u. from the Earth to the Sun = 500 sv. seconds or 8.3 sv. minutes
30 a. e. from the Sun to Neptune = 4.15 light hours
132 a.u. from the Sun - this is the distance to the Voyager 1 spacecraft, was noted on July 28, 2015. This object is the most remote of those that have been constructed by man.

Distances in the Milky Way and beyond:

1.3 parsecs (268144 AU or 4.24 light years) from the Sun to Proxima Centauri, the closest star to us
8,000 parsecs (26 thousand light years) - the distance from the Sun to the center of the Milky Way
30,000 parsecs (97 thousand light years) - the approximate diameter of the Milky Way
770,000 parsecs (2.5 million light years) - the distance to the nearest large galaxy - the Andromeda nebula
300,000,000 pc - scales on which the Universe is almost homogeneous
4,000,000,000 pc (4 Gigaparsec) is the edge of the observable universe. This is the distance traveled by the light recorded on Earth. Today, the objects that emitted it, taking into account the expansion of the Universe, are located at a distance of 14 gigaparsecs (45.6 billion light years).

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how many kilometers to space to shuttle orbit

Debris in Earth orbit threatens the continuation of space travel

Tens of millions of artificial objects, about 13 thousand of which are large objects, orbit the Earth, posing a threat to further space flights. This is stated in the quarterly report of the NASA department responsible for monitoring near-Earth space.

According to the document, there are 12,851 large objects of artificial origin in orbit, of which 3,190 are working and failed satellites and 9,661 rocket stages and other space debris. The number of space debris particles ranging in size from 1 to 10 cm is over 200 thousand , according to Interfax.

And the number of particles less than 1 cm, experts suggest, exceeds tens of millions. Basically, space debris is concentrated at altitudes from 850 to 1500 km above the Earth's surface, but there is also a lot of it at the flight altitudes of spacecraft and the International Space Station (ISS).

In August, the Mission Control Center conducted an ISS avoidance maneuver from a collision with a fragment of space debris, and in October it postponed the correction of the station's orbit due to the danger of a new collision.

Earlier, NASA also reported that the flight of the American shuttle Atlantis to repair the Hubble telescope could pose a danger to the crew. The telescope is in orbit about 600 km above the Earth, that is, almost twice as high as the ISS orbit, so the probability of meeting with space debris, according to experts, almost doubles.

If space debris located at altitudes below 600 km enters the atmosphere for several years and burns up in it, then debris located at altitudes of 800 km takes decades, and artificial objects at altitudes of thousands of kilometers and above hundreds of years. , according to NASA.

According to NASA spokesman Nicholson Johnson, who spoke in April at a meeting in Moscow of the 26th session of the Inter-Agency Space Debris Coordination Committee, there are two methods to combat the appearance of new space debris in orbit. One of them is the removal of fragments of launch vehicles from orbit using the fuel remaining on their board. The second method is the removal of spacecraft that have served their time into disposal orbits. According to experts, the lifetime of such devices at these points of the orbit can be 200 years or more.

Out of 13 thousand artificial objects, Russia and other CIS countries own 4528 fragments of space debris (1375 satellites and 3153 stages of rockets and other space debris).

The United States has 4259 objects (1096 satellites and 3163 stages of rockets and other elements of space technology).

The Chinese contribution to space debris is almost half that. The total number of objects listed for the PRC is 2774 (70 satellites and 2704 fragments of space technology and stages of launch vehicles).

France owns 376 artificial objects in Earth orbit, Japan - 175, India - 144, the European Space Agency - 74. Other countries - 521 objects of artificial origin.

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how many kilometers from earth to space?

from the earth to the uppermost shell of the earth 50,000 km
to the moon 80,000 km

Space is considered to begin at the level of 100 km. from the earth.

The conditional boundary of space is 100 km.
Conditional because there are no stretched ropes with signs: “Attention! Then space begins, flying on airplanes is strictly prohibited! “We just agreed.

