In some ways, astronomy is similar to the classic board game Clue.
Scientists investigate a vast but ultimately contained environment, gathering knowledge
and testing theories regarding a large mystery.
You can't cover every nook and cranny, but with the right balance of strategy and fortune,
you can gather enough clues to make a decent guess at the tidy answer—who, where, and
how—enclosed in a little yellow envelope at the heart of it all.
Only astronomers are attempting to determine the origin of odd flashes of radio signals
that reach Earth from the depths of space.
What exactly are these unusual radio signals?
Are they sent by intelligent aliens attempting to communicate with us?
Join us as we delve into the unusual radio transmissions recorded from space by NASA!
Astronomers have discovered light signals from the universe's oldest stars for the first
time.
The discovery of these signals is truly revolutionary because scientists currently know relatively
little about the early history of the universe.
In reality, they have not uncovered any early universe signals apart from the big bang's
afterglow.
While scientists have worked for years with limited information about the early universe,
they do know that after the big bang, the universe was a starless frigid realm made
up of radiation-covered hydrogen gas known as the cosmic microwave background.
As the early universe's history has remained a mystery, radiation can still be found in
space today.
Following this phase of nothingness was the dark age, a 100-million-year period during
which thick gas zones formed clumps that ultimately collapsed into the first stars.
The hydrogen atoms started to absorb radiation from the cosmic microwave background at a
typical wavelength as these gigantic blue stars lighted up the gas surrounding them.
Therefore, scientists think that the cosmic dawn may have left an impression on the cosmic
microwave background radiation as a drop in brightness in the spectrum, which should be
detectable today.
Finding this dip has been difficult, as experts have searched in vain for more than a decade.
Adding to the difficulty, scientists were unable to establish where in the spectrum
they should be looking.
The Edges, a little table-sized instrument, appears to have helped a team solve the puzzle.
The antenna was installed in a distant area of Australia where there are few human-made
radio waves that could interfere with the transmission.
The signal they discovered points to the origin of the cosmic dawn, which occurred approximately
180 million years after the Big Bang.
The observed drop was double the magnitude predicted by scientists, which was a startling
feature.
This suggests that the cosmos was cooler than previously thought, because the surrounding
hydrogen gas absorbed more radiation than scientists had imagined.
According to scientists, this indicates the presence of dark matter, as dark matter is
thought to be the cause of the hydrogen gas's loss of heat.
If this concept is accurate, it will be the first-time scientists have identified dark
matter through means other than gravitational effects, despite dark matter accounting for
around 85 percent of all matter in the universe.
The signals observed have defied many previously held scientific predictions.
Given how little we know about dark matter, these findings may help us get a little closer
to the reality.
However, this was not the only recent astronomical discovery.
Here's another mysterious signal from the vastness of the cosmos.
Despite the numerous potential sources of radio emissions, astronomers have identified
new and unique radio wave signals, unlike any before discovered!
The radio waves fit no known patterns of fluctuating radio sources, but they are coming from the
heart of our Milky Way galaxy!
The ASKAP radio telescope was used to make the finding.
ASKAP is a next-generation radio telescope that incorporates cutting-edge ICT systems
and unique receiver technology.
It consists of 36 antennas, each 12 meters in diameter, that act as a single device.
When ASKAP is operational, it will be capable of high dynamic wide-field imaging with revolutionary
phased array feeds, providing a distinct new capacity in radio astronomy.
ASKAP's design is unique among radio telescopes since its antennas have three-axis mobility
and will collect and magnify radio waves using phased array feeds or radio cameras rather
than 'single pixel feeds.'
Because of these characteristics, the telescope will be able to examine enormous areas of
the sky with unparalleled sensitivity and speed.
Why did the scientists think this radio wave was distinct from anything else they'd heard?
It has a very significant polarization, they explained.
This means that its light oscillates in only one direction, which rotates with time.
Aside from that, the brightness of the object varies by a factor of 100, and the signal
appears to switch on and off at random, unlike anything the scientists had ever seen before!
Initially, scientists suspected it was a pulsar or a sort of star that releases massive solar
flares.
However, the signals from this new source do not match those emitted by these celestial
objects!
While the study on the radio wave continues, the source of the signals has been identified
as ASKAP J173608.2-321635.
Despite the fact that the scientists were perplexed by the source of the emission, the
discovery was nothing short of astounding!
Six signals were identified by the scientists over a nine-month period in 2020.
However, when the scientists used optical telescopes to look for the source in visible
light, they found nothing.
The Parkes radio telescope in Australia came up empty as well.
This telescope, located just outside the town of Parkes in New South Wales' central west,
is one of four devices that comprise the Australia Telescope National Facility.
