
20221214: How Can Matter Be BOTH Liquid AND Gas?
 19:37: ... Factor in the relative distance of the center of the Milky Way and you get that ...


20221123: How To See Black Holes By Catching Neutrinos
 11:47: ... kilometers, which should approximately increase the detection rate by a factor of ...


20221116: Are there Undiscovered Elements Beyond The Periodic Table?
 11:01: There are so many factors at play that the only way to figure this out is to simulate the nucleus.


20221109: What If Humanity Is Among The First Spacefaring Civilizations?
 04:42: There are a bunch of other factors that cause this peak, which we go into in our episode on galactic habitable zones.
 05:44: The number of hard steps is a big deciding factor in how fast the universe can spawn intelligent life.
 08:49: So there are two main deciding factors of our birth rank: the number of hard steps and the maximum lifetime of habitable planets.


20221012: The REAL Possibility of Mapping Alien Planets!
 01:25: ... of the brightness of the exoplanet by a factor of a trillion, and a magnification of the surface details by a ...
 04:36: ... first place. And the planet's surface area would be expanded by a factor of around 100 billion. If only it were possible to remove ...


20220928: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?
 04:26: And the energy of that ground state electron is smaller than the rest mass energy of the electron by a factor of 137 squared.
 05:42: These factors multiply a sort of base probability to make the interaction more or less likely.
 11:20: ... example, the speed of light is the translation factor between the dimensions of space and time in relativity; it’s also the ...


20220921: Science of the James Webb Telescope Explained!
 04:11: ... and the expanding universe has stretched the light by more than a factor of ...
 16:46: That said, there are various plans to build socalled Higgs factories that don’t involve just building bigger and bigger colliders.


20220817: What If Dark Energy is a New Quantum Field?
 10:08: ... we happen to live in a period of the universe where these are within a factor of a few of each other, at exactly the time when the acceleration ...


20220630: Could We Decode Alien Physics?
 15:41: ... a single civilization in a million years or less is a strong factor to consider when pondering the Fermi paradox. We did an ...


20220622: Is Interstellar Travel Impossible?
 01:49: There are two factors that make interstellar travel difficult.
 08:02: Interstellar space is quite a bit less dense than the upper atmosphere  by a factor of around 10^16.
 08:26: ... Factoring in the relative densities, particle masses and speeds, the heat ...


20220601: What If Physics IS NOT Describing Reality?
 14:22: ... Milky Way could potentially host life based on various factors like abundance of necessary elements and there not being too ...


20220525: The Evolution of the Modern Milky Way Galaxy
 07:58: ... a few hundred lightyears thick, and is the main star factory of the Milky way. It’s home to the spiral arms and the big, bright ...
 16:02: ... common. The large moon has been proposed as an important factor in the appearance of life, which may have first appeared in ...


20220518: What If the Galactic Habitable Zone LIMITS Intelligent Life?
 05:24: ... not so fast. There is another factor to consider. Stars have habitable zones, but so do ...
 06:28: ... spread through the galaxy in supernova explosions. So a big factor in determining the galactic habitable zone is that enough ...
 07:36: ... for life yet. However these stars were incredible atom factories, rapidly burning their way up the periodic table and ...
 09:26: ... factors make the core the worst place in the galaxy. The extreme density ...
 13:03: ... factor that may explain the apparent absence of technological ...


20220504: Space DOES NOT Expand Everywhere
 03:48: ... z, but here adding the dimension of time. And this thing is the scale factor, which represents the overall size of the universe, and this is the thing ...
 04:26: ... and its growth represents the increase in the scale factor over ...
 07:45: ... Now the distance between those lines represents the growing scale factor. Let’s zoom in ...
 14:34: ... to start their train of reasoning with statements about external factors that they couldn’t directly observe. Unfortunately, practitioners of ...


