THE origin of a mysterious pulse emanating from space has finally been revealed by scientists after a year of investigation.
And it’s not quite an alien civilisation trying to contact Earth, according to a new study.
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The fast radio burst (FRB), detected at the Australian Square Kilometer Array Pathfinder in June 2024, only lasted less than 30 nanoseconds.
But it was so strong that it surpassed all other signals coming from the sky.
Scientists track these bizarre space signals to understand where they came from – and explanations include everything from black holes to alien technology.
Most FRBs come from deep within space – and so it was assumed this recent powerful signal was too.
However, researchers found that the pulse had been emitted from something much closer to home: a zombie satellite.
The Relay 2, a long-dead NASA satellite, had let out a powerful signal each time it passed over the astronomers’ signal detection tools.
The defunct satellite’s proximity to Earth, researchers said, made its signal so unusually clear.
Launched by Nasa in 1964, the communications satellite has been stuck in Earth’s orbit for decades.
It stopped working less than a year after launch, becoming another hunk of space debris.
Now – the Relay 2 hasn’t been emitting signals all this time.
It has been silent since its transponders broke in 1967, until now.
The research team, which published their findings in research paper archive arXiv, said it is unlikely the satellite has suddenly come back to life.
Instead, astronomers suggested that a build up of static electricity on the spacecraft reached a boiling point and then discharged – firing a pulse of energy over Earth.
Similar discharges have been seen before, the study noted.
Another possibility is that the satellite was hit by a micrometeroid – a small fleck of space rock.
While a micrometeoroid typically measures between a few micrometres to a few millimetres, the speed at which they are hurtling in Earth’s orbit means they can exert a fair amount of damage.
If the satellite was struck by such an object, the collision would have released a very small cloud of plasma, according to researchers.
This plasma can magnify an FRB signal, making it seem stronger.
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What is space debris?
Space debris is an umbrella term for any bit of junk, disused equipment and otherwise, that is currently stuck in Earth’s orbit.
And it has spiralled into a big problem since the dawn of the space age in the 1950s.
There are nearly 30,000 objects bigger than a softball hurtling a few hundred miles above Earth, ten times faster than a bullet.
It poses huge risks to satellites and the International Space Station (ISS), where crew occasionally have to maneuver out of the way of objects hurtling towards them.
In 2016, a fleck of paint managed to chip a window in the ISS because it was moving at such high speeds in Earth’s orbit.
The problem is, it’s not just a space issue – but Earth’s too.
Objects in space undergo a process called orbital decay, which means they orbit closer to Earth as time goes on.
Debris left in orbits below 600km normally fall back to Earth within several years.
While most space debris burns up on reentry to Earth’s atmosphere – there are some bits that don’t.
This is particularly the case with larger objects, like the EP-9 pallet.
A report by US watchdog, the Federal Aviation Authority, published last year warned that space debris that survived the fiery reentry could kill or injure someone on Earth every two years by 2035.
