Search the Community

These BBC videos are a bit "for the masses," but they do their job: Feb 6, 2019 - "Why Almost All the Universe Is Utterly Invisible" on bbc.com Just to throw something out there, since black holes are causing everything in each galaxy to swirl around them, why can't they be repelling everything that's outside of their galaxy? Doesn't it seem like galaxies are all pushing themselves away from each other, sort of like (for a visual example) two magnets whose negative poles are facing each other? If black holes have a such a strong attractive force, then why can't they have an equally impressive repulsive force? There. I just solved all the mysteries of the cosmos in two minutes. Only I could have done this. Sincerely, Donald

These are two really well-written articles: Apr 9 - "A Brief History of Black Holes As We Await the Big Reveal from the Event Horizon Telescope" by Sarah Kaplan and Joel Achenbach on washingtonpost.com Apr 10 - "See a Black Hole for the First Time in a Historic Image from the Event Horizon Telescope" by Sarah Kaplan and Joel Achenbach on washingtonpost.com And here it is, an actual Black Hole - this is one of the most important pictures ever taken:

This is fascinating and worth reading, as this problem stumped legendary physicist Richard Feynman. "MIT Scientists Have Just Figured Out How To Break Spaghetti into Two Pieces" by Michelle Starr on sciencealert.com

I read Stephen Hawking's (R.I.P.) "A Brief History of Time" not long after it was published in 1988, and even though everyone is saying how simple it is, I'm pretty much in the Charles Krauthammer camp: I found it almost 'incomprehensible' at the time. Granted, I'm much, much more educated now than I was then, so maybe it would be a walk in the park for me now, but it was not easy reading for me at age 28-ish. (I should add that Richard Feynman's book, "Six Easy Pieces," put me in the same boat: They were *not* easy. And then, I was foolish enough to tackle "Six Not-so-Easy Pieces," which I read more as a personal challenge than anything else - I remember nothing about it.) I think the problem might be that, while these are two scientific geniuses, they aren't great authors. Honestly, I question the myriad of five-star reviews, and all the comments saying they were reading "Six Easy Pieces" to their grade-school children. I don't believe it! There are two kinds of people who say they enjoy these books: those with a degree in physics, and those who are trying to impress people - I am neither. Grade-school children, my eye.

