Eric Lagatta, USA TODAY
Tue, July 25, 2023
A long exposure photo shows the Milky Way galaxy star cluster in March from Indonesia.
Mysterious radio wave pulses from deep in space have been hitting Earth for decades, but the scientists who recently discovered them have no concrete explanation for the origin of the signals.
For 35 years, the strange blasts of energy in varying levels of brightness have occurred like clockwork approximately every 20 minutes, sometimes lasting for five minute intervals. That's what Curtin University astronomers from the International Centre for Radio Astronomy Research (ICRAR) concluded in research published last week in the journal Nature.
The discovery of the signal, which researchers named GPMJ1839-10, has the scientists baffled. Believed to be coming from around 15,000 light years away from Earth, the signal has been occurring at intervals and for a period of time previously thought to be impossible.
“This remarkable object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the universe,” lead author Dr. Natasha Hurley-Walker said in a statement on ICRAR's website.
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First signal detected from 2018 data
Using data gathered in 2018, astronomers first detected another magnetar spinning much slower than usual and sending similar signals every 18 minutes. But by the time they analyzed the data in 2020, it was no longer producing radio waves, according to Hurley-Walker.
So they looked again, knowing that the chance was high they would find another long-term radio source.
The team of astronomers used the Murchison Widefield Array radio telescope in Western Australia to scan the Milky Way galaxy every three nights for several months. They didn't have to wait long to find what they were looking for.
Within no time, a new source was discovered in a different part of the sky, this time repeating every 22 minutes with five-minute pulses.
Studying records at the Very Large Array in New Mexico, which maintains the longest-running archive of data, the researchers discovered that the source's pulse was first observed in 1988.
What's even more alarming than that this radio signal was able to go undetected for more than three decades is that scientists have not determined with confidence what it could be.
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But before you go assuming that E.T. is trying to phone our planet, the researchers do have other theories about what may be causing it.
Even Hurley-Walker noted in an article she penned on The Conversation — a media outlet with articles written by academics and researchers — that it can be tempting to include extraterrestrial intelligence as a possible source of the signal. In fact, that's what happened when the first pulsar was discovered and astrophysicists nicknamed it "LGM 1" for "Little Green Men 1" before additional observations caused them to rule the possibility out.
The most likely culprit, researchers say, is pulsars, neutron stars that blink and rotate like lighthouses emitting energetic beams as they rotate toward and away from Earth. But pulsars slow down as time passes, their pulses growing fainter with age until they eventually stop producing radio signals.
What's more confounding: the object that the researches detected resembles a pulsar, but spins 1,000 times slower.
Another explanation researchers offer is that the object could be an ultra-long period magnetar, a rare type of neutron star with extremely strong magnetic fields that can produce powerful bursts of energy. But until recently, all known magnetars released energy at intervals ranging from a few seconds to a few minutes — far more often than the 22-minute intervals that this object emits radio waves, according to the study.
Magnetars also generate radio waves for several months before stopping, not for 35 years and counting, according to researchers. The radio emissions should be slowing down, but as observations show, it is not.
In fact, researchers note that it shouldn't be possible for it to produce radio waves at all. The object is spinning so slow as to fall below the "death line," a critical threshold where a star’s magnetic field becomes too weak to produce radio emissions.
To determine what's behind the mysterious pulsing, the astronomers said that additional observations and study are needed.
“Whatever mechanism is behind this," Hurley-Walker said in the statement, "is extraordinary.”
The discovery joins a list of mysterious finds this year beyond Earth's gravitational pull.
In May, researchers at Sandia National Laboratories unveiled strange findings after recording unidentified sounds in the stratosphere using solar-powered balloons.
And in January, NASA's James Webb Space Telescope discovered an exoplanet outside our solar system that shares similar qualities with Earth.
A strange signal from deep space has been detected every 22 minutes for more than 30 years. Scientists have no idea what is causing it.
Marianne Guenot
Marianne Guenot
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Mon, July 24, 2023
An artist's impression of a magnetar, a dying neutron star. Scientists think they've found a pulsating star that defies the physics of stars.
Mon, July 24, 2023
An artist's impression of a magnetar, a dying neutron star. Scientists think they've found a pulsating star that defies the physics of stars.
ICRAR
A mysterious object spotted in the cosmos is beaming radio waves toward Earth every 22 minutes.
Signals from this type of cosmic object usually slow down over time.
But this one has been sending signals for more than 30 years, and scientists can't figure out why.
A cosmic object that has been pulsing radio waves toward Earth every 22 minutes for more than 30 years has left scientists baffled.
The object is thought to be a dying star that is emitting energy from its poles. But it's spinning too slowly to exist.
"Assuming it's a magnetar, it shouldn't be possible for this object to produce radio waves. But we're seeing them," said Natasha Hurley-Walker, a radio astronomer from Curtin University in Australia who led the research, in a statement.
A phenomenal cosmic lighthouse that shouldn't exist
An artist's impression of the dying star, The star is thought to be a magnetar, which is ruled by intense magnetic fields, here shown in orange. ICRAR
This object, given the scientific name of GPM J1839−10, sets itself apart because it is remarkably slow and remarkably stable.
"Astronomers expect to see some repeating radio signals in space, but they usually blink on and off much more quickly," Hurley-Walker told The Conversation.
