Scientists Detect Strange Radio Signal from Space
Intro One of the biggest mysteries in astronomy
is the constant detection of strange radio signals from space.
So far, scientists have been unable to prove what causes these mysterious phenomena and
one of the most prevalent theories is that these signals may be messages from an alien
intelligence trying to contact us here on Earth.
There are many observatories dotted around the globe with the sole purpose of trying
to detect and understand these signals better.
Recent reports state that one such observatory has detected a strange new radio signal which
mimics the sound of a heartbeat.
Let’s take a closer look at this latest discovery.
Fast Radio Burst Fast radio bursts (FRBs) are super intense,
millisecond-long bursts of radio waves produced by unidentified sources in the distant cosmos.
Their discovery in 2007 by American astronomer Duncan Lorimer led to the term 'Lorimer Bursts'.
Since then, just a few dozen similar events have been observed in data collected by radio
telescopes around the world, building evidence that points to a variety of potential causes.
Only a handful of emissions have been traced to specific areas of the sky, most indicating
sources in other galaxies.
In 2020, a source within the Milky Way - most likely belonging to a type of neutron star
called a magnetar - was confirmed to be a fast radio burst emitter.
The flash of radio waves is incredibly bright if distant, comparable to the power released
by hundreds of millions of suns in just a few milliseconds.
This intensity suggests powerful objects like black holes and neutron stars could be involved,
with highly dense bodies such as magnetars and pulsars as likely culprits.
The events were once considered to be largely transient – they seemed to happen once,
without obvious signs of a repeat emission.
It was only in 2016 that astronomers found any evidence of multiple bursts from the same
source.
Several 'repeaters' have been identified since then, with some researchers venturing that
many, if not all FRB sources could routinely emit bursts in sequences too difficult to
detect using current instruments.
This hypothesis was supported when scientists reported in a discovery in 2020 that an FRB
observed three years previously had since repeated faintly on two more recent occasions.
Shortly after this report, astronomers with the Canadian Hydrogen Intensity Mapping Experiment
(CHIME) Collaboration published findings of the first FRB we know of that's repeating
in a distinct pattern.
The FRB has a predictable pattern of hourly activity over four days, followed by 12 days
of quiet.
With much still to learn about FRBs, their mechanism is one of the biggest mysteries
in modern astronomy.
Hidden Matter New research states that rapid bursts of radio
waves that originate millions to billions of light-years away from Earth could be used
as probes to investigate halos of difficult-to-see diffuse gas surrounding nearby galaxies.
According to the research, these radio bursts slow as they pass through the gas enveloping
the galaxies between their source and Earth.
This also has the effect of dispersing their radio frequencies.
Using this to investigate galactic gas haloes, researchers from the California Institute
of Technology (Caltech) found twice as much material as previously believed in these envelopes
that enshroud galaxies.
This has implications for how these collections of stars and planets evolve over great periods.
The astronomers looked at a sample of 474 distant FRBs with the Canadian Hydrogen Intensity
Mapping Experiment confirming that 24 FRBs intercepted by galactic halos were indeed
slowed down compared to others that traveled to Earth unimpeded.
Thus, this effect can be used to probe the material through which the FRB passes.
The use of more distant FRBs from outside our galaxy to investigate the massive pools
of gas that surround other galaxies has already revealed a surprise.
The astronomers found that there is more matter in gas haloes than previously believed, around
twice as much as predicted by theoretical models.
Because these gas halos are the remains of the same material that is used to form the
stars and planets a deeper investigation of them could lead to a better understanding
of how galaxies evolve over periods of billions of years.
Though researchers aren't currently certain of the origins of FRBs, they believe that
these pulses of electromagnetic radiation lasting from a fraction of a millisecond to
a few milliseconds are emitted by rapidly rotating magnetic dead stars called magnetars.
Evidence of this connection was provided in 2020 when Caltech's Survey for Transient Astronomical
Radio Emission 2 (STARE2) instrument was teamed with CHIME to detect a massive FRB erupting
in the Milky Way.
Since their discovery in 2007, hundreds of FRBs have been observed and these revelations
are expected to continue rolling in thanks, in part, to Caltech's 110-dish Deep Synoptic
Array, or DSA-110.
The project has already identified several FRBs and traced them back to the galaxies
from which they originated.
Caltech scientists have plans to build an even larger telescope array over the coming
years which will consist of 2,000 dishes.
Named DSA-2000, the project will be the most powerful radio observatory ever built and
could detect and identify thousands of FRBs and their sources each year.
There are many theories about what the cause of these radio signals may be.
One theory is that they may originate from a rapidly spinning neutron star.
When stars explode and die, they can end up as rapidly spinning neutron stars.
Astronomers think those found in a region with a high magnetic field might produce these
strange signals.
Two neutron stars colliding with each other is another possibility.
However, this scenario only works for cosmic signals that are only seen once, as the stars
are destroyed in the process.
Most of the fast radio bursts picked up by telescopes in the last decade or so are seen
once and then disappear.
Yet, two elusive signals have been found that burst into life again and again - and for
these, there must be a different explanation.
Another explanation may be a blitzar.
It is a rapidly spinning neutron star that collapses under its own weight and forms a
black hole.
