Understanding the Misconceptions of Science

Course No. 1397
Professor Don Lincoln, Ph.D.
Fermi National Accelerator Laboratory (Fermilab)
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Course No. 1397
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What Will You Learn?

  • Discover the scientific truths-and fictions-behind the famous story of how Benjamin Franklin's experiments with electricity.
  • Learn the important parameters neglected by Drake's famous equation about the existence of extraterrestrial life.
  • Break down the popular scientific misconception of evolution as a linear model.
  • Examine the differences between radiation that is dangerous and radiation that's part of everyday life.
  • Learn that, while an object cannot travel through space faster than the speed of light, the expansion of space itself can be faster.

Course Overview

Evolution. Relativity. The Big Bang. These and other scientific ideas have come to define our understanding of the modern world and how it works. But here’s a secret: What you learned about them in school isn’t necessarily the whole truth.

Science is, undeniably, a truly incredible field of human endeavor. In the last five centuries alone, we’ve been able to make startling advancements in human progress thanks to discoveries like electricity and magnetism, the germ theory of diseases, and the inner workings of atomic particles.

But for all its importance to our everyday lives, most of us who aren’t scientists don’t think too deeply about science. We settle for what we were taught in high school—and for the most part, that education was sound. Still, compromises had to be made, leaving most of us with conceptions of science that weren’t wrong, but also were just a piece of a larger, much more complex story. Misconceptions are even taught in fairly advanced science classes—and are still believed by people with quite respectable scientific educations.

Consider these commonly held scientific beliefs:

  • Planetary orbits are fixed ellipses.
  • We only use 10 percent of our brains.
  • Nothing travels faster than light.
  • A thrown object’s trajectory is a parabola.

They seem correct on the face of it, but they’re all misconceptions that aren’t entirely accurate. There’s much more to the story than you think. And Professor Don Lincoln, a Senior Scientist at the Fermi National Accelerator Laboratory, has crafted a magnificent 24-lecture course devoted to busting myths, clearing up confusion, and giving you scientific epiphanies that could change how you think about your everyday world. In Understanding the Misconceptions of Science, you’ll explore shocking truths about some of science’s most well-known—and often controversial—concepts, including the physics of flight, black holes, quantum mechanics, and even the possibility of extraterrestrial life. Ultimately, Professor Lincoln’s research-backed lectures offer newer, better, and more correct ways to understand what you were once taught.

Explore Misconceptions in Biology, Chemistry, and Beyond

“Science,” Professor Lincoln says, “is built on facts, sure. But it’s also a methodology for determining and accepting—or rejecting—those facts. And inherent in science is a perpetual level of uncertainty and ignorance. Science has to be prepared to change and grow.”

This ever-evolving nature of scientific knowledge and understanding is at the heart of Understanding the Misconceptions of Science. Professor Lincoln has structured this course as a broad survey that assumes little prior knowledge of the fields being covered, which includes chemistry, physics, biology, quantum mechanics, astronomy, mathematics, and more.

Almost every lecture is devoted to a single major scientific concept or discovery that is often misunderstood or over-simplified. At the start of the lecture, Professor Lincoln highlights how that particular misconception is commonly taught to students. Then, he takes you on a deep dive into how the science really works, and how recent discoveries and advances have reframed—and in some instances, shattered—commonly held ideas.

The result is a course that not only opens your eyes to just how large and mind-bending science is, but that can also spark a curiosity to investigate further.

Discover a Host of Scientific Epiphanies

What makes Understanding the Misconceptions of Science such an entertaining and engaging learning experience are the “aha!” moments packed into every lecture. Delivered with insight, clarity, and a dash of humor, these and other of Professor Lincoln’s scientific epiphanies will have you rethinking what you know—or thought you knew—about the world of science.

