Scientists just recorded the most intense
electromagnetic event in the universe.
We now have on record the highest energy photons
ever observed.
And it turns out, this may be able to tell
us something about how these events could
have shaped life on Earth so far... and just
how fried we would be if one happened nearby.
These incredibly intense events are called
gamma ray bursts, or GRBs for short, and are
considered the most energetic explosions in
our universe.
Gamma radiation is a kind of electromagnetic
radiation, and we’re looking out in space
for gamma rays in general, because they result
from all kinds of the most spectacular and
cataclysmic cosmic events out there: like
celestial bodies crashing into each other,
or matter getting sucked into black holes,
or stars exploding.
GRBs in particular can result from two things:
long GRBs are from star deaths, and short
GRBs are from collisions between things like
neutron stars.
A GRB from an exploding star is what scientists
think they've recently measured with the Major
Atmospheric Gamma Imaging Cherenkov Telescopes,
or MAGIC.
Two NASA satellites observed the GRB, and
told MAGIC to turn its eyes in that direction.
Then, more detailed observations of the radiation
itself were recorded by other observatories,
including the Hubble Space Telescope.
It was an awesome space-tool collaboration
to try and measure this event from as many
angles as we have.
Which is important, because events like this
release a huge stream of energy when the star
dies, before it decays into a neutron star
or a black hole.
And this most recent star explosion in particular
went out with quite a bang: photons from this
event carried one trillion electronvolts of
energy.
That’s the record for most energy of any
GRB we’ve ever recorded.
And this event is actually the only gamma
ray burst that has ever been recorded by MAGIC,
or any other earth-bound telescope.
See, high energy radiation like gamma rays
is absorbed by our planet’s atmosphere.
Which is good for us, because it keeps us
safe from that radiation, but bad for observing
exciting events like this.
So our understanding of GRBs so far has been
pretty limited.
Scientists have theorized that gamma ray bursts
this powerful were possible, but evidence
of that guess had never been observed until
now.
And honestly, the energy from this GRB has
kinda blown our minds.
Observations from the most recent GRB, and
a slightly less energetic one recorded in
2018, have opened up a whole new cosmological
door for us.
Because we hadn’t observed GRBs of this
magnitude before, we previously hadn’t been
able to tell how all of this crazy energy
is created during the death of a star.
So these new observations have confirmed one
of the prevailing ideas: shock waves from
the star’s explosion speed up electrons
that are already being emitted by the dying
star, accelerating them to nearly the speed
of light, which in turn generates magnetic
fields.
Those magnetic fields cause those super high-energy
electrons to interact with photons that are
being generated and launches those super high-energy
photons out into the rest of the universe.
That electron-photon energy interaction is
something called "inverse Compton scattering."
Thanks to evidence from these new observations,
scientists now have pretty strong evidence
that this could be what gives some of these
GRB events their extreme energy.
Uncovering new details about GRBs and what
they’re capable of may seem like some abstract
thing happening out in space, but this work
could actually have an effect on our lives
here on Earth.
The amount of energy released in the latest
GRB in the span of just a few seconds is equivalent
to all of the energy our Sun will release
over its entire 10-billion-ish year lifespan.
Which seems pretty relevant, especially because
scientists think that a gamma ray burst may
have been behind the Ordivician mass extinction
450 million years ago, one of the ‘big five’
extinction events that totally wiped out biodiversity
on earth.
And thanks to radiation signatures recorded
in the rings of a few ancient trees, it’s
thought that a GRB may have struck earth as
recently as the eighth century!
So while astronomers are keeping a close eye
on all of the nearby likely candidates, they
don’t think that any are likely to blast
us any time soon.
But it does still put learning more about GRBs
and how they work into pretty sharp relief.
Seems like an important thing to do.
If you want even more on surprisingly energetic
events out in space, check out this video
here, and subscribe to Seeker to make sure
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as it breaks.
If you have another recent space discovery
you want to see us cover here on the channel,
let us know down in the comments below and
as always, thanks for watching.
I’ll see you next time.
