Since July, the world has been watching
three Atlas speed through our solar
system. But in October, just as this now
infamous interstellar object started to
get close enough and bright enough to
Earth to study properly, our view of it
was blocked by something else. Rather
close and far brighter, our sun. The
groundbased telescopes that had been
tracking its every move for months were
now blinded at a most frustrating time.
We just begun to study its strange
molecular ratios, saw it change color
twice, and even spotted a strange and
unusual sunward tail that some suggested
might be evidence of artificial
propulsion.
Meanwhile, subjected to the sun's
intense radiation and moving at a
staggering 68 km/ second, it wasn't
clear if ThreeI Atlas would even survive
the journey around our star. But all was
not lost. Out in space, a fleet of
probes, telescopes, and even Mars rovers
were keeping a keen eye on ThreeI Atlas
as it dived towards Perihelion. Would it
make it out the other side, disintegrate
in the sun's searing heat? Or would it
do something else completely unexpected?
I'm Alex Mccoan and you're watching
Astramm. Join me as we dissect the
stunning new data from three eye atlases
Mars flyby. Find out what happened
behind the sun and analyze the smoking
gun evidence from a South African radio
telescope that could settle the debate
about whether we are looking at a
volatile comet or something that is
intelligently navigating the dark.
Before ThreeI Atlas even vanished behind
the sun, it gave us a warning that it
was no ordinary comet. In late August
and September, NASA used their Swift
observatory to watch three Atlas as it
approached the sun. Swift is designed to
spot gammaray bursts, but its UV
capabilities allowed it to see things
invisible to the human eye. In this
case, the glow of hydroxil or O
radicals. These molecules are the broken
fragments of water ripped apart by
sunlight. And what Swift detected was a
massive surge in those hydroxal
radicals. At a distance of 2.9
astronomical units, nearly three times
the distance from Earth to the Sun, 3i
Atlas was dumping water at a rate of 40
kg/s.
To put that in perspective, that's the
output of a fire hose running at full
blast. For a comet this far out where
temperatures are still freezing, this
was shocking. Standard models suggest
water ice shouldn't sublimate this
aggressively until it gets closer to the
sun. This fire hose behavior hinted that
threeey atlas wasn't just sublimating
water from its surface. It was likely
ejecting icy grains into its coma, which
were then melting independently, vastly
increasing the surface area. But before
we could find out more, this comet
dipped behind the sun and disappeared.
Throughout October 2025, Earth-based
telescopes had to take a break from
watching three Atlas. This was the worst
possible scenario for astronomers. The
most exciting moment of the comet's
journey was happening on the opposite
side of the sun from us. When warned by
the sun's radiation, it would be at its
brightest and would be outgassing
violently.
But while Earth may have been blind, we
already have plenty of probes and
telescopes in the deeper reaches of the
solar system, some of which were
perfectly positioned to watch the show
as the comet made its closest approach
to the sun.
A new study led by Kiang Chang from the
Lowel Observatory in Arizona and Carl
Batams from the US Naval Research
Laboratory aggregated data from three
specific spacecraft.
Stereo A, SOHO, and the newly launched
GOE 19 satellite. These three spacecraft
use chronographs to block out the sun's
disc, creating an artificial eclipse.
Usually they hunt for solar storms, but
in October they were hunting a comet and
what they saw was a metamorphosis.
For months as three Atlas approached the
inner solar system, its brightness had
been steadily increasing. Astronomers
measure the rate at which that
brightness increases as a power of an
object's distance from the sun or r.
Before October, 3 atlas's brightness was
increasing at a rate of roughly rus 3.8.
That is a respectable rate for a comet,
indicating active sublimation of
material from its nucleus. However,
inside two astronomical units, the
brightness slope didn't just steepen, it
went almost vertical. The new data shows
a brightness scaling of rus 7.5.
That's a huge increase. The comet was
shedding mass at a rate that defied
standard models for a simple dirty
snowball. It was bright enough that by
the time it emerged from behind the sun,
even amateur astronomers were able to
image it from Earth. These are some of
the images taken of the threeey atlas
during this time. In them, you can
clearly see a bright coma streaking out
behind the comet. Although the core of
ThreeI Atlas itself is a little harder
to make out, they were taken by
below. Then use my code Astramm 5 at checkout to get 5% off. The most telling
detail about this newly brightened
comet, though, was the color. For
months, observers saw three Atlas as
red, typical of dusty, organic rich
surfaces like those on Amua Mua. Then it
turned green to observers on Earth, as I
mentioned in my last video on this
comet. But the solar observatories saw
something different. Through the filters
of Lasco and Core 1 coronagraphs, Chang
and Batams reported that Threeey Atlas
appeared distinctly blue relative to the
sun.