In fact, there are a number of reasons why it was agreed that way, but they, too, are rather arbitrary.

From a height of 30 km already begins

first understand the terms, and then ask questions. space is the whole material world and the distance to it is 0 km. Outer space is a relatively empty part of space outside the atmospheres of celestial bodies. for the earth, the boundary of outer space lies on the Karman line - 100 km above sea level.

The earth is in it. How many meters from you to the room you are sitting in? Still be stricter in words! You didn't mean space, but only airless space, right? Strictly speaking, the atmosphere does not have a clear upper boundary. What signs of "cosmos" are you interested in?
Where you can't breathe? Already at 5 kilometers you can barely exist with shortness of breath. And at 10 - you will suffocate with a guarantee. However, the aircraft is even up to 20 km. there may still be enough air to stay on the wing. Stratostat can rise up to 30 km due to the huge reserve of lift. From this height, the stars are already clearly visible during the day. At 50 km - the sky is already completely black, and yet there is still air - it is there that the aurora "live", which eats nothing more than air ionization. At 100 km. the presence of air is already so small that the apparatus can fly at a speed of several kilometers per second and experience practically no resistance. Unless the instruments can detect the presence of individual air molecules. At 200 km. even the instruments will not show anything, although the number of gas molecules per cubic meter is still much greater than in interplanetary space.
So where does "space" begin?

250 kilometers. a practical question?

NASA considers the boundary of space 122 km

At this altitude, the shuttles switched from conventional maneuvering using only rocket engines to aerodynamic maneuvering with "reliance" on the atmosphere.

There is another point of view that defines the boundary of space at a distance of 21 million kilometers from the Earth - at such a distance, the gravitational influence of the Earth practically disappears.

1000-1100 km - the maximum height of the auroras, the last manifestation of the atmosphere visible from the Earth's surface (but usually well-marked auroras occur at altitudes of 90-400 km).

2000 km - the atmosphere does not affect satellites and they can exist in orbit for many millennia.

100,000 km - the upper boundary of the exosphere (geocorona) of the Earth noticed by satellites. The last manifestations of the earth's atmosphere ended, interplanetary space began.

from 150 km to 300 km, Gagarin flew around the Earth at an altitude of 200 km, and from St. Petersburg to Moscow 650 km

Most space flights are performed not in circular, but in elliptical orbits, the height of which varies depending on the location above the Earth. The height of the so-called "low reference" orbit, from which most spacecraft "push off", is approximately 200 kilometers above sea level. To be precise, the perigee of such an orbit is 193 kilometers, and the apogee is 220 kilometers. However, in the reference orbit there is a large amount of debris left over half a century of space exploration, so modern spacecraft, turning on their engines, move to a higher orbit. For example, the International Space Station ( ISS) in 2017 rotated at a height of about 417 kilometers, that is, twice as high as the reference orbit.

The height of the orbit of most spacecraft depends on the mass of the spacecraft, its launch site, and the power of its engines. For astronauts, it varies from 150 to 500 kilometers. For example, Yuri Gagarin flew in an orbit with a perigee of 175 km and apogee at 320 km. The second Soviet cosmonaut German Titov flew in an orbit with a perigee of 183 km and an apogee of 244 km. American "shuttles" flew in orbits height from 400 to 500 kilometers. Approximately the same height and all modern ships delivering people and cargo to the ISS.

Unlike manned spacecraft that need to return astronauts to Earth, artificial satellites fly in much higher orbits. The orbital altitude of a satellite in geostationary orbit can be calculated from data on the mass and diameter of the Earth. As a result of simple physical calculations, it can be found that geostationary orbit altitude, that is, one in which the satellite "hangs" over one point on the surface of the earth, is equal to 35,786 kilometers. This is a very large distance from the Earth, so the signal exchange time with such a satellite can reach 0.5 seconds, which makes it unsuitable, for example, for servicing online games.

