Daily Archives: June 2, 2023

No matter who you are, where you are, or how quickly youre moving, the laws of physics will appear exactly the same to you as they will to any other observer in the Universe. This concept that the laws of physics dont change as you move from one location to another or one moment to the next is known as the principle of relativity, and it goes all the way back not to Einstein, but even farther: to at least the time of Galileo. If you exert a force on an object, it will accelerate (i.e., change its momentum), and the amount of its acceleration is directly related to the force on the object divided by its mass. In terms of an equation, this is Newtons famous F = ma: force equals mass times acceleration.

But when we discovered particles that moved close to the speed of light, suddenly a contradiction emerged. If you exert too large of a force on a small mass, and forces cause acceleration, then it should be possible to accelerate a massive object to reach or even exceed the speed of light! This isnt possible, of course, and it was Einsteins relativity that gave us a way out. It was commonly explained by what we call relativistic mass, or the notion that as you got closer to the speed of light, the mass of an object increased, so the same force would cause a smaller acceleration, preventing you from ever reaching the speed of light. But is this relativistic mass interpretation correct? Only kind of. Heres the science of why.

Schematic animation of a continuous beam of light being dispersed by a prism. If you had ultraviolet and infrared eyes, youd be able to see that ultraviolet light bends even more than the violet/blue light, while the infrared light would remain less bent than the red light does. The speed of light is constant in a vacuum, but different wavelengths of light travel at different speeds through a medium.

The first thing its vital to understand is that the principle of relativity, no matter how quickly youre moving or where youre located, is still always true: the laws of physics really are the same for everyone, regardless of where youre located or when youre making that measurement. The thing that Einstein knew (that both Newton and Galileo had no way of knowing) was this: the speed of light in a vacuum must be exactly the same for everyone. This is a tremendous realization that runs counter to our intuition about the world.

Imagine youve got a car that can travel at 100 kilometers per hour (62 mph). Imagine, attached to that car, youve got a cannon that can accelerate a cannonball from rest to that exact same speed: 100 kilometers per hour (62 miles per hour). Now, imagine your car is moving and you fire that cannonball, but you can control which way the cannon is pointed.

As shown in an episode of Mythbusters, a projectile fired backward from a forward-moving vehicle at the exact same speed will appear to fall directly down at rest; the velocity of the truck and the exit velocity from the cannon exactly cancel each other out in this take.

This is what we commonly experience and also lines up with what we expect. And this is also experimentally true, at least, for the non-relativistic world. But if we replaced that cannon with a flashlight instead, the story would be very different. You can take a car, a train, a plane, or a rocket, traveling at whatever speed you like, and shine a flashlight from it in any direction you like.

That flashlight will emit photons at the speed of light, or 299,792,458 m/s, and those photons will always travel at that same exact speed.

That speed that the photons travel at will be the same as ever, the speed of light, not only from your perspective, but from the perspective of anyone looking on. The only difference that anyone will see, dependent on how fast both you (the emitter) and they (the observer) are moving, is in the wavelength of that light: redder (longer-wavelength) if youre mutually moving away from each other, bluer (shorter-wavelength) if youre moving mutually toward each other.

An object moving close to the speed of light that emits light will have the light that it emits appear shifted dependent on the location of an observer. Someone on the left will see the source moving away from it, and hence the light will be redshifted; someone to the right of the source will see it blueshifted, or shifted to higher frequencies, as the source moves toward it.

This was the key realization that Einstein had when he was devising his original theory of Special Relativity. He tried to imagine what light which he knew to be an electromagnetic wave would look like to someone who was following that wave at speeds that were close to the speed of light.

Although we dont often think of it in these terms, the fact that light is an electromagnetic wave means:

This was cemented in the 1860s and 1870s, in the aftermath of the work of James Clerk Maxwell, whose equations are still sufficient to govern the entirety of classical electromagnetism. You use this technology daily: every time an antenna picks up a signal, that signal arises from the charged particles in that antenna moving in response to those electromagnetic waves.

Light is nothing more than an electromagnetic wave, with in-phase oscillating electric and magnetic fields perpendicular to the direction of lights propagation. The shorter the wavelength, the more energetic the photon, but the more susceptible it is to changes in the speed of light through a medium.

Einstein tried to think of what it would be like to follow this wave from behind, with an observer watching electric and magnetic fields oscillate in front of them. But, of course, this never occurs. No matter who you are, where you are, when you are, or how quickly youre moving, you and everyone else always sees light move at exactly the same speed: the speed of light.

