How real is the asteroid threat?

The asteroid with catalog number 2016 RB1 was discovered by astronomers on September 5 of this year. Scientists from the Catalina Sky Survey Observatory (Tucson, Arizona) saw it. This is a rather unusual celestial body, its diameter is only 7-16 meters. September 7, he passed 40,000 kilometers from Earth. In other words, astronomers learned about the existence of 2016 RB1 just two days before the asteroid converges with the Earth, and the asteroid got close to our planet for a minimum distance.

The NASA Near Earth Object Program program studies and classifies celestial bodies that are dangerous to the Earth and our entire civilization. But, as we see, this program does not help detect all celestial bodies close to the Earth, representing a potential danger to us. Are there many unknown objects left? And in general - how dangerous are asteroids, maybe you shouldn't watch them?


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2016 RB1 due to its size is not particularly dangerous. Even if he fell to Earth, there would be no significant damage. Now the asteroid has gone to Venus. With her, he will get close to the minimum distance in October 2017. Then, in 2020, the asteroid will again be close to the Earth. But already farther than last time. Scientists say that there is no particular danger - a collision is ruled out.

On September 7, another asteroid, much larger than the 2016 RB1, got closer to the Earth. The diameter of this object (catalog number 2004 DQ41) is much larger and is more than a kilometer. The minimum distance that this asteroid closer to our planet was 15 million kilometers. There is nothing to worry about.

But we know that the Earth has repeatedly encountered large celestial bodies in its past. One of these clashes happened only three years ago.

Then, on February 15, 2013, a relatively small asteroid called the “Chelyabinsk meteorite” hit the Earth’s atmosphere. The fall of this celestial body was accompanied by a series of atmospheric explosions. In the Chelyabinsk region, quite a few fragments of an object with a total mass of 654 kg were found. According to experts, the age of the object exceeds 4 billion years.

This asteroid, according to scientists, was once a single whole with a larger celestial body. But about 300 million years ago, he broke away from the main body as a result of some kind of event. During this event, the object was heated to 650 degrees. Several tens of thousands of years ago, an asteroid that had already split off collided with another celestial body, becoming even smaller.

Its mass at the time of entry into the atmosphere of the Earth was approximately 13,000 tons, the diameter was 20 meters. In the atmosphere of Earth, the celestial body collapsed, some of its fragments reached the surface of the planet. All this caused a number of destruction in the Chelyabinsk region. There were victims, although there were no casualties (although 1,613 victims were a huge number). But if the asteroid were a bit larger, the consequences of the fall of such a celestial body on Earth could have been much more severe.

In the past of our planet, quite a few cases of the fall of quite large asteroids, which repeatedly became the cause of cataclysms. There are no traces of some collisions due to the fact that the geological activity of the planet, erosion, volcanic activity have erased all this over time. True, a number of "scars" are so powerful that they could only be smoothed over, but not completely destroyed. Many scientists even suggest that the moon was formed when the Earth collided with the largest celestial body. "Accident" occurred about 4.53 billion years ago. In addition, in the period from 4.1 to 3.8 billion years ago, asteroids and comets often fell to Earth. From this period on the moon there are very well marked marks.



On Earth, such traces are also there, and not one. For example, the Arizona crater , which is located 30 kilometers west of the city of Winslow. The size of the crater is very large. Its diameter is 1219 meters, depth - 229 meters. The edges of the crater rise above the plain at 46 meters. This is one of the most well-studied craters. It appeared relatively recently - only about 50 thousand years ago. Scientists believe that the crater was formed when a 50-meter meteorite fell, which weighed 300 thousand tons and flew at a speed of 45-60 thousand km / h. The power of the explosion from the fall is equal in power to 8000 Fatty-type atomic bombs. If such a meteorite fell now, then the fall would have strong negative consequences for people.

But this is nothing compared to what evils and destruction could now cause an asteroid, equal in size to that celestial body, which caused the appearance of the Chicxulub crater on Earth. This is an ancient impact crater with a diameter of about 180 kilometers and a depth of 17-20 km (meaning the initial depth). It is located on the Yucatan Peninsula.

Scientists believe that the crater was formed 65 million years ago, at the end of the Cretaceous. The diameter of the asteroid that fell to Earth then is estimated at 10 kilometers. The drop energy was 100 teratonnes in trotyl equivalent. The consequences were disastrous. This tsunami height of 50-100 meters, fires across the Earth, the activation of volcanoes. Climate-like changes followed. Some experts suggest that this asteroid was one of the reasons for the extinction of dinosaurs. Others disagree with them. Anyway, if such a giant asteroid fell on the Earth now, then our civilization in its current form would cease to exist.



Asteroids, which pass dangerously close to the Earth, are not so rare . Recently, astronomers have learned how to detect asteroids before they pass by the earth, or fall on its surface. In 2008, such an asteroid was discovered for the first time. He received catalog number 2008 TC3. This is a small piece of rock with a diameter of about 4 meters and weighing 80 tons. A day after the discovery, the object entered the atmosphere of the Earth and exploded somewhere in the Nubian desert.

