Light Travels in Both Time and Space

A groundbreaking achievement by physicists from Imperial College London has brought new insights into quantum physics by recreating the famous double-slit experiment in the dimension of time. 

Led by Professor Riccardo Sapienza from the Department of Physics, this research team explored how light interacts with a material whose optical properties can change within a few femtoseconds, revealing more about the fundamental nature of light.

The original double-slit experiment, first performed in 1801 by Thomas Young, showed that light behaves as a wave. Later experiments demonstrated that light also behaves as particles, revealing its quantum nature. 

In this classic experiment, light was passed through two physical slits, creating an interference pattern that displayed light’s wave properties. This experiment became crucial in understanding not just light but also the quantum behavior of particles like electrons and atoms.     READ MORE...

Geometry of Spacetime

When speaking of our universe, it's often said that 'matter tells spacetime how to curve, and curved spacetime tells matter how to move'. This is the essence of Albert Einstein's famous general theory of relativity, and describes how planets, stars, and galaxies move and influence the space around them.


While general relativity captures much of the big in our universe, it's at odds with the small in physics as described by quantum mechanics. For his PhD research, Sjors Heefer explored gravity in our universe, with his research having implications for the exciting field of gravitational waves, and perhaps influencing how the big and small of physics can be reconciled in the future.


A little over a hundred years ago, Albert Einstein revolutionized our understanding of gravity with his general theory of relativity. "According to Einstein's theory, gravity is not a force but emerges due to the geometry of the four-dimensional spacetime continuum, or spacetime for short," says Heefer. "And it's central to the emergence of fascinating phenomena in our universe such as gravitational waves."         READ MORE...

Ripples in Spacetime

Today, ESA’s Science Program Committee approved the Laser Interferometer Space Antenna (LISA) mission, the first scientific endeavor to detect and study gravitational waves from space.

This important step, formally called ‘adoption’, recognizes that the mission concept and technology are sufficiently advanced, and gives the go-ahead to build the instruments and spacecraft. This work will start in January 2025 once a European industrial contractor has been chosen.

LISA is not just one spacecraft but a constellation of three. They will trail Earth in its orbit around the Sun, forming an exquisitely accurate equilateral triangle in space. Each side of the triangle will be 2.5 million km long (more than six times the Earth-Moon distance), and the spacecraft will exchange laser beams over this distance. The launch of the three spacecraft is planned for 2035, on an Ariane 6 rocket.     READ MORE..., 

Uniting Gravity, Spacetime, and Quantum Theory

In a groundbreaking announcement, physicists from University College London (UCL) have presented a radical theory that unifies the realms of gravity and quantum mechanics while preserving the classical concept of spacetime, as outlined by Einstein.

This innovative approach, detailed in two simultaneously published papers, challenges over a century of scientific consensus and proposes a revolutionary perspective on the fundamental nature of our universe.

Dichotomy in modern physics
Modern physics rests on two contradictory pillars: quantum theory, which rules the microscopic world, and Einstein’s theory of general relativity, explaining gravity through spacetime curvature. These theories, despite their individual successes, have remained irreconcilable, creating a significant rift in our understanding of the universe.  READ MORE...

Theory Unites Gravity and Quantum Mechanics

A radical theory that consistently unifies gravity and quantum mechanics while preserving Einstein's classical concept of spacetime has been announced in two papers published simultaneously by UCL (University College London) physicists.

Modern physics is founded upon two pillars: quantum theory on the one hand, which governs the smallest particles in the universe, and Einstein's theory of general relativity on the other, which explains gravity through the bending of spacetime. But these two theories are in contradiction with each other and a reconciliation has remained elusive for over a century.

The prevailing assumption has been that Einstein's theory of gravity must be modified, or "quantized," in order to fit within quantum theory. This is the approach of two leading candidates for a quantum theory of gravity, string theory and loop quantum gravity.   READ MORE...

