Brainy Quote of the Day

Showing posts with label Special Relativity. Show all posts
Showing posts with label Special Relativity. Show all posts

Thursday, September 6, 2018

Impulse Speeds...

The simulated radio images in this not-to-scale artist's illustration show superfast jets blasting from the black hole created by the merger of two neutron stars, a dramatic event observed in August 2017. In the 155 days between two observations, the jet appeared to move 2 light-years, a distance that would require it to travel four times faster than light. This "superluminal motion" is an illusion created as the jet is pointed nearly toward the Earth; it is actually moving at about 97 percent light speed.
Credit: D. Berry, O. Gottlieb, K. Mooley, G. Hallinan, NRAO/AUI/NSF

Topics: Astrophysics, Cosmology, Einstein, Special Relativity, Star Trek

The dramatic neutron-star merger that astronomers spotted last year generated a jet of material that seemed to move at four times the speed of light, a new study reports.

"Seemed" is the operative word here, of course; the laws of physics tell us that nothing can travel faster through space than light. So, the superluminal motion was an illusion, which was caused by the jet's (still very fast) speed and the fact that it blasted almost directly at us, researchers said.

"Based on our analysis, this jet most likely is very narrow, at most 5 degrees wide, and was pointed only 20 degrees away from the Earth’s direction," study co-author Adam Deller, of the Swinburne University of Technology in Australia, said in a statement from the National Radio Astronomy Observatory (NRAO), a facility of the U.S. National Science Foundation (NSF).

Faster Than Light? Neutron-Star Merger Shot Out a Jet with Seemingly Impossible Speed
Mike Wall, Space.com

Wednesday, February 15, 2017

Crib Notes...

Topics: Einstein, General Relativity, Special Relativity

Sometimes I get questions clear out of the blue that are a joy to answer, as curiosity should be rewarded with a sincere response.

A friend emailed me (I left their name out to protect their privacy) and said: "I'm interested in many different things - I love How The Universe Works and Secrets of the Universe type programs. Of course there are things I don't understand but I get the basics. Anyway, I am watching one entitled 'Was Einstein Wrong?' and they talk about his General Theory of Relativity AND his Special Theory of Relativity. My question is are they the same theory and are names the interchangeable? When I search online for General it refers to E=mc2. When I search for Special, E=mc2 is the only equation that's displayed."

My friend also asked about this:


The program periodically shows this...but doesn't say what it is and no, I have no idea what it means, but is this the Special theory?

I have to admit, it's a refreshing thing not being trolled and actually asked questions about science.

I purposely didn't go into the math (but I left reference links below for the stout-of-heart), this was my reply:

Dear (friend's name omitted),

1905: The Special Theory of Relativity – think speed. Prior to Einstein, everything was in a slower, Newtonian universe, and Newton’s 3 Laws of Motion applied to things like inertia, acceleration and recoil.

However, as we started discovering things like the speed of light (186,232 miles per second, 300,000,000 meters per second), measured in the Michelson-Morley Experiment. “C” is just shorthand. It’s kind of lazy, but everyone knows what you mean when they see it or say it.

Alpha particles, electrons and measuring their speeds at some fraction of c, the Newtonian rules didn’t apply anymore. Special Relativity deals with objects or observers (or, frames of reference) that are moving with uniform velocities relative to each other, hence “relativity.”

Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. It introduced a new framework for all of physics and proposed new concepts of space and time, coining a new term for the public lexicon: space-time.

This was also called Einstein’s annus mirabilis, or “Miracle Year.” He published four papers: The Photoelectric Effect, Brownian Motion, Special Relativity and Mass-Energy Equivalence (E = mc-squared). A video: https://youtu.be/91XI7M9l3no

1915: Einstein then spent ten years trying to include acceleration in the theory and published his theory of general relativity in 1915. In it, he determined that massive objects cause a distortion in space-time, which is felt as gravity. Think of a bowling ball on a trampoline, in this case, space-time is the trampoline, the stars, planets, brown dwarfs, white dwarfs, black holes the bowling balls. One of the applications of General Relativity is Global Positioning Systems (GPS). This theory was confirmed in 1919 during a solar eclipse where Gravitational Lensing (bending of starlight) was observed.