20220323: Where Is The Center of The Universe?
 00:44: At least, once you factor out the selection biases of needing to be somewhere moderately hospitable.
 06:34: ... of this expanding hypersphere is represented in the math by the scale factor  and the scale factor increases as time ...


20220216: Is The Wave Function The Building Block of Reality?
 11:50: ... Sasso laboratory, a main source of noise, cosmic muons, was reduced by a factor of nearly 1 million. Then, they further shielded the crystal with layers ...


20220210: The Nature of Space and Time AMA
 00:03: ... described mathematically as the growth of something called the scale factor which is just a multiplicative factor that that um that essentially ...


20211229: How to Find ALIEN Dyson Spheres
 09:46: ... 1% of its star's light could shift the visibletoinfrared color by a factor of more than ...


20210803: How An Extreme New Star Could Change All Cosmology
 04:37: ... determines how bright the star appears to us  but there’s another factor at play there  how far away the star is. Measure the star’s brightness ...


20210721: How Magnetism Shapes The Universe
 13:29: ... this, but Stephen is SO generous and amazing that scientists have to factor in his personal magnetism when they calculate the Earth’s geomagnetic ...


20210623: How Quantum Entanglement Creates Entropy
 13:44: ... the 42% is no longer accurate  presumably it’s lower by a factor of more than 3, due to all the new debris and the fact that ...


20210616: Can Space Be Infinitely Divided?
 04:30: ... Heisenberg. Or close enough  A proper derivation gets you a factor of 1 over 4 ...
 06:39: ... how big this uncertainty is. Space is stretched by a factor equal to the effective mass times the gravitational constant ...


20210609: Are We Running Out of Space Above Earth?
 10:29: This will increase the number of satellites in orbit by a factor of more than 10.


20210413: What If Dark Matter Is Just Black Holes?
 02:02: In other words, most of the physical universe needs to be vast swarms of black holes that outweigh all the atoms in the universe by a factor of four.


20210407: Why the Muon g2 Results Are So Exciting!
 04:07: But the electron dipole moment is different from the classical one by this factor g.
 11:10: ... of course this was a systematic error, some unknown factor influencing the measurement that is not a new particle, the g2 team ...


20210224: Does Time Cause Gravity?
 00:27: Our GPS satellites tick faster by a factor of 1inabillion  enough to thrown their position accuracy off by 11km per day.


20201013: Do the Past and Future Exist?
 15:37: ... we can ask whatever advanced civilization to kindly shut down their factories so we can more carefully analize the atmosphere for much more ...


20201005: Venus May Have Life!
 15:09: ... the last catch  a few of you noticed I used the expression “factor a prime number”  which is dumb, because the factors of a prime number ...
 15:22: What I meant was factoring the product of two primes INTO those primes.


20200928: Solving Quantum Cryptography
 00:10: ... math problem is prime number factoring, and the new era of quantum computers may lay bare your indiscretions, as ...
 00:39: ... purchase, every login—is secured by the fact that it’s a lot harder to factor out prime numbers than it is to multiply them ...
 00:58: ... computers will take thousands to billions of years to find those factors, depending on the key ...
 01:08: ... an algorithm  Shor’s algorithm  that could use a quantum computer to factor a prime number in, well, a human lifetime, or a human ...
 01:51: ... tolerance” and/or support vastly more quibits to do the sort of prime factoring required for ...
 02:07: One option is to match quantum decryption with new quantum encryption techniques to replace prime factoring.
 02:55: Enter postquantum cryptography, or quantum resistant algorithms  which might replace our vulnerable prime factoringbased cryptography.
 03:13: Prime factoring is an example of what we call a oneway function.
 04:07: ... current dominant encryption protocol uses prime factors instead of colours, and this is the RSA protocol after Ron Rivest, Adi ...
 04:28: But prime factoring is only one example of a oneway function.
 04:40: ... you try prime factorization using a classical computer you’re stuck using an algorithm similar to ...
 05:01: This is laborious—it takes an insane amount of time to factor large numbers this way.
 05:05: Or you could run an insane number of computers in parallel to each check every different factor.
 05:24: It turns out there’s a structure to factorization that can be exploited by quantum computers.
 06:13: That doesn’t help us immediately  for the powers of large numbers, guessing the period is as hard as guessing the factors.
 07:23: ... you tried to use a quantum computer to guess the factors of a prime number, you’d read out one of the guesses but it’s no more ...
 07:38: ... of trying to hold possible prime factors in our quibits, our array of qubits holds these repeating moduli of ...
 08:15: Once you read out that period you can determine the prime factors.
 08:20: So far, quantum computers are stuck under 100 qubits and none have managed to factor a number higher than 21 with Shor’s algorithm.
 08:53: The answer is to find oneway functions that don’t have a known exploitable quality like the periodicity of prime factoring.
 13:05: Well, one important factor in this question is the age of the alorgithm.


