Placeholder Image

字幕列表 影片播放

  • 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

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級

南極洲爆發的 "幽靈粒子 "可能會打破標準物理學。 (‘Ghost Particles’ Erupting from Antarctica Could Shatter Standard Physics)

  • 5 0
    林宜悉 發佈於 2021 年 01 月 14 日
影片單字