00:00A vast expanse of white snow, freezing winds, lifeless landscapes, and weird, eerie signals seemingly coming from within Earth.
00:11These radio pulses occur in Antarctica, and no one can figure out what they are and where they're coming from.
00:19You see, scientists are running an experiment called ANITA, short for Antarctica Impulsive Transient Antenna.
00:25Basically, it's a bunch of detectors strapped to giant balloons and floating way up above the South Pole.
00:32Their job is to detect extremely high-energy neutrinos.
00:36How do they spot them?
00:38Right at the moment when neutrinos come into contact with ice and produce an intense, short burst of radio waves.
00:46Now, neutrinos are these tiny, almost massless particles that don't have an electric charge.
00:52They're everywhere, and billions of them are flying through you every second, even while you're watching this video.
01:00Neutrinos come from all over the place.
01:03From the Sun, exploding stars, deep space, even from under your feet.
01:09The Sun pumps them out non-stop as it fuses hydrogen into helium.
01:13Stars that are going off blast out huge bursts of neutrinos during supernova explosions.
01:19When high-energy cosmic rays hit our atmosphere, they make new neutrinos that rain down on us, too.
01:26And some even come from radioactive stuff decaying inside Earth.
01:31The oldest neutrinos have been flying through the universe since the Big Bang.
01:36But they're practically invisible, because they almost never react with anything.
01:41That's why scientists use unbelievable experiments like ANITA to try and catch even a few of them.
01:50But let's get back to that fateful day when everything changed.
01:54Normally, the radio signals produced by neutrinos bounce off the ice and fly upward.
02:00That's where ANITA can catch them.
02:02This is the whole point of the experiment.
02:06To study neutrinos and learn more about distant cosmic events, like supernovas or whatever's happening light-years away.
02:13But then something really weird happened.
02:16The detectors picked up radio waves that weren't bouncing off the ice at all.
02:20They looked like they were coming from below the horizon.
02:23From under the ice.
02:25Now, this shouldn't even be possible.
02:28According to everything we know about physics, signals can't just travel upward through solid rock and ice.
02:35One of the researchers, Stephanie Wiesel from Penn State, also said that those radio waves were coming in at super-steep angles, like 30 degrees below the surface.
02:46The only way that could happen is if the signal had passed through thousands of miles of solid rock before hitting the detector.
02:53But if that were true, the rock would have completely absorbed it.
02:57So, something just didn't add up.
03:00The team ran all the numbers and still got no clear answer.
03:03But for them, it was an interesting problem, since they didn't actually know what those anomalies were.
03:10What they did know was that they were probably not neutrinos.
03:14That's because if the team does detect a neutrino, that means it's traveled an insane distance without bumping into anything, possibly all the way from the edge of the observable universe.
03:26So, whatever Anita has picked up, it's not behaving like anything scientists have seen before.
03:32It might mean there's some totally new type of particle out there, or maybe something else is going on that we just don't understand yet.
03:39They published the findings in physical review letters, but the mystery remains unsolved.
03:45No one really knows what's going on under that Antarctic ice.
03:48Just that something out there isn't playing by the rules.
03:51Now, if scientists actually manage to detect and trace where those crazy fast particles come from, they can learn tons of stuff about the universe.
04:01Way more than even the biggest, most expensive telescopes allow us to see.
04:06You see, neutrinos basically zip through space almost at the speed of light, barely bumping into anything.
04:13It means they can carry untouched data about events that happened millions or even billions of light years away.
04:20That's why Whistle and a bunch of other researchers around the world have been building these insanely sensitive detectors to catch neutrino signals.
04:29Even the tiniest ones are super important, because in this field, one tiny blip of data can hold a treasure chest of information.
04:38So, researchers have been designing setups in both Antarctica and South America to catch these rare particles.
04:45ANITA is one of those detectors, and Antarctica's the perfect spot for it.
