A meteorite believed to be the world's second-largest has been discovered in Argentina, local media has reported. 

The 30-tonne space rock was found buried in the province of Chaco, some 800 km north-west of Buenos Aires. 

Explorers made the discovery on Saturday while scouring an area called Campo del Cielo [Field of the skies], which astronomers say was hit by a meteor shower some 4,000 years ago. 

Mario Vesconi, who heads Chaco's astronomy association, said that the discovery was remarkable because of the meteorite's size and weight. 

"We'll be weighing it again to make sure," Mr Vesconi told Argentinian news agency Telam. 

Millions of meteoroids enter the Earth's atmosphere every day, often leaving a trailing blaze of light behind them in what are colloquially referred to as 'shooting stars'. 

While most meteoroids end up being no smaller than a grain of sand by the time they hit the earth, some make it through the atmosphere and hit the ground as solid objects, or what astronomers call meteorites.

The world's largest meteorite, known as the Hoba, is in Namibia and weighs 60 tonnes. It was discovered in 1920 when a farmer struck the rock as he was ploughing his fields.