# Search PBS Space Time

## Results ### 2022-11-23: How To See Black Holes By Catching Neutrinos

• 02:18: ... be challenging, given that each neutrino has a minuscule interaction probability most of them pass straight through your ... ### 2022-10-19: The Equation That Explains (Nearly) Everything!

• 03:24: ... we’re calculating the path traveled by a ball through the air or the probability that two quantum particles will ... ### 2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?

• 05:34: Those probabilities depend on many things,  like the particles’ positions and momenta, spins, charges, masses, etc.
• 05:42: These factors multiply a sort of base probability  to make the interaction more or less likely.
• 05:49: That base probability comes from the coupling constant or coupling strength for the interaction.
• 06:02: ... square of alpha is the base probability that an electron will emit or absorb a photon, or in the case of two ... ### 2022-08-24: What Makes The Strong Force Strong?

• 12:57: ... combos appears to cancel out, but it's not really neutral because the probability of the green interaction is double the other ... ### 2022-08-03: What Happens Inside a Proton?

• 03:12: ... gives us a recipe book for adding up the  probabilities. We talked about this stuff in   some previous videos. But ...
• 04:17: ... of QED. As the interactions get more complicated,   their probabilities get smaller and smaller.  Diagrams with more than a few twists and ...
• 05:31: ... now with curly gluon lines.   Presumably then to calculate the probability of a given interaction we again just add up diagrams,   ...
• 06:02: ... Feynman diagrams when you’re calculating the interaction probability for your pair of   quarks. Adding new vertices doesn’t ...
• 07:53: ... the starting and final field configuration to  get the probability of that transition ...
• 08:58: ... we understand exactly what we’re trying to do here. We want the probability for   some wiggly quantum field wiggles between ...
• 10:43: ... more likely than others.   In the Feynman path integral, the probability of each path comes from adding up all the little   shifts in the ...
• 12:15: ... connections are the gluon field.   Getting rid of the quantum probabilities means this isn’t really even a quantum problem any ... ### 2022-07-20: What If We Live in a Superdeterministic Universe?

• 02:20: ... block of reality is the wavefunction, which describes the evolving probability distribution of all possible properties of the world, or of tiny parts ... ### 2022-06-22: Is Interstellar Travel Impossible?

• 05:26: This impact probability is way too high to be acceptable. ### 2022-06-15: Can Wormholes Solve The Black Hole Information Paradox?

• 07:24: ... you, the Richard Feynman’s path integral  calculates the probability of some quantum   particle traveling between two points by ... ### 2022-06-01: What If Physics IS NOT Describing Reality?

• 11:24: ... as pretty fundamental. It describes  the evolving distribution of probabilities for   the results you might get if you tried to  measure ...
• 15:25: ... Given that most of the   galaxy is empty space, what’s the probability  of stars colliding? Well for any given star   the chance is ... ### 2022-05-18: What If the Galactic Habitable Zone LIMITS Intelligent Life?

• 11:12: ... of star formation and folded in estimates for  the probability of the emergence of planets   based on heavy element ... ### 2022-01-12: How To Simulate The Universe With DFT

• 00:54: ... ol’ Schrodinger equation on the blackboard and solve it to learn the probability distribution of the electron locations, or the energy levels of the ...
• 02:19: ... find the wavefunction, and the square of that wavefunction gives the the probability distribution for where you’ll find the electron if you try to measure ... ### 2021-12-10: 2021 End of Year AMA!

• 00:02: ... interactions gives you the interaction that actually happens or the probability distribution of that interaction so each in that context every ... ### 2021-10-13: New Results in Quantum Tunneling vs. The Speed of Light

• 13:59: ... goes through solid bedrock so there’s a low probability that your quantum wavefunction will make it through - but if you do then ... ### 2021-09-21: How Electron Spin Makes Matter Possible

• 05:59: ... A wavefunction is this thing that holds information about the probability of a given property being observed. For example, the wavefunction ...
• 08:00: ... state of an electron. We’ll call it Psi. Psi gives the distribution of probabilities of some observable - for example, the location of the electron around ...
• 08:21: ... actual probability distribution is the square of that. We can never, ever observe Psi - all ... ### 2021-09-07: First Detection of Light from Behind a Black Hole

• 15:54: ... I would also imagine that the bigger the energy difference, the less probability of the field tunneling to the true minimum, so maybe those cancel ... ### 2021-08-18: How Vacuum Decay Would Destroy The Universe