04:52There's hardly any radio noise, there are no cities, no traffic, and no random interference.
04:57The setup is actually pretty cool.
05:00They attach a cluster of radio antennas to a giant balloon, send it a few dozen miles up into the sky,
05:07and make it float over the endless stretches of white ice.
05:10From up there, it points downward, listening for faint radio signals coming from deep inside the ice.
05:17When one of those super-rare neutrinos, specifically a tau neutrino, hits the ice,
05:22it creates another particle called a tau lepton.
05:25That lepton then shoots out of the ice and starts breaking down, losing energy and turning into smaller bits.
05:31That decay process gives off what's called an air shower,
05:34kind of like a spray of invisible sparks flying through the air.
05:38If we could actually see those air showers with our eyes,
05:42they'd look like someone waving a sparkler through the dark,
05:45bright streaks trailing behind as it moves.
05:49Studying the direction and pattern of these signals,
05:52the ones from the ice, ice showers,
05:55and the ones in the air, air showers.
05:58Scientists can figure out where the original particle came from.
06:02Usually it's super precise,
06:04kind of like bouncing a ball off the ground.
06:07You can predict where it'll go.
06:10But these weird new signals don't bounce the way they're supposed to.
06:14The angles are all wrong way steeper than anything the models can explain.
06:19So the team dug deeper.
06:21First, they looked at all the data from ANITA's multiple balloon flights.
06:26Then they compared it against tons of computer simulations of cosmic rays and neutrinos
06:30and filtered out all the usual background noise.
06:33They even cross-checked their results with other experiments like the Ice Cube detector,
06:38which is also located in Antarctica,
06:41and the Pierre Auger Observatory in Argentina.
06:44They wanted to see if anyone else had picked up similar upward-going air showers.
06:50And guess what?
06:51Things got even weirder.
06:52They found...
06:54nothing.
06:55No other detectors had picked up anything that could explain what ANITA had seen.
06:59That's why the researchers ended up calling the whole situation anomalous.
07:03It basically means, yeah, we have no idea what this is,
07:07but it sure isn't behaving like a neutrino.
07:10Whistle explained that the signals just didn't fit into the usual picture
07:13of how particles were supposed to act.
07:16Some people have floated ideas, like maybe it's some new kind of physics,
07:20or a hint of dark matter.
07:22Dark matter is basically that invisible stuff that keeps the universe from falling apart.
07:27It's everywhere.
07:28We just can't see it.
07:29Scientists have been trying to figure out what it actually is for almost a century,
07:35and it's still one of the biggest mysteries out there.
07:38Everything we can see, like stars, planets, people, dogs,
07:42makes up only about 5% of the universe,
07:44and dark matter makes up around 27%.
07:47The rest is something even stranger called dark energy.
07:52Scientists think dark matter is what gives galaxies their shape
07:56and holds everything together like cosmic glue.
07:59Without it, the universe would look totally different.
08:03It would be totally amazing to find out that this theory is true.
08:06But since Ice Cube and Augur haven't caught the same thing,
08:10that really limits the possibilities.
08:13Penn State has been in the neutrino-detecting game for almost a decade now,
08:17building detectors and analyzing all kinds of cosmic signals.
08:20And the team is already working on their next big project,
08:24a brand new detector called Pueo.
08:26It's going to be bigger, more sensitive,
08:28and way better at spotting those elusive neutrino signals.
08:32For now, this remains just one of those long-running cosmic mysteries
08:36that keep scientists awake at night.
08:38But the team is optimistic.
08:40When Pueo goes up, it'll have better sensors,
08:43which means if there really are more of these anomalies out there,
08:47this time, they'll catch them.
08:50And maybe then, we'll finally figure out what's behind them.
08:53That's it for today.
08:56So hey, if you pacified your curiosity,
08:58then give the video a like and share it with your friends.
09:01Or if you want more, just click on these videos
09:03and stay on the Bright Side!
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