Asteroid and Cometary Danger

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N. P. Laverov
Member of Presidium of the Russian Academy of Sciences
President of the Russian National Committee for UNEP
A.A. Medvedev
the First Deputy CEO of Federal State Unitary Enterprise SSIC of M.V. Khrunichev"

GLOBAL THREATS: ASTEROID AND COMETARY DANGER

Report at the 3rd UN World Conference on Disaster Risk Reduction
Sendai, Japan, March 15, 2015.

The aim of the report – to draw your attention to the real global threat for population of the Earth connected with possible collision of our planet with small bodies of the Solar system (SS). Elimination of this threat demands tight cooperation of efforts of the countries owning modern intellectual and technical means for its prevention.

Special danger is connected with asteroids – the remains of the initial space material which didn't convert into stone planets of the SS. Generally the asteroids are shapeless pieces of a stone and metals of the different sizes: from comparable to coastal "pebble" (few centimeters) to bodies with diameter more than 1000 meters. The largest of them have the cross sections of up to 1000 km in the diameter. It is considered that the asteroid more than 50 m in diameter can survive in the atmosphere of the Earth and reach its surfaces. The evidence of this is the "Chelyabinsk meteorite" which quite dangerously attacked South Ural region of the Russia last year.

It is known that over 90% of all asteroids are located in the Main belt located between Mars and Jupiter (Slide 1). In this belt about 200 million objects more than 100 m long are situated. Possible global risks of collisions of the Earth with them exist. Consequences of negative impact of the collisions on our planet depend on many properties of these objects: their sizes and forms, the speed of rotation, structure, density, porosity, precise parameters of their movement and many others. The meteoritic dust which is a product of disintegration of comets reduces transparency of the atmosphere and by that influences weather and climatic features of our planet. Falling of larger space bodies is followed by shock - explosive (or impact) processes. Negative consequences of these processes depend on weight of the space bodies and speed of their approaching the Earth reaching tens kilometers per second.

Recently it was established that collisions of asteroids and comets with the Earth occurs quite often. Hundreds of craters of impact origin were found and well studied on its surface (Slide 2). The big craters of these collisions testify to the extraordinary strong impacts on landscapes and the atmosphere of the Earth. Many researchers connect with these processes vast extinctions of biota in the past (1, 2).

In the last decade the attention of scientists to creation of ways of protection of the Earth against impacts of space bodies essentially increased. In the first turn, it is connected with appearance and successive development of new space methods of detection and observation for a large number of comets and asteroids. It was found that many of them regularly cross the Earth orbit some examples are given in the Slides 3 & 4 (3). Of course, not all of these bodies pose a global threat. The highest danger is considered to come from asteroids with diameter from hundreds of meters and more. Technical progress and improvement of quality of space facilities for their observation allow detection of an increasing number of space objects, potentially dangerous for the Earth (Slide 5). In 2010 year their number exceeded 1100 objects while at the end of the last century were known only about 100.

For example, in 2004 year the asteroid Apofiz with diameter of 270-415 m and weight so much as 25-100 million t was detected. It can pass in 2029 year at a distance of about 36 000 km from the Earth – at the height of the geostationary spacecrafts orbit (2, 4). The scientists believe that at reaching our planet its trajectory has to change. At further approach (in 2035-2039 years) the probability of collision of this body with the Earth can considerably increase. The world scientific community, including Russian scientists, realizes the serious danger to mankind connected with possible falling of an asteroid or comet of such sizes on the Earth. However, systematic collaboration in elimination of this threat has not been organized yet. The regular national and International conferences held in the world, including under the auspices of the UN, didn't consider specific ways for elimination of this threat yet. The engineers and scientists involved in creation of space ships and rockets and other equipment don't pay due attention to the solution of complex technological problems of parrying of this global threat to environment of our planet. Although progress in creation of new capabilities for detection of dangerous space bodies and determination of exact parameters of their movement exist (4), development of the devices capable to deflect or destroy dangerous space bodies lags far behind. At present it is unlikely to consider some approaches which are available in scientific publications as real "System of space protection of our planet" for future. Cooperation of scientists and engineers of the different countries for the successful solution of this problem (4) is highly required. This project, in our opinion, could pull together the countries advanced in space technologies in order to solve this problem for the for the benefit of the entire population of our planet. Examples of successful realization of a number of large international projects (Galley's comet, CERN, etc.) definitely testify to such opportunity.

Thank you very much for your attention.

REFERENCES

1. Laverov N.P., Medvedev A.A. Space research and technologies (including information): expansion of knowledge on world around. Part 1 // Science and technologies in the industry. M.: JSC RUSINTER, 2011. N 2. P. 3–32 (Russ.).

2. Degtyar’ V.G., Volkov V.A. Rocket concept of system of antiasteroid protection of the Earth. M.: Mashinostroenie/Mashinostroenie-Polet, 2013. 316 p (Russ.).

3. Laverov N.P., Medvedev A.A. Space research and technologies: expansion of knowledge on the surrounding world. M.: “Dobroe slovo”, 2012. 180 p (Russ.).

4. Asteroid and comet danger: yesterday, today, tomorrow. M.: Fizmatlit, 2010. Eds.: B.M. Shustov and L.V. Rykhlova. 386 p (Russ.).

3rd UN World Conference on Disaster Risk Reduction