Article Posted on : - Nov 19, 2014

WASHINGTON (PTI): Over 556 small asteroids smashed into the Earth over the last 20-years, NASA researchers have found, suggesting that fiery space rocks are bombarding into the planet's atmosphere at a stunning rate.

A map released by NASA's Near Earth Object (NEO) Programme shows that small asteroids frequently enter and disintegrate in the Earth's atmosphere with random distribution around the globe.

Released to the scientific community, the map visualises data gathered by US government sensors from 1994 to 2013.

The data indicate that Earth's atmosphere was impacted by small asteroids, resulting in a bolide (or fireball), on 556 separate occasions in a 20-year period between 1994 and 2013.

Almost all asteroids of this size disintegrate in the atmosphere and are usually harmless. The notable exception was the Chelyabinsk event which was the largest asteroid to hit Earth in this period, NASA said.

The new data could help scientists better refine estimates of the distribution of the sizes of NEOs including larger ones that could pose a danger to Earth.

"Finding and characterising hazardous asteroids to protect our home planet is a high priority," NASA researchers said.

"It is one of the reasons NASA has increased by a factor of 10 investments in asteroid detection, characterisation and mitigation activities over the last five years," they said.

NASA has also aggressively developed strategies and plans with its partners in the US and abroad to detect, track and characterise NEOs.

These activities will help identify NEOs that might pose a risk of Earth impact, and further help inform developing options for planetary defence, researchers said.