  • A (Less Than) Ideal Gas Law. The ideal gas law describes the relationship between pressure, volume, temperature, and the number of moles of molecules for an ideal gas. There’s just one problem: gases aren’t ideal. That’s where the helpful—and slightly more complex—van der Waals equation comes in.
  • Portrait of an Electron. We tend to think of electrons in an atom orbiting the nucleus like planets around a star. The scientific reality, however, is that electrons are simultaneously everywhere the laws of quantum mechanics allow. The truth is that most matter is just empty space, and what you’re made of aren’t simple spheres—but force fields.
  • Think outside the Punnett Square. Most human characteristics aren’t governed by a single gene. Take eye color, for example. As it happens, there are two important genes dealing with eye color, along with 10 other genes that play a minor role. Plus, the idea that dominant traits will be the most common (and recessive traits the rarest) is wrong.
  • Less Bomb, More Balloon. During the Big Bang, all the energy and matter of the universe wasn’t just sitting somewhere in space and then blew up. Rather, because matter and energy and space and time are interlinked, there was a tiny volume that wasn’t a singularity that expanded into our visible universe more like an expanding balloon.
  • Use Your (Whole) Brain. No, we don’t use just 10 percent of our brain, and a big reason is evolution. The brain uses about 20 percent of the energy consumed by metabolism, in spite of being only about 2 percent of the body’s mass. If 90 percent of the brain were not used, there would be a huge evolutionary pressure to reduce the size of brains and skulls.
  • Floating or Falling in Space. While you may see video clips of astronauts in the International Space Station doing flips and all sorts of things, the truth is that they’re not floating in zero gravity. The correct word we should be using to describe the state in which these astronauts are working and playing in is, rather, “free fall,” and the difference is more significant than you may think.

Along the way, you’ll develop a sharper understanding of some of the most fundamental concepts, equations, theories, and issues in contemporary science, including:

  • Faraday cages, metal shapes that help protect what’s inside from electrical charges and which are used to understand what happens when lightning strikes a car;
  • The Bernoulli equation, developed to better understand the laws of motion of fluids and also used (incorrectly) to explain how planes fly;
  • The twin paradox, the most famous paradox in special relativity that bundles together a pair of twins to study space travel, time dilation, aging, and movement;
  • Carbon-14 dating, a scientific method for piecing together how long ago something happened that’s actually a more complex process than it might seem; and
  • The Drake equation, which can provide an estimate of the number of civilizations in our galaxy that we could detect—but which also neglects important parameters.

Gain an Awareness for the Immensity of Science

As with many of our other science courses, Understanding the Misconceptions of Science takes a welcoming, introductory approach to topics and issues that might seem intimidating to the average non-scientist.

Professor Lincoln goes to great lengths to make his expertise accessible to everyone willing to open their mind to the possibility that what they think they know about science isn’t the whole truth. To that end, he’s crafted these lectures to include helpful graphics, animations, images, equations, and scientific terms that help you make better sense of what’s being discussed.

But what will keep you engaged, above all, is the energy and excitement of Professor Lincoln’s lectures. He’s an expert public speaker, dedicated to scientific outreach and education—efforts which have earned him the 2017 Andrew Gemant Award from the American Institute of Physics.

Understanding the Misconceptions of Science is about awareness and respect for what an immense undertaking scientific inquiry and experimentation is. “The real message here is just how little we know,” he says. “Science popularizations are entirely misleading on where we are in this effort. This isn’t to minimize our accomplishments. We’ve come a long way. But we have even further to go.”

Regardless of where you are in your own scientific adventures, this course will empower you with not just good science—but better science.