A blue hue in a cometry coma is the
signature of specific gas emissions,
fluoresence from carbon monoxide and
amide radicals. It suggests that as
three Atlas plunged towards perihelion,
it shed its dusty red outer cloak, the
intense solar heat penetrated that
protective layer and began boiling off
volatile ices from deep inside the
comet. The real comet, the blue,
violently outgassing engine inside, only
revealed itself when it got close enough
to the sun. But these solar probes
weren't the only ones watching.
Just before the solar encounter, Sri
Atlas paid a visit to our little red
neighbor, passing just 0.19 astronomical
units or about 28 million km from Mars.
This was a cosmic stroke of luck,
offering a unique opportunity for the
fleet of robots currently exploring the
red planet to observe. NASA's Mars
Reconnaissance Orbiter swiveled its
high-rise camera toward the visitor.
Now, High-Rise is powerful enough to
spot a coffee table on the Martian
surface from its orbit of 200 to 400 km
above. If anything was going to be able
to get a resolved picture of the
nucleus, it was this camera. But the US
government shutdown affected many of
NASA's departments, meaning it took
weeks for the pictures to be published.
The long wait to get a hold of these
images sparked conspiracy theories that
NASA had seen something unusual, perhaps
extraterrestrial in origin, and were
withholding it from the public eye. The
images finally released by NASA nearly 6
weeks later were underwhelming.
They show a fuzzy, unresolved blob. Even
from this distance, the nucleus was
hidden deep within a shroud of gas and
dust measuring 1,500 km across. Although
we didn't get a beautiful, pristine
photo of our interstellar visitor, at
the very least, this nondetection may
help scientists pinpoint how large three
atlas really is. But we already know
from observations made by the Hubble
Space Telescope that it is likely no
more than 2.8 km wide.
But MRO wasn't alone. ISSA were busy
imaging throughout Atlas with Mars
Express and the ExoMars Orbiter. And
NASA's Maven Orbiter used this
ultraviolet spectrograph to image the
comet's hydrogen envelope, revealing a
massive cloud of gas extending far
beyond the visible coma. Perhaps most
incredibly, the Perseverance rover
sitting in Yzero Crater, fresh from
discovering what might be evidence of
life on Mars, pointed its mast cam
skyward. In the resulting long exposure
images, ThreeI atlas appears as a faint
ghostly smudge drifting among the stars.
These images may not look like much, but
they are truly groundbreaking. This is
the first time we have ever imaged an
interstellar object from the surface of
another world. And then it was the
moment we've all been waiting for.
Parihelion.
As Threei Atlas emerged from behind the
sun in November, panic spread through
the astronomical community. Harvard
astrophysicist and avid threeey atlas
commentator Professor Avi suggested that
the comet had fragmented,
that it had exploded into 16 pieces. It
looked like our chance to observe this
rare interstellar visitor might be over
for good. His hypothesis was fueled by
calculations suggesting the comet's mass
loss was unsustainable.
With the brightness surging so
intensely, some models predicted the
nucleus must have disintegrated to
provide that much surface area for
sublimation.
However, new observations from the Lowel
Observatory and the virtual telescope
project have calmed these fears.
Astronomer Tang reported that the comet
appears perfectly normal and healthy.
There is no train of fragments, no
chaotic debris cloud. The nucleus
survived. The explosion was simply an
intense period of activity, a natural
firework show driven by the shedding of
that outer crust.
So, the comet is in one piece. But those
who have been following the story of
three Atlas over the last few months
will not be surprised to find out why
Avi Lobe was so concerned that it had
fragmented. Over the last few months,
Lobe had published a series of articles
on Medium. arguing that the comet's
behavior exhibits anomalies consistent
with extraterrestrial technology.
Specifically, No points to two features,
a sun jet appearing in images and what
he describes as non-gravitational
acceleration that keeps the object on a
remarkably straight trajectory.