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Where does the Cosmos begin?

Sea level - 101.3 kPa (1 atm.; 760 mm Hg. St.;) atmospheric pressure, medium density 2.7 1019 molecules per cm³.
. 0.5 km - 80% of the world's population lives up to this height.
. 2 km - up to this height lives 99% of the world's population.
. 4.7 km - MFA requires additional oxygen supply for pilots and passengers.
. 5.0 km - 50% of atmospheric pressure at sea level.
. 5.3 km - half of the entire mass of the atmosphere lies below this height (slightly below the top of Mount Elbrus).
. 6 km - the boundary of permanent human habitation.
. 8.2 km is the border of death without an oxygen mask: even a healthy and trained person can lose consciousness and die at any moment.

8.848 km - the highest point on Earth Mount Everest - the limit of accessibility on foot.

16 km - when in a high-altitude suit, additional pressure is needed in the cockpit. 10% of the atmosphere remained overhead.
. 18.9-19.35 - Armstrong's line - the beginning of space for the human body - boiling water at the temperature of the human body. Internal bodily fluids do not yet boil at this altitude, as the body generates enough internal pressure to prevent this effect, but saliva and tears may begin to boil with the formation of foam, eyes swell.
. 20 km - the upper boundary of the biosphere: the limit of the ascent of spores and bacteria into the atmosphere by air currents.

20 km - the ceiling of hot air balloons (hot air balloons) (19,811 m).

25 km - during the day you can navigate by bright stars.
. 25-26 km - the maximum height of the steady flight of existing jet aircraft (practical ceiling).
. 15-30 km - the ozone layer at different latitudes.
. 34.668 km - a record altitude for a balloon (stratospheric balloon) controlled by two stratonauts.
. 35 km is the beginning of space for water or the triple point of water: at this altitude, water boils at 0 ° C, and above it cannot be in liquid form.
. 37.65 km - a record for the height of existing turbojet aircraft (Mig-25, dynamic ceiling).

38.48 km (52,000 steps) - the upper limit of the atmosphere in the 11th century: the first scientific determination of the height of the atmosphere from the duration of twilight (Arabic scientist Alhazen, 965-1039).
. 39 km - the height record for a human-controlled stratospheric balloon (Red Bull Stratos).

51.694 km - the last manned altitude record in the pre-space era (Joseph Walker on the X-15 rocket plane, March 30, 1961)
. 51.82 km - a record altitude for a gas unmanned balloon.
. 55 km - the atmosphere does not affect cosmic radiation.
. 40-80 km - maximum air ionization (transformation of air into plasma) from friction against the body of the descent vehicle when entering the atmosphere with the first cosmic velocity.
. 70 km - the upper limit of the atmosphere in 1714 according to the calculation of Edmund Holley (Halley) based on the data of climbers, Boyle's law and observations of meteors.

100 km - the official international boundary between the atmosphere and space - the Karman line, which defines the border between aeronautics and astronautics. Aerodynamic surfaces (wings) starting from this height do not make sense, since the flight speed for creating lift becomes higher than the first cosmic speed and the atmospheric aircraft turns into a space satellite. The density of the medium at this height is 12 billion molecules per 1 cm³

122 km (400,000 ft) - the first noticeable manifestations of the atmosphere during the return to Earth from orbit: the oncoming air begins to turn the Space Shuttle nose in the direction of travel, air ionization from friction and heating of the body begins.
. 150-180 km - the height of the perigee of the orbit of the first manned space flights.
. 302 km - the maximum height of the first space flight (Yu.A. Gagarin, Vostok-1, April 12, 1961)

320 km - the registered boundary of the atmosphere in 1927: the discovery of the Appleton layer reflecting radio waves.
. OK. 400 km - the height of the orbit of the International Space Station

500 km - the beginning of the inner proton radiation belt and the end of safe orbits for long-term human flights.
. 1000-1100 km - the maximum height of the auroras, the last manifestation of the atmosphere visible from the Earth's surface (but usually well-marked auroras occur at altitudes of 90-400 km).

