The mysterious rays shooting at us from spaceRandall Smitham September 1, 2019 100 Comments
You may think the greatest, most perplexing
mysteries of the universe exist way way out
there, at the edge of a black hole, or inside
an exploding star.
But some of them surround us, all the time.
I can show you.
In this container, we’re going to catch
some super-fast subatomic particles that are
raining down on us from space.
They’re called cosmic rays.
And exactly where some of them come from is
part of this 100-year-old mystery in physics.
Cosmic rays are a form of radiation.
“Rays” is a misnomer — they’re actually
little bits of atoms whizzing by us, even
through us, all the time.
Every square centimeter of Earth at sea level,
including the space at the top of your head,
gets hit by one of these particles every minute.
We can’t feel them, and they don’t cause
our bodies any harm,
But they can, sometimes, do weird things:
Like make computers malfunction by messing
with their memory.
Scientists have been studying cosmic rays
since the early 1900s, when a physicist went
up in a hot air balloon and discovered the
radiation increases the higher you go — meaning
that it comes from somewhere in space.
Since then, they’ve found out ways to make
these little bits of atoms visible — like
we’re gonna do here.
We’ve built something called a cloud chamber.
Up here is felt that we’ve soaked with a
super-concentrated solution of rubbing alcohol.
And at the bottom here is dry ice which is
So when the alcohol vapor goes down to the
bottom and gets really cold — it condenses
and forms a cloud.
And when the cosmic rays come shooting in
from space — the alcohol vapor forms into
little droplets and you can actually trace
their path through the cloud.
Okay, let’s look.
I saw one!
The particles in our cloud chamber are traveling
from space at nearly the speed of light, as
are the untold others passing by you and through
you right now.
When they hit our atmosphere, the impact is
so powerful that the atoms of radiation burst
open — tearing apart in violent, cascading
That’s what we see in the cloud chamber:
atomic shrapnel that has reached the ground.
Scientists have determined that some of these
rays come from the sun’s atmosphere, in
the form of solar wind, and others from exploding
But the most powerful rays are the most puzzling
— they don’t even come from our own galaxy.
They come from some unknown source out in
The energy from the very most powerful ray
recorded had enough power to turn on a light
bulb for a second or more.
That force is comparable to a top tennis pro
hitting a ball with all their strength.
It doesn’t sound that impressive, but think
of this: all that energy is squeezed into
an area smaller than an atom.
To try to figure out what entity could be
shooting these incredibly powerful rays at
us, scientists use massive cosmic ray observatories,
with detectors not too different from our
Well… you know, they’re on a higher budget
and they’re more advanced.
One in the South Pole uses a block of ice,
a whole cubic kilometer, to track the rays
instead of vapor.
Another one in Argentina has 1,600 huge water
tanks, spread out over 1,000 square miles.
But instead of just observing cosmic rays
as they shoot by, scientists use sophisticated
technology to trace the atomic shrapnel backward.
There, they can reconstruct the original cosmic
ray that hit at the top of the atmosphere.
But confirming their source in the deep reaches
of space isn’t so easy, because these cosmic
rays don’t always travel in a straight line.
Instead, the various magnetic fields of the
universe and the galaxy, put them on
Scientists have a few suggestions.
The cosmic rays could be created in the violent
hearts of galaxies far away.
Another leading hypothesis is that they’re
not produced by exploding stars, per se, but
by bouncing around the shockwaves produced
by those explosions.
There is also the possibility that some of
the rays are produced by forces and objects
we don’t know about — or interact with
things like dark matter, in ways we don’t
Or they could come from strange objects left
over from the big bang.
I mean aliens could be shooting these at us…
but I doubt it.
What scientists need is more data, more observations
to be able to pinpoint the sources in the
sky these particles are coming from.
If scientists can figure out where the most
powerful cosmic rays come from, it means they’re
discovering one of the most powerful things
in the entire universe.
Perhaps the most powerful thing in the entire universe.
That might open up an entirely new branch
of physics, teaching us about how the universe
was formed, and about how matter can be pushed
to the extreme.
But until their origin is discovered, we can
think of cosmic rays as messengers from the
A reminder we’re a part of it, and that
there’s still a great deal of mystery out