20200908: The Truth About Beauty in Physics
 12:25: ... results from the hidden workings of our brains  many factors contribute subconsciously to this qualitative sense of ... yes, that ...


20200824: Can Future Colliders Break the Standard Model?
 08:01: ... is currently in a long upgrade process, with the final result being a factor of a couple increase in power  but more importantly a factor of 5 ...
 09:43: But why build a Higgs factory?


20200708: Does Antimatter Explain Why There's Something Rather Than Nothing?
 09:19: ... The exact energy of one of these states is determined by many different factors: the precise mass and charge of the particles, their orbital angular ...


20200630: Dissolving an Event Horizon
 09:51: ... electrons have very tiny masses for comparatively large charge  just factoring the electrons mass, it should be easy to send a black hole over the ...
 14:40: ... THINK the idea is that when you rescale both space and time by the same factor, you also rescale the interaction probabilities to that the interaction ...


20200615: What Happens After the Universe Ends?
 02:01: This is perhaps the simplest conformal transformation  just multiplying or dividing all dimensions by the same scaling factor.


20200608: Can Viruses Travel Between Planets?
 00:42: And it’s increasingly believed that they are critical factors in the process of evolution, perhaps even in precellular days.
 15:01: ... masses of the Cavendish experiment are very close together, you need to factor in the Casimir force between them to get an accurate measurement of the ...


20200527: Does Gravity Require Extra Dimensions?
 10:53: ... larger than the sizescale of those dimensions  depending on other factors  most importantly depending the strength with which gravity interacts ...


20200511: How Luminiferous Aether Led to Relativity
 16:07: Well that’s easy  the universe has expanded by a factor of 1100 since the CMB was released.


20200504: How We Know The Universe is Ancient
 07:40: ... to us than they really were. In fact he got distances wrong about a factor of two too small. Overnight the universe doubled in ...


20200331: What’s On The Other Side Of A Black Hole?
 03:14: ... projection, the separation of lines of longitude are multiplied by a factor that depends on their latitude  and that multiplication factor becomes ...


20200324: How Black Holes Spin Space Time
 12:36: ... influenced by hull shape, ship mass, power plant output, and many other factors. And World of Warships captures the feel of complex motion dynamics ...


20200218: Does Consciousness Influence Quantum Mechanics?
 15:49: ... like the speed of light and the gravitational constant are just scaling factors and so varying them shouldn't lead to quantum particles  but perhaps ...


20200211: Are Axions Dark Matter?
 12:47: ... number of possible configurations of particles in the universe  10^90 factorial. Now, I assume Ethan got that number by imagining swapping around every ...


20191217: Do Black Holes Create New Universes?
 07:00: ... stars and so far fewer black holes would form  and of course these factors also seem to be essential for ...
 10:33: Now perhaps the extra .17 can be factored into the uncertainties of the theory...
 10:59: ... black hole production, and it’s just a happy coincidence that the same factors also favor ...
 15:09: And by similar, I mean within a factor of a few.