Nerd Trivia: 3/14/2015 was Einstein’s birthday, and such was used as National Pi Day (3.14159 – get it?), and 100 years on November 25th of his paper on General Relativity, but you can’t get Pi out of 11/25/15, o_9.

On the symbolic equation above:

This is Tensor Calculus, or Differential Geometry. Einstein learned it from Grossmann (a mathematician) to describe space-time curvature in General Relativity. The Mu (μ) and Nu (ν) are Tensor coordinates; G in the numerator next to 8π is Newton's gravitational constant (“c” in the denominator you know). Believe it or not, Einstein struggled a little bit as Grossmann taught him; Einstein in turn taught him physics. His related quote:

“Do not worry about your difficulties in mathematics. I can assure you that mine are greater.”

One of my favorite quotes from Einstein. Albert Einstein was a contemporary of Paul Robeson, and due to the way Jews were treated (and exterminated) in Germany by the Nazis, he was a champion of Civil Rights:

From "Ideas and Opinions," by Albert Einstein:

"It seems to be a universal fact that minorities--especially when the individuals composing them can be recognized by physical characteristics--are treated by the majorities among whom they live as an inferior order of beings. The tragedy of such a fate lies not merely in the unfair treatment to which these minorities are automatically subjected in social and economic matters, but also in the fact that under the suggestive influence of the majority most of the victims themselves succumb to the same prejudice and regard their kind as inferior beings. This second and greater part of the evil can be overcome by closer association and by deliberate education of the minority, whose spiritual liberation can thus be accomplished.

"The resolute efforts of the American Negroes in this direction deserve approval and assistance."

Mein Weltbild (my conception of the world), Amsterdam: Querido Verlog, 1934, pp 117-118.

Einstein’s advice to a little girl that wanted to be a scientist: Dear Professor Einstein

As you can tell, I'm a BIG fan. :-)

Blessings,

Reggie

The long answer on “c”: http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/c.html

Helpful math reference links:

Wikipedia: Einstein Field Equations (EFE), not to be confused with "BFE," of course.

Wolfram Physics

Special Relativity
General Relativity

"Let us remember: One book, one pen, one child, and one teacher can change the world." Malala Yousafzai
"It is the supreme art of the teacher to awaken joy in creative expression and knowledge." Albert Einstein

Friday, April 22, 2016

Starshot...

ESA/Hubble/NASA
The star system α Centauri is more than 4 light years from the Sun.
Topics: Physics Humor, Space, Space Exploration, Special Relativity, Star Trek

0.20 x 3.00 x 108 m/s = 6 x 107 m/s isn't warp drive, but it's still pretty fast. We'll also get to see some phenomena in the universe that would normally take us decades to visit, and within our lifetimes so long as our sturdy cell-sized craft and their respective sails aren't punctured with micro meteors or picked off by V'Ger. The benefit to us on Earth will be the spin off technology. As with the original space race, we won't be the only ones with small ships and tall sails out there.

Space has long fascinated humans, but few have dared to initiate an interstellar space programme. Now a coalition of entrepreneurs and scientists aims to design a fleet of laser-powered spacecraft that could reach α Centauri, the star system closest to the Solar System, in just two decades. The group envisions probes that could complete that journey — a distance of 4.37 light years (1.34 parsecs) — at 20% the speed of light.

“For the first time in human history we can actually do more than observe the stars,” said Yuri Milner, a Russian Internet billionaire who is funding the initiative, at a 12 April press conference in New York. “We can reach them.”

Called Breakthrough Starshot, the programme is based on an idea that has been around for decades: the solar sail. The theory is that a lightweight space sail could harness the momentum carried by photons in order to travel without fuel.

The Breakthrough Starshot team is betting that a burst of concentrated lasers, fired from the ground, could rapidly accelerate a mobile-phone-sized device equipped with microelectronics and a tiny sail — providing much more energy than could be harnessed from the Sun. Whereas NASA’s plutonium-powered New Horizons spacecraft took nine years to reach Pluto, the “nanocraft” envisioned by Breakthrough Starshot would pass by the dwarf planet and exit the Solar System in three days.