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24 lectures
 |  Average 30 minutes each
  • 1
    What the World Gets Wrong about Science
    Start your journey through some of the most jarring misconceptions of science with this introductory look at the nature of science itself. You’ll examine ways the scientific method deviates from the way it’s taught, the true definitions of terms like “theory” and “model,” and the relationship science shares with philosophy. x
  • 2
    Franklin's Kite and Other Electrifying Myths
    It turns out the usual story of Benjamin Franklin’s discovery of electricity using just a kite and a key isn’t exactly true. Get the real story behind this and other misunderstandings about electricity and reframe the way you think about how electricity works—in nature, in batteries, and throughout your home.. x
  • 3
    The Ideal Gas Law (It's Not Ideal)
    Here, Professor Lincoln reveals the ways in which common teachings about gases and their properties are idealizations that ignore important considerations such as the size of atoms. Topics include the limitations of the Ideal Gas Law (PV=nRT) and the importance of the van der Waals equation. x
  • 4
    From the Ground Up: How Flying Works
    Get a whirlwind introduction to the scientific truths about how planes fly through the air. This lecture overturns the (often-very-wrong) way flight is taught in introductory physics classes and focuses on two relevant subjects involved in flight: air circulation and how the wing pushes air downward. x
  • 5
    From the Sky Down: How Falling Works
    Introductory physics classes tell you that a ball thrown on the surface of the earth follows a parabola. What happens when you take away the simplifying assumptions in this scenario? How do we factor in air resistance and the Earth's rotation? What happens when an object falls from very great heights? x
  • 6
    Myths of Orbital Motion
    In this lecture, revisit some of the common misconceptions we have about how the universe works, with a focus on our solar system. Two myths you'll bust: that the orbits of planets are all fixed ellipses and that astronauts on the International Space Station live in zero gravity. x
  • 7
    What's Inside Atoms?
    Discover a very different idea about the real essence of matter as it relates to the molecules and atoms of chemistry. Learn to think about matter as entirely empty space, not tiny balls; consider the inside of a proton and neutron; and ponder the question of where, exactly, mass comes from. x
  • 8
    The Truth Is in Here: The Science of Aliens
    There are some popular misconceptions about alien life that science-fiction writers have said often enough that we take them to be likely or true—but are they? Professor Lincoln unpacks the possibility of silicon-based life and truths about the Drake equation, which posits the number of possible civilizations in our universe. x
  • 9
    Misconceptions about Evolution
    It's often the misconceptions about evolution that lead people to not believe in it. This lecture tackles four prevalent myths about the theory of evolution: that it explains how life began, that it states humans descended from chimpanzees, that evolution has a goal, and that evolution means more complex organisms will evolve. x
  • 10
    Nutrition’s All About You—and Your Gut Biome
    How do misconceptions about nutrition spread? What if what you learned about digestion isn't the entire story? In this lecture, examine the unseemly alliance between science, advertisers, and the media; and make sense of the important role that a fascinating microbe ecosystem plays in how the human gut works. x
  • 11
    Humans Are Not Peas: Myths about Genetics
    It might surprise you to know that most human characteristics—including eye color—aren’t governed by a single gene. Nor do dominant genes always become more common over time. As you’ll discover, we owe these and other misconceptions about genetics to the Punnett squares you first encountered in high school biology. x
  • 12
    Getting Smarter about Intelligence
    Focus your attention on popular myths about the human brain. There's the myth that we only use 10 percent of our brain power, the concept that people can be right- or left-brained, and the complexities of learning styles and IQ scores to consider. Use current science to make sense of how your brain works. x
  • 13