The Physics of Immortality

From your own experiential perspective, the laws of physics are stacked against you if you ever hope to achieve immortality. From a thermodynamic perspective, every system tends toward increasing entropy-and-disorder, and the only way you can combat that is by constantly inputting an external source of energy; in other words, your body and mind will eventually break down. 

And although you might try to leverage the power of relativity to dilate time and slow its passage, that will never work from your individual perspective; time only dilates or slows relative to an observer in a different reference frame from your own.

While this may confine a human’s dream of immortality to solutions that rely on technological enhancements or science-fiction level technology that relies on novel physical laws and/or phenomena, there’s still plenty for relativity to say about living forever: at least, relative to the rest of the Universe. 

While nearly all of us living today will certainly be dead in another century, should we all remain on Earth, the lessons from both special and general relativity teach us that there are a few physical situations that we should strive for if we truly want to maximize the amount of time that we can spend as living creatures within our Universe. Here’s the key insight we all need to understand.

The foundation of relativity: spacetime

Even though we normally credit Einstein with overcoming the disparate ideas of space and time that had held sway since the time of Newton and coming up with the revolutionary concept of a four-dimensional fabric that weaves them both together — spacetime — it wasn’t Einstein at all that came up with that key insight. 

It’s true that 1905 was indeed a banner year for Einstein, with the two key insights that powered special relativity key among them:

1. That the laws of physics are invariant, or that they do not change, in all non-accelerating frames of reference.
2. And that the speed of light in a vacuum, c, is identical for all observers, regardless of their motion or of the motion of the light source in question.

READ MORE...

Spacetime - Is It Real?

An illustration of heavily curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. At large distances, the spatial curvature is indistinguishable for equal mass black holes, neutron stars, white dwarfs, or any other comparably massed object. Credit: JohnsonMartin/Pixabay




When most of us think about the Universe, we think about the material objects that are out there across the great cosmic distances. Matter collapses under its own gravity to form cosmic structures like galaxies, while gas clouds contract to form stars and planets. Stars then emit light by burning their fuel through nuclear fusion, and then that light travels throughout the Universe, illuminating anything it comes into contact with. 

But there’s more to the Universe than the objects within it. There’s also the fabric of spacetime, which has its own set of rules that it plays by: General Relativity. The fabric of spacetime is curved by the presence of matter and energy, and curved spacetime itself tells matter and energy how to move through it.

But what, exactly, is the physical nature of spacetime? Is it a real, physical thing, like atoms are, or is it merely a calculational tool that we use to give the right answers for the motion and behavior of the matter within the Universe?


It’s an excellent question and a tough one to wrap your head around. Moreover, before Einstein came along, our conception of the Universe was very different from the one we have today. Let’s go way back to the Universe before we even had the concept of spacetime, and then come forward to where we are today.

The journey from macroscopic scales down to subatomic ones spans many orders of magnitude, but going down in small steps can make each new one more accessible from the previous one. Humans are made of organs, cells, organelles, molecules, atoms, then electrons and nuclei, then protons and neutrons, and then quarks and gluons inside of them. This is the limit to how far we’ve ever probed nature.Credit: Magdalena Kowalska/CERN/ISOLDE team

At a fundamental level, we had long supposed that if you took everything that was in the Universe and cut it up into smaller and smaller constituents, you’d eventually reach something that was indivisible. Quite literally, that’s what the word “atom” means: from the Greek ἄτομος: not able to be cut. 

The first record we have of this idea goes back some 2400 years to Democritus of Abdera, but it’s plausible that it may go back even farther. These “uncuttable” entities do exist; each one is known as a quantum particle. Despite the fact that we took the name “atom” for the elements of the periodic table, it’s actually subatomic particles like quarks, gluons, and electrons (as well as particles that aren’t found in atoms at all) that are truly indivisible.   READ MORE...

Space Time - Quantum Magic

Maybe quantum chaos will lead to a better theory of gravity.