20191209: The Doomsday Argument
 03:03: He got a value that was a factor of 10 higher than what would be observed 10 years later when dark energy was discovered.
 04:05: ... off by a factor of 2  which considering the method, and the fact that dark energy could ...


20191202: Is The Universe Finite?
 04:31: The combination of these factors determine the geometry.


20191118: Can You Observe a Typical Universe?
 15:09: Much of the parameter space that the constants of nature could have taken eliminate one or more of these factors.


20191111: Does Life Need a Multiverse to Exist?
 09:56: So there must be factors which bring that number down to nearly zero.
 14:34: ... disagrees with a lot of these 'rare earth' type scenarios because the factors we talk about are needed for OUR evolutionary tree, but other types of ...


20191104: Why We Might Be Alone in the Universe
 02:40: ... rare earth hypothesis posits exactly this  that a range of factors made Earth exceptionally unusual and uniquely able to produce ...
 08:16: And the moon’s later tidal influence may also be an important factor in enhancing ongoing tectonic activity.
 10:04: ... are a few other possible rare Earth factors  we may have an unusually hospitable atmosphere and water content and ...
 11:08: ... are many factors that shaped Earth’s formation and development  what if the Cambrian ...
 11:54: It’s very possible that a combination of extremely unlikely factors means it’s extremely rare for planets to spawn intelligence.


20190930: How Many Universes Are There?
 03:34: The scale factor – or radius of the universe – increased by a factor of at least 10^26 in less than 10^32 seconds.
 03:50: Well, a scale factor or radius increase of 10^26 means a volume increase of that cubed – so 10^78.
 04:44: And our number of new bubble universes should multiply by the same insane factor each second.
 08:58: ... argument goes like this: if the number of new universes increases by a factor of some impossibly large number every second, then the vast, vast ...


20190916: Could We Terraform Mars?
 05:34: ... maybe double the current amount of CO2 in the atmosphere – which is a factor of around 100 times too low to make a ...
 17:32: ... to have transitioned between two stable or semistable states that are a factor of 10^27 different in ...


20190826: How To Become an Astrophysicist + Challenge Question!
 10:46: ... the horizon and flatness problems That is all distance is increased by a factor of 10 to the power of 26 Every 10 to the power of negative 32 seconds ...


20190806: What Caused the Big Bang?
 00:09: ... inflationary expansion multiplied the size of the universe by a larger factor than in the following 13 and a half billion years of regular ...
 03:48: ... and monopole problems inflation needs to expand the universe by a factor of 10 to the power of 25 in less than 10 to the power of negative 30 ...


20190718: Did Time Start at the Big Bang?
 03:27: ... about the size of an expanding infinite universe in terms of the scale factor That's the distance between any two points in space at some moment in ...
 04:20: So when I talk about rewinding the expansion, I mean running the clock backwards to track a shrinking scale factor.
 04:28: One way to do that is to keep halving the scale factor.
 04:38: ... and dense as you like But it'll still be infinite, spatially, the scale factor is incredibly small But an incredibly small number times infinity is ...
 05:07: That last tiny step is a doozy The scale factor goes from incredibly small to zero.


20190606: The Alchemy of Neutron Star Collisions
 02:47: ... star merger that formed these elements must have been an important factor here is that neutron star mergers are rare all shortlived rprocess ...
 13:02: ... a factor of a hundred at the beginning of reionization. And so electrons were ...


20190516: The Cosmic Dark Ages
 04:29: ... the universe was around 1/1000 of its current size. It expanded by a factor of 100 before the epoch of reionization started, and it’s expanded by a ...
 13:43: ... computer security protocols under development that don't rely on prime factoring. Thanks everyone for emphasizing this. Quantum cryptography may indeed ...


