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A New Clue in the Search for the Universe’s Missing Mass · The Quark Side - Quantum Physics Podcast

• 0:01
  Speaker 1: Welcome to the Quarkside Quantum Physics Podcast, an exploration of
• 0:05
  Speaker 1: the fundamental structure of reality, where quantum laws govern matter, energy,
• 0:11
  Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
• 0:16
  Speaker 1: and understanding begins at the smallest scales.
• 0:27
  Speaker 2: Imagine putting everything in the known universe on a giant
• 0:31
  Speaker 2: cosmic scale.
• 0:32
  Speaker 3: Right.
• 0:32
  Speaker 2: Like you load up all the stars, all the black holes,
• 0:35
  Speaker 2: the planets, the device you are listening to this on
• 0:38
  Speaker 2: right now, even the air in the room around you.
• 0:40
  Speaker 3: Everything we know.
• 0:41
  Speaker 1: Everything.
• 0:42
  Speaker 2: Now imagine looking at the readout on that scale and
• 0:45
  Speaker 2: realizing that 85% of the weight is just completely unaccounted for.
• 0:50
  Speaker 3: It really boggles the mind when you frame it like that.
• 0:53
  Speaker 2: I mean, I want you to really just sit with
• 0:55
  Speaker 2: that for a second. Everything we have ever seen, studied,
• 0:58
  Speaker 2: or interacted with is just a tiny floating fraction of reality.
• 1:03
  Speaker 2: The vast majority of the universe is made up of
• 1:05
  Speaker 2: a substance that physically surrounds us, that literally holds entire
• 1:09
  Speaker 2: galaxies together. But we can't see it. We can't touch it.
• 1:13
  Speaker 2: And for decades, we've had no idea what it really is.
• 1:17
  Speaker 2: We are basically holding a ghost, and we just call
• 1:20
  Speaker 2: it dark matter.
• 1:21
  Speaker 3: It truly is the ultimate cosmic mystery. You know, it's
• 1:24
  Speaker 3: this incredibly humbling reminder of just how much we still
• 1:28
  Speaker 3: have to learn.
• 1:28
  Speaker 2: Right.
• 1:29
  Speaker 3: Because we know this ghost has to be there, due
• 1:31
  Speaker 3: to the gravitational pull it exerts on the things we
• 1:33
  Speaker 3: can't actually see. Like, if you look at how fast
• 1:36
  Speaker 3: galaxies spin, the math simply doesn't work without it.
• 1:39
  Speaker 2: They spin way too fast, right?
• 1:41
  Speaker 3: Exactly. Without the massive gravitational glue of dark matter holding
• 1:44
  Speaker 3: everything together, those galaxies would just, well, spin apart and
• 1:48
  Speaker 3: fly off into the void. But because it doesn't interact
• 1:51
  Speaker 3: with light or regular matter in any way we've been
• 1:54
  Speaker 3: able to easily measure, it has just remained entirely hidden
• 1:57
  Speaker 3: from us.
• 1:58
  Speaker 2: Okay. Let's unpack this because today we are exploring a
• 2:02
  Speaker 2: massive paradigm shift in how astrophysics approaches that hidden universe.
• 2:08
  Speaker 2: We are moving past the old comfortable assumptions about what
• 2:11
  Speaker 2: this ghost might be. Instead, we're examining a completely mind-bending
• 2:16
  Speaker 2: new theory that was recently put to the ultimate test
• 2:19
  Speaker 2: in this massive underground laboratory.
• 2:21
  Speaker 3: It's a huge pivot.
• 2:23
  Speaker 2: It really is. I mean, for decades, scientists have been
• 2:25
  Speaker 2: tirelessly searching for a single, simple grain of invisible sand.
• 2:30
  Speaker 2: But what if we've been failing to find it because
• 2:33
  Speaker 2: we should have been looking for an entire invisible sandcastle.
• 2:36
  Speaker 3: That analogy, oh, it perfectly captures the shift in thinking
• 2:40
  Speaker 3: happening right now in the global physics community.
• 2:42
  Speaker 2: The sandcastle versus the grain of sand. Exactly.
