Have you ever tried to listen to your favorite radio station only
to find it garbled or replaced by a different station?
Well if so, you might’ve been the victim of something known as
a “Sporadic-E Layer.” They’re concentrations of electrically
charged gas called plasma in a region of space known as the
ionosphere.
They act kind of like mirrors in the sky, and bounce radio
transmissions over the horizon and interfere with your radio,
kind of like two people trying to talk over each other.
Even though we’ve known about these layers for over 80 years
now, we still don’t fully understand them because they
occur at an altitude that is really difficult to explore.
The air there is so thin that we can’t fly an aircraft, but it’s
just thick enough that if we were to try to orbit a satellite
it would burn up in the atmosphere.
So we’ve only ever been able to explore a handful.
Well, one planet where the atmosphere is much thinner is
the planet Mars.
And one satellite that is currently exploring Mars is the
MAVEN orbiter.
One of the instruments on MAVEN is called STATIC.
It’s designed to measure plasma escaping from the ionosphere,
this upper atmospheric layer of Mars.
And in the data, scientists were seeing that when MAVEN would fly
through a certain region of the atmosphere, POOF!
There was this big density enhancement of this plasma
concentration.
Scientists realized that they had discovered the Martian
equivalent of these layers!
It’s exciting because now we have a place that we can go to
directly explore these layers with a satellite.
MAVEN has encountered more of these layers at Mars than we’ve
ever been able to explore here at Earth.
At Earth, the layers are temporary and unpredictable, but
at Mars they seem to be almost permanent and long-lived at
predictable locations.
Also, scientists found something that they didn’t even know could
exist.
MAVEN discovered the opposite of a layer.
They’re calling it a “rift” and it’s where the sky has been
pulled apart.
And rather than a concentration of this plasma, there’s a
depletion.
Many models said this actually couldn’t happen, but yet they do
exist and we find them at Mars.
This demonstrates how little we actually know, and how much
there still is to discover.
These layers are so common – they happen over our heads all
the time.
You yourself have probably detected one of these with your
own radio, even if you weren’t aware of it.
And who would’ve thought that one of the best ways to explore
them would be to send a spacecraft 300 million miles to
the red planet.
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