20190509: Why Quantum Computing Requires Quantum Cryptography
 01:21: For example, a quantum computer can calculate the prime factors of large numbers extremely quickly.
 01:27: This is bad because prime factoring is a cornerstone of internet cryptography.
 02:32: It's a mathematical process that can't be undone with the public key  only with its prime factors, which only you have.
 02:41: All of this works as long as the public key can't be easily factorized back into its two primes.
 02:47: ... is another type of oneway function  it's much, much harder to factorize large numbers than it is to create them by multiplication in the first ...
 03:01: Once quantum computers can factorize public keys quickly the entire public key system falls apart.


20190501: The Real Science of the EHT Black Hole
 04:09: Another important factor is that any two telescopes can only measure the angular separation in one direction on the sky.


20190424: No Dark Matter = Proof of Dark Matter?
 00:03: ... in a galaxy like this the dark matter would outweigh the stars by a factor of 400 the team has since found a second galaxy in the same group that ...


20190410: The Holographic Universe Explained
 11:04: In good stringtheorist style, Maldacena defined incorporated that scale factor into be a new spatial dimension.


20190328: Could the Universe End by Tearing Apart Every Atom?
 04:32: ... constant. So now the pressure term is A, negative and B because of this factor of 3 it's a bigger influence than the density so this whole party in the ...


20190320: Is Dark Energy Getting Stronger?
 13:57: What we have here is a tantalizing clue that our accepted understanding the factors that drive the expansion of the universe may be off.


20190220: Secrets of the Cosmic Microwave Background
 07:42: ... to the speed of sound times the amount of time that they had to collapse Factoring in the expansion of the universe over that time that size should be ...


20190207: Sound Waves from the Beginning of Time
 03:21: ... fact, dark matter outweighs baryons by a factor of five, Which means it was, by far, the dominant gravitational ...
 07:03: And now over thirteen and a half billion years later, the universe is expanded by a factor of 1,100.


20190124: The Crisis in Cosmology
 02:15: Until the new millennium, the best we could do was to estimate H0 within a factor of 2,...
 05:55: ...is a hell of a lot better than the old factor of 2 uncertainty.
 07:21: ...now stretched by a factor of 1,100 by its near 14 billion year journey...
 07:40: The blue regions are a factor of 100,000 cooler than the red regions,...


20190109: Are Dark Matter And Dark Energy The Same?
 09:15: ... with a negative cosmological constant should have a sinusoidal scale factor. ...


20181212: Quantum Physics in a Mirror Universe
 00:02: ... connected to quantum spin but for any particle with mass motion doesn't factor into it it's not the same as olicity it's best to think of quantum ...


20181206: Did Life on Earth Come from Space?
 00:37: ... when a media is slave to advertiser demands well this is definitely a factor when both the media outlet and the writer live or die by that month's ...


20181025: Will We Ever Find Alien Life?
 07:13: ... current number of communicative civilizations by combining a series of factors. ...
 07:23: ... are astrophysical factors like the rate of star formation and the fraction of these stars that ...
 07:47: The biological and sociological factors are so poorly understood that estimates of the number of civilization vary between none to tens of thousands.
 07:57: ... now that we have a much better understanding of the astrophysical factors and are also pretty sure that there aren't tens of thousands of advance ...
 09:37: That is perhaps it's one of the biological factors of the Drake equation that keeps the number of aliens low.
 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.


20181010: Computing a Universe Simulation
 04:50: Again, the Bekenstein bound is the event horizon surface area in Planck areas with an extra factor of a quarter that Stephen Hawking figured out.
 05:55: ... cetera, and not just atoms, you need to scale up the surface area by a factor of 10 billion and the radius by a factor of ...
 09:09: ... can do 3 by 10 to the power of 82 logical ops per second, a factor of 10 to the power of 20 slower than the computational speed of the ...
 09:20: ... its own evolution at maximum speed, our black hole computer would take a factor of 10 to the power of 20 longer or 10 to the power of 30 years to ...


20181003: How to Detect Extra Dimensions
 10:10: ... other important factor here in order to determine how much intensity was lost by the ...


