- [Crew] So you brought us in here to tell us, after all this, that there's more we don't know? (laughs) (plucky music) - Where to start? There's been a discovery it was announced yesterday that indicates there's
potentially new physics that we don't know of. (laughs) I know it's a big statement! Fermilab in Illinois is where
this experiment was done. Have you ever heard of the standard model? Have you ever seen anything
that looks like this? - Yeah.
- Yeah? This is basically all the
particles that we know of and all the forces that we know of, electrons, protons, everything
that make over our atoms. There's evidence from this experiment that there's maybe something beyond that. This is huge because the standard model has been like, a work of decades. It comes from theory and experimentation, and one of the last particles that we had theorized from the standard model and then discovered was the Higgs Boson, which was that massive experiment at CERN. So, for there to not even
be theorized particles, you know what I mean?
- Yeah. - It's not even in our theory, it's just evidence that there's
something beyond our theory. Beyond our theory and beyond
anything we've ever seen. So, that is what this announcement means. Or potentially means. So, I say potentially because what the experiment was
that was just announced, it's not precise enough for it to be considered a big scientific announcement. Okay, so what it is is
very complicated. (laughs) Have you ever heard of a muon? No! Great, okay. But you've heard of electrons. They're in these terrible models of atoms. There are other particles
that are not as common. They are actually a lot of them, for example, the Higgs boson. Another example is neutrinos, and then another example is the muon. And the muon is, oh-- The muon was discovered in 1936 because they were looking at the way that electrons
move in a magnetic field. And then they see another
particle come through, and it has a much wider arc. And they're like, "What the heck is that?" So if you've ever heard that, if you've got just a
uniform magnetic field and you shoot a charged particle
through it, it'll curve. Have you heard of this? Okay, does it make sense? Okay, good, I'm glad I asked. What is another example of this happening? Oh, in CERN! The reason that particles
go around and around is because they're charged particles and they're going around in these big magnetic fields,
and it makes them curve. And then when they collide
and all this stuff comes off, they're watching how they
curve in a magnetic field. That's why you see all these spiral lines coming off of the collision, because if a particle has a negative
or a positive charge, it'll curve one way or the
other way in a magnetic field. If it doesn't have a charge
at all, like a neutron, it just goes straight. So you'll see those spirals, and then you'll see the straight lines. So there's these guys, and then they see another particle come through, and it has a much wider arc. Much wider means that it has more mass. So they found this particle,
they're like "What is that?" It turns out it is just
like the electrons, a lot of people call it
the cousin to the electron, but it has 207 times the mass. Oh, so that's when they
discovered the muon. If you had a bunch of muons instead of electrons in your atoms, you would be way heavier. I don't know how much heavier. Um, okay so! The measurement that
was just made was that-- Ugh, this is the part where
it's going to get really tricky. You know how a top that's spinning will kind of wobble around? If the top were in space,
it wouldn't do that. It would just spin, it wouldn't wobble. The reason that it's wobbling is because it's spinning in a gravitational field, and gravity is having an effect on the top and making it wobble. Can you accept that? Good, 'cause I don't want to go in-- Similarly, there's another really complicated property of
particles called spin. It's not like the particles
actually spinning, it's just a property, but when you put a particle
with magnetic magnetic spin in magnetic field, it'll
wobble in a similar way. The amount that it would wobble is something that we can predict. Say that the amount of
wobble is supposed to be two. The amount it's supposed to wobble is called the G factor, and the theoretical number is supposed to be two for the muon. Now there's something else
weird that we've theorized, which has that the wobble
should also be affected by (laughs) something that people call quantum foam. Have you heard of the idea that there are constantly particles popping in and out of existence in the vacuum of space? Yeah, okay. So those particles popping in and out--- When that happens, they can
interact with a particle, a real particle that exists like a muon, and then they can affect that wobble. I know that this is getting to the point where it's like, okay, what is the point of all of this? We've got quantum foam
effecting the wobble, but we're almost there. And we have a number for that, and it's like, it's close to the two. It's like 2.00, and then
there's this added correction, 2, 3, 3, 1 8 3 6 2 0. 8,6 and the eight six in
parentheses for the error. Now that's obviously a very precise, theoretical measurement. 12 digits of precision
that we think we know, the theoretical amount of
the effect of the wobble from the quantum foam. They did a measurement of the G factor, of the amount of wobble, and they saw it didn't match the theoretical number. So it didn't match it by... Tn the last four digits
of that 11 digit you saw, instead of 3, 6, 2 0,
you saw a 4, 1, 2, 2. - [Crew] So does this already mean that the foam is not causing it? - No, it doesn't mean that
the foam is not causing it. It means that there's probably particles that we don't know of or
forces we don't know of. Because we have such a precise idea of how the wobble should change based off of known particles, and how we know they
pop up into existence. So, if we measure something different, most likely it must be that
the physics is different. - [Crew] So you brought
us in here to tell us, after all this, that there
is more we don't know? (laughs) The newest discovery in physics, we might know less than we thought! - But it's, it's the way that we don't know more that's important! - [Crew] Physicists. - It's not like, "Oh, we don't know what happened before the big bang." It's like, no, we're seeing evidence for something specific to go look for. Right here's the moment
when physicists are like, "Oh my God, let's go
