A group of leading international scientists is calling for a significant increase in investment by governments in research into asteroids that could potentially threaten Earth.
The call comes on the first annual World Asteroid Day.
On this day 107 years ago, a meteor exploded in the skies above the Tunguska region of Russia.
The blast flattened 80 million trees over a 2,000sq.km area.
Prominent astronomers, astronauts and other campaigners around the world are holding today's event.
They argue that we do not know enough about near Earth objects, which could cause widespread death and destruction if they were to strike our planet today.
They claim governments are not investing enough in developing tools to detect and potentially deflect such lumps of space rock.
They want a 100-fold increase in effort and funding in the area, and will be highlighting the issue at events around the world.
However, other experts say the threat is negligible and that today's day of action is scaremongering.
They claim such investment would be better spent on other challenges that pose a more immediate risk to life on our planet.