    Exposing the Truth about Radiation
    Radiation is one of the most misunderstood of all scientific phenomena. Get the scientific truths about this subject by investigating the four types of ionizing radiation, including alpha radiation, beta radiation, gamma radiation, and neutron radiation. Then consider how much radiation you encounter every day—and how much of it you can ignore. x
  • 14
    Does Carbon-14 Dating Work?
    Clarify oversimplified ideas concerning how carbon dating works and get a stronger appreciation of just how complicated and sophisticated a scientific technique it is. While dating objects under 60,000 years old has become relatively easy, the current accuracy of modern science depends on taking subtle effects into consideration. You'll learn why doing it precisely takes some care. x
  • 15
    How Statistics Can Lie to You
    The best way to read statistics correctly: Understand the various ways they can be misused to fool you. Here, Professor Lincoln discusses how averages and percentages can make certain statistics seem shocking, reveals how you should rethink the confidence threshold of 95 percent that scientists use, and more. x
  • 16
    Does Thermodynamics Disprove Evolution?
    Take on a few of the simpler misunderstandings revolving around heat as it relates to thermodynamics: the ways heat energy moves and changes. Is it correct to say heat always rises? Are entropy and disorder synonymous? How do we often misinterpret the second law of thermodynamics, and what does it tell us about evolution? x
  • 17
    How Relativity Is Misunderstood
    At its core, relativity is about something very simple: how two people in relative motion see the world differently. In the first of two lectures on misunderstandings about relativity, explore the Lorentz transforms, then journey through a seeming paradox that disappears once you use the Lorentz transforms properly. x
  • 18
    E=mc2 and Other Relativity Myths
    Get the truth about the most famous equation in science. Ponder the most notorious paradox in special relativity, known as the twin paradox. Discover whether or not we really can travel faster than the speed of light. Strengthen your appreciation of how, despite its mind-blowing nature, relativity is the way the world works. x
  • 19
    Why Do Black Holes Get Such a Bad Rap?
    Few astronomical bodies are more misunderstood—and more mysterious—than black holes. Can they actually reach out and grab matter near them? Do they have a singularity at their core? Find out in this journey that takes you from outside the Schwarzschild radius to inside the event horizon and beyond. x
  • 20
    What Banged, and Was It Big?
    Develop a better, more scientifically accurate mental picture of the Big Bang. What exactly happens is hard to get your head around, but the key involves understanding the links between matter, energy, space, and time. And all you need to grasp this fascinating concept is a common balloon. x
  • 21
    Can You Go Faster Than Light?
    In this lecture, Professor Lincoln explains the various ways in which talking about the speed of light can lead to a misunderstanding of whether or not particles can travel faster than light. Learn why it’s more accurate to say objects cannot move through space faster than light—but space itself can. x
  • 22
    Untangling How Quantum Mechanics Works
    Examine the peculiarities of quantum mechanics in an effort to better understand what's going on in the quantum world. Get a whirlwind introduction that covers everything from the wave function and the behavior of electrons to the double-slit experiment and the surprising differences between classical and quantum mechanics. x
  • 23
    Untangling What Quantum Mechanics Means
    Dig deeper into misconceptions about quantum mechanics, with a focus on the complicated, the contradictory, and the downright sketchy. What happens to an electron when you're not looking at it? Can a cat be both alive and dead at the same time? Should we connect quantum mechanics with Buddhism and Taoism? x
  • 24
    Is There a Theory of Everything?
    Searching for a theory of everything is a grand, epic saga. Start your own search with this engrossing investigation of the building blocks of the cosmos and the forces that hold them together—both of which are required to even begin to develop a fundamental theory that answers all questions. x