• 10:10: ... it’s inevitable. At any instant in time there’s a tiny but real probability that a patch of   space will tunnel between the false and ... ### 2021-07-21: How Magnetism Shapes The Universe

• 16:05: Each infinitesimal location can be thought of as a “world” and some worlds have more weight - more probability than others.
• 16:46: A related point is regarding probability.
• 16:49: ... world per option, then what does that mean for the different weights - probabilities of those different wavefunction ...
• 17:10: ... probabilities must be reflected in the number of worlds for each quantum outcome - ...
• 17:25: If the splitting only made one world per distinct outcome then indeed probability would be destroyed.
• 17:31: ... see differences in likelihood, and therefore probability is not destroyed, so IF the many worlds explanation is right then the ... ### 2021-07-13: Where Are The Worlds In Many Worlds?

• 03:46: Where a pond ripple is an oscillation in surface height, the wavefunction is an oscillation in probability, or more accurately probability density.
• 07:57: ... high and low points in the wavefunction - meaningful blips in the probability ... ### 2021-07-07: Electrons DO NOT Spin

• 07:30: ... describes how quantum objects behave as evolving distributions of probability - as wavefunctions.It  was proving amazingly successful at ... ### 2021-06-23: How Quantum Entanglement Creates Entropy

• 06:38: ... we call the wavefunction - that’s the distribution of   probabilities of all the possible properties the system could have if you tried ... ### 2021-05-19: Breaking The Heisenberg Uncertainty Principle

• 07:35: ... the x-axis and amplitude is plotted on the y-axis—as a fuzzy circle of probability, where the area of the circle is proportional to Planck’s constant, ...
• 08:03: ... in the opposite dimension, so that the total area of this squeezed probability disk remains the ... ### 2021-04-21: The NEW Warp Drive Possibilities

• 14:18: The probability that a particle will interact with other massive virtual particles is proportional to the square of that particle’s own mass. ### 2021-04-07: Why the Muon g-2 Results Are So Exciting!

• 08:19: The probability of interaction between a particle and some massive virtual particle is proportional to mass squared. ### 2021-03-23: Zeno's Paradox & The Quantum Zeno Effect

• 02:44: Rather, each state has an amplitude that determines the probability of finding the arrow in that state were you to try to observe it.
• 02:58: ... to that observation, the arrow exists as just the distribution of probability amplitudes of its position; its wavefunction is spread between the start ...
• 04:34: But because you start watching it close to the beginning of its journey, there’s very little probability of it collapsing to the end. ### 2020-11-04: Electroweak Theory and the Origin of the Fundamental Forces

• 04:50: ... try an example: In quantum mechanics, the wavefunction determines the probabilities of certain outcomes being measured for observables like particle ...
• 06:49: The ‘U’ stands for unitary and tells us that elements of this group preserve vector length, or in our case quantum probability. ### 2020-10-20: Is The Future Predetermined By Quantum Mechanics?

• 02:53: ... as well defined reality but rather as distributions of probability that describe all possible states that, that chunk of the universe could ... ### 2020-09-28: Solving Quantum Cryptography

• 06:35: ... give an output, are in a quantum superposition of 0 and 1, with some probability of either being measured when you try to read out the ...
• 06:48: ... and each state represents a different number, each with a different probability. ... ### 2020-07-28: What is a Theory of Everything: Livestream

• 00:00: ... has gone horribly wrong you know things like infinite energies or probabilities greater than one these kinds of things indicate that there's something ... ### 2020-06-30: Dissolving an Event Horizon

• 14:17: ... have something called an interaction crosssection, which defines the probability of another particle interacting with the electron as a function of ...
• 14:40: ... both space and time by the same factor, you also rescale the interaction probabilities to that the interaction rate scales in the same way ... So a pair of ... ### 2020-03-16: How Do Quantum States Manifest In The Classical World?

• 17:40: ... result of that measurement. And the wavefunction itself defines the probability of a given branch "collapsing". The Many Worlds interpretation states ... ### 2020-03-03: Does Quantum Immortality Save Schrödinger's Cat?