• 2:44
  Speaker 3: For the longest time, the search was entirely focused on
• 2:47
  Speaker 3: looking for that one fundamental grain of sand. But to
• 2:51
  Speaker 3: understand why this new sandcastle theory is so revolutionary, we
• 2:54
  Speaker 3: first have to understand the really rigid conceptual box that
• 2:58
  Speaker 3: physicists have been trapped in for years.
• 3:00
  Speaker 2: Let's define that box for the listener then. Up until
• 3:03
  Speaker 2: very recently, the status quo in astrophysics was essentially this.
• 3:07
  Speaker 2: Dark matter doesn't interact with radiation, meaning it doesn't absorb
• 3:11
  Speaker 2: or emit light.
• 3:12
  Speaker 3: Right.
• 3:12
  Speaker 2: It doesn't interact with regular matter. The only way it
• 3:15
  Speaker 2: affects the universe is via gravity. And for a long time,
• 3:19
  Speaker 2: the two most prevalent theories to explain what it actually
• 3:22
  Speaker 2: was were things called axions.
• 3:24
  Speaker 3: Which act almost like an incredibly light invisible wave. Right.
• 3:28
  Speaker 2: And another candidate called WIMPS, which stands for Weakly Interacting
• 3:31
  Speaker 2: Massive Particles.
• 3:33
  Speaker 3: Yes, axions and WIMPS have been the absolute heavyweights of
• 3:36
  Speaker 3: theoretical physics for a long time. And while they are
• 3:39
  Speaker 3: very different concepts mathematically, they share one absolutely foundational assumption.
• 3:44
  Speaker 2: Which is?
• 3:45
  Speaker 3: They both assume that dark matter exists entirely as elementary particles.
• 3:50
  Speaker 2: Meaning they are the absolute smallest possible building blocks of nature. Like,
• 3:54
  Speaker 2: you just can't break them down any further.
• 3:56
  Speaker 3: Precisely. If you think about regular matter, the stuff we
• 4:00
  Speaker 3: are made of, an atomic nucleus is not an elementary particle.
• 4:03
  Speaker 2: Right, because you can split an atom.
• 4:06
  Speaker 3: Exactly. You can break a nucleus down into its constituent
• 4:09
  Speaker 3: protons and neutrons, and you can break those down even further.
• 4:13
  Speaker 3: But the standard assumption for dark matter was always that
• 4:15
  Speaker 3: it was just one singular, unbreakable dot.
• 4:19
  Speaker 2: Wait, I have to jump in here, because... Thinking about
• 4:22
  Speaker 2: this logically, why would scientists assume that? I mean, the
• 4:27
  Speaker 2: 15% of the universe that we can actually see is
• 4:30
  Speaker 2: absurdly complex. We have protons and neutrons binding together to
• 4:34
  Speaker 2: make an entire periodic table of wildly different chaotic elements.
• 4:40
  Speaker 2: Why on earth did physicists just assume that the other
• 4:43
  Speaker 2: 85% of the universe had to be one basic unbreakable particle?
• 4:48
  Speaker 2: That just feels incredibly limiting.
• 4:51
  Speaker 3: It is limiting, for sure, but you have to remember
• 4:53
  Speaker 3: how physics traditionally operates. Simplicity is standard practice when you
• 4:58
  Speaker 3: are charting the unknown.
• 4:59
  Speaker 2: Like Occam's razor.
• 5:01
  Speaker 3: Exactly. It's Occam's razor applied to quantum mechanics. When you
• 5:04
  Speaker 3: are dealing with something you can't see or measure directly,
• 5:07
  Speaker 3: you start by building the simplest possible mathematical model. You
• 5:11
  Speaker 3: don't assume a complex system of interactions until the universe
• 5:15
  Speaker 3: actually forces you to.
• 5:17
  Speaker 2: I guess that makes sense.
• 5:18
  Speaker 3: But this raises an important question today. Because decades have
• 5:22
  Speaker 3: gone by. Extensive, incredibly well-funded searches for these simple axions
• 5:27
  Speaker 3: and WIMPs have completely eluded detection. We haven't found a
• 5:31
  Speaker 3: single one. So the universe is finally forcing our hand.
