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They might not be your typical UFOs, but astronomers do occasionally discover
unidentified objects floating in the depths of space.
Take ORCs for example.
While they might share a name with creatures from fantasy books
and tabletop adventures, they’re not some kind of weird, scary extraterrestrial.
ORC is actually short for Odd Radio Circle, and while we have a few clues
to work with, the truth is, we don't know what they are.
In the grand scheme of astronomical mysteries, ORCs are pretty new to the scene.
As the name suggests, Odd Radio Circles look like, circles.
And they’re visible in the radio band of the electromagnetic spectrum.
And they're odd!
The first ones were spotted back in 2019, and as of early 2023,
we’ve only spotted six potential ORC candidates.
Four of those candidates are loners,
and the other two form a sort of double feature, connected by, like, a tail.
And what’s odd about them is that, as far as we know,
they’re only visible at radio wavelengths.
Usually, you see space stuff emitting electromagnetic radiation,
otherwise known as light, all over the spectrum.
But for some reason, ORCs are stuck in radio.
And the reason could vary depending on the ORC candidate.
For example, one might be an ancient supernova remnant.
And that double ORC might just yet be another radio galaxy…
a galaxy that just happens to be emitting more radio waves than normal.
The astronomers working on this puzzle
don’t really consider those to be true ORCs.
Because if we set those aside, we’re left with three ORCs that all have
another thing in common: each have a galaxy smack dab in the middle.
Now, that could be a complete coincidence.
When we look up into space, all of the 3D universe is flattened into our 2D sky.
That’s probably why ORCs look circular too.
They’re most likely spherical… or a long horn shape…
but both of those look like circles when you see them head-on.
But the running hypothesis is that these galaxies are the ORCs’ point of origin..
And there are a few competing hypotheses
to explain what these galaxy-encircling objects actually are.
One states that they were born of two galaxies merging.
Not only did all the stars and dust smush together into one big galaxy,
the two supermassive black holes at their cores did, too.
And that merger created a huge explosion and shockwave
that extended, like, a million light years beyond the galaxy.
Another proposal states that ORCs are shockwaves created
after a galaxy goes through a phase when it makes a bunch of new stars.
All those baby stars create a kind of stellar wind, blowing ever outward
until something from beyond the galaxy pushes back just enough
to stop that wind from expanding.
Either way, you get something pretty darn spherical
that will look like a circle from way over here.
But where do all the radio waves come from?
Well, these shockwaves don’t just carry a bunch of dust and gas along for the ride.
They carry magnetic fields, too.
And eventually, those fields are sent crashing into the intergalactic medium…
the stuff between galaxies.
That collision will accelerate a bunch of electrons out there
just minding their own business.
And because electrons are charged particles,
they’ll interact with the magnetic fields in a very specific way.
They start spiraling around and around,
emitting a kind of light called synchrotron radiation.
Synchrotron radiation can be pretty much any wavelength,
but its radio signal is way stronger.
In fact, this radiation is one of the dominant sources of radio waves
throughout the universe.
Meanwhile, the synchrotron radiation emitted at other wavelengths
is so weak that we can’t really detect those signals from Earth.
In other words, ORCs might technically be emitting other kinds of light,
we just haven’t detected it yet.
Researchers are currently analyzing data from an all-sky survey called eROSITA
to see if they can find these ORCs emitting x-rays.
In which case, that would make them ORX-C…?
OXARC…?
Which isn’t as good as ORC, but, you know, either of those.
Take them astronomers.
I give those to you.
But synchrotron radiation isn’t the only potential explanation
for our mysterious friends.
Some researchers claim that ORCs are radio jets shooting out from black holes.
Big cones of stuff emitting radio waves as they’re flung away
from the center of the galaxy.
We see these sticking out of plenty of galaxies throughout the universe,
but they usually point out to the sides.
ORCs may be the very special,
very rare case where they’re pointed exactly, directly at us.
But other astronomers dismiss this hypothesis on the basis of
“They’re just too darn round.”
Sure, we’ve only discovered a handful of these things, but not one is an ellipse.
If ORCs are actually these super long radio jets poking out of the galaxies,
the chances are way more likely that our vantage point would be just a little off-center.
We’d be discovering not O-R-Cs, but O-R-Es.
So these mystery objects are probably a new perspective
on some familiar astronomical phenomenon.
But that doesn’t mean there aren’t some more…novel ideas out there.
One duo sitting over in SciFi Hypothesis Corner
has suggested that ORCs are the throats of wormholes.
That one doesn’t seem to be taken very seriously by the broader community,
but hey, just wanted to let you know about it, because that’s cool.
The key to solving any of these mysteries is going to be more data.
Looking closely at other wavelengths, looking with even more sophisticated
radio telescopes, and looking at the data we’ve already got using new models.
In time, these astronomical UFOs may finally be identified.
And when that happens, maybe they’ll be a little less odd
than astronomers first thought.
But maybe they’ll be something entirely new.
I personally, though, would keep the name either way.
At least until we find some actual space orcs.
We don’t want things to get too confusing.
Real-life ORCs might be a little too different
from your typical fantasy creature to make for good merch.
But you know what does?
Real-life unicorns!
Over at DFTBA.com/SciShow, you can get this adorable sticker set
celebrating the one-horned animals of our actual world.
We’ve even made those horns into rainbows,
because who wouldn’t want one of those?
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