Five years later, in 2014, an asteroid was again found heading towards Earth. The 2014 AA object, 2-4 meters in size, entered the Earth’s atmosphere 21 hours after its detection. He fell into the ocean.

Observation and again observation

Generally speaking, asteroids are frequent guests in the Luna-Earth system. One of the last large objects, asteroid 2004 BL86, was discovered in January last year. This 300-meter cliff was 1.2 million kilometers from Earth, three times farther than the Moon is from us. According to the physicist Mark Boslough (Mark Boslough), asteroids with a diameter of 20 meters pass through a geostationary orbit every two years. Similar asteroids pass through the orbit of the moon about once a week. 40-meter objects pass near the Earth (at a distance approximately equal to the distance from the Earth to the Moon) several times a year.

Alan Harris, an astronomer asteroid specialist, estimates that about 200 million objects with a diameter of 6 meters and more are our neighbors. That is, such objects may not be constantly close to the Earth. But their orbits pass nearby, and sooner or later we see them nearby. Harris claims that objects with a diameter of 6 meters and above fall to Earth approximately every two years.

NASA uses the Catalina Sky Survey system to monitor its dangerous neighbors. All detected objects that may be dangerous to the Earth are cataloged. In 1998, the US Congress instructed NASA to detect at least 90% of the “neighbors” of the Earth with a diameter of 1 kilometer or more. In 2005, Congress ordered NASA to track asteroids, which are 140 meters and above.

Asteroids are not only watched by NASA, so now scientists have a fairly detailed map of the orbits of potentially dangerous celestial bodies for the Earth with a detailed classification of these bodies. At the moment, more than 12,000 objects are known, of which 1% are comets, and the rest is asteroids. Some of them are very large, their diameter is a kilometer or more. Most of the size - from 100 to 300 meters. Such asteroids can cause the largest damage on Earth, similar to the effects of nuclear bombardment.

How dangerous are asteroids?

Very dangerous. The threat posed by our closest asteroid neighbors is quite real. According to expert estimates, an asteroid equal to the destructive force of the Tungussky meteorite falls to Earth approximately once every 500 years. Asteroids, equal in size to what caused the formation of the Arizona crater, appear on our planet every few thousand years. And giants like the asteroid that created the Chiksulubsky crater, fall once in a hundred million years. But all this statistics. The giant can fall to Earth as next year, and after 100 million years.

As mentioned above, such giants are the end of our entire civilization. Smaller asteroids can cause severe local destruction within the same country. But one can only guess about the consequences of such destruction if an asteroid, even of a small size, falls somewhere in a densely populated industrial region.

12,000 asteroids close to Earth are not all. According to some experts, their number is higher and can reach 200 thousand (diameter 100 meters and above). But the problem is that asteroids with a diameter of less than 100 meters represent a significant danger to people. Already 25-meter object can cause significant damage in the scale of the city and the suburbs. Anything larger is a regional issue. Even more - global.

How to protect yourself?

The main task of mankind now is the mapping of potentially dangerous celestial bodies. With this, NASA and other organizations are coping. But the picture is still incomplete. And even the task of detecting 90% of potentially dangerous objects is not all that needs to be done. After all, one of the asteroids, which are not included in the number of observables, can already approach the Earth with great speed. Now scientists have discovered and cataloged about 50% of objects close to the Earth, ranging in size from a few hundred meters and up.

Work must continue. And it is all the more important that new, previously unknown to scientists objects can appear in our system. These are possible guests from the asteroid belt or even the Kuiper belt. And in the Oort cloud, astronomers estimate, there may be more than 2 trillion comets. Maybe some of them, unknown to scientists, have already entered the trajectory that will lead it to Earth? Anything can happen.



The main threat is not the asteroid belt, which has been studied quite well, but the mentioned distant regions of space, about which we do not yet know almost anything. The threat is the small asteroids that are not tracked. This refers to objects the size of the meteorite Chelyabinsk. They are not a global problem, but if such an asteroid falls somewhere in a densely populated region, then the consequences cannot be called pleasant. And to find them, if possible, then at the last moment, just before the fall.

Asteroid threat to most people seems insignificant and unrealistic. In fact, everything is much more real than most believe. Of course, this does not mean that now you need to start worrying more about the asteroids, earning a nervous breakdown. But to know and understand the problem is necessary.

Now NASA has launched OSIRIS-Rex (Origins Spectral Interpretation Resource Identification Security Regolith Explorer), this is the probe that asteroid Bennu has to study. In addition to studying the celestial body, the probe must take samples of the rock and go back to Earth with these samples. Expected return time is 2023. NASA experts believe that this asteroid is one of the most dangerous celestial objects known to man. In 2135 it will pass only 300 thousand kilometers from the Earth.

Creating an effective asteroid detection system, developing a security system is what humanity needs. This should not be done by a single country, but by the entire world community.