• 5:35
  Speaker 2: So the failure to find that simple grain of invisible
• 5:38
  Speaker 2: sand means we have to radically rethink everything. Which brings
• 5:42
  Speaker 2: us to the alternative idea that is being spearheaded by
• 5:45
  Speaker 2: Jocelyn Monroe at the University of Oxford. Ah, yes. Alongside
• 5:48
  Speaker 2: this huge network of collaborators. Yes.
• 5:51
  Speaker 3: And it's a fascinating approach.
• 5:52
  Speaker 1: Yeah.
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  Speaker 2: So about a decade ago, they proposed this idea, this
• 5:57
  Speaker 2: theory that honestly sounds almost like science fiction. They suggested
• 6:01
  Speaker 2: that dark matter might actually have its own nuclear physics.
• 6:05
  Speaker 3: It's a brilliant pivot and highly, highly necessary pivot in
• 6:10
  Speaker 3: how we view the cosmos. So under this theory, we
• 6:13
  Speaker 3: aren't looking for like single isolated elementary particles anymore. Right. Instead,
• 6:18
  Speaker 3: the idea is that in the incredibly dense chaotic environment
• 6:22
  Speaker 3: of like the very, very early universe, these tiny dark
• 6:25
  Speaker 3: particles crashed into each other and they bound together much
• 6:29
  Speaker 3: like our own protons and neutrons did. Okay. So they
• 6:32
  Speaker 3: formed massive composite objects, what physicists are now calling dark nuclei.
• 6:37
  Speaker 2: And we aren't just talking about two or three particles
• 6:40
  Speaker 2: clumping together here, right? This theory suggests these ultra-heavy composite
• 6:44
  Speaker 2: particles could potentially contain billions or vastly more microscopic constituents
• 6:49
  Speaker 2: all bound together into one massive structure.
• 6:52
  Speaker 1: Exactly.
• 6:53
  Speaker 2: But let me push the implications of this because here's
• 6:55
  Speaker 2: where it gets really interesting. If dark matter has its
• 6:59
  Speaker 2: own nuclei and it binds together, are we talking about
• 7:02
  Speaker 2: the potential for literal dark atoms? Could there be an
• 7:05
  Speaker 2: entirely invisible periodic table of dark elements floating around us
• 7:09
  Speaker 2: right now?
• 7:10
  Speaker 3: That is the staggering implication, yeah. If dark matter can
• 7:13
  Speaker 3: bind together, then dark chemistry is a very real possibility.
• 7:16
  Speaker 2: Wow.
• 7:17
  Speaker 3: What's fascinating here is how fundamentally this changes the target
• 7:20
  Speaker 3: for experimental physicists. If you are hunting for a tiny,
• 7:24
  Speaker 3: single wimp, you build a detector designed to catch a
• 7:27
  Speaker 3: microscopic point.
• 7:28
  Speaker 2: Makes sense.
• 7:29
  Speaker 3: But if you are suddenly hunting for a massive, dark
• 7:32
  Speaker 3: nucleus made of billions of constituents, your old tools are
• 7:36
  Speaker 3: completely useless. You cannot use a net designed for minnows
• 7:39
  Speaker 3: to catch a whale.
• 7:40
  Speaker 2: Right. So if the target just went from a microscopic
• 7:43
  Speaker 2: minnow to a massive whale, how do you even begin
• 7:46
  Speaker 2: to build a net for something that big?
• 7:47
  Speaker 3: You have to sit down and mathematically figure out how
• 7:50
  Speaker 3: a massive dark nucleus would actually behave if it passed
• 7:53
  Speaker 3: through a physical detector here on Earth.
• 7:54
  Speaker 2: Okay.
• 7:55
  Speaker 3: That theoretical groundwork is what led to the formation of
• 7:58
  Speaker 3: a major international network of physicists known as the Dark
• 8:01
  Speaker 3: Side Collaboration.
• 8:02
  Speaker 2: First of all, the Dark Side Collaboration is just an
• 8:05
  Speaker 2: incredible name for a physics team.