Image Credit: kakteen/Shutterstock.com

All the world’s a stage and the stage itself is space-time where all the laws of physics are merely players. But maybe space-time is not the fundamental aspect that it is believed to be. A team of researchers from Japan’s RIKEN suggests that space-time could emerge from quantum properties, and one in particular that is involved in it is called quantum magic.

That is not something out of a Marvel movie despite sounding like it. It is actually a mathematical measure of how difficult is to simulate a quantum state on a regular (read that as non-quantum) computer. It turns out that apart from the simplest quantum states, anything with a bit of chaos will end up being maximally magical, which is a wonderful mathematical euphemism for we can’t model them.

How does that relate to space-time? Well, there is a quantum theory that needed an extra ingredient and that particular flavor might be quantum magic. The theory is called bulk quantum gravity and it was proposed in the 1990s to try to reconcile gravitational and quantum theories. A requirement is that space-time is something that emerges from the theory, not something that is assumed a priori.

“Physicists have long been fascinated about the possibility that space and time are not fundamental, but rather are derived from something deeper,” lead author Kanato Goto of the RIKEN Interdisciplinary Theoretical and Mathematical Sciences, said in a statement.  READ MORE...

Quantum Entanglement: Spacetime is an illusion

This past December, the physics Nobel Prize was awarded for the experimental confirmation of a quantum phenomenon known for more than 80 years: entanglement. As envisioned by Albert Einstein and his collaborators in 1935, quantum objects can be mysteriously correlated even if they are separated by large distances. But as weird as the phenomenon appears, why is such an old idea still worth the most prestigious prize in physics?

Coincidentally, just a few weeks before the new Nobel laureates were honored in Stockholm, a different team of distinguished scientists from Harvard, MIT, Caltech, Fermilab and Google reported that they had run a process on Google’s quantum computer that could be interpreted as a wormhole. Wormholes are tunnels through the universe that can work like a shortcut through space and time and are loved by science fiction fans, and although the tunnel realized in this recent experiment exists only in a 2-dimensional toy universe, it could constitute a breakthrough for future research at the forefront of physics.

But why is entanglement related to space and time? And how can it be important for future physics breakthroughs? Properly understood, entanglement implies that the universe is “monistic”, as philosophers call it, that on the most fundamental level, everything in the universe is part of a single, unified whole. It is a defining property of quantum mechanics that its underlying reality is described in terms of waves, and a monistic universe would require a universal function. 

Already decades ago, researchers such as Hugh Everett and Dieter Zeh showed how our daily-life reality can emerge out of such a universal quantum-mechanical description. But only now are researchers such as Leonard Susskind or Sean Carroll developing ideas on how this hidden quantum reality might explain not only matter but also the fabric of space and time.

Entanglement is much more than just another weird quantum phenomenon. It is the acting principle behind both why quantum mechanics merges the world into one and why we experience this fundamental unity as many separate objects. At the same time, entanglement is the reason why we seem to live in a classical reality. It is—quite literally—the glue and creator of worlds. 

Entanglement applies to objects comprising two or more components and describes what happens when the quantum principle that “everything that can happen actually happens” is applied to such composed objects. Accordingly, an entangled state is the superposition of all possible combinations that the components of a composed object can be in to produce the same overall result. It is again the wavy nature of the quantum domain that can help to illustrate how entanglement actually works.

Picture a perfectly calm, glassy sea on a windless day. Now ask yourself, how can such a plane be produced by overlaying two individual wave patterns? One possibility is that superimposing two completely flat surfaces results again in a completely level outcome. But another possibility that might produce a flat surface is if two identical wave patterns shifted by half an oscillation cycle were to be superimposed on one another, so that the wave crests of one pattern annihilate the wave troughs of the other one and vice versa. If we just observed the glassy ocean, regarding it as the result of two swells combined, there would be no way for us to find out about the patterns of the individual swells. 