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Your professor

Don Lincoln

About Your Professor

Don Lincoln, Ph.D.
Fermi National Accelerator Laboratory (Fermilab)
Don Lincoln is a Senior Scientist at Fermi National Accelerator Laboratory (Fermilab). He is also a Guest Professor of High Energy Physics at the University of Notre Dame. He received his Ph.D. in Experimental Particle Physics from Rice University. Dr. Lincoln’s research has been divided between Fermilab’s Tevatron Collider, until its close in 2011, and the CERN Large Hadron Collider, located outside Geneva,...
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Reviews

Understanding the Misconceptions of Science is rated 4.3 out of 5 by 27.
Rated 4 out of 5 by from Good course for science buffs In chapter-1 the good professor explains how science has made significantly more POSITIVE contribution to humanity than previous centuries of ignorance, superstition & fear. I totally agree. With such come-ons (including politics), I'm always wondering when the HOOK will be thrown at me. At 70, I was asked by my grand nephew "what's the best advice you've ever learned?" My response: "Listen to A, then listen to B - then listen to what A says about B and what B says about A", unquote. So when the good professor (who I find a likable fellow) says QUOTE: "the theory of evolution? No serious scientists question it". HA! I fall out of my chair laughing. No, Doc - I don't see the EMPEROR's NEW CLOTHES! Reminds me of when it comes to dinosaurs on Venus and canals on Mars - "no serious scientists would question it". Then, 1,000 years ago, the "serious scientists" told the emperor "we've amassed it all - there is NO MORE knowledge to learn". MY! How wonderful & wise!!! So on this subject (evolution chapter), I've heard the clever doctor hotshots on BOTH sides slug it out. As a history buff - we're all dancing around the MAIN ISSUE here - it's not about evolution: but the world's past ALLERGIC reaction to the [self-proclaimed] "infallible" Roman Catholic leadership suppressing free thought as evidenced by burning many at the stake (primarily their own Bruno), house arrest of Galileo, telling musicians that "going from this note to that note is sin", endless wars with protestants & other censorships. The world wanted OUT! Enter "evolution". Another of my TGC courses entitled "Science Wars: what scientists know and how they know it" - clearly defined what science IS and what it is NOT. I recall (in summary) "the ability to create, predict or reproduce - supported with documented lab test results and mathematical formulas" --- and the reason art, music, philosophy and religion can NOT be called "science". I agree. So: shall we discard ART, MUSIC and PHILOSOPHY because it's not the new god of "science"? One "scientist" said "you're nothing but a BAG of atoms". BTY - some would say "science" is only DISCOVERY since science cannot CREATE a single atom, living cell, or explain the origin of gravity or the strong nuclear force that holds the electrons & nucleus together (they can only calculate its effects). As such, inventions arise. Where's the MATH NERD formulas for evolution? Reconstruct a skeleton from a tooth fragment? WAY over in east Africa where few (if any) can verify? The theory is so full of holes, that even if I was a devout atheist or staunch agnostic, I would still laugh at it. Where are the innumerable in-between species in the fossils? They should be EVERYWHERE!! Explain DISTINCT species now...there shouldn't be any. It barely qualifies as a HYPOTHESIS; much less a THEORY. Since the doc is also a Star Trek fan -- remember Kirk's famous quote? "I want that THIRD alternative!" I use my mental trash can daily. Before delving into the nit-picking details, look at the big picture first: "NOTHING CAN ESCAPE A BLACK HOLE!" is the mantra. By definition, a BH can NOT explode. Yet the universal singularity, black hole (whatever you call it) explodes. Contradiction? In the last chapter (24) the good doc says: "most theories end up being wrong. A lot of ideas out there - and very few truths". Will the REAL truth please stand up! If the "blind leading the blind" all have a CONSENSUS - then it MUST be the truth….prevalent in the political world. Not to throw out the baby with the bath water - YES, I do recommend this course. With the many subjects presented in this course - I'm left with this pondering thought: when a [real] THEORY reaches it's maximum threshold - then it may become irrelevant or obsolete. Blood letting? I also bought the doc's TGC course THE THEORY OF EVERYTHING. Buy VIDEO - not audio. Good job doc!
Date published: 2019-09-15
Rated 5 out of 5 by from Illuminating This course was a truly wonderful experience where one really gets to the bottom of many fascinating areas of science. Many surprising misconceptions are illuminated by the expertise of a Senior Scientist at Fermi National Accelerator Laboratory -what more could one ask. I hope that Professor Lincoln will work with Great Courses to deliver an Understanding the Misconceptions of Science, Part Two. Excellent!
Date published: 2019-09-12
Rated 5 out of 5 by from Brilliant exposition of misconceptions of science Professor Lincoln lives up to is excellent bona fides as a particle physicist and senior scientist at Fermilab. Touching on many different aspects of various sciences from evolution to quantum theory, he presents the facts together with common misunderstandings . Of particular interest to me was his lecture on radiation: "Probably the most misunderstood aspect of science..." With much concern about whether cell phones are safe and what the new 5G networks might do to our health, his clear explication about the differences between electromagnetic radiation and ionizing radiation was very helpful and reassuring. Dr. Lincoln is clever, funny, casual, and an engaging teacher. Some of the lectures get a bit heavy with math, but even there Dr. Lincoln presents complex concepts with ease and lucidity. I thoroughly enjoyed this course.
