Astronomers have catalogued the 40,000th Near-Earth space rock, 2,000 of which could hit the planet – and more potential colliders are being discovered all the time
At least 40,000 asteroids have been identified as ‘Near Earth’ – and the Armageddon threat is growing, boffins say.
Astronomers have announced they have catalogued the 40,000th near-Earth space rock – and 2,000 of them could hit the planet triggering disaster.
More potential threats are being discovered all the time due to telescopic tech advancements.
The 40,000 landmark is a milestone in the detection of asteroids that orbit close to Earth and highlights the scale of the threat they pose to the planet, according to scientists.
Near-Earth asteroids can range from a few feet to several miles wide and travel on orbits that bring them close to Earth.
This makes them key objects for scientists and planetary defence experts. Asteroids are rocky remnants left over from the Solar System’s formation over four billion years ago.
While most are found in the main asteroid belt between Mars and Jupiter Near-Earth asteroids – aka NEAs – have orbits that bring them within 28 million miles of the planet.
Luca Conversi, manager of the European Space Agency’s Near-Earth Object Coordination Centre, said: “The number of discoveries is rising exponentially from one thousand at the beginning of the century to 15,000 in 2016 and 30,000 in 2022.
“As the next generation of telescopes enter operation we expect the number of known NEAs to continue to grow at an even higher pace.”
The first Near-Earth asteroid to be discovered was 433 Eros in 1898 by German astronomer Carl Gustav Witt at the Urania Observatory in Berlin.
It is 20 miles wide, seven miles deep and currently 180 million miles from Earth in the constellation of Libra, according to live tracking data.
Orbital studies suggest gravity might shift it into an Earth-crossing orbit in one to two million years.
Since it was discovered experts have identified thousands more.
New eyes-in-the-skies – including the Vera C Rubin Observatory in Chile and the European Space Agency’s Flyeye telescopes which boast wide insect-like fields of vision – will reveal even more potential threats.
Once a discovery is made scientists study the asteroid’s path.
Computer software is then used to predict its orbit years, decades or centuries into the future – revealing whether it is likely to hit Earth.
Increased observations can refine the predicted trajectory of asteroids – either increasing or decreasing the probability they will hit Earth.
The European Space Agency said nearly 2,000 near-Earth-asteroids have a ‘non-zero chance’ of impacting the planet within the next century.
Most are small but experts say the largest – up to one mile wide – would cause global damage if they hit Earth.
Scientists have said they are confident the vast majority of the biggest asteroids have been discovered and are being monitored.
They are now focussed on identifying mid-sized asteroids – between 300ft and 900ft across – which are harder to spot but could cause regional damage.
Current predictions suggest only 30% of them have been spotted.
Iain Todd, of BBC’s Sky at Night magazine, said: “Since that discovery of Eros humanity has catalogued a vast number of known near-Earth asteroids.
“As scientists detect more and learn more about these nearby space rocks it gives us a greater picture of the potential threat to our planet from space, and how to keep ourselves safe.”