Okay, hold on: We are three-dimensional people, living in a three-dimensional world. We have length, width, and height. We're cubes and spheres; not squares and circles. Even if something has 1/1000000000000000th of a micron of height, it's still living in the third dimension - it would have to have zero height to live in two dimensions. Picture a square, perfectly flat, platform on the ground that goes on for a long, long way - perhaps even to infinity (or, perhaps not). Now, picture a small, circular shadow on that platform. That shadow has length and width, but since it has zero height, it is a two-dimensional object. (Ignore any trace, sub-microscopic height an actual shadow might have, and pretend it's zero - this is for the purposes of visualization). So the shadow can move along the platform, to-and-fro, however it pleases (ours is a sentient shadow), as long as it stays within its universe - it has no idea where the platform ends, or even *if* it ends - maybe it does, maybe it doesn't. Now imagine a human walking along the platform, and encountering the shadow. The curious human reaches down and sticks a fingertip on it, and the shadow responds by going, "What the hell was that? This circle just 'appeared,' and then it 'disappeared.'" (the circle being the absolute end of the fingertip - the part with zero height - which probably doesn't really exist, but for our purposes, it does). The shadow can't "look up and see us," because it has no concept of height - even if we were one-inch above it, it wouldn't know we were there. You've heard the phrase, "You can't be in two places at once," but since we're three dimensional creatures, visiting a two-dimensional world, we *can* be in two places at the exact same time: All we need to do is take one fingertip on each hand, and put them on two different points of the platform. For the shadow to be in both of these places, it would need to make a voyage across the platform; for us, it's simply a matter of bending down and touching it in two places. Since the platform is perfectly flat, it is impossible for the shadow to see both of our fingertips at the same time (unless we place both of them on top of the shadow, which might be big enough for us to do this, or it might not be). --- Picture the Earth revolving around the Sun. During its orbit, it is *always* in one place at any given time, although it travels its elliptical orbit, making one complete revolution each year. In March, it's impossible for Earth to be in the same position on that ellipse where it would be in July. But throughout the course of its orbit, the Earth is always a sphere (or close enough) - it always exists in three dimensions. Now, draw a map of every single possible position the Earth would be in during the entire elliptical orbit. What would it look like? It would look something like a doughnut (or a torus, if you will). That's a three-dimensional *approximation* of a fourth dimension, the fourth dimension being "time" - that torus never exists in reality, but over the course of a year, or a single revolution, the Earth will have covered every single point on that torus - the key phrase being, "over the course of a year." It takes *time* to complete the revolution. Meet Blorp, our four-dimensional creature, who exists in different time periods *at once* (I'd say "at the same time," but that doesn't make any sense). If Blorp was big enough, he'd be able to take two of *his* fingertips (which would be a sphere, not a circle), and touch our Earth simultaneously, both in March, and in July. Whereas for us three-dimensional creatures on Earth, we'd have to make a voyage through our universe to travel from March to July on our elliptical orbit. If Blorp stumbled across our universe, at the same moment in time we were there, we'd say, "What the hell was that? And why did it appear, and then disappear?" It's because Blorp came into our spacetime, and then left it - he could come back anytime he chooses, just by reaching down with his fingertips, and he could also exist simultaneously in our present, our past, and our future (he could use a toe to visit our past - maybe he'll even be wearing his Time Jorps (Jorp was a fourth-dimensional athlete, who was able to leap great distances through time - some say he is the GOAST (Greatest of All-SpaceTime)). Sorry - I'm not really well-versed in fourth-dimensional humor. --- For our two-dimensional shadow, the journey takes place along a two-dimensional platform. For us, our journey takes place along a three-dimensional space, and we must travel to get from one point to the other. But what about Blorp? Is it possible that there could even be a 5th dimension (no, not this, you ninnies) that Blorp is unaware of? A five-dimensional creature named Trung who could reach out with her (higher forms of life are surely female) fingertips, and touch two different spacetime-spacetimes in Blorp's universe? --- Have you ever heard of the term, "tesseract? A tesseract is a theoretical, four-dimensional object which can easily be drawn to approximation: A tesseract is to a cube, as a cube is to a square. In other words, it's a cube in different places at once, represented as such: This picture shows the progression from 0-dimensions (a point) to 1 (a line) to 2 (a square) to 3 (a cube) to 4 (a tesseract). It gets a lot more complicated than this, but if you can understand the 4th dimension, it's simple to understand the 5th dimension - just take that tesseract, draw a second tesseract, and connect all the corresponding dots, just like you did when you took a square, and turned it into a cube. The funny thing is that this is actually a *two-dimensional* representation of a four-dimensional tesseract, i.e., it has length and width, but it doesn't project out from your computer screen, so it has no height (technically, it does, but only a negligible amount). It's also a two-dimensional representation of a zero-dimensional point (which has neither length nor width). This progression should also help you understand a 4-dimensional tesseract: * A point doesn't actually exist in our world - there is zero length, width, or height, so