Nature: Billionaire backs plan to send pint-sized starships beyond the Solar System
Jeff Tollefson

Related link
Tech Insider: 'Starshot' wants to launch tiny robots to a star 25 trillion miles away
Kevin Loria

Thursday, September 10, 2015

Reality Since Einstein...

Neils Bohr and Albert Einstein
Topics: Einstein, Special Relativity, General Relativity, Nobel Prize, Spacetime, Steven Weinberg, World Science Festival

A discussion at the World Science Festival with Brian Green, Gabriela González, Samir Mathur, Andrew Strominger, Cumrun Vafa, and fellow Nobel Laureate Steven Weinberg. In celebration of the 100th anniversary of Einstein's general theory of relativity, leaders from multiple fields of physics discuss its essential insights, its lingering questions, the latest work it has sparked, and the allied fields of research that have resulted. If not for the modern age of electronics with the Internet, television, smart phones and quantum mechanics, you can at least be thankful to him for your GPS not getting you lost.

Friday, June 5, 2015

Cartoon Physics...

Image Source: Amazon.com
Topics: Comic Books, Physics Humor, Physics and Pop Culture

Comic books are our modern mythology. We await with baited breath the donnybrook also known as Batman v Superman, though we don't yet know why the "Super Friends" start their inevitable bromance with a grudge match. Avengers: Age of Ultron answered who else was "worthy" enough - Vision - to lift Thor's hammer - forged in the heart of a dying star, which kind of suggests a Brown Dwarf or White Dwarf, meaning nothing in the universe worthy or not should be able to lift a teaspoon of Mjolnir (except apparently, a nail on the wall of Dr. Jane Foster's apartment in "Dark World" - seriously, look again). Technically, Vision came to life from it, so a one-armed curl shouldn't be past his AI abilities. Of course, there are others who lift "the smasher" - including the Hulk, who heretofore couldn't no matter how mad he got!

Currently in vogue on television are series like Agents of Shield (with the exception of enhanced humans and demigods, pretty terrestrial in its physics); Arrow (essentially, Batman with a bow); Gotham (that is so dark, it's a wonder Bruce Wayne or Jim Gordon WANT to stay there); and of course the breakout hit, the societal, self double entrendre: The Flash.

The series ended (spoiler alert) with a lot of cockeyed physics, like running at twice the speed of sound, colliding with a single proton in an accelerator and opening a wormhole so his nemesis - The Reverse Flash (a really pissed-off psychopath that comes back to create The Flash to KILL him - ahem: keep up), so he could go home. Home in this case, the 25th Century, bypassing Kirk and Picard's paltry epochs by two centuries where they apparently have time travel, but no cows for hamburgers, if Rev is to be "believed." The cliffhanger was Barry doing the heroes sacrifice of running into a black hole opening above Central City - that in real world physics would have killed most of the population with its radiation and ground the Earth into hamburger meat, Flash included. Ray Bradbury would be proud of the echo from his "A Sound of Thunder," an apocryphal foundation for time travel stories since its inception.

Of course, it's all hokey fun. Doing a serious and somewhat tongue-in-cheek search on the actual physics of superluminal (i.e. faster than light speed travel) resulted an interesting paper and related article [1, 3]; some humorous posts [2, 4], also tongue-in-cheek funny. Humor is always a good hook for STEM lectures and teenagers.

I enjoy the shows just like anyone else. For any story line to sell its audience, there is the usual suspension of belief in the verisimilitude of the fictional world and its "laws of cartoon physics." Alas, poor Yorick - our laws are binding. Even the Batman - my favorite, since he was for me the most believable - can't escape the laws we're subject to on a daily basis - like all of us mere mortals subject to Entropy, he wears out too. Life without magic is kind of a drag, but there's still much wonder in reality.

For any of these shows, I become that kid on 25th and Cleveland Avenue in Winston-Salem, NC that used to enjoy a nerdy Saturday with my best friend - trading and reading comic books, something sadly I don't think kids do much of anymore. I'm trying not to be the sour physics guy pointing out every impossibility in a movie or TV series - as I've gotten older, I'm better in large groups at keeping my mouth shut.