• 09:36: ... some people used much more sophisticated probability arguments including Bayesian analysis or thinking in “observer years” ...
• 09:46: But none of that helped - the probability for humanity's survival to the year 3000 remained at about a percent or lower. ### 2020-02-24: How Decoherence Splits The Quantum Multiverse

• 02:34: ... probability for a system going from one state to another can be calculated by ...
• 03:38: ... - a quantum particle seems to pass through two slits simultaneously as a probability wave that ultimately “collapses” to leave it as a single position on a ...
• 04:28: The probability of the photon having reached this particular spot is determined by the sum of all possible trajectories to that spot.
• 04:57: Because the wavefunction is amplified at that spot, there’s a high probability of the particle landing there.
• 05:22: That’s destructive interference and the probability of the particle ending up there goes to zero. ### 2020-02-18: Does Consciousness Influence Quantum Mechanics?

• 02:51: Instead it travels as an abstract “probability wave” - something we call a wavefunction.
• 02:58: That probability wave defines the location of the electron at any point IF you try to measure it.
• 03:34: ... seems essential because our large-scale, classical world isn’t made of probability clouds, it’s made of objects with clearly definable ... ### 2020-02-03: Are there Infinite Versions of You?

• 02:39: But one of those monkeys will correctly complete Cymbeline and all of Shakespeare’s First Folio with a probability of 1/100^3.75 million.
• 02:58: This is an unthinkably small probability.
• 03:01: ... it’s not zero probability, and the Infinite Monkey Theorem tells us that any non-zero probability ...
• 03:57: ... probability of getting every particle just right is unthinkably smaller than the ...
• 04:06: ... it’s not a zero probability, and so with infinite regions of the universe - infinite trials, the ... ### 2020-01-27: Hacking the Nature of Reality

• 04:44: The S-matrix is a map of the probabilities of all possible outgoing particles, or out-states, for a given set colliding particles - in-states. ### 2020-01-20: Solving the Three Body Problem

• 10:30: ... for a pseudo-random system, statistical mechanics lets us calculate the probability of the system being in any part of that phase space at any one ... ### 2019-12-17: Do Black Holes Create New Universes?

• 16:35: Well, from the Prince of France's perspective, the answer to that question is a probability of 1.
• 16:41: From everyone else's perspective, the answer is a probability of 0.
• 17:11: ... you ask him for the probability that he's the Prince of France he should probably say 1 in 33 million, ... ### 2019-12-09: The Doomsday Argument

• 08:01: In fact we can use statistics to estimate the probability of our species lasting a certain amount of time. ### 2019-11-18: Can You Observe a Typical Universe?

• 07:19: By the Copernican principle, we are most likely to observe a very typical environment - this is just a statement of probability.
• 07:32: ... status as observers when we interpret our environment - including the probability of being in ...
• 08:21: ... from a high entropy state, then the lower the entropy the less probability of that region ...
• 10:47: We should take into account what we already know - our “priors” - before assessing any probabilities. ### 2019-11-04: Why We Might Be Alone in the Universe

• 11:40: ... events were phenomenally unlikely - we simply can’t assign them larger probabilities until we get more evidence - which ideally means seeing them happen more ... ### 2019-10-07: Black Hole Harmonics

• 13:12: ... levels of science you’re going to need to have a solid understanding of probability. ...
• 13:24: Brillaint.org has a new course on probability fundamentals that include interactive challenges and problems to solve.
• 13:35: You can Learn probabilistic basics, such as fairness, expected value, and symmetry, in their course Probability Fundamentals. ### 2019-09-30: How Many Universes Are There?

• 03:05: We assumed that there’s a fixed but unknown probability that a bubble universe will form in any given volume of inflating space.
• 04:51: This gives us a ridiculously large number of universes even if the probability of making one per unit of volume is insanely low.
• 11:29: He proposes that there may be something off in the logic of weighing up probabilities over bubble universes. ### 2019-08-06: What Caused the Big Bang?

• 11:51: ... in order for inflation to last long enough to do its job, the probability for the appearance of a bubble can't be too high and that rules out ... ### 2019-07-01: Thorium and the Future of Nuclear Energy

• 02:49: ... U-235 is useful because it's highly fissile which means it has a high probability of intercepting a stray Neutron and splitting It's fissile in the ... ### 2019-05-09: Why Quantum Computing Requires Quantum Cryptography

• 08:07: ... random result – Albert sends a 1 but Niels will get a 1 or 0 with equal probability. ... ### 2019-02-07: Sound Waves from the Beginning of Time

• 13:26: ... expands towards the infinite future, does that expansion outpace the probability of collapsing into a big crunch due to everything quantum tunneling ... ### 2018-11-21: 'Oumuamua Is Not Aliens

• 14:47: This in turn changes the probabilities of oscillation and suppresses oscillations to tau neutrinos. ### 2018-11-14: Supersymmetric Particle Found?