it's essentially nothingness (but we draw it as a dot). * There is an infinite number of points in a line. (Look at the picture, and chew on that one until you understand it.) * There is an infinite number of lines in a square. * There is an infinite number of squares in a cube. * There is an infinite number of cubes in a tesseract. --- Why can't someone take molded plastic, and make an actual tesseract? The answer to this question is not easy to grasp, but I'm going to make it easy for you: Let's recall that the Earth is (approximately) a sphere, and the drawing of a full year of revolution is (approximately) a torus. During that revolution around the Sun, there are an infinite number of positions that the Earth is in (think about it: no matter how small the progression, even one-trillionth of a second's-worth of progression, you can *always* cut that progression in half. And you can cut it in half again. And so on. If you don't understand that there are an infinite number of places the Earth can be during a single year, stop here and get it sorted out - it's really not difficult). Let's suppose that some gigantic outer-space creature made a molded-plastic model of the entirety of the Earth's revolution - it would look like a torus (or doughnut) with a perimeter of almost 93-million miles. Personally, I could go in for that doughnut, if it wasn't made out of molded plastic. But this giant torus is *not* a four-dimensional figure; it's essentially a model - a molded, plastic model - of a four-dimensional figure in three dimensions. And this is the easy part: Do you agree that the Earth is always - *always* a sphere, and cannot be in two places at once? That's obvious, right? Since that's the case, the only way that a four-dimensional figure could actually exist (as opposed to a plastic approximation of one) is if we stepped into a fourth dimension (in this case, adding "time" as our additional dimension), and that sphere we call Earth was in a year's-worth of positions *simultaneously*. The Earth would still be a sphere, but in our fourth dimension, it would be in an infinite number of places simultaneously, i.e., it would be a *real* torus which is comprised of three-dimensional matter plus the additional dimension of time: Remember, the Earth itself is a sphere, and must always be a sphere. This is where you really need to use your imagination to visualize, because I'm asking you to visualize a single object (the Earth) at different moments in time, but all of the moments are happening at once. That's the *real* fourth dimension, not just a model of one. Back to our tesseract. That plastic molding that looks like a tesseract is *not* a tesseract, because a tesseract can only exist in a fourth dimension; it's merely a model of one. Just as the Earth is always a three-dimensional sphere, a cube is always a three-dimensional cube. And for a real, honest-to-goodness tesseract to exist, that cube - that one, same cube - would need to be in an infinite number of places, simultaneously, and for that to happen, there would need to be our fourth dimension of time added to the scenario. Does that make sense? Resstated, a tesseract consists of one cube, and *only* one cube; it's just that there are different moments in time involved (again, this is where you really need to use your imagination). Imagining a tesseract is no more difficult than imagining a square. Squares *do not exist* in our known universe - they are theoretical constructs only. No matter how thinly you shaved down the height, you could always cut it again by half, and you will never, ever get to "zero height," because that would be a two-dimensional object, which doesn't exist in our three-dimensional world. Think about yourself, from the moment you were born, until the moment you die. If you could simultaneously "see" yourself at *every single position and location* where you (existed, exist, will exist) during the entirety of your lifetime, you would be "seeing" the fourth dimension. And you'd be damned well embarrassed at how many times you'd be seeing yourself at that McDonald's drive-thru. And you know what? There's an entire branch of mathematics that deals with you being at that McDonald's drive-thru, simultaneously, albeit at different times of your life. This concept is called "self-intersection," and the branch of mathematics is called "Intersection theory" - you have, at that same, damned, fattening, gross, McDonald's drive thru where you've drunkenly scarfed cheeseburgers, exactly 412 times in your life, intersected with yourself in the fourth-dimension. Seriously: Blorp can see, with a single glance, all 412 times you've scarfed those cheeseburgers. There are other 3-dimensional objects that never revisit a position where they've been before (picture an asteroid hurtling through space, for all of infinity). There are all sorts of terms dealing with these various scenarios, some of which you've possibly heard of before: manifolds, Klein bottles, Möbius strips, etc. I find these all to be quite disturbing, because our three-dimensional eyes, and puny little brains, struggle mightily to understand them, and these are all nothing more than catalysts for making yourself vomit (especially after having visited that damned McDonald's drive-thru the Tuesday before your 20th birthday - Remember? When you crammed down that fourth Big Mac on a dare?). Look at this crap. We're never going to understand it, and all it does is make you dizzy, so just follow my advice in the next section. Sorry I went off-course. --- In summary, the big question (and it's a *damned big* question) is: Do other dimensions exist? This is, I believe, a problem somewhat similar in nature to the "beginning of time," or "end of space" issues. And the answer is ... Have as much sex as possible. --- I'm also sorry to say that Trung's fingertip, if we continue with our examples, would be a duocylinder. The upshot of all this is that I think it's easier to understand the notion of higher dimensions by looking down at the lower ones - which we were all taught about in elementary school (and which also don't actually exist in our world).