20180920: Quantum Gravity and the Hardest Problem in Physics
 10:02: We talk about this more in our episode on the g factor.


20180912: How Much Information is in the Universe?
 04:07: We only drop factors of 2.


20180815: Quantum Theory's Most Incredible Prediction
 01:53: ... the theory and experiments behind one of these tests, measuring the G factor, or in simple English, measuring the anomalous magnetic dipole moment of ...
 05:23: This difference between the quantum versus classical magnetic moments for the electron is called the G factor.
 05:58: So measurements say the G factor is around 2.
 06:45: This messiness messes with the interaction of the electron and the magnetic field to shift the G factor slightly.
 09:04: ... field when we calculate the electrons magnetic dipole moment and it's G factor. ...
 09:17: If we consider only the first interaction I showed along with similar primary ones, you calculate a G factor of exactly 2.
 10:11: Over time, physicists have included more and more corrections refining the prediction of the G factor to increasing precision.
 10:39: To actually measure the G factor with the same high precision as these calculations requires some cunning.
 11:09: And the rate of this precession tells us the electron G factor.
 11:15: The measured G factor agrees with the calculated value to 10 decimal places.


20180718: The Misunderstood Nature of Entropy
 06:09: That microstate is a factor of 2 times 10 to the power of 107 less likely than one of the many smoothly mixed microstates.


20180516: Noether's Theorem and The Symmetries of Reality
 04:07: ... the last classic example, if the factors driving the laws of motion are symmetric under rotation for example, ...


20180502: The Star at the End of Time
 04:25: The heating core causes red dwarf fusion rates to increase by a factor of 10 or more, particularly towards the ends of their lives.


20180411: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!)
 02:35: ... cuts and splices, and processes that data to build and control an entire factory of protein molecular machines, which in turn, power the entire ...


20180110: What Do Stars Sound Like?
 05:48: The internal rotation of the star is also a key factor.


20171213: The Origin of 'Oumuamua, Our First Interstellar Visitor
 10:11: And you have to divide that MV by the Lorentz factor.
 10:14: That factor, the square root of one minus V squared on C squared, approaches 0 as velocity approaches the speed of light.


20170920: The Future of Space Telescopes
 00:27: ... Telescope, will succeed the Hubble Space Telescope with more than a factor of five increase in collecting ...
 02:24: ... to a million times fainter than the central star, but no where near the factor of 10 billion difference between the Earth and the ...
 03:54: Configured right, glare is suppressed by a factor of 10 billion at 50 milliarcseconds from the star.
 05:30: ... improve resolution by a factor of two, you need to double the diameter of the scope, which means the ...


20170913: Neutron Stars Collide in New LIGO Signal?
 04:39: But that's a factor of 10 smaller than the 30 solar mass black holes that merged in the first LIGO detection.


20170802: Dark Flow
 05:32: Once you factor out the Hubble flow, on average, those clusters seem to be drifting in the same direction.


20170719: 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.


20170712: Solving the Impossible in Quantum Field Theory
 06:59: Every additional vertex in an interaction reduces its contribution to the probability by a factor of around 100.


20170621: AntiMatter and Quantum Relativity
 16:04: We will try to keep our accuracy to within a factor of a thousand next time.


20170517: Martian Evolution
 06:49: ... Mars compared to Earth means it'll be harder to produce vitamin D. This factor is believed to result in the paler complexions found at high latitudes ...


20170503: Are We Living in an Ancestor Simulation? ft. Neil deGrasse Tyson
 06:30: You can mess with any of those numbers and still remain within those few factors of 10.
 12:00: With a little imagination, yet more mind factory universes can be conceived and simulated "usses" multiply exponentially.


20170405: Telescopes on the Moon
 08:18: Maybe I'm biased by the cool factor, but this all sounds like a great reason to get back to the moon, both robotically and in person.


