Astronomers have lost track of nearly 900 asteroids that could be on a deadly collision course with Earth
- Near-Earth asteroids orbit uncomfortably close to our planet’s own trajectory
- Organisations like Nasa track thousands of them to ensure they don’t hit Earth
- New study shows that nearly 900 of the objects have been lost by astronomers
- This means the objects will reappear without warning, and some could be heading directly for our planet
Astronomers have lost track of nearly 900 near-Earth asteroids.
These space rocks, which orbit uncomfortably close to our planet, were spotted just once by scientists.
Researchers were unable to continue tracking them, which means they have no way of knowing if they are on a collision course with Earth.
Despite fears they could smash into Earth, experts say there is a ‘low chance’ of of surprise near-Earth asteroids causing damage.
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Astronomers have lost track of nearly 900 near-Earth asteroids that could be on a doomsday collision course with our planet (stock image)
Near Earth asteroids (NEAs) are space rocks that come within 30 million miles (48 million km) of Earth’s orbit.
So far, astronomers have spotted more than 8,000 near-Earth asteroids that are at least 460 feet (140 meters) wide.
This is large enough to wipe out an entire city.
Between 2013 and 2016, 17,030 NEAs were listed by the International Astronomical Union’s Minor Planet Centre in Cambridge, Massachusetts.
Of these, 11 per cent – nearly 1,900 – were labelled ‘initially unconfirmed’, meaning they were observed a few times but not enough to pin down their orbit.
In a new study, researchers at the Minor Planet Centre combed through the data to find out why astronomers lost track of so many of the objects.
They discovered that astronomers were often too slow to track their orbits.
NEAs are typically picked out by asteroid survey systems that use telescopes powered by artificial intelligence to scan large swathes of the night sky.
Each of these space rocks, which orbit uncomfortably close to our planet’s own trajectory, had been spotted once but scientists have not continued tracking them. Pictured is a visualisation of the orbits of 1,400 near-Earth asteroids released by Nasa in 2014
These systems then submit their findings for confirmation from a secondary source, and the researchers found that a delay between these two readings is often the reason NEAs are lost.
Some telescopes take more than 20 hours to report potential NEAs, making them almost impossible to spot again and confirm.
‘We need to act fast,’ study lead author Dr Peter Vereš told New Scientist.
‘Tomorrow, that object could be on the other side of the sky, and nobody really knows where it will be.’
To make their finding the team looked at data from some of Earth’s most prolific asteroid hunting systems, including Pan-STARRS, the Catalina Sky Survey, the Dark Energy Survey, and the Space Surveillance Telescope.
WHAT ARE THE DIFFERENT TYPES OF SPACE ROCKS?
An asteroid is a large chunk of rock left over from collisions or the early solar system. Most are located between Mars and Jupiter in the Main Belt.
A comet is a rock covered in ice, methane and other compounds. Their orbits take them much further out of the solar system.
A meteor is what astronomers call a flash of light in the atmosphere when debris burns up.
This debris itself is known as a meteoroid. Most are so small they are vapourised in the atmosphere.
If any of this meteoroid makes it to Earth, it is called a meteorite.
Meteors, meteoroids and meteorites normally originate from asteroids and comets.
For example, if Earth passes through the tail of a comet, much of the debris burns up in the atmosphere, forming a meteor shower.
They studied the influence of telescope positions and motion, brightnesses of objects, submission delays between sources, and more.
The team also analysed the size of each potential-NEA based on the brightness of their initial readings, finding that 900 were likely asteroids.
The largest of the lost rocks appears to measure a few kilometres across, Dr Vereš told New Scientist.
For comparison, the asteroid that wiped out the dinosaurs is believed to have measured around 6.2 miles (10km) across.
One hundred and two of the unconfirmed NEAs were larger than 140 metres making them ‘potentially hazardous.’
Dr Vereš added that regardless of how close the objects get it is unlikely they would be large enough to destroy Earth.
‘We believe that the largest ones – planetary killers larger than one kilometer – those are basically all found,’ the astronomer told New Scientist.
‘I would say the danger is coming from objects we haven’t discovered yet,’ he said.
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