This is one of the most entertaining (and hilarious!) ten-minute videos I've found on YouTube:

No, I was writing quickly, and just assumed that the two Equinoxes would be when the Earth was exactly 1 AU away from the sun, but now that you mention it, there's no particular reason I should have assumed this. The 12-hour days have to do with tilt, and not distance. I also assumed that the Winter Solstice was when the Earth was at the maximum AUs from the Sun, and the Summer Solstice was when the Earth was at the minimum AUs from the Sun, but again, these were just automatic assumptions I made without even thinking about it (in fact, it's just about the exact opposite). This is, quite literally, something you learn in freshman science class, if not before (yes, I took Astronomy because it was an easy A). Do you think the 1-AU moments are exactly 3 months away from the perihelion and the aphelion? I couldn't find anywhere that says when they occur, although I did find one webpage that said they did occur exactly twice a year.

Okay, half the people reading have no earthly (pun intended) clue as to what I'm talking about, so let me define some terms: Decuple (pronounced deck-CUP-pull) means "10" just like Triple means "3" or Quadruple means "4." Syzygy is an Astronomical term that's very simple: Anytime three celestial bodies are in a line, you have syzygy (it's nothing more than "a configuration.") The pronunciation is easy too: SIH-zih-gee. For example, anytime you have an eclipse, you have syzygy (three bodies in alignment), but an eclipse is just one of many, many examples. Here's one more term that many of you have probably heard: the "Transit of Venus." We had one of these a few years ago, and it's when Venus passes between the Earth and the Sun - the problem being that Venus is so small that you don't even notice it's happening. If Venus was large enough to block out the sun (it isn't), you'd have an eclipse; what you have instead is a Transit of Venus. And, you also have syzygy, i.e., the Sun, Venus, and Earth are all in alignment: You could draw a hypothetical straight line, and it would touch all three celestial bodies. So, my mind started to drift, and I began to wonder ... On Mar 21, 1894, from the perspective of Saturn (i.e., you're standing on Saturn), there were two simultaneous transits that took place: the Transit of Venus *and* the Transit of Mercury. Now bear in mind, this is from the perspective of Saturn - time for another term defined: An Astronomical Unit is the average distance that the Earth is from the Sun. Since Earth's orbit is elliptical, it's almost always a little more than 1 AU, or a little less than 1 AU. The actual distance is exactly 1 AU at exactly two moments per year: during the vernal and autumnal equinoxes, and even then, it's only for an instant - a period of time so short in duration that it essentially doesn't even exist. Okay, so the Earth is about 1 AU away from the Sun. Saturn, however, is almost 10 AUs away from the Sun, or about ten-times the distance from the Sun as the Earth is. So you can imagine how small the Sun would look if you were standing on Saturn. I don't know if it would be 1/10th the size, because I don't know if it's an exact inverse (I suspect it's more complicated than that, but regardless, the Sun would look pretty damned small). Now, I'm not certain that these simultaneous transits resulted in a quadruple syzygy. For a quadruple syzygy to have happened, you would need to be able to draw a mathematically perfect straight line, and have it touch the Sun, Mercury, Venus, and Saturn. Just because both Mercury and Venus were in transit doesn't necessarily mean they were in a straight line, but given how small the Sun must look from Saturn, they must have been pretty damned close - for a quadruple syzygy to have occurred, there would have had to have been a Venus-Mercury eclipse that took place during the double transit (I'm not even sure there's a term for this): Venus would have needed to eclipse Mercury *while* the two were in transit of the Sun (does that make sense?) In that case, you would have had a quadruple syzygy (again, I don't even know if this is a term); otherwise, you would have instead had two "regular" syzygys that happened to be *really* close together. I'm proposing the possibility of an decuple syzygy: I'm wondering if it is theoretically and physically possible for someone to be (hypothetically) standing on Pluto, and have every single planet in alignment. In other words, you could draw a straight line that would be touching the Sun, Mercury, Venus, Earth, Mars, Neptune, Saturn, Uranus, Neptune, and Pluto - ten celestial bodies that you could draw a line through. Actually, it doesn't matter if someone is standing on Pluto or not; the only thing that matters is the alignment. Assuming time sprawls forward into infinity, and that each planet orbits the sun at a different velocity, it's perfectly logical to hypothesize that, at some point - maybe trillions or quadrillions of years from now (assuming the Sun doesn't explode) - all ten celestial bodies in our solar system will be in alignment. Bear in mind: The planets all orbit the sun in the same plane; otherwise, this might be mathematically impossible; given that they *do* orbit in the same plane, I don't see how it *can't* happen, at some point in the ever-so-distant future. It should not take a very complex computer model to predict the exact moment in time when this would occur. It can actually become even more complicated than the scenario I've proposed: Some planetary moons are larger than Pluto, and Ceres - a dwarf planet in the asteroid belt - isn't all that far behind Pluto in size. So, yes, you could perhaps have dodecuple syzygy if 12 bodies were to be in alignment. Any thoughts on this, other than that I should maybe get a life, and maybe work on my restaurant reviews?