20170329: How Time Becomes Space Inside a Black Hole
 12:55: ... has to be an integer factor, because if the EM field were pushing halfway through the time crystal ...


20170119: The Phantom Singularity
 14:52: ... 999 out of 1,000, huh, that's odd, moments are due to some unaccounted factor that is totally within our current understanding of ...


20170111: The EM Drive: Fact or Fantasy?
 06:05: The big one seems to be that thermal effects could still be a factor, in particular, deformation of the device or the scale due to thermal expansion.


20161109: Did Dark Energy Just Disappear?
 06:35: ... fact, there are only two factors that can change the way our universe expands: there are things that tend ...


20161102: Quantum Vortices and Superconductivity + Drake Equation Challenge Answers
 03:24: ... planets in that region  that's "N (sub) ast" for "astrophysical factor"  times the probability that a technological civilization will form on ...
 05:59: Now there are several biotechnological factors that seem important in making technologicallycapable life.


20161005: Are We Alone? Galactic Civilization Challenge
 00:19: ... number as a combination of astrophysical, biological, and sociological factors, each of which narrows the range of stars in our galaxy that may have ...
 00:33: ... factors include the rate of star formation in the Milky Way, the number of ...
 00:49: And finally, you need to factor in the average lifetime of the typical advanced civilization.
 00:56: When Frank Drake formulated his equation in the early '60s, most of the factors going into it were hopelessly unconstrained.
 01:31: In the last 50 years, we've learned a lot more about some of Drake's factors.
 01:36: ... some progress with the biological factors, as we push the fossil record back closer and closer to the formation of ...
 02:00: The sociological factors, and in particular, the average lifespan of a technological civilization, are still the subject of wild guesswork.
 02:09: The area where we've made the most progress is in the astrophysical factors.
 02:48: ... such a tight constraint on the astrophysics, but with the other factors being pretty hopeless, some researchers have decided to reframe the ...
 03:03: ... universe, what would that say about the biological and sociological factors in the Drake ...


20160914: SelfReplicating Robots and Galactic Domination
 05:34: It deploys initial solar panels and mining bots, and uses these resources to build a factory.
 05:42: That factory includes larger solar power plant, a stripmining operation, and perhaps more assemblers.
 07:02: Given B, we should see replication factories in our own solar system.


20160824: Should We Build a Dyson Sphere?
 04:40: Energy supply is the big limiting factor at the start, so it takes about 10 years to build the first collector.


20160720: The Future of Gravitational Waves
 02:48: Two more factors help with the certainty.


20160608: New Fundamental Particle Discovered?? + Challenge Winners!
 06:13: The consensus is that this is much smaller than anthropogenic factors.
 09:20: More precisely, for how many past and future doublings of the scale factor are they both at least 10% of the energy content of the universe?
 10:36: And we can just use the scale factor of the universe as the side length of our box.
 10:42: In fact, let's just use R for the ratio of past to present scale factors.
 10:57: Put all of this into our original equation and rearrange, and we get this equation for the ratio of scale factors.
 11:21: So you need to double that 0.36 about 1.5 times to get to the current scale factor of 1.
 11:36: It will happen when the universe is larger by a factor of 1.57, or about 0.7 of a single doubling.
 12:10: Now to do that, you need to integrate the first Friedmann equation over the scale factors that you got for the main part of the question.


20160525: Is an Ice Age Coming?
 13:09: But photons also get spread out and they get red shifted, so they do lose energy inversely proportional to the increasing scale factor.


20160518: Antigravity and the True Nature of Dark Energy
 03:32: a is the scale factor, sort of like the size of the universe.
 03:41: It's the acceleration of the scale factor.
 10:56: In the first Friedmann equation, we see it as an exponential change in the scale factor.