Date published: 2019-09-01
Rated 5 out of 5 by from The Rest of the Story After watching this series on Great Courses Plus, I bought a copy for each of the college bound members of my extended family because I knew it would be great for their future studies.
Date published: 2019-08-02
Rated 5 out of 5 by from Useful review of info from other courses. I had recently completed the courses on Astrophysics, Quantum Mechanics, and The Theory of Everything and this summarized much of the information from a unique perspective.
Date published: 2019-07-31
Rated 4 out of 5 by from Overall Enjoyable Because I so greatly enjoyed Dr. Lincoln's course "The Theory of Everything", I was impelled to purchase this one also. If the first course can be rated 5 stars, this is a 4 star course. It covers a wide range of topics, but I found those on physics more enlightening than those on biology (maybe because I came in knowing more about biology). Nonetheless, the discussion of IQ was full of facts of which I was unaware. In the realm of physics, I particularly liked those on black holes, the big bang, and quantum mechanics. The one on electricity provided me with the new knowledge that electrons do not flow through conductors as water does through a pipe, but I would have liked to learn more about how their bouncing around in a wire accomplishes what we know electricity does accomplish. I also now have a better understanding of Foucalt's pendulum. On a different note, Dr. Lincoln's puts to death the notion that the Twin Paradox in special relativity is explicable because of acceleration of the fast moving twin, but at the same time he recommends Wolfson's course on relativity that explains the paradox by acceleration. One critic of this course takes Dr. Lincoln to task for goofiness. The problem is that his jokes are rehearsed, not spontaneous, so they almost always fall flat. Yet, in a way, they are charming because they are the quintessence of nerdiness, to which Dr. Lincoln freely admits in The Theory of Everything. In summary, this course provides some new insights that supplement other Great Courses, and I think it is a worthwhile purchase.
Date published: 2019-07-31
Rated 5 out of 5 by from Understanding the Misconceptions of Science I have genuinely enjoyed listening and watching Dr. Lincoln’s lectures in this course, Understanding the Misconceptions of Science, and his other Teaching Company course, The Theory of Everything: The quest to Explain All Reality. He has an engaging style and is always thought provoking. I have learned a lot from his presentations and highly recommend his courses to all who want a better understanding of science and physics in particular. One of his lectures was especially thought provoking. This was the lecture, “E=mc2 and Other Relativity Myths.” The subject in particular is the Twin Paradox. I’ll add a little background for general readers. 1. Einstein proposed that the laws of physics were the same in all uniformly moving frames. These are frames of reference that move in a constant direction with a constant speed. For simplicity, I’ll just call them “frames.” Then Einstein says there is no preferred (or absolute) frame – all frames are equally valid. 2. One set of laws that should hold in all such frames are Maxwell’s Equations. These equations pertain to electric and magnetic fields and they predict that the speed of light should be c = 299,792,458 meters/second. As a consequence of the first statement above, this is the exact speed that every uniform frame should measure, even if the origin of the light is from some other frame. An experimenter in one frame should measure the speed of light as c. This same experimenter, looking into a second experimenter’s frame, should see that this second experimenter also measure this same speed c using their meter sticks and clocks. 3. There is a special set of equations that convert position and time coordinates in one frame to those in another frame and that leave Maxwell’s Equations the same. These are known as the Lorentz Transformation. There is a constant in these equations called gamma which equals one over the square root of one minus the velocity squared divided by the speed of light squared. Here the velocity is the velocity of one frame with respect to the other. 4. In Dr. Lincoln’s discussion, we have two twins: Abby who stays at home on Earth and Gabby who is a space trekker and goes to Tau Ceti in a uniform frame with a velocity v that is 99.9% the speed of light. 5. According to the Lorentz Transformation, as Space-trekker Gabby goes by Stay-at-home Abby, Abby sees Gabby’s clock go slower than hers by the factor of gamma. One might think that this is a simple observation problem. As Abby looks at Gabby’s clock through a telescope, Abby sees images that are delayed due to the finite speed of light and so it looks like Gabby’s clock is running slow. However, Abby is smart and has compensated for this light delay, and she still inferentially perceives Gabby’s clock runs slower. We can invert the Lorentz Transformation and think about how Gabby sees Abby’s clocks. This inverse transformation looks exactly the same as the original except that the sign of the velocity has been flipped. (Gamma remains the same since the velocity is squared and the change in sign makes no difference.) Things that we said about one frame we can now say the same about the other. Therefore, Gabby sees Abby’s clock slow down by this same factor gamma. So, Gabby sees Abby age more slowly and Abby sees Gabby age more slowly. Who is right? They both are! This is the crux of the Twin Paradox. In short, each frame always thinks the other has slower ticking clocks. If one of these twins was right and the other wrong, then there would be a preferred frame. Since there is no preferred frame, both Abby and Gabby are correct in their perceptions of the other. Abby’s and Gabby’s frames are equally valid and say the same thing about the other. This conclusion flies in the face of our common sense, but there is no way to physically validate who is actually younger given our uniformly moving frames. (See note #8 below.) Dr. Lincoln also disagrees saying, "Obviously, they can't be both younger than the other." But such is the strange world of Relativity. 