As we gaze up at the night sky, we might feel as though we know the universe like the back
of our hands.
We've charted the stars, mapped the planets, and even sent probes deep into space to explore
the great unknown.
But what if everything we thought we knew about the cosmos was about to change?
That's precisely what scientists are grappling with as they receive strange, hair-raising
signals from Voyager 1, a probe that has been beaming back invaluable data for decades.
What could these signals mean, and could they spell doom for Voyager's mission?
Join us as we delve into the mystery of Voyager's eerie transmissions and unlock the secrets
of the cosmos.
Since the 1970s, Voyager space probes have been integral in humanity's pursuit of understanding
the outer planets.
While they weren't the first of their kind, the Voyager probes were engineered to venture
even further into our solar system.
Thanks to the data collected by their predecessors, such as Pioneer 10, the Voyagers were able
to withstand the radiation found around planets like Jupiter and Saturn.
Their main mission was to capture detailed imagery of these colossal planets via flybys.
Assembled at NASA's Jet Propulsion Laboratory, Voyager 1 was outfitted with cutting-edge
technology, including a top-of-the-line communication system that could operate beyond our solar
system's limits.
Some of these instruments are essential to Voyager's mission, such as the Cassegrain
12-foot antenna used to send and receive radio waves through NASA's Deep Space Network.
This network was specially designed to ensure that the Voyager space probes' signals could
be received from any angle of Earth's rotation.
In addition to this antenna, Voyager was equipped with a digital tape recorder capable of recording
up to 67 megabytes of data.
This was crucial because deep space can disrupt signal transmission, and in the event that
Voyager is unable to transmit a signal, the saved data can be transmitted at a later time
when a direct line of transmission is established.
To ensure Voyager stays on course despite the unpredictable radioactive particles found
in the outer regions of our solar system, the probe was built with several components,
including three-axis stabilization gyroscopes, 16 high hydrazine thrusters, and a computerized
referencing instrument.
All these work together to keep the probe's radio antenna pointed towards Earth, ensuring
we receive the valuable data it sends back to us.
These instruments enabled Voyager 1 to keep its antenna pointed towards Earth, even in
the midst of unpredictable and volatile conditions in deep space.
However, powering these instruments and systems for decades required a constant supply of
energy.
While previous space probes relied on solar panels to harness solar energy, Voyager 1
was designed with a different power source in mind.
NASA engineers anticipated that Voyager 1 would eventually venture beyond the range
of sunlight, and thus built the probe with three radioisotope thermoelectric generators,
or RTGs.
These generators contained 24 pressurized spheres of plutonium-238, a stellar fuel choice
due to its half-life of 87 years and slow degradation over time, which produced heat
that was converted to electricity to power the probe's components.
At the start of its journey, Voyager 1's RTGs generated about 470 watts of electricity,
a number that has decreased by nearly 50 percent over the course of the probe's 45-year journey.
Despite the recent discovery of strange signals from Voyager 1, the probe has remained steadfast
and reliable since its launch, providing invaluable insights into the inner workings of our own
solar system.
And far from the Sun's protective embrace, the edge of our Solar System appears to be
a cold, empty, and dark place.
For a long time, the yawning space between us and the nearest stars was thought to be
a terrifyingly vast expanse of nothingness.
It was something that humans could only see from afar until recently.
Astronomers ignored it, preferring to focus their telescopes on the glowing masses of
our neighboring stars, galaxies, and nebulae.
However, for the past few years, these two spacecrafts have been beaming back our first
glimpses of this strange region known as interstellar space.
As the first man-made objects to leave our Solar System, they are venturing into uncharted
territory billions of miles from home.
No other spacecraft has travelled as far.
And they have revealed that beyond the boundaries of our solar system lies an invisible region
of chaotic, frothing activity.
“When you look at different parts of the electromagnetic spectrum, that area of space
is very different from the blackness we perceive with our eyes,” says Michele Bannister,
an astronomer at the University of Canterbury in Christchurch, New Zealand, who studies
the outer reaches of the Solar System.
“Magnetic fields are fighting and pushing and tied up with each other.
The image you should have is like the plunge pool under Niagara Falls.”
Instead of tumbling water, however, the commotion is caused by the solar wind, an unceasing
and potent flow of charged particles, called plasma, that shoots out in all directions
from the Sun.
This wind clashes with a mixture of gas, dust, and cosmic rays that drifts among the star
systems, known as the "interstellar medium".
For over a century, scientists have been working to decipher the composition of the interstellar
medium, aided by powerful tools like radio and X-ray telescopes.