But not everything about light is the same for all observers. The fact that the observed wavelength of light changes dependent on how the source and the observer are moving relative to one another means that a few other things about light must change as well.

This last part is critical for our understanding, because momentum is the key link between our old school, classical, Galilean-and-Newtonian way of thinking and our new, relativistically invariant way of thinking that came along with Einstein.

The size, wavelength, and temperature/energy scales that correspond to various parts of the electromagnetic spectrum. You have to go to higher energies, and shorter wavelengths, to probe the smallest scales. Ultraviolet light is sufficient to ionize atoms, but as the Universe expands, light gets systematically shifted to lower temperatures and longer wavelengths.

Light, remember, ranges in energy tremendously, from gamma ray photons at the highest energies down through X-rays, ultraviolet light, visible light (from violet to blue to green to yellow to orange to red), infrared light, microwave light, and finally radio light at the lowest energies. The higher your energy-per-photon, the shorter your wavelength, the higher your frequency, and the greater the amount of momentum that you carry; the lower your energy-per-photon, the longer your wavelength, the lower your frequency, and the smaller your momentum is.

Light can also, as Einstein himself demonstrated with his 1905 research into the photoelectric effect, transfer energy and momentum into matter: massive particles. If the only law we had was Newtons law the way were used to seeing it as force equals mass times acceleration (F= ma) light would be in trouble. With no mass inherent to photons, this equation wouldnt make any sense. But Newton himself didnt write F= ma like we often suppose, but rather that force is the time rate of change of momentum, or that applying a force causes a change in momentum over time.

The inside of the LHC, where protons pass each other at 299,792,455 m/s, just 3 m/s shy of the speed of light. Particle accelerators like the LHC consist of sections of accelerating cavities, where electric fields are applied to speed up the particles inside, as well as ring-bending portions, where magnetic fields are applied to direct the fast-moving particles toward either the next accelerating cavity or a collision point.

So, what does that mean momentum is? Although many physicists have their own definition, the one Ive always liked is, Its a measure of the quantity of your motion. If you imagine a dockyard, you can imagine running a number of things into that dock.

A large superyacht, MotorYacht GO, crashed into the Saint Maartens Yacht Club dock. The large amount of momentum in the yacht caused it to crash through wood, concrete, and even reinforced steel as it destroyed the dock. Momentum, for very large masses moving even at slow speeds, can be disastrous.

The problem is, going all the way back to Newton, that the force you exert on something is equal to a change in momentum over time. If you exert a force on an object for a certain duration, its going to change that objects momentum by a specific amount. This change doesnt depend on how fast an object is moving alone, but only by the quantity of motion it possesses: its momentum.

So what is it, then, that happens to an objects momentum when it gets close to the speed of light? Thats really what were trying to understand when we talk about force, momentum, acceleration, and velocity when we near the speed of light. If an object is moving at 50% the speed of light and it has a cannon thats capable of firing a projectile at 50% the speed of light, what will happen when both speeds point in the same direction?

You know you cant reach the speed of light for a massive object, so the naive thought that 50% the speed of light + 50% the speed of light = 100% the speed of light has to be wrong. But the force on that cannonball is going to change its momentum by exactly the same amount when fired from a relativistically-moving frame-of-reference as it will when fired from rest. If firing the cannonball from rest changes its momentum by a certain amount, leaving it with a speed thats 50% the speed of light, then firing it from a perspective where its already moving at 50% the speed of light must change its momentum by that same amount. Why, then, wouldnt its speed be 100% the speed of light?

A simulated relativistic journey toward the constellation of Orion at various speeds. As you move closer to the speed of light, not only does space appear distorted, but your distance to the stars appears contracted, and less time passes for you as you travel. StarStrider, a relativistic 3D planetarium program by FMJ-Software, was used to produce the Orion illustrations. You dont have to break the speed of light to travel 1,000+ light-years in less than 1,000 years, but thats only from your point of view.

Understanding the answer is the key to understanding relativity: its because the classical formula for momentum that momentum equals mass multiplied by velocity is only a non-relativistic approximation. In reality, you have to use the formula for relativistic momentum, which is a little bit different, and involves a factor that physicists call gamma (): the Lorentz factor, which increases the closer you move to the speed of light. For a fast-moving particle, momentum isnt just mass multiplied by velocity, but mass multiplied by velocity multiplied by gamma.