Again, this ends in the destruction of the star, so could not produce a repeating signal.
Black holes are implicated in many theories - from a neutron star falling into a black
hole to a collapsing black hole or dark matter hitting one.
While some believe the signals are entirely natural in origin, others have speculated
that they could be evidence of extraterrestrial activity.
New Questions A few months ago, it was reported that an
international team of astronomers discovered a second persistently active fast radio burst,
posing questions about the nature of the mysterious phenomena.
The new source, Fast radio burst 20190520B, was initially detected with the Five-hundred-meter
Aperture Spherical radio Telescope (FAST) in Guizhou, China, on May 20, 2019, and found
in data in November that year.
Follow-up observations by the Jansky Very Large Array program led by Caltech found weaker,
constant radio emissions associated with the FRB, also allowing the Subaru telescope in
Hawaii to localize the source to be within the fringes of a dwarf galaxy nearly 3 billion
light-years from Earth.
The biggest surprise of this discovery for scientists was that the new FBR seemed to
be a perfect twin to an earlier discovery.
Many believe that the first such association between an FBR and a radio source may have
been a coincidence because it was hard to explain.
However, the newer second example shows that it may be a real and critical part of the
life of an FBR.
The discovery raises new questions about the nature of FRBs, such as if the sources of
the FRBs evolve, or whether different kinds of sources are capable of emitting FRBs.
One of the key questions in the field of FRBs is whether all FRB sources repeat.
Scientists favor the theory that if all sources do repeat, their activity levels drop precipitously
as the source ages.
Since FRB 20190520B is only the second of around 500 known FRBs to have a so-called
PRS counterpart and both are extremely active, they could, hypothetically, represent the
youth of the radio burst.
Another special feature of FRB 190520B is its dispersion measurement, which indicates
its emissions passed through the highest density of electrons of any FRB before being observed
on Earth.
This suggests the FRB is active in a local plasma environment, such as that created by
a supernova, and is a newly created source.
While providing insights into the environment of FRB 190520B, the large disparity in dispersion
measurements with other FRBs calls into question their use as "cosmic yardsticks" for measuring
distances.
Scientists say that an evolutionary path for FBRs is possible, but with just two sources
it is hard to tell.
We need to find more data and constrain this evolutionary stage model.
We need more signals at a different age to prove that the burst is fading away all the
time.
Cooperation between astronomers and facilities across the globe will be crucial in finding,
localizing, and characterizing these mysterious phenomena, as it has been in the case of FRB
190520B.
Heartbeat Signals More recently, astronomers at the Massachusetts
Institute of Technology have picked up repetitive radio signals from a galaxy billions of light-years
from Earth.
Scientists have not been able to pinpoint the exact location of the radio waves yet,
but suspect the source could be neutron stars, which are made from collapsed cores of giant
stars.
The signals have been occurring steadily and last up to three seconds.
Most fast radio bursts, or FRBs, only last a few milliseconds.
The report states that within this window, the team detected bursts of radio waves that
repeat every 0.2 seconds in a clear periodic pattern, similar to a beating heart.
On Dec. 21, 2019, researchers at the Dominion Radio Astrophysical Observatory in British
Columbia, Canada, picked up a signal of a potential FRB.
Not only was it very long, lasting about three seconds, but there were periodic peaks that
were remarkably precise, emitting every fraction of a second.
This is the first time the signal itself is periodic.
Data on the bursts, including their frequency and how they change based on where the source
is located in proximity to Earth, could help researchers determine at what speed the universe
is expanding.
Most FRBs, which are strong bursts of radio waves from galaxies billions of light-years
away, last just a few milliseconds before blinking out and are one-off events.
This new signal — FRB 20191221A — lasts up to three seconds, making it 1,000 times
longer than the average FRB, and also has the clearest repeated pattern discovered thus
far.
Going forward, the researchers will attempt to catch further bursts from the same source
that could help to more conclusively reveal what is causing these FRBs.
The signal FRB 20191221A was first detected by CHIME on Dec. 21, 2019, and its unusual
nature was immediately spotted by scientists.
When the researchers from MIT analyzed the pattern of this signal from a distant galaxy,
they found similarities with emissions from radio pulsars and magnetars closer to home
in the Milky Way.
There is one key difference between FRB 20191221A and signals from these objects within our
galaxy, however, the former is over a million times brighter than the latter.
Scientists believe that the highly luminous flashes of FRB 20191221A could indicate that
the radio pulsar or magnetar emitting them is usually much less bright.
This could mean that some unknown mechanism or event has caused it to emit a train of
brilliant bursts, in an unusual three-second window.
CHIME continuously scans the sky over Earth as our planet rotates and is fortunately positioned
just right to catch this rare burst.
The instrument, an interferometric radio telescope made up of four large parabolic reflectors,
is no stranger to spotting FRBs.
Since it commenced operations in 2018, it has spotted hundreds of these bursts.
Astronomers hope that future telescopes will detect thousands more FRBs each month and
periodic signals like FRB 20191221A could be amongst them.
Outro If you found the video informative, please
consider checking out this one which talks about the James Webb Telescope’s terrifying
discovery at the edge of the Universe!
Do you think Fast Radio Bursts are signals from an alien civilization?
Please share your thoughts in the comments section below.