At the end of their life, stars can collapse into neutron stars, superdense objects that pack billions of tons of matter into tiny little spaces, per NASA.
Some neutron stars shoot brilliant beams of light and energy from their magnetic poles. We only pick up the signal as the beam washes over our planet, similar to the light from a lighthouse blinking to a boat offshore.
These create repeated blips on Earth that are so consistent that scientists that first detected them wrongly thought they could be communications from aliens in outer space. But since then, they have figured out they are the gasps of a dying star beaming through the universe.
This star is crossing the death line
Scientists expect pulsating neutron stars to slow down until they reach a "death line." This is a theoretical threshold that dictates that stars that are too slow are about to die. This threshold is usually thought to be crossed when the pulses slow to more than a few minutes apart.
But the pulses coming from GPM J1839−10, the team found, came every 22 minutes. And these could last up to five minutes each, defying all expectations.
"The object we've discovered is spinning way too slowly to produce radio waves," Dr Hurley-Walker said.
This wasn't the first time a super slow object like this one had been spotted.
The same team had previously spotted another slow object that pulsed every 18 minutes or so, lasting up to a minute each. The team postulated the beams were coming from a magnetar, a neutron star with intense magnetic fields.
But GPM J1839−10 had one more science-defying surprise in its pocket.
A dying star that refuses to die out
A segment of the Murchison Widefield Array in Western Australia that was used to pick up the signal from the star.
A mysterious object spotted in the cosmos is beaming radio waves toward Earth every 22 minutes.
Signals from this type of cosmic object usually slow down over time.
But this one has been sending signals for more than 30 years, and scientists can't figure out why.
A cosmic object that has been pulsing radio waves toward Earth every 22 minutes for more than 30 years has left scientists baffled.
The object is thought to be a dying star that is emitting energy from its poles. But it's spinning too slowly to exist.
"Assuming it's a magnetar, it shouldn't be possible for this object to produce radio waves. But we're seeing them," said Natasha Hurley-Walker, a radio astronomer from Curtin University in Australia who led the research, in a statement.
A phenomenal cosmic lighthouse that shouldn't exist
An artist's impression of the dying star, The star is thought to be a magnetar, which is ruled by intense magnetic fields, here shown in orange. ICRAR
This object, given the scientific name of GPM J1839−10, sets itself apart because it is remarkably slow and remarkably stable.
"Astronomers expect to see some repeating radio signals in space, but they usually blink on and off much more quickly," Hurley-Walker told The Conversation.
At the end of their life, stars can collapse into neutron stars, superdense objects that pack billions of tons of matter into tiny little spaces, per NASA.
Some neutron stars shoot brilliant beams of light and energy from their magnetic poles. We only pick up the signal as the beam washes over our planet, similar to the light from a lighthouse blinking to a boat offshore.
These create repeated blips on Earth that are so consistent that scientists that first detected them wrongly thought they could be communications from aliens in outer space. But since then, they have figured out they are the gasps of a dying star beaming through the universe.
This star is crossing the death line
Scientists expect pulsating neutron stars to slow down until they reach a "death line." This is a theoretical threshold that dictates that stars that are too slow are about to die. This threshold is usually thought to be crossed when the pulses slow to more than a few minutes apart.
But the pulses coming from GPM J1839−10, the team found, came every 22 minutes. And these could last up to five minutes each, defying all expectations.
"The object we've discovered is spinning way too slowly to produce radio waves," Dr Hurley-Walker said.
This wasn't the first time a super slow object like this one had been spotted.
The same team had previously spotted another slow object that pulsed every 18 minutes or so, lasting up to a minute each. The team postulated the beams were coming from a magnetar, a neutron star with intense magnetic fields.
But GPM J1839−10 had one more science-defying surprise in its pocket.
A dying star that refuses to die out
A segment of the Murchison Widefield Array in Western Australia that was used to pick up the signal from the star.
Pete Wheeler, ICRAR
Looking through archives, Hurley-Walker said the team uncovered GPM J1839−10's "real surprise."
This object's pulses had been picked up, unnoticed, by observatories around the world for years, beaming "like clockwork, every 1,318.1957 seconds, give or take a tenth of a millisecond," per Hurley-Walker.
This goes against what we know about neutron stars. These are expected to die out in months. For instance, the 2018 object only blazed for a short while, between January and March 2018.
But the first record of GPM J1839−10's pulses dates back to 1988 — about 33 years ago.
This could mean the object is a new type of stellar system altogether.
"This remarkable object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the universe," said Hurley-Walker.
The team will now be trying to reconcile their observations with what we know about the physics of stars.
"Whatever mechanism is behind this is extraordinary," she said.
Looking through archives, Hurley-Walker said the team uncovered GPM J1839−10's "real surprise."
This object's pulses had been picked up, unnoticed, by observatories around the world for years, beaming "like clockwork, every 1,318.1957 seconds, give or take a tenth of a millisecond," per Hurley-Walker.
This goes against what we know about neutron stars. These are expected to die out in months. For instance, the 2018 object only blazed for a short while, between January and March 2018.
But the first record of GPM J1839−10's pulses dates back to 1988 — about 33 years ago.
This could mean the object is a new type of stellar system altogether.
"This remarkable object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the universe," said Hurley-Walker.
The team will now be trying to reconcile their observations with what we know about the physics of stars.
"Whatever mechanism is behind this is extraordinary," she said.
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