Travel the Universe with astrophysicist Ethan Siegel. Subscribers will get the newsletter every Saturday. All aboard!

Applying the same force that you applied to an object at rest to an object in motion, even in relativistic motion, will still change its momentum by the same amount, but all of that momentum wont go into increasing its velocity; some of it will go into increasing the value of gamma, the Lorentz factor. For the earlier example, a rocket moving at 50% the speed of light that fires a cannonball at 50% the speed of light will result in a cannonball traveling at 80% the speed of light, with a Lorentz factor of 1.6667 along for the ride. The idea of relativistic mass is very old and was popularized by Arthur Eddington, the astronomer whose 1919 solar eclipse expedition validated Einsteins theory of General Relativity, but it takes a certain liberty: it assumes that the Lorentz factor () and the rest mass (m) get multiplied together, an assumption that no physical measurement or observation can test for.

Time dilation (left) and length contraction (right) show how time appears to run slower and distances appear to get smaller the closer you move to the speed of light. As you approach the speed of light, clocks dilate toward time not passing at all, while distances contract down to infinitesimal amounts.

The whole point of going through all of this is to understand that when you moveclose to the speed of light, there are many important quantities that no longer obey our classical equations. You cant just add velocities togetherthe way Galileo or Newton did;you have to add them relativistically.

You cant just treat distances as fixed and absolute; you have to understand thatthey contract along the direction of motion. And you cant even treat time as though it passes the same for you as it does for someone else; the passage of time is relative, anddilates for observers moving at different relative velocities.

A light-clock, formed by a photon bouncing between two mirrors, will define time for any observer. Although the two observers may not agree with one another on how much time is passing, they will agree on the laws of physics and on the constants of the Universe, such as the speed of light. A stationary observer will see time pass normally, but an observer moving rapidly through space will have their clock run slower relative to the stationary observer.

Its tempting, but ultimately incorrect, to blame the mismatch between the classical world and the relativistic world on the idea of relativistic mass. For massive particles that move close to the speed of light, that concept can be correctly applied to understand why objects can approach, but not reach, the speed of light, but it falls apart as soon as you incorporate massless particles, like photons.

Its far better to understand the laws of relativity as they actually are than to try and shoehorn them into a more intuitive box whose applications are fundamentally limited and restrictive. Just as is the case with quantum physics, until youve spent enough time in the world of relativity to gain an intuition for how things work, an overly simplistic analogy will only get you so far. When you reach its limits, youll wish you had learned it correctly and comprehensively the first time, all along.

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Does mass increase when nearing the speed of light? - Big Think

You know a story is going to be fun when it starts with a question that makes you laugh: What is the most boring number in the world? It's a legitimate mathematical question, and it turns out there are interesting numbers (prime numbers, powers of 2) and not-so-interesting numbers. You can probably anticipate the paradox: If a number is especially boring, doesn't that make it interesting? Theoretical physicist Manon Bischoff, who is an editor for our partner publication Spektrum in Germany, showshow to sort numbers for boringness and why it matters.

I admit I was skeptical when we first started discussing a story proposal about treating a person with multiple personalities. Weren't some of the classic cases exaggerated or made up? But the fascinating account of Ella by therapist and anthropologist Rebecca J. Lesterexplains how dissociative identity disorder can develop and manifest. It's a hopeful and generous story that takes us inside the therapeutic process and reveals how someone can start to heal from extreme trauma.

When a weather disaster strikes, people want to know whether climate change is to blame. And if so, to what degree? The field of attribution science has advanced dramatically in the past decade. As investigative journalist Lois Parshley writes, researchers are now able to say how much worse or more likely floods, hurricanes, wildfires, droughts, and other disasters were made by the human-caused climate crisis. This knowledge can help people respond to unfolding disasters and plan for future ones.

Drug-resistant hookworms are spreading among pet dogs, and researchers have traced their origins to greyhounds raised for racing. The parasites can kill puppies and occasionally cause nasty infections in people. Science journalist Bradley van Paridon describes how the superparasite evolved and traveled through greyhound racetracks, rescue dogs and dog parks.

Electrons move in mysterious ways. They're too fast to observe in detail as they jump through crystals or perform feats of quantum tunneling that let them escape energy barriers. To understand the bizarre properties of matter, physicists are creating models made of light. Physicist Charles D. Brown II shares how his light-based version of graphene lets him study how particles behave in a crystal lattice. In the author's words, Quantum physics is a trip!