1372 km - the maximum height reached by man in the prelunar era (September 12, 1966, Gemini 11).
. 2000 km - the atmosphere does not affect satellites and they can exist in orbit for many millennia.
. 12,756 km - we moved away at a distance equal to the diameter of the planet Earth.
. 27,000 km is the smallest distance from the Earth, at which the discovered asteroid 2012 DA14, 44 m in diameter and weighing about 130 thousand tons, flew in advance (over 1 day).

35,786 km is the height of the geostationary orbit, a satellite at this height will always hang over one point on the equator. In the first half of the 20th, this height was considered the theoretical limit of the existence of the atmosphere. If the entire atmosphere rotated uniformly with the Earth, then from this height at the equator the centrifugal force of rotation would exceed gravity and the air particles that went beyond this boundary would scatter in different directions.

OK. 100,000 km is the upper boundary of the exosphere (geocorona) of the Earth noticed by satellites. Atmosphere ended, interplanetary space began
. 363 104 - 405 696 km - the height of the Moon's orbit above the Earth.
. 401,056 km - the absolute record for the height at which a person was (Apollo 13, April 14, 1970).

21,000,000 km - at this distance, the gravitational influence of the Earth on flying objects practically disappears.
. 40,000,000 km is the minimum distance from the Earth to the nearest large planet Venus (up to Mars 56-58 million km).
. 149,597,870.7 km is the average distance from the Earth to the Sun. This distance serves as a measure of distance in the solar system and is called the astronomical unit (AU).
. 4,500,000,000 km - the radius of the boundary of the near-solar interplanetary space - the radius of the orbit of the most distant large planet Neptune.

8,230,000,000 km - the boundary of the Kuiper belt - the belt of small ice planets.
. 18,435,000,000 km is the distance to today's farthest spacecraft, Voyager 1.

9 460 730 472 580, 8 km - light year - the distance that light travels in 1 year. Used to measure interstellar and intergalactic distances.
. up to 20,000,000,000,000 km (20 trillion km, 2 light years) - the gravitational boundaries of the solar system (Hill's Sphere) - the boundary of the Oort Cloud, the maximum range of planets.
. 30,856,776,000,000 km - parsec - a more narrowly professional astronomical unit for measuring distances, equal to 3.2616 light years.
. OK. 40,000,000,000,000 km (40 trillion km, 4.243 light years) - the distance to our nearest star Proxima Centauri
. OK. 300,000,000,000,000 km (300 trillion km, 30 light years) is the size of the Local Interstellar Cloud through which the Solar System is currently moving (density 300 atoms per 1 dm³).

OK. 3,000,000,000,000,000 km (3 quadrillion km, 300 light years) is the size of the Local gas bubble, which includes the Local Interstellar Cloud with the Solar System (50 atoms per 1 dm³).

OK. 300,000,000,000,000,000 km (300 qdrln km) is the distance from the Sun to the nearest outer edge of the halo of our Milky Way galaxy. Beyond it stretches a black, almost empty and starless intergalactic space with small spots of several nearby galaxies barely visible without a telescope.
. OK. 2,000,000,000,000,000,000,000,000,000 km - the boundary of the Milky Way subgroup (15 galaxies).

OK. 15,000,000,000,000,000,000 km (15 quintillion km) - the boundary of the Local Group of galaxies (more than 50 galaxies).
. OK. 1,000,000,000,000,000,000,000 km (1 sextillion km, 100 million light years) - the boundary of the Local Supercluster of Galaxies (Virgo Supercluster) (about 30 thousand galaxies).
. The Whale-Pisces Supercluster Group
. OK. 435,000,000,000,000,000,000,000 km (435 sextillion km, 46 billion light years) is the boundary of the observable Universe (about 500 billion galaxies).

how many kilometers from earth to space? and got the best answer

Answer from WinterMax[guru]
as such, there is no clear boundary between the earth's atmosphere and the vacuum of space. As the concentration of the gas decreases as it rises, the pressure decreases.
It is generally accepted that the atmosphere rises above the earth by about 800 km. But the main layer (and this is 99% of all gas) is located in the first 122 km.
By the way, the distance to the moon is about 380,000 km.