• 8:07
  Speaker 3: It really is.
• 8:08
  Speaker 2: But let's look at the trap they actually built to
• 8:10
  Speaker 2: catch this ghost. Because the engineering scale here is wild.
• 8:15
  Speaker 2: We are talking about the DarkSide 50 experiment.
• 8:17
  Speaker 3: It's an incredible feat of engineering. The DarkSide 50 detector
• 8:21
  Speaker 3: operated from 2013 to 2020. And they couldn't just build
• 8:24
  Speaker 3: this in a standard university laboratory.
• 8:26
  Speaker 2: No, they had to go underground.
• 8:29
  Speaker 3: Way underground. It was housed deep at the Laboratorio Nazionale
• 8:33
  Speaker 3: del Gran Sasso in Italy, which is the world's largest
• 8:36
  Speaker 3: underground research facility.
• 8:38
  Speaker 2: Why do you have to put a dark matter detector
• 8:39
  Speaker 2: deep inside a mountain, though? Why not just build a
• 8:42
  Speaker 2: really thick lead box in a basement somewhere?
• 8:45
  Speaker 3: Because the surface of the Earth is just constantly being
• 8:47
  Speaker 3: bombarded by cosmic rays. High energy particles from exploding stars
• 8:51
  Speaker 3: and solar wind.
• 8:52
  Speaker 2: Oh, right.
• 8:53
  Speaker 3: If you put a sensitive detector on the surface, those
• 8:56
  Speaker 3: cosmic rays would light it up like a Christmas tree.
• 8:58
  Speaker 3: It would be completely blinded by the background radiation of space.
• 9:01
  Speaker 2: Got it.
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  Speaker 3: So by placing the laboratory deep inside an Italian mountain,
• 9:06
  Speaker 3: the thousands of feet of solid rock act as a
• 9:08
  Speaker 3: natural filter, absorbing those cosmic rays and creating an incredibly
• 9:12
  Speaker 3: quiet environment so you can listen for the faintest possible signals.
• 9:17
  Speaker 2: Okay, so we go deep into an Italian mountain to
• 9:19
  Speaker 2: find some peace and quiet, and we build the trap.
• 9:22
  Speaker 3: Yes.
• 9:23
  Speaker 2: The core of this trap is essentially a cylindrical tank
• 9:26
  Speaker 2: filled with liquid argon. The detector sits there in the
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  Speaker 2: dark waiting for a dark matter particle to drift through
• 9:33
  Speaker 2: the earth and hit the argon. But wait, I have
• 9:35
  Speaker 2: a massive problem with this. Go ahead. The fundamental definition
• 9:39
  Speaker 2: of dark matter, which we established just a few minutes ago,
• 9:43
  Speaker 2: is that it does not interact with regular matter. It
• 9:46
  Speaker 2: just passes through us like a ghost. Right. So if
• 9:49
  Speaker 2: that is true, how on earth is it going to
• 9:52
  Speaker 2: hit an argon nucleus inside a tank? It feels like
• 9:55
  Speaker 2: a massive contradiction in the science.
• 9:57
  Speaker 3: It's a very sharp observation, actually. and it gets right
• 10:00
  Speaker 3: to the heart of the physics. When physicists say dark
• 10:03
  Speaker 3: matter doesn't interact, they mean it completely ignores the electromagnetic force.
• 10:08
  Speaker 2: Which is why we can't see it with light. Exactly.
• 10:11
  Speaker 3: And it also ignores the strong nuclear force.
• 10:14
  Speaker 1: However.
• 10:15
  Speaker 3: Theories like WIMP's hinge on the idea that dark matter
• 10:18
  Speaker 3: might feel the weak nuclear force.
• 10:20
  Speaker 2: The weak nuclear force. Wait, that's the one responsible for
• 10:23
  Speaker 2: radioactive decay, right? Exactly.
• 10:25
  Speaker 3: It operates on an incredibly tiny subatomic scale. So dark
• 10:30
  Speaker 3: matter particles aren't crashing into argon atoms like two cars
• 10:33
  Speaker 3: colliding on a highway.
