I study Astronomy a lot and am very much interested in this subject for many years which includes using telescopes and i think it doesn't show a huge threat.

"Asteroids with diameters of 5-10m impact the Earth's atmosphere approximately once per year, with as much energy as atomic bomb dropped on Hiroshima, approximately 15 kilo tonnes of TNT. These ordinarily explode in the upper atmosphere, and most or all of the solids are vaporized.Objects of diameters of order 50 meters strike the Earth approximately once every thousand years, producing explosions comparable to the one observed at Tunguska in 1908.Asteroids with a diameter of one kilometer hit the Earth an average of twice every million year interval.Large collisions with five kilometer objects happen approximately once every ten million years."

The thing i would say for people to be worried about is solar wind created by the sun when it has violent solar flares. They predicted in the next 10 years or so a huge one may be sent straight to earth causing billions of tones of charged particles to be sent into the earths atmosphere causing power plants to over load and causing power cuts all over the world. I would say there is more change of this happening then a asteroid any near earth object to hit the earth.

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