• 10:13: The probability of a chance association with a supernova is around 3%, so it's unlikely but it does happen. ### 2018-10-31: Are Virtual Particles A New Layer of Reality?

• 15:15: The Fermi paradox must be explained by a very long chain of soft filters that add up to extremely small probability or one or more hard filters. ### 2018-10-25: Will We Ever Find Alien Life?

• 11:46: Depending on the destruction probability-- let's call it the wacko factor-- you might expect civilizations to last from decades to thousands of years.
• 12:22: I guess it depends on the relative probabilities. ### 2018-09-20: Quantum Gravity and the Hardest Problem in Physics

• 02:41: That math started with the Schrodinger equation, which tracks these probability waves through space and time. ### 2018-09-12: How Much Information is in the Universe?

• 14:27: ... radioactive elements, but can be used for anything that has a constant probability of decaying in a given amount of ...
• 14:43: The actual amount of time it takes to decay is random, and there's a constant probability of it happening at every set interval. ### 2018-08-23: How Will the Universe End?

• 15:43: All they have is their quantum wave function, which tells the probability of the particle's location, momentum, spin, direction, et cetera.
• 15:56: But that spatial sprint really just tells us the probability of finding the electron, say, here or here or here. ### 2018-07-25: Reversing Entropy with Maxwell's Demon

• 12:13: If different microstates can have different probabilities, then you need to include those probabilities in your equation for entropy. ### 2018-07-18: The Misunderstood Nature of Entropy

• 11:11: Stunningly, its foundations are in probability theory.
• 11:16: To really get stat mech, you have to get probability.
• 11:20: Brilliant.org has a great course on probability that's solidly founded on exercise-based learning. ### 2018-07-11: Quantum Invariance & The Origin of The Standard Model

• 03:11: The square of the magnitude of this wave function tells us the probability distribution of a particle's position.
• 05:56: That shouldn't change our probabilities for the positions of the particles, but what about observables besides positions? ### 2018-06-13: What Survives Inside A Black Hole?

• 11:57: How is probability conserved when an electron and a positron annihilate each other?
• 12:18: ... by quantum-field theory, and unitary evolution and the conservation of probability and information still works ...
• 12:34: Now it's the evolution of the fields, not the particles, that conserves probability.
• 13:06: ... wave function prescribes the probability of observing a given value for a property when the observation is made, ... ### 2018-05-23: Why Quantum Information is Never Destroyed

• 04:36: It ensures conservation of information and time-reversal symmetry because of an even more fundamental rule-- the conservation of probability.
• 05:02: ... in quantum mechanics, that means the probability distribution of all of its properties, which you can get by taking the ...
• 05:10: ... example, the wave function of a particle encapsulates the probability that it will be found in this or that location if we were to try to ...
• 06:10: Remember that the wave function encapsulates the distribution of probabilities for a given property.
• 06:15: By definition, those probabilities should add up to 1.
• 06:19: But that just means there's 100% probability that any given property will have some possible value, even if that value is zero.
• 06:27: In the case of particle position, probability of adding to 1 just means that the particle is definitely somewhere.
• 06:39: The probabilities should continue to sum to 1.
• 06:56: ... is a non-negotiable statement about how probability works, but the condition also ensures time-reversal symmetry and ...
• 07:05: ... states must remain independent of each other in order to preserve probability. ...
• 07:21: If they did, then the probabilities for the initial states or for the final state can't both sum to 1.
• 07:27: ... quantum states A and B can't both become quantum state C. The sum of the probabilities prior to the merger would not equal the sum of the probabilities after ...
• 07:41: The only type of evolution that preserves probability and unitarity is the evolution that also preserves the number of quantum states.
• 08:12: That value seems to be chosen randomly based on the probability distribution encoded in the wave function. ### 2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series

• 08:06: The magnitude of the wave function squared is the probability distribution for the particle. ### 2017-07-26: The Secrets of Feynman Diagrams

• 00:19: ... MUSIC] Feynman's path integral shows us that to properly calculate the probability of a particle traveling between two points, we need to add up the ...
• 00:57: To calculate the probability of any quantum system evolving between two states, we need to sum over every conceivable intermediate state.
• 01:27: ... needed to calculate the contribution of that family to the total probability. ... ### 2017-07-19: The Real Star Wars