• 10:35
  Speaker 2: Right, because they don't have that kind of physical substance.
• 10:38
  Speaker 3: Yeah, it's more like a phantom drifting through a wall.
• 10:40
  Speaker 3: But once in a blue moon, it's weak force field
• 10:43
  Speaker 3: perfectly grazes the weak force field of an argon nucleus.
• 10:47
  Speaker 3: That incredibly rare fleeting interaction causes the argon nucleus to
• 10:52
  Speaker 3: physically flinch.
• 10:53
  Speaker 2: It flinches?
• 10:54
  Speaker 3: Yes, the atomic nucleus recoils. And when an argon nucleus
• 10:58
  Speaker 3: recoils inside liquid argon, it bumps into its neighbors, causing
• 11:02
  Speaker 3: a tiny ripple of energy.
• 11:03
  Speaker 2: Oh, wow.
• 11:05
  Speaker 3: That energy briefly excites the argon atoms, and as they
• 11:08
  Speaker 3: settle back down, they release a single, incredibly faint flash
• 11:12
  Speaker 3: of light called scintillation.
• 11:14
  Speaker 2: Okay, that actually makes a lot of sense. So we
• 11:17
  Speaker 2: bury a giant thermos of liquid argon inside a mountain,
• 11:21
  Speaker 2: turn off all the lights, and wait for this phantom
• 11:23
  Speaker 2: to graze an argon atom just right, causing it to
• 11:26
  Speaker 2: flinch and produce a tiny flash of light.
• 11:29
  Speaker 3: That is exactly the mechanism, yes.
• 11:31
  Speaker 2: But here is the part I'm struggling with now. A
• 11:35
  Speaker 2: flash is just a flash. If we were looking for
• 11:38
  Speaker 2: Jocelyn Monroe's massive composite dark nucleus instead of a simple
• 11:42
  Speaker 2: WIMP bullet, how does a flash of light tell the
• 11:46
  Speaker 2: team which one hit the tank?
• 11:48
  Speaker 3: This is where the genius of the DarkSide 50 data
• 11:50
  Speaker 3: analysis comes into play. You aren't just looking for light.
• 11:53
  Speaker 3: You are looking for structural fingerprints.
• 11:56
  Speaker 2: Okay.
• 11:57
  Speaker 3: If you are hunting a WIMP, which is an elementary particle,
• 12:00
  Speaker 3: it is unimaginably small. It is just a point in space.
• 12:04
  Speaker 3: If a WIMP interacts via the weak force, it's only
• 12:06
  Speaker 3: going to happen once. It hits one argon nucleus, you
• 12:10
  Speaker 3: get one tiny flash of light, and the WIMP is gone.
• 12:12
  Speaker 3: A single recoil.
• 12:14
  Speaker 2: Like a single invisible bullet passing through a forest. It
• 12:17
  Speaker 2: might graze one tree trunk, leave one mark, and that's it.
• 12:21
  Speaker 2: One hit, one flash.
• 12:24
  Speaker 3: Exactly. But composite dark matter is fundamentally different. Because it
• 12:28
  Speaker 3: is a massive dark nucleus made of billions of constituents
• 12:32
  Speaker 3: bound together, It actually takes up physical space. It has
• 12:35
  Speaker 3: width and depth. In physics, we say it has a
• 12:38
  Speaker 3: specific form factor.
• 12:40
  Speaker 2: So instead of a single bullet, a composite dark nucleus
• 12:44
  Speaker 2: is like a massive, tangled, invisible tumbleweed rolling through that
• 12:49
  Speaker 2: same forest.
• 12:50
  Speaker 3: Oh, that's a great analogy.
• 12:51
  Speaker 2: Or like a massive flock of invisible birds. Because it
• 12:55
  Speaker 2: is so wide and complex, it isn't just hitting one
• 12:58
  Speaker 2: tree trunk. It's brushing against multiple branches, snapping twigs, and
• 13:02
  Speaker 2: rustling leaves all along its path through the forest.