Lob argues that the mass loss required
to produce such acceleration by natural
outging would be immense. potentially
enough to disintegrate the object. He
suggests that if the gas cloud isn't
massive enough to account for the
thrust, we must consider artificial
propulsion.
As fun as this is to think about and
perhaps even to hope is true, in this
case, unfortunately, standard cometry
science offers robust natural
explanations for these phenomena. First,
the sun would jet. Normally, we expect
comets to have a tail or trail of gas
and dust expelled from the comet, pushed
behind it by the solar wind. Three
Atlas, however, appears to have a second
tail in the opposite direction, facing
towards the sun instead of away from it.
Images from the 2meter Twin Telescope in
Spain's Canary Islands, taken on the 2nd
of August, but first released in
October, show this jet close up. This
image, a composite of 159 exposures
lasting 50 seconds each, shows three
Atlas as a big black dot in the center
of a white glow. But the break in this
glowing ring shows a jet of material
blasting off the comet in the direction
of the sun. Now, while this might look
like a thruster firing against the
direction of motion, this sunward jet is
a reasonably common feature in comets.
As a comet approaches the sun, the side
of the comet facing it will heat up
faster. If there's a weak spot on the
surface, sublimating gases can then
shoot out of the comet towards the sun.
The solar wind pushes this material
back, creating a fan or spiral structure
that from Earth's perspective can look
like a forwardfacing spike. So, this is
not an unusual thing to see. In fact,
similar features were observed on comet
Halley, Neoise, and comet 67P.
Second, let's address the
non-gravitational acceleration. This is
the rocket effect caused by outgassing
and is a standard feature of all active
comets. A new dynamical study by Goldie
Auja and Shashikaren Gananish modeled
threei Atlas's trajectory over the last
100 years. They found that its
acceleration was entirely consistent
with the fire hose, water loss, and the
massive CO2 release we've observed. The
comet is losing mass rapidly, just as
log calculated it would need to, but the
survival of the nucleus suggests it is
dense and structurally sound, not that
it is artificial. Furthermore, the
straight line trajectory law mentions is
largely a matter of perspective and
reference frames. In a hyperbolic orbit,
the object travels fast enough that
gravity bends its path less than a
captured object, making it appear
straighter. But it is still following
the predictable laws of Kepler and
Newton. While Loe's hypothesis serves a
valuable purpose by pushing us to
question our assumptions, the current
weight of evidence, the chemical
identification of cyanides, water, and
that massive carbon dioxide load
strongly supports the theory that three
atlas is a natural object. And the
Mircat radio telescope array in South
Africa has now effectively ended the
debate. MICAT detected a faint but
distinct signal at 1,665
and 1,667
MHz. This is an absorption line of the
hydroxal radical. We mentioned hydroxal
earlier with the Swift telescope, but
this new radio detection is crucial.
Radio waves can penetrate the thickest
dust clouds, giving us a direct look at
the gas density. The detection confirms
the presence of water and lots of it.
This is the first time we've detected
radio emissions from an interstellar
object. It confirms that three Atlas is
chemically similar to the comets in our
own solar system. It is a wet icy body
venting water vapor as it heats up. If
it were a dry, rocky spaceship or a
defunct probe, this signal simply
wouldn't exist.
This effectively seals the deal. Three
Atlas is made of water and carbon, the
building blocks of nature, not some
exotic extraterrestrial alloy. So much
for the alien spaceship theory. This
object is undeniably a comet. But that
doesn't mean it's not surprising us in
other ways.
One of the biggest assumptions we make
about interstellar objects like three
Atlas is that they are pristine. We
imagine them as perfectly preserved time
capsules unchanged since the birth of
their parent star systems. But a new
paper by Roma Majiolo from the Royal
Belgian Institute for Space Aronomy and
his colleagues challenges this idea
entirely. In fact, it suggests that we
have been looking at interstellar
objects all wrong. Threeey atlas, they
argue, is not pristine. It is cooked.
The evidence comes from the chemistry
revealed by observations from the James
Web Space Telescope and the Sphere X
mission, which detected an extreme
abundance of carbon dioxide. In typical
solar system comets, water is the
primary driver of activity. You usually
see a lot of water and a little bit of
CO2. The ratio of CO2 to water in a
normal comet is about 0.12.
In 3i Atlas, that ratio is 7.6. Six.