Answer from Alexey Kochetkov[guru]
from the earth to the uppermost shell of the earth 50,000 km
to the moon 80,000 km

Answer from Yoehmet[guru]
Space is considered to begin at the level of 100 km. from the earth.

Answer from Beaver[guru]
The conditional boundary of space is 100 km.
Conditional because there are no stretched ropes with signs: "Attention! Then space begins, flying by planes is strictly prohibited!", We just agreed.
In fact, there are a number of reasons why it was agreed that way, but they, too, are rather arbitrary.

Answer from ****** [guru]
From a height of 30 km already begins

Answer from Hard childhood[guru]
first understand the terms, and then ask questions. space is the whole material world and the distance to it is 0 km. Outer space is a relatively empty part of space located outside the atmospheres of celestial bodies. for the earth, the boundary of outer space lies on the Karman line - 100 km above sea level.

Answer from Dmitry Nizyaev[guru]
The earth is in it. How many meters from you to the room you are sitting in? Still be stricter in words! You didn't mean space, but only airless space, right? Strictly speaking, the atmosphere does not have a clear upper boundary. What signs of "cosmos" are you interested in?
Where you can't breathe? Already at 5 kilometers you can barely exist with shortness of breath. And at 10 - you will suffocate with a guarantee. However, the aircraft is even up to 20 km. there may still be enough air to stay on the wing. Stratostat can rise up to 30 km due to the huge reserve of lift. From this height, the stars are already clearly visible during the day. At 50 km - the sky is already completely black, and yet there is still air - it is there that the auroras "live", which are eaten by nothing more than air ionization. At 100 km. the presence of air is already so small that the apparatus can fly at a speed of several kilometers per second and experience practically no resistance. Unless the instruments can detect the presence of individual air molecules. At 200 km. even the instruments will not show anything, although the number of gas molecules per cubic meter is still much greater than in interplanetary space.
So where does "space" begin?

Answer from Igor Borukhin[newbie]
250 kilometers. a practical question?

Answer from Christianity is the religion of progress[guru]
NASA considers the boundary of space 122 km
At this altitude, the shuttles switched from conventional maneuvering using only rocket engines to aerodynamic maneuvering with "reliance" on the atmosphere.
There is another point of view that defines the boundary of space at a distance of 21 million kilometers from the Earth - at such a distance, the gravitational influence of the Earth practically disappears.

Answer from NAMIK[newbie]
128 km

Answer from Chernobushka[expert]

1000-1100 km - the maximum height of the auroras, the last manifestation of the atmosphere visible from the Earth's surface (but usually well-marked auroras occur at altitudes of 90-400 km).
2000 km - the atmosphere does not affect satellites and they can exist in orbit for many millennia.
100,000 km - the upper boundary of the exosphere (geocorona) of the Earth noticed by satellites. The last manifestations of the earth's atmosphere ended, interplanetary space began.

Answer from Yana Mazina[newbie]
from 150 km to 300 km, Gagarin flew around the Earth at an altitude of 200 km, and from St. Petersburg to Moscow 650 km

Answer from Magneto[active]
122 km (400,000 ft) - the first noticeable manifestations of the atmosphere during the return to Earth from orbit: the oncoming air begins to turn the Space Shuttle nose in the direction of travel, air ionization from friction and heating of the body begins.

Answer from Yotudia Creative[newbie]
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Answer from [email protected] [newbie]
So many selfies and other shit from the ground, why are there no adequate shootings from space and flights?! Only monotonous mounting cuts .. and illogical conditions for existence in orbit