• 13:06
  Speaker 3: That is a perfect way to visualize the form factor.
• 13:09
  Speaker 3: Because the dark nucleus has this massive internal structure, a
• 13:13
  Speaker 3: single dark object wouldn't just ping one argon atom and leave.
• 13:17
  Speaker 3: It is so large that it could scatter several times
• 13:19
  Speaker 3: as it passes through the liquid argon tank.
• 13:22
  Speaker 2: Oh, I see.
• 13:23
  Speaker 3: It would leave a distinct trail of multiple recoils. Ah.
• 13:26
  Speaker 2: So you aren't just looking for a single isolated flash.
• 13:30
  Speaker 2: you are looking for a very specific sequential pattern of flashes.
• 13:34
  Speaker 2: That sequence physically proves that the invisible object passing through
• 13:38
  Speaker 2: your tank has structure and size.
• 13:40
  Speaker 3: Precisely. You are looking for the signature of something that
• 13:44
  Speaker 3: takes up space. The multiple scatter signature is essentially the
• 13:48
  Speaker 3: fingerprint of the whale.
• 13:50
  Speaker 2: Okay, the trap makes perfect sense now. The Darkside 50
• 13:53
  Speaker 2: detector ran deep under that Italian mountain for seven years
• 13:57
  Speaker 2: from 2013 to 2020.
• 13:57
  Speaker 1: Mm-hmm.
• 13:59
  Speaker 2: And the collaboration recently published an exhaustive, meticulous analysis of
• 14:04
  Speaker 2: all the data they collected over those seven years in
• 14:07
  Speaker 2: the journal Physical Review D. They combed through every tiny
• 14:11
  Speaker 2: flash of light looking for that specific tumbleweed signature. What
• 14:15
  Speaker 2: did they actually find?
• 14:17
  Speaker 3: They found absolutely nothing.
• 14:20
  Speaker 2: Nothing?
• 14:20
  Speaker 3: Zero. They found zero evidence of composite dark matter interacting
• 14:24
  Speaker 3: with the argon nuclei.
• 14:27
  Speaker 2: I have to be honest. I am really struggling to
• 14:30
  Speaker 2: see why this is making news then. I mean, they
• 14:32
  Speaker 2: spent seven years, millions of dollars, and a literal mountain
• 14:36
  Speaker 2: of argon, and they found absolutely nothing. Why aren't we
• 14:41
  Speaker 2: calling this a massive, frustrating failure? Usually when a scientific
• 14:45
  Speaker 2: experiment finds nothing, it just quietly disappears into an archive somewhere.
• 14:49
  Speaker 2: So what does this all mean? Why is this null
• 14:52
  Speaker 2: result so important?
• 14:55
  Speaker 3: That is a very natural reaction. It definitely feels anticlimactic
• 14:59
  Speaker 3: at first glance. But if we connect this to the
• 15:01
  Speaker 3: bigger picture of advanced physics, a null result like this
• 15:04
  Speaker 3: is actually a profound leap forward.
• 15:07
  Speaker 2: How so?
• 15:08
  Speaker 3: Well, in the search for something entirely unknown, mapping out
• 15:11
  Speaker 3: the void, proving where things definitely aren't, is just as
• 15:14
  Speaker 3: vital as proving where they are.
• 15:15
  Speaker 2: Okay, I think I'm tracking.
• 15:17
  Speaker 3: Because they knew mathematically exactly what a dark nucleus should
• 15:21
  Speaker 3: look like in the detector. They knew what the form
• 15:23
  Speaker 3: factor should be. The fact that they didn't see that
• 15:26
  Speaker 3: specific multiple scatter signature allowed the team to completely rule
• 15:30
  Speaker 3: out a massive range of proposed properties for ultra-heavy dark matter.
• 15:34
  Speaker 2: So they learned something by not finding it.
• 15:37
  Speaker 3: Exactly. Jocelyn Monroe and her team proved that the internal
• 15:40
  Speaker 3: structure of dark matter has observable consequences that dictate how
• 15:44
  Speaker 3: sensitive a detector needs to be.
• 15:46
  Speaker 2: It's almost like playing a giant cosmic game of Battleship.