Smiley Faces

1. Physics arXiv: How superluminal motion can lead to backward time travel
Robert J. Nemiro and David M. Russelly
2. Geek: Quantum physics just solved one of the great paradoxes of time travel, Graham Templeton
3. Scientific American: Time Travel Simulation Resolves “Grandfather Paradox”, Lee Billings
4. PBS News Hour: Spider-Math and Bat-Physics: Science in a Superhero World, Rebecca Jacobson

Saturday, April 18, 2015

Age of Einstein...

Image Source: Biography.com
Topics: Einstein, Special Relativity, Space Exploration, Spaceflight, Spacetime

It was Einstein that entered the term "warp" into our lexicon before the notion was popularized on the original Star Trek. That warp was gravity from the mass of objects like planets, suns; wormholes and black holes. It has lived on in the discovery of the intermediate vector boson ("W" and Z0particle), theorized by Dr's Sheldon Lee Glashow, Abdus Salam and Steven Weinberg, meaning his was the "shoulder of [a] giant" these men stood on when they made their discovery. The foundation of the Higgs Boson were courses in special and general relativity as well as quantum mechanics, the root of all things micro and nano electronic. In a way, he's achieved immortality.

The link below is a PDF that goes through a primer of the physics at the high school level, which is appropriate. The more we understand about the physics that is all around us, the less we are frightened by, or put off by it. As we increase our intellectual acumen in STEM fields, is it too much to request such a self-study of those who wish to be our leaders, and possibly possess the nuclear codes?

This brief book is for the inquisitive reader who wishes to gain an understanding of the immortal work of Einstein, the greatest scientist since Newton. The concepts that form the basis of Einstein’s Theory of Special Relativity are discussed at a level suitable for Seniors in High School. Special Relativity deals with measurements of space, time and motion in inertial frames of reference (see chapter 4). An introduction to Einstein’s Theory of General Relativity, a theory of space, time, and motion in the presence of gravity, is given at a popular level. A more formal account of Special Relativity, that requires a higher level of understanding of Mathematics, is given in an Appendix.

Historians in the future will, no doubt, choose a phrase that best characterizes the 20th-century. Several possible phrases, such as “the Atomic Age”, “the Space Age” and “the Information Age”, come to mind. I believe that a strong case will be made for the phrase “the Age of Einstein”; no other person in the 20th-century advanced our understanding of the physical universe in such a dramatic way. He introduced many original concepts, each one of a profound nature. His discovery of the universal equivalence of energy and mass has had, and continues to have, far-reaching consequences not only in Science and Technology but also in fields as diverse as World Politics, Economics, and Philosophy.

Free Physics Book: The Age of Einstein
Frank W. K. Firk
Professor Emeritus of Physics
Yale University

Tomorrow: The Unraveling

Thursday, March 19, 2015

General Relativity...

Image Source: MIT Open Course Ware - General Relativity
Topics: Black Holes, Einstein, Special Relativity, GPS, Gravity, General Relativity, Spacetime, Wormholes

The 100th anniversary of the General Theory of Relativity also happens to have coincided with Einstein's birthday and the American Nerd-inspired Pi Day last Saturday (I say American, because it works when you use the dating sequence 3-14-15, and breaks down if you use military or European dating formats: e.g. 14 March 15; 14.3.15). Star Trek abused the word "warp" ad nauseum to get their astronauts from one side of the galaxy to the other in record time to solve galactic issues before the ending credits. Space is still vast, and getting to even our own solar system's planets in a human lifetime will take something more than conventional chemical rockets and Newtonian momentum, hence NASA's concentration on breakthrough propulsion technologies up to and inclusive of warp drive. Quoting one of the articles whose link I give below:

In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. It introduced a new framework for all of physics and proposed new concepts of space and time.

Einstein then spent ten years trying to include acceleration in the theory and published his theory of general relativity in 1915. In it, he determined that massive objects cause a distortion in space-time, which is felt as gravity. [1]

It is our current, best description in modern physics of gravity, and along with its effects, our Global Positioning Systems in our cars and smart phones; the evolution of stars into Brown Dwarfs; White Dwarfs, Black Holes and the theoretical possibility of Wormholes. It has outlived Einstein and proven its usefulness time and again.