Many scientists will laugh at this question, but I suspect a lot of people have simply never thought of it before. Which force is stronger: gravity, or magnetism? To answer this question, take a compass and hold it. The needle will point to the North. Now, let go of it. The compass will fall to the ground, and if it doesn't shatter upon impact, the needle will probably spin around about five times, before once again settling down and pointing towards the North. That should answer your question: Gravity is *much* stronger than magnetism. To be exact, gravity is 137-times stronger than magnetism *at the planetary level*. There is, of course, an exception to this rule: Electromagnetism is stronger at the atomic and sub-atomic levels, so things are not as obvious as they might initially seem. Also, suppose a paper clip is lying on the ground, and you touch it with a magnet, and try to lift it off the ground. Which force wins: gravity or magnetism? Ponder that one as the paper clip has been raised to eye-level. And then there's this: Which leads us into tensile strengths ...

"Observation of Gravitational Waves from a Binary Black Hole Merger" by B.P. Abbott et al on journals.aps.org Yesterday, two separate detectors (in Hanford, WA and Livingston, LA) simultaneously observed a transient gravitational wave signal. I know this is "out there" stuff for a "restaurant website," but these waves are thought to be curvatures of spacetime which propagate outward from the source. For Einstein's two Theories of Relativity to be true, these needed to exist (i.e., Einstein predicted their existence), and Sep 14, 2015 was the first confirmation (heavily peer-reviewed, and the news released just yesterday), so this is a big deal. "Gravitational Waves, Einstein's Ripples in Spacetime, Spotted for First Time" by Adrian Cho on sciencemag.org "Einstein's Gravitational Waves Found at Last" by Davide Castelvecchi and Alexandra Witze on nature.com "Gravitational Waves Detected, Verifying Part of Albert Einstein's Theory of General Relativity" by Robert Lee Hotz on wsj.com