20160511: The Cosmic Conspiracy of Dark Energy Challenge Question
 03:38: We can think of that linear size as the scale factor of the universe.
 03:43: ... the scale factor, the size of the universe, only needed to be around 20% smaller than it ...
 03:55: Assuming a constant expansion rate, a constant increase in the scale factor, that means it was only two to three billion years ago.
 04:30: That's 100 doublings of its scale factor so its linear dimension, not its volume.


20160504: Will Starshot's Insterstellar Journey Succeed?
 08:10: Is the scientific payoff worth the money or is the awesome factor alone worth the investment?


20160413: Will the Universe Expand Forever?
 04:48: That letter a is called the "scale factor," and it represents the size of the universe.


20160406: We Are Star Stuff
 04:40: As well as providing us with all of their glorious entropyresisting energy, stars are element factories, stellar alchemists.
 10:04: Our universe is an element factory, producing building blocks capable of becoming you in all your stunning complexity.


20160330: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners!
 05:37: But our estimate of the total mass isn't accurate enough to bother factoring this in.


20160323: How Cosmic Inflation Flattened the Universe
 06:17: ... needed to increase the size of the universe by a factor of at least 10 to the power of 26 in less than 10 to the minus 32 ...


20160316: Why is the Earth Round and the Milky Way Flat?
 01:07: ... bridges, like the VerrazanoNarrows Bridge in New York, has to factor in the changing direction of down due to the curvature of Earth's ...


20160309: Cosmic Microwave Background Challenge
 03:36: Within a factor of two or so is fine.


20160302: What’s Wrong With the Big Bang Theory?
 07:52: ... exponentially accelerating expansion in which it increased in size by a factor of at least 10 to the power of ...


20160217: Planet X Discovered?? + Challenge Winners!
 04:06: To determine the observed tick rate, you also have to factor in the travel time of light.
 06:06: That's the Lorentz factor.
 06:15: Combine these and you get what we call the Doppler factor, which looks like this.
 06:20: The length of the observed second decreases by this factor for an approaching clock and increases for a receding clock.


20151022: Have Gravitational Waves Been Discovered?!?
 03:16: ... make gwaves that lengthen or contract our space here on Earth by a factor of 10 to the power of minus 21 or ...


20151015: 5 REAL Possibilities for Interstellar Travel
 01:43: This balance is factored into something we call the Wait Calculation, and we want to get this right.
 05:20: Assuming we can scale up production of antiprotons by a factor of say 100 trillion, trillion, then pion rockets may be a possibility.
 07:21: These tech issues need to be factored into the Wait Calculation.
 09:25: We just have to increase the world's nuclear arsenal by a factor of 200, which we shouldn't do unless it's a question of extinction.


20150930: What Happens At The Edge Of The Universe?
 02:29: So we have to factor in the time interval, especially when space is changing.


20150805: What Physics Teachers Get Wrong About Tides!
 01:50: So right up front, I want to make some assumptions to simplify the analysis and to remove unimportant factors from the picture.


20150624: The Calendar, Australia & White Christmas
 04:14: Other factors could bring the south a white Christmas even sooner.


20150506: Should the First Mars Mission Be All Women?
 00:54: Lots of factors disqualify you from NASA before you even begin including, currently, height restrictions.


20150409: How to Weigh a Fart
 01:10: That number may be off by a factor of two or so, but I doubt it's off by a factor of 10.


20150408: Could You Fart Your Way to the Moon?
 02:48: In truth, even starting out from low Earth order, you'd be short of Earth's escape velocity by a factor of about a billion.
 07:19: A lot of factors come into play.


20150401: Is the Moon in Majora’s Mask a Black Hole?
 06:34: Once you factor in tidal forces, I don't see how you avoid this conclusion.


20150311: What Will Destroy Planet Earth?
 04:53: ... we're going to talk about anyway just because of the sheer awesomeness factor death by expanding ...


20150304: Should We Colonize Venus Instead of Mars?
 01:17: Depending on the launch window, the round trip can be 30% to 50% shorter, which is a major factor for manned missions.


20150218: 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.