• 15:49
  Speaker 2: You call a coordinate, and it's a miss. It feels
• 15:52
  Speaker 2: disappointing in the moment, but Now you know the aircraft
• 15:55
  Speaker 2: carrier absolutely isn't in that quadrant.
• 15:57
  Speaker 3: That's a great way to put it.
• 15:59
  Speaker 2: You don't have to waste years of time and funding
• 16:01
  Speaker 2: checking those squares again. It sharpens the target by telling
• 16:05
  Speaker 2: the global physics community exactly where not to look.
• 16:08
  Speaker 3: That is exactly right. By proving that certain masses and
• 16:11
  Speaker 3: structures of dark matter don't exist in the way we
• 16:14
  Speaker 3: might have originally hypothesized, they have vastly narrowed the parameter space.
• 16:19
  Speaker 3: And knowing exactly where not to look paves the way
• 16:21
  Speaker 3: for the next massive leap in technology— Because the search
• 16:24
  Speaker 3: is far from over. It is about to get supersized.
• 16:28
  Speaker 2: So where do we point the next missile in this
• 16:30
  Speaker 2: game of Battleship?
• 16:32
  Speaker 3: The insights gathered from the DarkSide 50 experiment have laid
• 16:35
  Speaker 3: the groundwork for its successor, which is actually scheduled to
• 16:37
  Speaker 3: launch in 2027. It is called DarkSide 20K.
• 16:42
  Speaker 2: Let's talk about the scale of DarkSide 20K. Because scaling
• 16:45
  Speaker 2: up physical engineering like this introduces some insane challenges. This
• 16:50
  Speaker 2: new detector is going to use roughly 1,000 times more
• 16:53
  Speaker 2: liquid argon than DarkSide 50 did.
• 16:56
  Speaker 3: It is massive.
• 16:57
  Speaker 2: A thousand times bigger. That's like going from a backyard
• 17:00
  Speaker 2: swimming pool to a massive subterranean lake of liquid argon.
• 17:05
  Speaker 3: The scale really is breathtaking. And the reason you build
• 17:08
  Speaker 3: a lake instead of a pool is entirely about sensitivity.
• 17:11
  Speaker 3: If these weak force interactions are as unbelievably rare as
• 17:15
  Speaker 3: we now know them to be, you need a vastly
• 17:17
  Speaker 3: larger net to catch them.
• 17:19
  Speaker 2: You just need more atoms for them to bump into. Exactly.
• 17:22
  Speaker 3: With that massive increase in volume comes a massive increase
• 17:25
  Speaker 3: in sensitivity. Jocelyn Monroe predicts that DarkSide 20K will do
• 17:29
  Speaker 3: far more than just hunt for simple wimps. She believes
• 17:33
  Speaker 3: this new detector has the sensitivity to open the door
• 17:35
  Speaker 3: to eventually observing actual dark chemistry signatures.
• 17:39
  Speaker 2: It proves that our existing experimental models can be pushed
• 17:42
  Speaker 2: far outside the conventional boundaries. We can actually test for
• 17:46
  Speaker 2: dark matter candidates that look wildly different. and vastly more
• 17:50
  Speaker 2: complex than anything we've assumed before.
• 17:53
  Speaker 3: Absolutely.
• 17:54
  Speaker 2: But let's bring this all back down to earth for
• 17:56
  Speaker 2: a second, directly to the listener. If you were listening
• 17:59
  Speaker 2: to this right now, going about your day, commuting to work, or,
• 18:02
  Speaker 2: you know, doing the dishes, why should you care about
• 18:05
  Speaker 2: dark chemistry? What does this ultimately change for our understanding
• 18:09
  Speaker 2: of reality?
• 18:10
  Speaker 3: Well, it changes everything because we are on the verge
• 18:13
  Speaker 3: of mapping out the hidden fabric of reality. Think about
• 18:16
  Speaker 3: human history for a moment. When conventional experiments first revealed
• 18:19
  Speaker 3: the structure of our own atomic nuclei, it completely revolutionized
• 18:23
  Speaker 3: our understanding of the universe. It led to technological leaps
• 18:27
  Speaker 3: that define the modern world. Everything from medical imaging and
• 18:31
  Speaker 3: radiation therapy to nuclear power came from simply understanding the
• 18:35
  Speaker 3: invisible internal structure of regular matter.
