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  • You may think scientists stationed in Antarctica are just playing with penguins or studying

  • leopard seals.

  • But some of them are down there to fly balloons or watch ice cubes.

  • Special balloons and special ice cubes.

  • Like the balloon-based experiment ANITA, which has seen things we thought weren’t possible,

  • and could show us that our current knowledge of particle physics is just the tip of the

  • iceberg.

  • ANITA, short for the Antarctic Impulsive Transient Antenna, was designed to study ultra-high-energy

  • cosmic neutrinos by taking advantage of the ice sheets that blanket Antarctica.

  • Now I know you are already an expert in neutrinos because you watch all my videos, right?...

  • Right??

  • Okay then, quick refresher: neutrinos are ultra lightweight and chargeless particles

  • that almost never interact with other matter.

  • Because of those properties, they can travel through entire planets without being affected.

  • At least that’s true for the low energy neutrinos we usually talk about.

  • That variety mostly comes from atomic decay deep inside the sun act like me at a party;

  • rarely interacting with anything.

  • These are the same neutrinos we use massive tanks of ultrapure water like the Super-Kamiokande

  • detector to spot.

  • But there are other types of neutrinos, and the ultra-high energy variety is something

  • of a different animal.

  • They have widercross sectionsmeaning theyre more likely to collide with other

  • particles as they pass.

  • Theyre made during high-energy collisions like when cosmic rays and photons interact.

  • Then they zip along through the universe until they reach us here on Earth.

  • Because of that bigger cross section, they don’t penetrate very far before they interact

  • with something, causing a cascade of particles that gives off what scientists describe as

  • a “snapof radio frequencies.

  • To pick up these fairly faint signals, known as Askaryan pulses, scientists need somewhere

  • without a lot of other radio signals.

  • They also need a lot of a radio transparent medium so the high-energy particle interaction

  • can occur, but the Askaryan pulses can still propagate.

  • A medium like ice.

  • And that is why the ANITA experiment was flown over Antarctica.

  • Attached to a NASA long Duration Balloon, the antenna flew a total of four missions

  • from 2006 to 2016, staying aloft between three and five weeks at a time.

  • While it was up there it picked up the refracted radio signals coming from the ice below.

  • Scientists basically turned an entire continent into a scientific instrument.

  • That is some comic-book villain logic.

  • And it totally worked.

  • Actually, it worked so well it spotted something we can’t explain with our current particle

  • physics.

  • On multiple occasions, ANITA detected signals coming straight up from beneath it, meaning

  • in theory they must have traveled through the earth as opposed to just skimming through

  • the ice at an angle.

  • Since ultra high-energy neutrinos interact much more frequently than their low-energy

  • counterparts, they shouldn’t be able to travel through the entire Earth.

  • To double check there was no mistake, they looked through the results of another Antarctic

  • based neutrino detector, IceCube.

  • Not the rapper-turned-actor, he's not down there.

  • Making use of stable ultra-clear ice, IceCube’s sensors monitor a cubic kilometer of ice for

  • neutrino interactions starting 1500 meters below the surface.

  • Sure enough, the data revealed three other events where particles seemed to come straight

  • up from below.

  • Three detections may not sound like a lot, but mathematically it’s way more than they

  • should be seeing.

  • It shouldn’t even happen once.

  • This is potentially huge news for particle physics.

  • If we can rule out the idea that these are neutrinos that are blasting at us from one

  • specific place so intensly that the detectors can see them –– what’s called thepoint

  • source hypothesis’ –– then these can’t be ultra-high energy neutrinos at all.

  • Which means NOTHING in the standard model explains it.

  • This means it could point to other theories that could supplant or expand the standard

  • model one day.

  • But scientists aren’t ready to throw out the standard model just yet.

  • More data is necessary, so ANITA’s proposed successor, the Payload for Ultrahigh Energy

  • Observations, may continue the hunt for these inexplicable interactions.

  • The resulting data from it, and experiments like ANITA and IceCube could help tell the

  • Large Hadron Collider where to look as it searches for particles outside the standard

  • model.

  • Of course, we can’t discuss Antarctic research

  • without acknowledging the giant penguin in the room: the climate crisis.

  • Check out this episode of Focal Point about scientists creating anIce Vaultin

  • Antarctica to store glaciers’ “memoriesbefore theyre gone forever.

  • And for more stone-cold-stunning science news, subscribe, and I’ll see you next time on Seeker.

You may think scientists stationed in Antarctica are just playing with penguins or studying

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南極から噴出した「ゴースト粒子」が標準物理学を覆す可能性がある (‘Ghost Particles’ Erupting from Antarctica Could Shatter Standard Physics)

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    林宜悉 に公開 2021 年 01 月 14 日
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