• 16:37: A few of you asked why it is that each additional vertex reduces the probability contribution of a given Feynman diagram by around a factor of 100.
• 16:57: The probability of that interaction is governed by the coupling constant between those fields.
• 17:07: In fact, the probability amplitude added at each vertex is proportional to the square root of the fine structure constant.
• 17:15: The probability itself is the square of the probability amplitude.
• 17:28: ... the electron field, so every additional vertex, another one of these 1% probability events has to ... ### 2017-07-12: Solving the Impossible in Quantum Field Theory

• 06:38: Every other way to scatter the electrons contributes less to the probability of the event.
• 06:50: It turns out that the probability amplitude of a particular interaction depends on the number of connections, or vertices, in the diagram.
• 06:59: Every additional vertex in an interaction reduces its contribution to the probability by a factor of around 100.
• 07:17: A three-vertex interaction would contribute about 1% of the probability of the main two-vertex interaction.
• 07:56: And more complicated interactions add even less to the probability.
• 14:10: [INAUDIBLE] points out that the final probability for a particle journey is the square of the length of the complex probability amplitude vector.
• 14:20: Probability is the square of the probability amplitude.
• 14:25: ... the sense I wanted to relay is that the total probability depends on the length of the summed probability amplitudes-- so the ...
• 14:37: ... also correctly points out that the individual paths don't have different probability amplitude lengths taken separately, but rather, they're pointing in the ...
• 15:06: ... applying the principle of least action in the determination of probability amplitudes, it turns out that the "crazy" paths, including the ... ### 2017-07-07: Feynman's Infinite Quantum Paths

• 01:27: ... that fills the intervening space interacts with itself and defines the probability of that particle actually showing up at a given point on the ...
• 03:40: ... out a way to combine the infinite paths to give a very real finite probability of a particle reaching its final ...
• 05:33: ... the contributions from all of those infinite possible paths to find the probability of a particle making that simple journey from A to ...
• 05:46: Feynman's paths don't each have some separate probability of occurring.
• 05:50: Instead, each path contributes what we call a probability amplitude to the entire A-B journey.
• 05:58: Schrodinger's wave function and Feynman's path integral describe this probability amplitude thing.
• 06:05: Now, regular probabilities are normal positive numbers between 0 and 1.
• 06:10: However, probability amplitudes are what we call complex numbers.
• 06:15: We can think of each path's probability amplitude as a vector or an arrow of a certain length and direction in an imaginary 2D space.
• 06:26: The total length of each arrow gives the probability of that path being taken.
• 06:32: But to get the total probability that a particle travels from A to B, you connect the probability amplitude arrows for all possible paths end to end.
• 06:44: The length of the arrow connecting the start and the end of this chain represents the total probability from all paths.
• 06:52: But if two parts contribute individual probability amplitudes that point in exactly opposite directions, they cancel each other out.
• 07:13: Now, when Feynman used this action quantity to figure out the probability amplitudes of his infinite paths, something amazing happened.
• 07:27: Only the most sensible paths, those with the least action, added significantly to the probability.
• 10:04: The quantum action principle gives the probability amplitude of changes in the state of the field.
• 10:10: ... includes motion of the photon, but it also includes the probability amplitude of a photon's energy moving from the electromagnetic field ...
• 11:04: In fact, they lead to rampant, uncontrolled infinite probabilities. ### 2017-06-28: The First Quantum Field Theory

• 06:38: ... event or interaction can happen in multiple different ways and the probability of the interaction depends on correctly counting those different ...
• 07:03: That means you get the wrong probabilities. ### 2017-05-03: Are We Living in an Ancestor Simulation? ft. Neil deGrasse Tyson

• 11:03: He posits a type of Bayesian reasoning, so assessing the probability of the hypothesis being true by taking into account prior probabilities.
• 11:12: ... producing the most brains, because that universe would give the maximum probability of our own existence, which is the one thing we know for sure is ...
• 16:13: It's also possible to imagine this happening randomly, albeit with stunningly low probability. ### 2017-04-26: Are You a Boltzmann Brain?

• 09:25: ... idea of Boltzmann brains is as a lesson in caution-- caution in arguing probabilities before really understanding the prior ... ### 2017-03-15: Time Crystals!