• 18:38
  Speaker 2: And regular matter is only 15% of the universe. Exactly.
• 18:42
  Speaker 3: For all of human history, we thought the universe was
• 18:45
  Speaker 3: just the things that lit up. Now we know we
• 18:47
  Speaker 3: are just the foam on the surface of an ocean.
• 18:50
  Speaker 3: Dark matter is the ocean itself.
• 18:53
  Speaker 2: That is wild.
• 18:54
  Speaker 3: Soon, with experiments like DarkSide 20K, we might be able
• 18:57
  Speaker 3: to map the structure of the substance making up the
• 18:59
  Speaker 3: vast majority of our cosmos. We are trying to understand
• 19:03
  Speaker 3: the ultimate blueprint.
• 19:05
  Speaker 2: We are finally trying to read the rest of the book.
• 19:08
  Speaker 2: We've been staring at the table of contents for a century.
• 19:11
  Speaker 2: Assuming we knew the whole story. And now we are
• 19:14
  Speaker 2: physically building the tools to read the actual chapters.
• 19:17
  Speaker 3: That's beautifully said.
• 19:19
  Speaker 2: To recap this incredible journey we've been on today, we
• 19:22
  Speaker 2: started by realizing that 85% of the universe's mass is
• 19:26
  Speaker 2: just unaccounted for. We challenged the decades-old assumption that this
• 19:30
  Speaker 2: missing mass has to be made of simple, unbreakable particles.
• 19:34
  Speaker 2: We explored the radical theory that dark matter might have
• 19:37
  Speaker 2: its own complex nuclear physics. binding together into massive invisible sandcastles.
• 19:42
  Speaker 2: And we descended deep into an Italian mountain to understand
• 19:46
  Speaker 2: how a vat of liquid argon could capture the faint
• 19:49
  Speaker 2: physical And even though they didn't catch the whale this time,
• 19:41
  Speaker 2: they proved that the net fundamentally works. They mapped the void,
• 19:44
  Speaker 2: and they really sharpened the spear for the next hunt.
• 19:46
  Speaker 2: They absolutely did. And as we wrap up today, I
• 19:48
  Speaker 2: want to leave you with one final mind-bending concept to
• 19:51
  Speaker 2: mull over. We've talked about invisible dark particles binding together.
• 20:12
  Speaker 2: We've talked about the potential for dark chemistry and an
• 20:15
  Speaker 2: entire invisible periodic table of elements.
• 20:18
  Speaker 3: Yeah.
• 20:19
  Speaker 2: But if dark matter isn't just a basic cloud of
• 20:21
  Speaker 2: uniform particles, if it can bind together into incredibly complex
• 20:25
  Speaker 2: heavy structures, could there be entire invisible dark structures out
• 20:30
  Speaker 2: there in space?
• 20:31
  Speaker 3: That's a huge question.
• 20:32
  Speaker 1: Right.
• 20:33
  Speaker 2: Could there be massive dark matter asteroids or even entire
• 20:36
  Speaker 2: dark planets passing right through our solar system? or right
• 20:40
  Speaker 2: through the room you are sitting in. Completely undetectable to us,
• 20:44
  Speaker 2: except by their faint gravitational pull.
• 20:47
  Speaker 3: It is a profound and honestly humbling thought. If dark
• 20:51
  Speaker 3: chemistry exists, the invisible universe might be just as incredibly rich, chaotic,
• 20:57
  Speaker 3: and complex as the one we can actually see.
• 21:00
  Speaker 2: An entire invisible universe, operating by its own rules, right
• 21:04
  Speaker 2: alongside ours. Thank you so much for joining the conversation.
• 21:08
  Speaker 2: and exploring the unseen edges of reality with us today.
• 21:13
  Speaker 2: Keep looking up and keep wondering about what you can't see.