"Falling" (1967) by James Dickey (1923-1997, author of "Deliverance") At the end of this post, you'll be able to answer these questions nearly instantly, and you'll remember how to do it for the rest of your life. What I'm about to tell you is no more advanced than what a middle-school child learns in science class (and forgets the moment the test is over). We all know the names Pythagoras and Galileo. Pythagoras (c570BC - c495BC) is most famous for the Pythagorean Theorem (which has nothing to do with this). He was a Greek scholar, philosopher, and mathematician, and was clever enough to devise the following mathematical formula. Don't stop here - this is *easy*! Note that the drawing is a "square." The numbers on top are just 1, 2, 3 .... The numbers on the left are the number of dots in that section (count them and see). You should be able to clearly see that this drawing can be extended to infinity. But what does it represent? Let's take the number 3. Count up all the dots in sections 1-3, and you'll get 9 dots, or, 3-squared. With the number 4, count up all the dots in sections 1-4, and you'll get 16 dots, or 4-squared. This is all very easy to see, and intuitive as a graph; unfortunately, it needs to be represented as a formula. Don't leave! Skip the following line if you need to because it's not that important: For any number (call it "X"), it's square is equal to the first "X" odd numbers, added up. Don't leave! With the number 4, it's square is equal to the sum of the first 4 odd numbers: 1 + 3 + 5 + 7 = 16. Hi-Fi was rumored to be a square as well: [Exit Pythagoras] [Enter Galileo] Galileo (1564-1642) is one of absolute most famous scientists in history, and his accomplishments are so vast that listing them here would be pointless. There really isn't any "one thing" he's most famous for; he's a lot like Leonardo da Vinci - just a total Renaissance man, and you'd have to put him on any Top 10 list of "Scientific Contributions To Mankind" for his lifetime achievements. Galileo was fascinated by Pythagoras, and one of the things he did was take this formula by Pythagoras - purely mathematical - and apply it to the real world. In other words, he took pure Math, and applied it to Physics. Galileo figured out that the above figure corresponded almost exactly to how fast objects fell. This is what he figured out. Don't leave! This is just as easy. Here are a few details that you can skip because for the purposes of understanding this, you don't need to know them; just be aware that they exist: SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME 1. In reality, this applies only to objects falling in a vacuum. Things like drag (stick your arm out the window of a moving car) and buoyancy (a cork floating on water) are important to scientists, but not for us. 2. All things - no matter what their weight, mass, or density - fall with the same acceleration and speeds. This has been proven, and you can count on it being true: in a vacuum, a feather will fall exactly as fast as a brick, and they'll hit bottom at the exact same time. 3. There is an upper-bound called terminal velocity which happens when the forces of drag + buoyancy cancel out the force of gravity. Since you've made it this far, you are hereby rewarded by the trailer of the 1994 film with the same name: SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME - SKIP ME Are you still here? Okay, we're almost done. Don't leave! Here is what Galileo figured out, using what Pythagoras did as a basis (note that the metric system was not introduced until 1668, after Galileo's death): For every 1/4-second increment spent falling, you cover the distance shown by adding up the numbers on the left side of the above figure. Examples: 1/4-second: You fall 1 foot. 1/2 second: You fall 1 + 3 feet. 3/4 second: You fall 1 + 3 + 5 feet. So for every 1/4-second interval that something falls, just add up the odd numbers. That's it! Now, ask yourselves: how far do you fall in one second? Two seconds? Hint: one second is four 1/4-second intervals; two seconds is eight 1/4-second intervals. (The answers are 16 feet (1+3+5+7) and 64 feet (1+3+5+7+9+11+13+15), respectively.) As a shortcut which makes it even easier, you can just take the square of the number of 1/4-second intervals (for one second, it's 4-squared; for two seconds, it's 8-squared; for 5 seconds, it's 20-squared which is greater than the length of a football field). You are now free to live the rest of your life knowing that if you fall for much longer than one second, you're pretty much fucked. PS - the sheriff at the end of Deliverance was James Dickey himself: Does anyone know why Dickey gets in and drives off in the passenger's side of the car? Is this some weird mirror-image thing? Or was this filmed in England?

"Particle Fever" is perfect for people who have heard of the Large Hadron Collider and the Higgs Boson Particle, but don't know why they're important, or have any idea about the mathematics behind them. Its target audience is "intelligent laymen," and the documentary is not condescending (well, maybe in parts, but in general, no). You will walk away from this 100-minute film with a conversational understanding of both the collider and the boson, and will get to live through the same thrill the scientists lived through while "confirming its existence." It really is quite an exciting ride. Along the way, you'll meet people who seem like you and me, but are, in reality, some of the top scientists in their fields - the type of people who get nominated for Nobel Prizes, and at no time will you be bored. It is said that hiring Walter Murch to be the film's editor really made it stand apart from generic documentaries - he brought just enough of Hollywood into it that it's suspenseful. This should be shown in every high school in the country, so students can have a basic understanding of these important concepts. You won't regret investing the time watching it. SPOILER ALERT One of the most poignant moments of the film is seing Peter Higgs (of the Higgs Boson) tearing up as it looks like his particle - which he theorized in 1964 (fifty years ago!) being all-but confirmed in a second, independent measurement. Higgs won the Nobel Prize for Science later in 2013 for this confirmation. It should be mentioned, however, that there are criticisms of the Standard Model, and here is one particularly hostile put-down of the model by gadfly-crank, Alexander Unzicker. I do not know enough theoretical physics to voice an opinion on whether this man is just an angry quack, or if he makes some valid points (I suspect it's a little of both - the Standard Model and some of its offshoots is ridiculous in its complexity, and it *does* seem like physicists these days are designing experiments around theories, instead of vice-versa).