• 11:47: That gives you an idea of the average probability of alignment, but not all of those will have planets. ### 2016-12-21: Have They Seen Us?

• 10:50: Simple probability says that any other civilization is likely to be ahead of us on the curve. ### 2016-11-30: Pilot Wave Theory and Quantum Realism

• 02:27: One aspect of that radical thinking was that the wave function is not a wave in anything physical but an abstract distribution of probabilities. ### 2016-11-02: Quantum Vortices and Superconductivity + Drake Equation Challenge Answers

• 02:52: I asked you to figure out some probabilities regarding the existence of other technological civilizations in our galaxy.
• 03:24: ... region -- that's "N (sub) ast" for "astrophysical factor" -- times the probability that a technological civilization will form on any given habitable ...
• 05:25: So I'd take that as a very crude estimate of the maximum probability for Earth to have developed us.
• 05:38: Probably it's lower, though. Frank and Sullivan low-balled the probability and set the "A" value as 0.01, instead of 1. ### 2016-10-26: The Many Worlds of the Quantum Multiverse

• 00:44: Instead, they seem to behave as probability clouds of all properties they might have were we to try to measure them.
• 10:02: ... coherent histories interact or why the wave function translates to probabilities the way it ... ### 2016-10-05: Are We Alone? Galactic Civilization Challenge

• 04:13: If the true probability of producing civilizations is higher, then there have been-- and perhaps still are-- advanced species in our galaxy.
• 04:38: ... on any habitable planet within 100 light years, how low would that probability of technological emergence need to ... ### 2016-08-10: How the Quantum Eraser Rewrites the Past

• 01:19: It's a probability wave that does all the usual wave-like stuff like making interference patterns, until something happens to collapse it. ### 2016-08-03: Can We Survive the Destruction of the Earth? ft. Neal Stephenson

• 11:15: ... suggests that the wave function is nothing more than a distribution of probabilities, and that when the wave function collapses, the properties of the ... ### 2016-07-20: The Future of Gravitational Waves

• 05:41: ... our last challenge question, we asked you to calculate the probability that an alpha particle-- so a package of two protons and two neutrons-- ...
• 06:09: All those individual probabilities combine to give you a 50% chance of decay after 0.3 microseconds. ### 2016-06-29: Nuclear Physics Challenge

• 01:34: The challenge for today is for you to figure out the tunneling probability for an alpha particle to escape from a polonium 212 nucleus.
• 02:04: ... need to find the tunneling probability for each one of these encounters with the wall-- a probability that will ...
• 03:04: ... of your own diagrams, plus some basic algebra is enough to get you the probability that an alpha particle will tunnel out of the polonium 212 nucleus on ... ### 2016-06-15: The Strange Universe of Gravitational Lensing

• 11:37: Prior to that, it exists only as its wave function, which is a distribution of probabilities of these properties.
• 11:45: ... description of things as probabilities works, but it's also not deterministic in that in order for the wave ...
• 12:16: The wave function that we calculate defines the probability that we will observe a particular set of physical properties. ### 2016-06-01: Is Quantum Tunneling Faster than Light?

• 00:35: Each specific state has a certain probability of being true when the object is observed.
• 00:52: There is a distribution of probabilities for each of an object's quantum properties.
• 01:39: It can be described as a wave packet of positioned probability.
• 04:10: There remains a tiny tail of probability outside the nucleus, beyond the reach of the strong nuclear force. ### 2015-11-18: 5 Ways to Stop a Killer Asteroid

• 02:47: But small probabilities have a way of adding up to a certainty, over time. ### 2015-03-18: Can A Starfox Barrel Roll Work In Space?

• 07:22: I wanted them to be based on understand physics that had some non-microscopic probability of occurring.
• 08:24: The probability is near zero, way lower than one in a billion.
• 08:28: ... so much empty space between star systems and galaxies that the probability of any two of them colliding would be similar to the probability of two ... ### 2015-02-18: Is It Irrational to Believe in Aliens?

• 00:33: With probability statistics, we just need to get a handle on the factors at play in the emergence of intelligent life as we know it.
• 01:08: Multiply these two probabilities by the 200 billion planets and, voila, you know how many Wookies, or Covenant, or Vulcans you should expect.
• 01:30: Whenever anyone, even a scientist, quotes a number for the "probability" of life arising, it's pretty much a complete guess.
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