1. Space.com: Einstein's Theory of General Relativity, Nola Taylor Redd
2. Einstein-Online: General Relativity
3. Princeton University Press: Relativity: The Special and the General Theory
100th Anniversary edition, Edited by Hanoch Gutfreund & Jürgen Renn
4. Physics Central: Einstein's Relativity and Everyday Life, Clifford M. Will (think GPS)

Saturday, March 14, 2015

Pi Day and Einstein...

We're wearing them!
Topics: Blerd, Circle, Circumference, Geek, Geometry, Math, Nerd, Pi Day

...and yes as you can see, we have our official T-shirts!

Pi Day is celebrated on March 14th (3/14) around the world. Pi (Greek letter “π”) is the symbol used in mathematics to represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159.

Pi has been calculated to over one trillion digits beyond its decimal point. As an irrational and transcendental number, it will continue infinitely without repetition or pattern. While only a handful of digits are needed for typical calculations, Pi’s infinite nature makes it a fun challenge to memorize, and to computationally calculate more and more digits.

Ultimate nerd out: It's Albert Einstein's birthday! It's also the 100th anniversary of the General Theory of Relativity, that led to the discovery of Black Holes. Trivia: Black Holes was a subject - like quantum mechanics he couldn't bring himself to believe in, though his work contributed to both.

Info from Celebration Site: PiDay.org
Biography.com: Fascinating Facts About Pi Day & Birthday Boy Albert Einstein
NBC News Weird Science: Pi Day Hits a Milestone, Alan Boyle

Thursday, February 26, 2015

DSR and Gravity's Rainbow...

Dr. Stephen Hawking of Cambridge University alongside illustrations of a black hole and an event horizon with Hawking Radiation. He continues to engage his grey matter to uncover the secrets of the Universe while others attempt to confirm his existing theories. Credit: Photo: BBC, Illus.: T.Reyes

Topics: Big Bang, Black Holes, Einstein, DSR, Gravity, Spacetime, Special Relativity

We've come a long way in 13.8 billion years; but despite our impressively extensive understanding of the Universe, there are still a few strings left untied. For one, there is the oft-cited disconnect between general relativity, the physics of the very large, and quantum mechanics, the physics of the very small. Then there is problematic fate of a particle's intrinsic information after it falls into a black hole. Now, a new interpretation of fundamental physics attempts to solve both of these conundrums by making a daring claim: at certain scales, space and time simply do not exist.

Let's start with something that is not in question. Thanks to Einstein's theory of special relativity, we can all agree that the speed of light is constant for all observers. We can also agree that, if you're not a photon, approaching light speed comes with some pretty funky rules – namely, anyone watching you will see your length compress and your watch slow down.

But the slowing of time also occurs near gravitationally potent objects, which are described by general relativity. So if you happen to be sight-seeing in the center of the Milky Way and you make the regrettable decision to get too close to our supermassive black hole's event horizon (more sinisterly known as its point-of-no-return), anyone observing you will also see your watch slow down. In fact, he or she will witness your motion toward the event horizon slow dramatically over an infinite amount of time; that is, from your now-traumatized friend's perspective, you never actually cross the event horizon. You, however, will feel no difference in the progression of time as you fall past this invisible barrier, soon to be spaghettified by the black hole's immense gravity.

So, who is "correct"? Relativity dictates that each observer's point of view is equally valid; but in this situation, you can't both be right. Do you face your demise in the heart of a black hole, or don't you? (Note: This isn't strictly a paradox, but intuitively, it feels a little sticky.)

And there is an additional, bigger problem. A black hole's event horizon is thought to give rise to Hawking radiation, a kind of escaping energy that will eventually lead to both the evaporation of the black hole and the destruction of all of the matter and energy that was once held inside of it. This concept has black hole physicists scratching their heads. Because according to the laws of physics, all of the intrinsic information about a particle or system (namely, the quantum wavefunction) must be conserved. It cannot just disappear.

Why all of these bizarre paradoxes? Because black holes exist in the nebulous space where a singularity meets general relativity – fertile, yet untapped ground for the elusive theory of everything.

Enter two interesting, yet controversial concepts: doubly special relativity and gravity's rainbow.