What sounds perfectly ordinary when we talk about waves has the most bizarre consequences when applied to competing realities. If your neighbor told you she had two cats, one live cat and a dead one, this would imply that either the first cat or the second one is dead and that the remaining cat, respectively, is alive—it would be a strange and morbid way of describing one’s pets, and you may not know which one of them is the lucky one, but you would get the neighbor’s drift. Not so in the quantum world. 

In quantum mechanics, the very same statement implies that the two cats are merged in a superposition of cases, including the first cat being alive and the second one dead and the first cat being dead while the second one lives, but also possibilities where both cats are half alive and half dead, or the first cat is one-third alive, while the second feline adds the missing two-thirds of life. In a quantum pair of cats, the fates and conditions of the individual animals get dissolved entirely in the state of the whole. Likewise, in a quantum universe, there are no individual objects. All that exists is merged into a single “One.”  READ MORE...

One Way Time Travel

Have you ever made a mistake that you wish you could undo? Correcting past mistakes is one of the reasons we find the concept of time travel so fascinating. As often portrayed in science fiction, with a time machine, nothing is permanent anymore – you can always go back and change it. But is time travel really possible in our universe, or is it just science fiction?

Our modern understanding of time and causality comes from general relativity. Theoretical physicist Albert Einstein's theory combines space and time into a single entity – "spacetime" – and provides a remarkably intricate explanation of how they both work, at a level unmatched by any other established theory.

This theory has existed for more than 100 years, and has been experimentally verified to extremely high precision, so physicists are fairly certain it provides an accurate description of the causal structure of our Universe.

For decades, physicists have been trying to use general relativity to figure out if time travel is possible. It turns out that you can write down equations that describe time travel and are fully compatible and consistent with relativity. But physics is not mathematics, and equations are meaningless if they do not correspond to anything in reality.  READ MORE...

Lost in Spacetime

Einstein’s forgotten twisted universe

There’s a kind of inevitability about the fact that, if you write a regular newsletter about fundamental physics, you’ll regularly find yourself banging on about Albert Einstein. As much as it comes with the job, I also make no apology for it: he is a towering figure in the history of not just fundamental physics, but science generally.

A point that historians of science sometimes make about his most monumental achievement, the general theory of relativity, is that, pretty much uniquely, it was a theory that didn’t have to be. When you look at the origins of something like Charles Darwin’s theory of evolution by natural selection, for example – not to diminish his magisterial accomplishment in any way – you’ll find that other people had been scratching around similar ideas surrounding the origin and change of species for some time as a response to the burgeoning fossil record, among other discoveries.


Even Einstein’s special relativity, the precursor to general relativity that first introduced the idea of warping space and time, responded to a clear need (first distinctly identified with the advent of James Clerk Maxwell’s laws of electromagnetism in the 1860s) to explain why the speed of light appeared to be an absolute constant.

When Einstein presented general relativity to the world in 1915, there was nothing like that. We had a perfectly good working theory of gravity, the one developed by Isaac Newton more than two centuries earlier. True, there was a tiny problem in that it couldn’t explain some small wobbles in the orbit of Mercury, but they weren’t of the size that demanded we tear up our whole understanding of space, time, matter and the relationship between them. But pretty much everything we know (and don’t know) about the wider universe today stems from general relativity: the expanding big bang universe and the standard model of cosmology, dark matter and energy, black holes, gravitational waves, you name it.

So why am I banging on about this? Principally because, boy, do we need a new idea in cosmology now – and in a weird twist of history, it might just be Einstein who supplies it. I’m talking about an intriguing feature by astrophysicist Paul M. Sutter in the magazine last month . It deals with perhaps general relativity’s greatest (perceived, at least) weakness – the way it doesn’t mesh with other bits of physics, which are all explained by quantum theory these days. The mismatch exercised Einstein a great deal, and he spent much of his later years engaged in a fruitless quest to unify all of physics.  READ MORE...