Some of the most distinctive languages on Earth are still spoken, but just barely, by people who live on the Andaman Islands off the coast of India. Andamanese people arrived to the archipelago about 50,000 years ago, and according to genetic and linguistic studies, they were largely isolated until recently. Linguist Anvita Abbi worked with the last speakers of several local languages to preserve and understand their heritage. She discovered that the grammar of Andamanese languages is fundamentally based on the parts of the body, unlike any known language family.

What's the future of fusion? Is it always going to be another 20 or 30 or 50 years away? In our cover story, author Philip Ball examines recent advances in fusion energy, including the first reaction that created more energy than was used to trigger it. Fusion will not be part of our urgently needed transition from fossil fuels to renewable energy. But there's still a chance it could succeed ... in another 20 or 30 or 50 years. Ball cuts through the hype and explores the physical limitations and opportunities of the energy that powers stars.

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Answering Questions about Boring Numbers, Disasters, Fusion, and ... - Scientific American

In theaters June 2

THE PLOT:

Miles Morales (Shameik Moore) a.k.a. Spiderman, is now a household name in Brooklyn NY, saving citizens from those who wish to harm them. Yet, being a superhero is lonely as Miles longs to see Gwen (Hailee Steinfeld) again Spiderwoman from an alternate universe.

As Miles struggles to break free from his parents image of him as a kid, he encounters The Spot (Jason Schwartzman) a local villain hell-bent on getting revenge on Miles for transforming him into what he has become.

With The Spot creating havoc, Gwen and other Spidermen and women from alternate universes work to stop him, but Miles discovers a truth from his allies that, for him, is just as sinister as any villainous plan and he plans to stop it.

KENTS TAKE:

Spiderman: Across the Spider-verse is the second chapter in the ongoing Sony animated Spiderman series and is the first half of a two-part story.

Miles is back and is still working through his feelings and situation. His uncle turned out to be The Prowler and is now dead. He learned that he is not the only Spiderman in the universe and has fallen for Gwen, a Spiderwoman in an alternate universe. Spiderman is also a local celebrity in Brooklyn, and this celebrity comes with pitfalls, such as the guest-hosting of Jeopardy, the failed baby powder endorsement, and his attempt to grow a moustache. Miles is a teenager through and through, pushing back at his parents who still see him as a kid while he fights to be heard and understood.

Directors Joaquin Dos Santos, Kemp Powers and Justin K. Thompson bring us a vibrant, colorful, and wildly creative animated feature. Mixing and matching animation styles, this film will keep viewers attention throughout its 2 hours and 15-minute running time. Using interesting and unusual perspectives, we follow Miles and Gwen as they traverse Brooklyn and the multiverse following their spidey-senses to lead them to a truth that is very relevant to Miles.

Writers Phil Lord, Christopher Miller and Dave Callaham manage to pull off a rare occurrence creating a sequel to a successful film that is as good, if not better than the first film. This film is not political, it isnt preachy, and it certainly isnt your traditional superhero film what it is, is an action-packed coming-of-age story about a regular kid who is special and the struggles he endures as he transitions from childhood to adulthood. This heartfelt, emotional film isnt sappy, its real, real life, real feelings in an unreal setting. A setting with splashes of color, hidden places, dark shadows, freedom, beauty, and wonder. Miles likes Gwen and Gwen likes him back, but this isnt a sappy romance, its the awkward moments, the unspoken words and the silences that define their relationship.

The cast is excellent and adds depth to this feature, but the strength of performance by Shameik Moore as Miles elevates this film and creates an honesty that is vital to its success.

Another notable strength of this film is its soundtrack. From modern rap to classic R&B, this soundtrack covers a diverse musical palette and weaves perfectly into the story helping to define and create moods.

Spiderman: Across the Spider-verse is the first Summer Blockbuster to hit theaters and its recommend that this cool, action-packed, memorable story be seen on the big screen. This is one of those instances where getting caught in a spiders web will be a positive experience.

LYNNS TAKE:

Pop art, quantum physics and pathos collide in a grand superhero spectacle, resulting in this Spider-Man: Across the Spider-Verse, sequel being a mind-blowing amalgamation of next-level animation like but surpassing the 2018 original.

However inventive and clever it is, though, about half of the storyline is incoherent and panders to fan service -- and the sensory-overload-on-steroids style is overwhelming and exhausting. Yet, were all locked in.

This 2 hour and 20- minute eye-popping extravaganza takes place across six dimensions, has 240 characters in it and had over 1,000 animators working on it the most ever.