Parkes has a diameter of 64 meters, making it one of the largest single-dish telescopes
dedicated to astronomy in the southern hemisphere.
It began operations in 1961, and since then, the surface, control system, focus cabin,
receivers, computers, and cabling have all been modified to keep the telescope at the
forefront of radio astronomy.
The telescope is now 10,000 times more sensitive than it was when it was first built.
However, it was unable to locate the source of the radio signal!
Fortunately, there is the MeerKAT radio telescope in South Africa, which consists of 64 interconnected
sensors.
A receptor is the entire antenna structure, including the primary reflector, sub-reflector,
and any receivers, digitizers, or other electronics.
The core area, which is approximately 1 km in diameter, has 48 of the receptors.
MeerKAT is more powerful than Parkes, therefore astronomers resorted to it to help them solve
the mystery of this odd radio signal!
The signal was recognized by Meerkat, but it was irregular and erratic, indicating that
the source was very different.
Despite being present for weeks in previous ASKAP observations, this source vanished in
a single day.
Astronomers must now pinpoint the source of these strange signals; they have a list of
possible sources to study.
First, the radio waves could be coming from a distant star.
Stars are one of a few sources that may release polarized emissions, but because their x-ray
and radial luminosities are frequently correlated, astronomers expect only detecting x-rays from
them.
Furthermore, near-infrared emission would be significant and noticeable, thus scientists
rule out stars because the source does not have a particularly modest ratio of x-ray
infrared to radio emission.
The next most likely source of this radio emission is a pulsar.
So, what is a pulsar, exactly?
Pulsars are interesting spherical compact objects the size of a large city but with
a mass higher than the sun.
However, they are not stars, or at least not live stars.
Pulsars are neutron stars, which develop when a star more massive than the sun runs out
of fuel in its core and collapses in on itself.
This celestial death is generally followed by a gigantic explosion known as a supernova.
A neutron star is the dense nugget of material that remains after this violent death.
Despite its allure, pulsars were not found to be the source of the ASKAP j173608.2-321635
radio emission.
Why?
This is owing to the source's lack of pulsed emission.
It's most likely a pulsar with a lot of scattered energy, an ultra-long period, or a pulsar
in an eccentric binary system.
However, it does not appear to be a conventional pulsar.
A magnetar is another possibility!
What exactly is a magnetar?
It's about magnets, as the name suggests, but on a massive scale.
If a magnetar is positioned halfway between the Earth and the Moon, the effect will be
felt by everyone on the planet since all credit cards on the planet will be wiped.
If you were to come within 600 miles or 1000 kilometers of a magnetar, you would kill quickly
because the magnetic field would destroy your body, ripping electrons from your atoms and
turning you into a cloud of monatomic ions, which are single atoms without electrons.
But that's not the only weird thing about these strange objects.
Magnetars produce enormous amounts of energy in the form of flares, x-rays, and gamma-ray
bursts.
As a result, they are linked to extreme events in the universe, making them the strangest
phenomena in the universe, along with black holes.
So, what ruled out magnetars as the source of this radio signal?
Magnetars, on the other hand, have relatively flat spectra, which indicates that the strength
of emission does not vary considerably with frequency.
This contradicts the source's observable nature.
Periodicity searches using a Meerkat disqualify magnetars, which have typical intervals of
1 second to 10 seconds.
However, there is a probability that it is a one-of-a-kind ultra-long period magnetar
that has to be investigated further.
Another possible source of the radio signal is a Galactic Center Radio Transient, or GCRT.
In fact, this one seems more credible.
The spectra of GCRTs are steep, highly polarized, and do not emit x-rays.
However, just three galactic center radio transients have been found, and their sources,
if they are even the same, are unknown.
Furthermore, the time scale on which the emission varies for ASKAP j173608.2-321635 does not
match the time periods of other galactic center radio transients.
The source of this radio wave is still a mystery that experts are eager to solve.
So, where do we go from here?
The experts intend to keep a close eye on the object and use the tools at their disposal
to look for additional clues as to what it could be.
However, assistance is on the way, which may speed up their work and provide many new ideas.
Within the next decade, the transcontinental square kilometer array radio telescope will
be operational.
This project is an international collaboration to build the world's largest radio telescope,
with a collecting area of more than a square kilometer.
The size of the SKA represents a significant advancement in both engineering research and
development toward producing and delivering a one-of-a-kind instrument, with full design
and planning presently well underway.
Astronomers believe that the capabilities of this telescope will help humanity solve
mysteries like this latest discovery while also opening up large new areas of the cosmos
to study in the radio spectrum.
Let us know what you think of this unusual radio signal in the comments area below.