6. Dr. Lincoln introduces a third twin, Tabby, who happens to be traveling in a uniform frame going from Tau Ceti to Earth with velocity v. (This is the same speed that Gabby has while going away from Earth.) Tabby passes by Tau Ceti at the same time that Gabby passes by Tau Ceti. Gabby shows a sign with time information that is picked up by Tabby, but otherwise there is no physical connection between Tabby and Gabby as they pass Tau Ceti. 7. Since Tabby is in a uniform frame, Abby can look at Tabby’s clock and see that it runs slower than hers, again by this factor gamma. A point should be emphasized is that Tabby can look at Abby’s clock and see that Abby’s clock also runs slower than hers by this same factor of gamma. Abby thinks Tabby is aging more slowly and Tabby thinks Abby is aging more slowly. As before with Abby and Gabby, both Abby and Tabby are correct! Dr. Lincoln states that Abby is stationary and Tabby is the one who has actually aged more slowly than Abbey, but this conclusion cannot be made based on these uniformly moving frames. Abby’s frame is not stationary with respect to either Gabby’s frame or Tabby’s. Dr. Lincoln should consider a follow-on problem: While we have the perception of how Abby sees Gabby’s and Tabby’s clocks, we need to also look to see how Gabby and Tabby see Abby’s clock. 8. To see if one twin, say Gabby, has actually aged less than Abby, we would need to have Abby and Gabby together as identical twins, send Gabby on a space trek, and then bring her back to Stay-at-home Abby for a side-by-side comparison. However, this process violates the assumption of the special case of uniform motion. If Gabby were to be continuously in uniform motion for the duration of the experiment, then Gabby and Abby could be together at one point in space at one instant of time, but would never meet again. In this special case of uniform frames, the question of which twin ages slower cannot be answered. For a fuller description of how these twins age, we would have to go to the more general case of non-uniform frames in order to bring Gabby back to Earth. I would like to see Dr. Lincoln spend more time explaining this fascinating aspect of the Twin Paradox. 9. The following is just extra stuff: The essential requirement to insure that the speed of light is always measured to be the same constant, c, in every uniform frame causes our everyday “common sense” to be invalid. We are inclined to think there is a nice separation between time, which should run the same for everyone, and space, which should be independent of time. However, this common sense is incorrect and we have to accept a world that does not conform to our everyday expectations. We have to consider an integrated thing called “space-time.” To elaborate on this idea, we need to set up a spatial dimension, call it x, in the direction from Abby to Tau Ceti. Abby has marked off uniform intervals along this dimension. She has also placed clocks at each interval. These clocks tick at exactly the same rate (ultra precise) and Abby has synchronized them so that they all read exactly the same time. Abby also has observers at each clock that can peer into other frames. Gabby also has a spatial dimension parallel to Abby’s going from Abby to Tau Ceti. Gabby’s frame is, as before, moving in the positive x direction with velocity v. Gabby has marked off uniform intervals and these intervals have the same length as those in Abby’s frame. Gabby has also set up clocks that tick at exactly the same rate and at the same rate as Abby’s, and they are all synchronized to read exactly the same time. (Note of caution: it is not trivial how we can set up this experimental situation and be guaranteed that the clocks all tick at the same rate and the length units are also all the same.) As these frames slide by each other, unusual effects are noticed. First, Abby’s observers look at Gabby’s clocks and sees that they are not at all synchronized. The ones ahead of Gabby show times that are delayed and they are delayed more the farther ahead one looks. The ones behind Gabby are advanced and become progressively more advanced the further behind one looks. Gabby has a strong disagreement with Abby (like some sisters I know). Gabby says all of her clocks are synchronized to read the same time and she thinks that Abby’s clocks are the ones that are not synchronized. Furthermore, as Abby looks at Gabby’s clocks as they pass by, they tick at a slower rate than Abby’s clocks. Gabby looks at Abby’s clocks and sees them tick more slowly. Abby thinks that Gabby’s length measures shorter than hers, and Gabby thinks Abby’s lengths are shorter. Both perceptions are correct. Both frames are equally valid and neither one is preferred over the other. (What I have described here is the Lorentz transformation in physical terms rather than mathematical ones.) Note that the position affects the perceived time and that time affects the perceived position - hence the expression, space-time. There is no such thing as an absolute time and it may not make any sense to say that two events in the universe happened at the same time. The notion of simultaneity does not apply in general. 10. It was the brilliance of Einstein to take the simple statement that the speed of light must be constant in all frames and lead us to such mind-bending consequences!
Date published: 2019-07-19
Rated 4 out of 5 by from Ups and Downs Some interesting subjects and some too basic. Very good for those who have had no college science and did not pay attention in high school physics and chemistry. Great lecturer. If you have done most of the Great Courses science series you don't need this. If not, it could be right for you.
Date published: 2019-07-14
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