The Spider-Man mythology, easily relatable for teens who understood creator Stan Lees metaphors for figuring out their place in the world, began as a socially inept high school student who was bitten by a radioactive spider, and thus developed superpowers. That was in 1962, and in fighting crime in his subsequent Marvel Comics issues, Peter Parker would eventually learn with great power comes great responsibility.

Since 2002, there have been eight live-action Spider-Man movies, plus his role in The Avengers franchise, not to mention a past TV series, Broadway musical, video games and books.

The three co-directors Joaquim Dos Santos, Kemp Powers, and Justin K. Thompson mash parts of the old films with elements of the comic books. That comic imagery, added in with drawing and painting styles of the 20th and 21st centuries, results in a visually stunning work. Art historians will be in for a treat.

And comic book fans will be delirious about the Easter eggs no doubt courtesy of cheeky producers Phil Lord and Chris Miller who finally won an Oscar for directing the first movie (previously robbed for The Lego Movie) but only co-wrote this script with David Callaham, a veteran of the first and Shang-Chi and the Legend of the Ten Rings.

I understand their desire to throw in as many gags for the super-fans, but that darn muddled narrative lets the rest of us down. And their need to fiddle with the Spider-Man canon to keep it fresh and interesting. Sure, there are compelling human emotional touches (dead relatives, loved ones in peril), but the hyper-kinetic storytelling weakens the overall effect for those not in the zone.

Another sticking point is that the middle entry in this animated world ends with a cliffhanger, then states Miles will return in Spider-Man: Beyond the Spider-Verse. It is set for a March 29, 2024, release -- frustrating to viewers who like things resolved before waiting for another one, because this one just ends without a resolution.

And if you did not see Spider-Man: Into the Spider-Verse released four and a half years ago, you will be lost here. As a quick recap, Miles Morales, a black Hispanic Brooklynite, was juggling his life between being in high school and a Spider-Man, but when Wilson Kingpin Fisk uses a super collider, he finds out that others from across the Spider-Verse have been transported to his dimension.

This time, 15-year-old Miles remains on Earth 42, but as he discovers more multi-verses, he meets dozens of other Spider-People. In this global take, we meet a Spider-Man India (Karan Soni), a cockney street punk Spidey named Hobie (Daniel Kaluuya), a snarling, hulking vampire Spidey Miguel OHara (Oscar Isaac), and a pregnant Spider-Woman, motorcycle mama Jessica Drew (Issa Rae). Saving the world is tough business, and there are existential crises happening.

Miles mentor, Peter Parker (Jake Johnson), is shown as a young father, married to MJ (Zoe Kravitz), who brings his baby along for the adventures. Sad girl Gwen Stacy (Hailee Steinfeld) is a combo grrrl rocker and a Spider-Girl whose anguished storyline is equal to Miles.

While one can applaud the energy and the dazzling visuals of non-stop action, characters are often frazzled, and the pace is so frenetic that you feel like you are trapped in this parallel universe too. Whos good, whos evil, and who may be both?

Shameik Moore has returned to voice Miles, and hes dandy as the angsty teen who is exasperating to his parents because of his time-management skills (they dont know hes keeping the bad guys in check, at least his neighborhood in Queens).

His parents are voiced by Brian Tyree Henry and Luna Loren Valdez, joining a slate of major talent whose vocal work is solid but does not immediately identify them. Yet, its easy to place J.K. Simmons as J. Jonah Jameson, SNLs Rachel Dratch as the principal, and Jason Schwartman as the revenge-seeking villain The Spot (a standout).

Hyper and hypnotic, Spider-Man: Across the Spider-Verse has pushed forward the genre and is a fun fan experience. The propulsive score by composer Daniel Pemberton is also a plus. I give the animation an A+ but the story a B-.

Its a lot to juggle sci-fi, action, adventure, family, comedy, drama, and fantasy in one animated feature, and this film does display heart, even if the movie cant stand on its own.

After two decades of superhero comics ruling the bombastic blockbuster box office, whats next? Has art opened another dimension? One of the Spider-Verses greatest strengths is that it still surprises, and these multiverses show no signs of maxing out.

One thing is for certain, the enthusiasm for this head-spinning series is not waning anytime soon (even with the grumbling about waiting for the next sequel). Its as if weve hopped on one of the wildest amusement parks rides ever, and we need to see where it leads.

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Spiderman: Across the Spider-verse | Reel World | timesnewspapers ... - Webster-Kirkwood Times, Inc.