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Despite how we normally talk about it, space
is anything but an empty vacuum:
The Sun is, for example, constantly shooting
out
streams of charged particles and other radiation
that interact with Earth.
It’s kinda like space weather, and just
like regular weather, it gets a little dangerous.
Like, solar flares throw out huge amounts
of high-energy radiation,
which can damage electronics and threaten
astronauts in space.
So, being able to predict the next big flare
is a huge goal for researchers.
And last month in the journal Science,
one team published a model that might actually
be able to do it.
The exact process that causes solar flares
is still a bit of a mystery,
which is why it’s been so hard to predict
them.
But we know it has something to with the Sun’s
magnetic field.
To be a little more specific, the lines of
its magnetic field sometimes get all tangled up.
And to straighten themselves out, they break
and reconnect.
This is officially called magnetic reconnection.
And according to this team of scientists in
Japan,
a certain kind of magnetic reconnection might
go on to produce a flare.
It requires two loops in the magnetic field
to be close enough and roughly aligned with
one another.
If something comes along and disturbs them,
the loops can get tangled and reconnect to
form a bigger loop shaped like the letter M.
Or what the authors call a double-arc instability.
As that loop grows upward, it triggers more
magnetic reconnections below it.
Then, those field lines move upward, triggering
another reconnection, and so on.
It’s a positive feedback loop that stores
a bunch of energy.
And that energy eventually gets released as
a solar flare.
Now, the key is, that instability only seems
to form at boundaries where
the Sun’s magnetic field switches polarity,
positive on one side, negative on the other.
In other words, what we might call the north
pole swaps sides.
Also, the magnetic field above the area, in
the Sun’s atmosphere,
has to be weak enough for this runaway feedback
loop to happen.
So, the hypothesis is: If you monitor the
instability of the magnetic field at these boundaries,
and if you monitor the strength of that instability
compared to the magnetic field above it...
...you can predict when and where a solar
flare will happen, and how strong it will be.
The team didn’t just leave it at that, though:
They also built a model to run on a supercomputer.
Then, they tested it, looking at data collected
by
NASA's Solar Dynamics Observatory between
2006 and 2019.
The data covered roughly 200 active regions
of the Sun’s surface.
And seven of them produced nine powerful flares.
For the most part, the model was able to predict
that
these flares would happen with up to about
20 hours of warning.
That would be enough time for astronauts and
electric companies to start preparing.
Of course... it also predicted three flares
that never happened, and it missed two that did.
But in its defense, those two were not normal
flares:
They didn’t come with the massive plasma
ejection that usually comes with solar flares.
They may have also originated far above the
Sun’s surface,
and the team admitted that their model doesn’t
work as well up there.
Still, some of the previous methods we’ve
used to predict solar flares
have done worse than a computer making random
guesses.
So, if testing confirms that this new model
at least mostly works,
it’ll be our first real, predictive tool.
Our next story takes us out of the solar system
and into the center of the Milky Way.
Last week in the journal Nature, astronomers
reported that
our galaxy is farting blobs of cold gas, and
they haven’t the foggiest idea why.
Now, these weren’t the exact words used
in the paper, I’m summarizing it.
A decade ago, astronomers found two huge bubbles
coming from the center of the galaxy, filled
with plasma, hot gas, and gamma radiation.
They’re called Fermi Bubbles, and they stretch
roughly
30,000 light-years above and below the Milky
Way’s disk.
But it’s not clear what’s making them.
Maybe it’s nearby star formation, or maybe
it’s the galaxy’s supermassive black hole.
And now, there’s even more of a mystery.
Using the Atacama Pathfinder Experiment based
in Chile,
a team was studying two hydrogen gas clouds
within the Fermi Bubbles.
And they spotted something weird: cold blobs
of carbon monoxide gas. And big ones.
They measured a few light-years across and
weighed in at around 380 Suns each, at minimum.
And it’s a complete mystery how they got
there.
To fling such dense, cold gas out of the center
of the galaxy,
the supermassive black hole would need to
be radiating a lot more energy than it is now.
Or the rate of star formation would need to
be a lot higher to create enough of a stellar wind.
That’s the stream of particles that stars
send out as space weather.
Still, one thing we do know is that some of
this gas is escaping the galaxy.
The team estimated that the amount comes out
to
around a tenth the mass of our Sun each year.
That might not sound like much,
but it’s enough to significantly affect
how many stars can form.
So, learning more about these cosmic blobs
could help us understand more about how the
center of our galaxy will change.
Also, although we don’t know why this is
happening,
scientists have seen something similar in
distant, more massive galaxies.
And since we now have a version of this on
our cosmic doorstep,
it’ll be easier to study and learn more
about how those galaxies change over time, too.
So, not bad for some cosmic fart bubbles.
Thanks for watching this episode of SciShow
Space News!
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