A Pixelated Space...

The search for signatures of quantum gravity forges ahead.
Sand dunes seen from afar seem smooth and unwrinkled, like silk sheets spread across the desert. But a closer inspection reveals much more. As you approach the dunes, you may notice ripples in the sand. Touch the surface and you would find individual grains. The same is true for digital images: zoom far enough into an apparently perfect portrait and you will discover the distinct pixels that make the picture.

The universe itself may be similarly pixelated. Scientists such as Rana Adhikari, professor of physics at Caltech, think the space we live in may not be perfectly smooth but rather made of incredibly small discrete units. “A spacetime pixel is so small that if you were to enlarge things so that it becomes the size of a grain of sand, then atoms would be as large as galaxies,” he says.

Adhikari and scientists around the world are on the hunt for this pixelation because it is a prediction of quantum gravity, one of the deepest physics mysteries of our time. Quantum gravity refers to a set of theories, including string theory, that seeks to unify the macroscopic world of gravity, governed by general relativity, with the microscopic world of quantum physics. At the core of the mystery is the question of whether gravity, and the spacetime it inhabits, can be “quantized,” or broken down into individual components, a hallmark of the quantum world.

“Sometimes there is a misinterpretation in science communication that implies quantum mechanics and gravity are irreconcilable,” says Cliff Cheung, Caltech professor of theoretical physics. “But we know from experiments that we can do quantum mechanics on this planet, which has gravity, so clearly they are consistent. The problems come up when you ask subtle questions about black holes or try to merge the theories at very short distance scales.”

Because of the incredibly small scales in question, some scientists have deemed finding evidence of quantum gravity in the foreseeable future to be an impossible task. Although researchers have come up with ideas for how they might find clues to its existence—around black holes; in the early universe; or even using LIGO, the National Science Foundation-funded observatories that detect gravitational waves—no one has yet turned up any hints of quantum gravity in nature.  READ MORE...

Einstein Proven Right Again!

Researchers have conducted a 16-year long experiment to challenge Einstein’s theory of general relativity. The international team looked to the stars — a pair of extreme stars called pulsars to be precise – through seven radio telescopes across the globe. Credit: Max Planck Institute for Radio Astronomy

The theory of general relativity passes a range of precise tests set by pair of extreme stars.

More than 100 years after Albert Einstein presented his theory of gravity, scientists around the world continue their efforts to find flaws in general relativity. The observation of any deviation from General Relativity would constitute a major discovery that would open a window on new physics beyond our current theoretical understanding of the Universe.

The research team’s leader, Michael Kramer from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany, says: “We studied a system of compact stars that is an unrivaled laboratory to test gravity theories in the presence of very strong gravitational fields. To our delight we were able to test a cornerstone of Einstein’s theory, the energy carried by gravitational waves, with a precision that is 25 times better than with the Nobel-Prize winning Hulse-Taylor pulsar, and 1000 times better than currently possible with gravitational wave detectors.” He explains that the observations are not only in agreement with the theory, “but we were also able to see effects that could not be studied before”.

Ingrid Stairs from the University of British Columbia at Vancouver gives an example: “We follow the propagation of radio photons emitted from a cosmic lighthouse, a pulsar, and track their motion in the strong gravitational field of a companion pulsar.

We see for the first time how the light is not only delayed due to a strong curvature of spacetime around the companion, but also that the light is deflected by a small angle of 0.04 degrees that we can detect. Never before has such an experiment been conducted at such a high spacetime curvature.”

Dance of pulsars. Animation of the double pulsar system PSR J0737-3039 A/B and its line of sight from Earth. The system — consisting of two active radio pulsars — is “edge-on” as seen from Earth, which means that the inclination of the orbital plane relative to our line of sight is only about 0.6 degrees.