look for new particles! Let's go look for new forces." Okay, maybe it's not that important to you to go look for new particles, but have you seen CERN, it's huge! Like that entire experiment was looking for one new particle. - [Crew] I wonder what they're going to do to look for what's making that change. - I know, I know! There's nothing specific to look for yet because it doesn't fit our theories! Like, when we looked for the Higgs boson, it was part of the standard model theory. Yeah, it was like, there's
the Higgs right there. Here's a grayed-out box of a
particle we have a theory for, and then we discovered it and like, boop! Fill that in with a color. But we're seeing an anomaly. We're seeing something
act differently than we ever predicted before. - [Crew] It's like
winning a bingo and then someone's like, look, a alphabet. - Or it's like winning at bingo, and then you get another bingo card. Bingo plus! - [Crew] Yeah, that's pretty crazy. It doesn't fit the standard model. - I know! So it could be new particles, new forces, or something wrong about
our current theory. But we know so much
about our current theory, and so many of our very expensive, very precise experiments
have verified what we know. So for the idea that some of
it to be wrong is almost as inconceivable as for
there to be new particles and new theories, which is also
inconceivable at this point. But yeah, it's exciting. - [Crew] How come they're confident there's something really big to find? Why can't it just something
they haven't thought of? Anything magnetic on earth? Where we are, our place in the galaxy? - So one reason that they're
confident about this result is that it was done before, in 2001. So it was originally done
in Brookhaven National Labs in 2001, and it was such
a big result at the time that they're like, "We
have to verify this." And so they took the big ol' magnet, a big superconducting magnet, 50 foot in diameter, here it is. See that red thing? That's the magnet arriving at Fermilab to a big party and a big celebration because it was transported
3,200 miles to upgrade it. I went to Fermilab in 2016, and the only picture I took besides like, oh, this is a pretty
view down the building, was of this diagram that shows the path that the magnet took. So this is not technically
a discovery yet. And the reason I said that is because you need a certain amount of certainty. You need a certain certainty to consider a scientific announcement as like, an actual discovery. And you need it to be
something called Five Sigma, which is just like, a statistical amount. The exciting thing is that they
verified a result from 2001, But, again, normally, and rightfully, five Sigma is the amount of certainty that you usually need to make
this type of announcement. So, since they're only at 4.2 Sigma scientists are being
careful and saying like, "Yes, this is exciting. We verified a result from
a previous experiment, so that's promising, but it's not promising enough because we don't have enough certainty." They're going to keep it here, and they're going to
upgrade the experiment for future runs get more precision. The chance that this measurement
is a random fluctuation, like a random statistical error in the measurement is one in 40,000. Like not enough that I
would bet my life on, but-- - [Crew] These are usually
so small or so big, that's like, weirdly a normal number. Physicists are usually talking about like the billions or the quantum. - Right, right right right. We know enough of that to make a good enough prediction of what the change in this little
wobble, G factor, should be, and we see something different. That's it! Big announcement. Yay, okay. And cut. So actually, when I
was doing my experiment looking for dark matter in college, when we first turned it on, one of the first things we saw was a muon. PI, the person running
the experiment, was like, "Oh, see that blip, that signal? That's a muon." We just detected these cosmic ray muons, which are these particles raining down. - [Crew] That device, was
it used to detect muons? - We were making a detector
that was looking for actually neutrons. All of these are just different particles. And the device was like this, I'm making it this big,
but it was actually like-- I dunno, what's here to here, ten feet? In this big chamber full of
this fluid called scintillator. It's a really cool fluid,
because if you just like, barely look in there,
you see a little glow. So a particle will come
through this scintillator and they'll cause it
to glow along the path. And then we had detectors on either end that would capture the light, and so you'd see, oh, a
particle came through. Cause we got a little
bit of blip of light, which meant that something
came through our scintillator. That's how the detector worked. So we turned it on, and we were like, we got a little flash of
light, that's probably a muon. We just saw a cosmic ray muon. Any more questions? Okay. The other really cool thing
that muons were used for was to verify one of the predictions of special relativity from Einstein, specifically time dilation. And this was a long time ago, 1941. Have you heard of time dilation? The basic idea is that if
we were moving really fast, like if I was jetting
through the universe, then time would tick slower
for me, which is cool. There's a lot, I mean,
there's a lot more to it. Basically time ticks differently depending on whether you're moving or not. If you went and traveled around the earth a bunch of times in a
really fast rocket ship and came back, you would have aged less than I would have aged. That was a prediction of relativity, but not verified until later. And one of the verifications was this really cool experiment. The thing about muons is that they don't live very long. They have a mean lifetime
of 2.2 microseconds. But there are a lot of them, constantly raining down on us, because a lot of them are
produced when cosmic rays come from the universe and
they hit our atmosphere. Imagine you can measure
how many muons there are, like go up on top of a
hill and measure how many are coming through a little area, and then go down to the
bottom of the mountain, and you know how fast these
muons are supposed to decay. So you should go to the bottom and you should only see a certain number, because the rest of them
should have decayed. But what happened is they
saw more at the bottom than they should have,
more were surviving. But what that means is that, because these muons are going so fast time is ticking slower for them. They're actually not decaying because they haven't reached that mean lifetime. So that was a verification of this idea of relativity. Does that make sense? - [Crew] I read Ender's Game.
(laughs)
Thank you for posting this! She explained it in a very entertaining and interesting way
I feel both smarter & dumber after watching this.
Sweet Dee went to college.