Through their efforts, they have pieced together that this medium is comprised of ionized hydrogen
atoms, dust, and cosmic rays that mingle with dense gas clouds, where stars are born.
But its precise nature beyond our solar system has remained largely a mystery, primarily
because the Sun, all eight planets, and a distant disc of debris known as the Kuiper
Belt are all contained within the heliosphere, a giant bubble formed by solar wind.
As the Sun and its planets speed through the galaxy, this bubble acts as an invisible shield
against the interstellar medium, blocking the vast majority of hazardous cosmic rays
and other particles.
The heliosphere is also surprisingly vast, hinting at a lower density of interstellar
medium than anticipated.
The Sun's movement through space is akin to a boat gliding through water, forming a "bow
wave" and trailing a wake, perhaps even with tails resembling those of comets.
However, because the Voyagers exited through the "nose" of the heliosphere, no information
was obtained about the tail.
According to Elena Provornikova, a postdoctoral researcher at the Johns Hopkins University
Applied Physics Laboratory, the heliopause is estimated to be roughly one astronomical
unit thick, or 93 million miles, which is the distance between the Earth and the Sun.
“It's not really a surface.
It's a region with complex processes.
And we don’t know what’s going on there.”
And since no spacecraft has ever made it beyond the heliosphere in the history of mankind
and space exploration, scientists have been closely monitoring the voyagers' signal feedback
from this region.
However, they were astonished when, during one observation cycle, Voyager 1 began transmitting
unknown and completely alarming data.
The data showed impossible scenarios that couldn't be explained by the known laws of
physics in interstellar space.
Officials from NASA's Jet Propulsion Laboratory revealed that the mysterious data originated
from Voyager 1's altitude articulation and control system, also known as AACS.
The system was responsible for measuring and calculating the orientation of Voyager 1 and
its antenna, ensuring that the probe maintained a direct line to Earth for optimal signal
transmission and orientation.
Scientists were baffled as to the origin of this terrifying signal and junk data that
Voyager 1 transmitted back.
This was because the probe was still able to observe, gather, and transmit data back
to Mission Control on Earth, indicating that it was functioning normally.
Although the data sent back by Voyager 1 was essentially useless due to corruption, it
is still remarkable that the spacecraft has exceeded its intended lifespan of 45 years.
Despite having multiple systems shut down to conserve power, both Voyagers 1 and 2 have
consistently transmitted reliable data throughout their mission.
As Voyager 1 continues its journey and travels 14.5 billion miles away from Earth, communication
delays of over 22 hours make it difficult for Mission Control to quickly solve any problems
that arise.
After weeks of searching for an explanation for the strange signals being sent back, NASA
finally discovered that the AACS system responsible for keeping Voyager 1's antenna pointed towards
Earth was inadvertently sending data through a corrupted computer.
Although the data was accurate, the corruption caused by the outdated system resulted in
the transmission of junk data back to Earth.
The scientific community has widely speculated that Voyager 1 most likely encountered some
form of cosmic radiation containing charged particles that distorted system commands,
causing the switch to the corrupted computer.
This is still just a theory, as NASA has yet to explain what they believe caused the system
malfunction.
While mission controllers believe this was an isolated incident, there is widespread
speculation that a similar situation could occur again due to the unknown nature of interstellar
space.
The Voyager story, however, has a twist.
Even though they've left the heliosphere, they're still vulnerable to many of our Sun's
other influences.
The light of the Sun, for example, would be visible to the naked eye from other stars.
Our star's gravity also extends far beyond the heliosphere, holding in place the Oort
Cloud, a distant, sparse sphere of ice, dust, and space debris.
Despite floating in interstellar space, Oort objects continue to orbit the Sun.
While some comets have orbits that extend all the way to the Oort cloud, a region 186-930
billion miles (300-1,500 billion km) away is generally thought to be too far away for
us to send our own probes.
These distant objects have barely changed since the Solar System's inception and may
hold the key to understanding everything from how planets form to the likelihood of life
arising in our universe.
Every new wave of data from the Voyagers brings with it new mysteries and questions, leading
scientists to wonder what else lies beyond the heliosphere.
According to Provornikova, there could be a hydrogen layer surrounding the heliosphere
that remains a mystery to scientists.
Additionally, the heliosphere seems to be heading towards an interstellar cloud made
of dust and particles from past cosmic events, and no one knows the impact this will have
on the boundary and on those of us living within it.
Despite the unknown, Voyager 1 and 2, two tiny probes carrying metal components and
small parabolic dishes, will continue to venture out into the depths of space and provide us
with more insights into this uncharted territory.
Will Voyager 1 uncover something inexplicable out there?
Let us know your thoughts in the comments.