Think about that. This comet has nearly
60 times more carbon dioxide relative to
water than we expect. It is practically
a dry ice bomb. Where did this excess
come from? Maji proposes a fascinating
mechanism. Galactic cosmic rays.
For the billions of years that 3i Atlas
drifted between the stars, it was
constantly bombarded by high energy
particles from supernova and active
galactic nuclei. These particles slam
into the comet's surface, penetrating
meters deep into the ice. When they hit,
they break chemical bonds. The model
suggests that over billions of years,
this radiation converts simple carbon
monoxide and water ice into carbon
dioxide and complex organic solids. It
effectively creates a processed crust, a
layer of radiation burned chemical slag
that extends about 15 to 20 m deep.
Because 3II Atlas is so small and
because it is eroding fast, what we are
seeing right now isn't the deep
primordial interior of the comet, we are
seeing this cooked crust sublimating
away. Srii Atlas has in effect caught
the mother of all tans and now it's
peeling.
This finding implies that any object
that has spent eons in the void will
look like this. We may never see a truly
pristine interstellar object until we
catch one that is incredibly young or
until one breaks apart completely to
reveal its unaltered core.
Three Atlas might have more CO2 than
other comets, but that's not all it's
been hiding. Joseph Trigo Rodriguez and
his colleagues compared the light
spectrum of three Atlas to meteorites
found on Earth. What they discovered was
staggering. Threei Atlas's spectrum
looks very similar to that of CR
carbonacious condrites, rare primitive
meteorites that contain tiny grains of
iron and nickel material. So 3II Atlas
might well be carrying those metals,
too. In fact, reports from the UVES
spectrograph at the VLT in Chile spotted
nickel and iron in its coma back in
September with their data showing the
comet to have a high nickel to iron
ratio. This was unexpected. It's unlike
any comet seen in our solar system
before, even 2i Borisovv, another
interstellar visitor we spotted in 2019.
The VT team noted that the nickel to
iron ratio reduced as 3i atlas
approached the sun, suggesting that
comet 3i could soon become
indistinguishable from solar system
comets in this respect.
Why would it be important to find metals
inside 3i atlas? Well, when water ice
melts inside the comet's porous crust,
perhaps heated by the sun or by internal
pressure, it comes into contact with
these metal grains. In the presence of
metal catalysts, water and carbon
compounds can undergo what are called
fissure drops reactions. These are
exothermic reactions. They release heat.
This creates a feedback loop. The heat
melts more ice which reacts with more
metal releasing more heat. This in turn
builds up pockets of intense pressure
under the crust until the surface
ruptures and a jet of gas and dust
explodes outwards. This cryovvulcanism
could explain the surge in brightness,
the jets, and the massive release of
material. It also explains why the comet
is rich in nickel and iron gas.
So, where does three Atlas go from here?
As of November 2025, the comet is
emerging from the solar glare. It has
survived its perihelion, though the
intense mass loss has likely altered its
surface forever. It is now outbound,
racing away from the sun and back toward
the interstellar dark. But there's more
to be had from this comet. As we publish
this video, 3II Atlas will have just
passed as close to Earth as it will ever
get. And on the 16th of March, 2026,
comet will pass about 0.35 astronomical
units from the gas giant Jupiter. Models
suggest this will be a remarkably close
approach passing inside Jupiter's
hillphere or the region where the
planet's gravity dominates over the sun.
While it won't be captured, it's moving
way too fast. Jupiter's gravity will
tweak the trajectory of three Ilas one
last time before it leaves the solar
system.
Crucially, this flyby offers a potential
observation window for the Juno
spacecraft, which is currently orbiting
Jupiter. If Juno is still operational by
then, we might get one final close-up
look of this interstellar traveler from
the perspective of the outer solar
system.
The story of the Rei Atlas is far from
over, but it has already taught us more
in a few months than we learned in
decades of theory about what's outside
our solar system. It is revealed that
the space between stars is not just an
empty void, but a cosmic radiation oven
that physically transforms the objects
drifting through it. It has shown us
that even small fuzzy blobs can contain
complex chemical engines capable of
driving jets and surviving the inferno
of the sun. And while it may not be an
alien spaceship, a rock that has
traveled for billions of years, carrying
the scars of its journey across the
galaxy to tell us its story is in its
own way just as miraculous.
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