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  • 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 were 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 weve 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 theyre 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 thebig 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 you catch all the latest space news

  • 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.

Scientists just recorded the most intense electromagnetic event in the universe.

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B1 中級

這場伽馬射線爆發是有史以來最強大的能量事件。 (This Gamma-Ray Burst Was the Most Powerful Energy Event Ever Recorded)

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    林宜悉 發佈於 2021 年 01 月 14 日
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