BEIJING - Chinese scientists have appealed to further strengthen international cooperation in space exploration, aiming to reduce the risk of near-Earth objects.

Compared to global issues like food security, energy shortage, climate change, cyber attacks and environmental pollution caused by human activities, more serious threats to our globe may come from space, said Chen Jiansheng, an academician with the Chinese Academy of Sciences (CAS) and a senior astronomer, at a conference promoting science literacy.

There are more than 18,000 near-Earth asteroids - around 800 have a diameter greater than 1 km. Researchers have discovered 180 giant impact craters on our planet, which exhibit the formidable power that a small celestial object could generate when hitting the Earth.

Evidence found in the strata in Kamba county, Southwest China's Tibet Autonomous Region, showed that Earth suffered a major asteroid impact about 65 million years ago, which might have led to the extinction of dinosaurs.