Laser emitter with unattainable for today capacity of 202 terawatt could destroy an asteroid with a diameter of 7.5 kilometers, caused the extinction of the dinosaurs 65 million years ago, which casts doubt on all such projects "asteroid protection", state physics in an article published in journal of Physics Special Topics.

Astronomers and many state authorities of Russia and other countries seriously consider the collision of the Earth with one of large asteroids or comets that pass relatively close to the orbit of our planet. As protection from such disasters are offered protection system based on nuclear weapons or heavy duty lasers, located on the orbital platforms.

A group of British physicists under Henry Simms (Henry Simms) from Leicester University (UK) has calculated the laser power to destroy the asteroid-"killer dinosaurs", leaving a 100 km of the Chicxulub crater in the Gulf of Mexico.
According to Simms and his colleagues, the laser beam will affect matter asteroid in several ways. First, the light will melt and evaporate breed heavenly bodies that will create a kind of jet thrust. Secondly, a powerful laser beam will have its own pressure, and will "take" the asteroid in the direction of motion of the beam.

The authors have taken into account these factors and calculate how much power it is necessary to develop the laser to shoot down the asteroid's mass was 4.42 trillion tons from course to collision with the Earth.

According to them, the minimum the power of the radiator is 202 terawatt per square meter, inaccessible to modern terrestrial technologies. This finding casts doubt on the feasibility of many initiatives to protect Earth from asteroids using satellites shipboard lasers.

However, from a technical point of view, the construction of such a laser is possible, if scientists can create a power source capable of delivering the required amount of energy for pumping emitter.