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  • [Sun] Flares to full!

  • [Earth] SHIELDS UP!...

  • HA!

  • [Sun] FIRE EVERYTHING!

  • [Earth] There's a crack in the shields!!

  • WHAT DO WE DO?!

  • Hey sunny dispositions, Trace with Julian for DNews.

  • The Sun and the Earth are in a constant battle, thanks to the Sun's tendency to be an unfathomably

  • large mass of incandescent gas...

  • Yes, absolutely, it's a gigantic nuclear furnace where hydrogen is built into helium...

  • At temperatures of millions of degrees!

  • But as a resultthe sun is constantly releasing highly energized particles blasted away from

  • these nuclear reactions.

  • Mostly these particles are protons and electrons with some alpha particles (the nuclei of helium),

  • and heavier charged particles thrown in like the nuclei of magnesium, sulfur, iron, neon,

  • carbon, and titanium among others.

  • Sometimes, the sun gets excited and releases a mass of superheated, charged plasma -- called

  • a coronal mass ejection or CME.

  • We've talked about them before.

  • They're crazy.

  • And that's when the Earth's magnetosphere is really challenged.

  • These CMEs can be strong enough to damage satellites, force airplanes to change course

  • to avoid them, disrupt electronics on the ground, and force astronauts to stay in the

  • shelter of the International Space Station.

  • The main thing stopping those pungently radioactive, highly charged particles from hitting you

  • and me on top of the head, is the Earth's trusty magnetic fieldgenerated by the

  • movement of iron through our mantle.

  • The magnetosphere works like a shield, protecting us from harmful CMEs and other charged particles,

  • but our shield system has a crack in it!

  • That's right, new research from the GRAPES-3 muon telescope reads like a battle report

  • from Star Trek.

  • Trace's Log, Stardate: June 22, 2015.

  • A plasma ejection from the sun struck the planet at 2.5 million kilometers per hour.

  • The energetic collision caused a compression of the magnetosphere between 2 and 5.5 times

  • the width of Earth itselfcausing magnetic storms and radio blackouts all over the planet.

  • We suspect the Romulans are involved.

  • No we don't.

  • Trace out.

  • Okay, lemme 'splain.

  • A muon telescope is a cosmic ray detector.

  • It's designed to keep an eye on cosmic rays breaching the magnetosphere -- it's looking

  • for cracks.

  • And it found one.

  • The magnetosphere is powerful, but not perfect.

  • According to the data, published in Physical Review Letters, the GRAPES-3 spotted a 20

  • giga electron volt collision with the magnetosphere and then some leakage!

  • A CRACK IN THE FIELD!!!

  • REVERSE THE POLARIZATION!

  • Sorry.

  • For perspective, the Large Hadron Collider, the world's most powerful particle accelerator

  • can hit a top energy of about 26 GeV when accelerating only few protons at a time.

  • This solar assault lasted for 2 hours at 20 GeV and coronal mass ejections are filled

  • with plasma stretching half the distance from Earth to the sun.

  • Luckily for us down here under the shield, it deflected the burst of solar plasma

  • But CMEs aren't the only thing attacking Earth at any given moment -- there are also cosmic

  • rays.

  • To keep up the Star Trek references, the Sun is likethe Romulan Fleet, but cosmic rays

  • are more like a few shuttlecraft or escape pods.

  • They're from other galaxies, black holes and the like, and while they're few, they are

  • also constantly trying to leak down to us

  • This is where the "crack" comes in.

  • When the CME assaulted the magnetosphere at such high energy, our field deflected it.

  • But while it did that, some low-energy cosmic radiation leaked through!

  • At that point, the energy was likely absorbed by molecules in our atmosphere before it hit

  • you or me.

  • In fact, the muon detector doesn't directly detect cosmic rays or coronal mass ejections

  • at all.

  • Instead, it detects muons -- subatomic particles -- that are created when cosmic rays hit the

  • molecules of air in our atmosphere!

  • So GRAPES-3 detected this burst of activity (the crack) that normalized after the CME

  • ended; shield integrity is nominal.

  • Even though we're okay down here, astronauts on orbit are less so.

  • People in space are bombarded with cosmic rays!

  • Unlike some larger energetic particles of a CME, cosmic rays can penetrate the walls

  • of the ISS (and the astronauts inside).

  • There's even a name for when one flies through an astronaut's eyeball...

  • It's called Cosmic Ray Visual Phenomena -- and the ray basically causes the rods and cones

  • to activate, creating a sparkle or spot.

  • Astronaut Don Pettit describes it like "dancing faeries."

  • Of course, long term exposure to cosmic rays, like on a trip to Mars, could cause permanent

  • damage to brain cells.

  • Not good.

  • Luckily for us, the mantle keeps turning under our feet, generating our magnetosphere shield,

  • and keeping us safe from both CMEs and cosmic raysand from brain damage.

  • Mostly.

  • Mostly.

  • Worried about radiation messing with your brain?

  • Find out how exactly this invisible thing affects your DNA here.

  • What's your favorite Star Trek episode?

  • Tell us in the comments and please make sure to subscribe for more DNews.

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B2 中高級 美國腔

地球的磁屏蔽破裂,我们注定要失败吗?(The Earth's Magnetic Shield Cracked, Are We Doomed?)

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    joey joey 發佈於 2021 年 04 月 28 日
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