Phys.org:
Space-time theory may reconcile black hole conundrum
Vanessa Janek, Universe Today

Thursday, January 15, 2015

Annus Mirabilis...

Source of Quote: Brain Quotes
Topic: Einstein

History note: Today is the actual birthday of Dr. Martin Luther King, Jr. More on that Monday.

Einstein's first paper on the photoelectric effect was received March 18 and published June 9. He proposed, inspired by Max Planck, the idea of light energy in packets, or "quanta."

The Latin phrase annus mirabilis is rightly translated "year of wonders" as well as "year of miracles." 1492 saw the discovery of the West Indies by Columbus and the birth of grammar construction for modern language. 1543: the scientific revolution with Andreas Vesalius, "De humani corporis fabrica" (On the Fabric of the Human Body), and Nicolaus Copernicus "De revolutionibus orbium coelestium" (On the Revolutions of the Heavenly Spheres) in Nuremberg, Germany. It was applied to a poem written in 1667 by John Dryden, commenting on the Battle of Lowestoft fought by English and Dutch ships in 1665; the Four Days Battle of June 1666, and finally the victory of the St. James's Day Battle a month later. The second part of the poem deals with the Great Fire of London that ran from September 2–7, 1666. He wrote this escaping the Great Plague of London at Charlton in Wiltshire. The poem contains 1216 lines of verse, arranged in 304 quatrains. The reference has had many iterations and uses up to and since Einstein. Source: Wikipedia

We are now 110 years from the event that birthed the modern age of physics and technology we now find commonplace enough to take for granted by a guy in a patent office that at the time, didn't feel he was too successful. He would thankfully be proven in this instance quite wrong in his self-assessment.

"Do not worry about your difficulties in mathematics, I assure you that mine are greater."

"It is the supreme art of the teacher to awaken joy in creative expression and knowledge."



Hyper Physics: The Photoelectic Effect
The Library of Congress: The Annus Mirabilis of Albert Einstein

Saturday, August 23, 2014

TARDIS...

Source: Fan Pop
For Time And Relative Dimensions In Space, of course! I was introduced to The Doctor in the 80's by fellow Air Force Lieutenant Beth Richards: she hooked me on it. (If you're reading this Beth, I'm still a big fan.) The eleventh Doctor appears tonight, I think it's the same actor as in the other BBC series I follow, The Musketeers. I need to visit England again. Haven't been since 2000.

Although, "freezing" the TARDIS chameleon circuit in the shape of a London phone box/booth in the age of I-phones is complete nostalgia...most kids probably wouldn't know it if it materialized in front of them, landing on their foot! It used to make sense, trust me.

Found this Dr. Who special on Daily Motion. Enjoy!


Doctor-Who-7x98-Special-The-Science-of-Doctor-Who by jose-hita-9

BBC America: Doctor Who
Twitter: #newtowho


Tomorrow: If You Meet The Buddha

Friday, May 17, 2013

Flying Mirror...


A dense sheet of electrons accelerated to close to the speed of light can act as a tuneable mirror that can generate bursts of laser-like radiation in the short wavelength range via reflection. A team of physicists from the Max-Planck-Institute of Quantum Optics (MPQ) in Garching, the Ludwig-Maximilians-Universität (LMU) München, the Queens University Belfast (QUB) and the Rutherford Appleton Laboratory (RAL) near Oxford created such a mirror in a recent experiment. The scientists used an intense laser pulse to accelerate a dense sheet of electrons from a nanometre-thin foil to close to the speed of light and reflected a counter-propagating laser pulse from this relativistic mirror. With this experiment, the physicists managed to carry out a Gedankenexperiment (thought experiment) formulated in 1905 by Albert Einstein stating that the reflection from a mirror moving close to the speed of light could in principle result in bright light pulses in the short wavelength range. The researchers report on their results in Nature Communications, 23. April, 2013.

In everyday life, reflections of light are usually observed from surfaces that are at rest such as the reflection from a piece of glass or a smooth surface of water. But, what happens if one creates a mirror moving incredibly fast, close to the speed of light? This question was answered more than a century ago by Albert Einstein in 1905 in his theory of special relativity. Now, an international team of researchers investigated that question in an experiment.

Max Planck Institute: Light bursts out of a flying mirror