Is space junk dangerous for the earth?

See - what is it in the sky? This is a bird! This is a plane! This is Superman! What the garbage flew through the sky of Australia? Last week, Australians from the cities of Melbourne and Brisbane reported - and even removed - that a large burning object flew across the sky (pictured above). Unlike the meteor that hit Russia in February 2013, this object was created by people.

Very soon, scientists realized that this was the third stage of the Russian Soyuz rocket, with the help of which meteorological satellites were launched on July 8.

Although the fireworks were serious enough to alarm, most of the space debris falls to Earth completely unnoticed.

Some parts of the spacecraft fall intowithin a few days after launch, but most - after a longer time. For sixty years after the launch of Sputnik, which became the first Earth satellite in 1957, people launched more than 7,500 satellites into orbit.

Those that are on low near earthThe orbit - within 500 kilometers - passes through a very thin layer of the atmosphere, which acts as a gradual brake on the satellite trajectory. In the absence of human intervention, these satellites slowly move to the Earth in a spiral for 10–20 years, depending on the exact orbit and shape.

The Hubble Space Telescope is on a lownear-earth orbit for 24 years and lasted so much just because the astronauts returned it to a higher orbit at each visit for maintenance.

Over a thousand active satellites are onEarth orbit right now. Slightly more than half of them were put into low Earth orbit. Almost all others are in geostationary orbit, that is, they orbit around the Earth at the speed of its rotation. For telecommunication companies serving the country, this is important because the satellite is always above the country.

The geosynchronous 24-hour circulation period requiresvery high orbit. According to the 400-year law of Newton, the orbital speed depends only on the mass of the body around which the orbit is located (in this case, the Earth) and the radius of the orbit (the radius of the Earth plus the height of the satellite above the Earth). That is why Hubble, rather large space stations, small early satellites and other satellites in low-Earth orbit fly around our globe in just 90 minutes.

Geosynchronous satellites work differently. Their orbit will be stable for a long time. Rather, satellites will fall on LEOs or space debris and dead satellites that engineers and space agencies cannot control. Active satellites can be controlled from Earth.

As shown by the film "Gravity", uncontrolledspace junk can be very dangerous. In the film, if someone did not watch, the Russian rocket destroys the non-working satellite, starting a destructive and deadly chain reaction: garbage destroys other satellites, picks up speed and eventually destroys the space station on which the astronauts settled.

In 1985, the United States played muscles,demonstrating anti-missile capabilities in the Star Wars style, blowing up the P78 solar observatory. In addition to bare science, this led to the creation of small fragments. China repeated the success of the USA in 2007. But, according to the laws of physics, nothing disappears without a trace. Just in the orbit of the Earth more tiny fragments appear that can accelerate to extreme speeds. And smaller fragments are harder to track than larger ones.

For space objects being watched. The United States has cataloged more than 39,000 artificial objects in orbit. About 60% of them re-entered the atmosphere; 16,000 remain in orbit today. Of these, only 5% are represented by working satellites or payload that can be controlled, while 95% are inactive space debris.

According to NASA estimates, the orbit of the Earth floats aroundhalf a million parts of space junk, which is much smaller than the one that can be tracked. But even a nut-sized piece of garbage can cause serious damage.

Satellite technology has made it possible to work phones worldwide. A side effect is that they can fall back to Earth.

Fortunately, only the largest and hardest debrisDo not burn on the way to Earth. In 1979, the NASA Skylab space station fell to Earth and caused some concern. Several debris were found in Australia. Fragments of the German X-ray astronomical observatory ROSAT also reached the Earth.

Simply calculate the re-entry path.spacecraft into the atmosphere since its movement is tracked. But with an increase in the rate of fall, there may appear details that are difficult to predict. There is a definite difference between how an object burns and how it falls apart. Large fragments continue to rush down until the smaller ones simply burn in the atmosphere. Where the main part of garbage will fall is usually incomprehensible.

The good news is that the surface of the earthrepresented by land only one quarter, and most land is uninhabited. Therefore, damage to people and their property is rarely inflicted. Most debris falls harmlessly and without witnesses.

The probability of serious damage is extremely small. But a large piece of metal or a large asteroid that fell in the right place at the right time can be disastrous.

The only possible way to gradually secure the planet and prevent the escalation of the problem is to start collecting space debris. We do not want to follow the footsteps of dinosaurs?