This cosmic laboratory known as the “Double Pulsar” was discovered by members of the team in 2003. It consists of two radio pulsars which orbit each other in just 147 min with velocities of about 1 million km/h. One pulsar is spinning very fast, about 44 times a second. The companion is young and has a rotation period of 2.8 seconds. It is their motion around each other which can be used as a near perfect gravity laboratory.  READ MORE...

Was Einstein Wrong?

As in history, revolutions are the lifeblood of science. Bubbling undercurrents of disquiet boil over until a new regime emerges to seize power. Then everyone's attention turns to toppling their new ruler. The king is dead, long live the king.

This has happened many times in the history of physics and astronomy. First, we thought Earth was at the center of the solar system — an idea that stood for over 1,000 years. Then Copernicus stuck his neck out to say that the whole system would be a lot simpler if we are just another planet orbiting the sun. Despite much initial opposition, the old geocentric picture eventually buckled under the weight of evidence from the newly invented telescope.

Then Newton came along to explain that gravity is why the planets orbit the sun. He said all objects with mass have a gravitational attraction towards each other. According to his ideas we orbit the sun because it is pulling on us, the moon orbits Earth because we are pulling on it. 

Newton ruled for two-and-a-half centuries before Albert Einstein turned up in 1915 to usurp him with his General Theory of Relativity. This new picture neatly explained inconsistencies in Mercury's orbit, and was famously confirmed by observations of a solar eclipse off the coast of Africa in 1919.  TO READ MORE, CLICK HERE...

How Einstein Imagined Spacetime

Something happened in Europe at the start of the 20th century. What happened was, human beings began to sense the reality of hyperspace. The thing called hyperspace, in movies like Star Wars, the thing that you reach by traveling faster than light—it started to shimmer into existence in the early 1900s. 

Like a gorgeous mirage, hyperspace wavered into being, in philosophy, science, literature and art. The science is Albert Einstein’s general theory of relativity. There are two kinds of art I want to share. First, the water lily paintings of Claude Monet. Secondly, there’s that amazing innovation in narrative prose—the stream of consciousness. Let’s start with the paintings. They make it so obvious.

The Orangerie is quite an experience. “Orangerie” means a place where they grow oranges. But this is a place where they grow experiences of gorgeous paintings.

The Orangerie is a pair of oval-shaped rooms in the Jardin des Tuileries in Paris. In these rooms, you can visit Claude Monet’s astounding water lilies paintings. It’s more than visiting. It’s being inside them. It’s not an experience you can forget. 

Immersive, strangely anticipatory of VR, you find yourself surrounded by gigantic ovals of color. An oval is a circle that’s been squeezed, just like spacetime isn’t totally regular but is squeezed and stretched by gravity. An oval is also an egg, an obvious container that isn’t just a container, but a living habitat for an embryo. The visitors are the embryos. And Monet’s paintings are the yolk, a gorgeous, mauve-blue-green yolk.

Floating in the yolk are little blobs, the water lilies. The water lilies appear not as objects in empty space. They melt into the water. It’s as if they are manifestations of the warp and flow of Monet’s beloved pond at Giverny. It’s as if the water lilies are an intrinsic part of their habitat: go figure. 

Ecological thought holds this to be true, a truism, even. But imagine what it was like to see that, first. You’re Claude Monet, and you’re seeing the slowly rippling, smooth, transparent liquid of your pond at Giverny. The pond contains so much else—water weeds, shadows, the sky… and water lilies.  TO READ MORE, CLICK HERE...

Gravitational Waves

As in history, revolutions are the lifeblood of science. Bubbling undercurrents of disquiet boil over until a new regime emerges to seize power. Then everyone's attention turns to toppling their new ruler. The king is dead, long live the king.

This has happened many times in the history of physics and astronomy. First, we thought Earth was at the center of the solar system — an idea that stood for over 1,000 years. Then Copernicus stuck his neck out to say that the whole system would be a lot simpler if we are just another planet orbiting the sun. Despite much initial opposition, the old geocentric picture eventually buckled under the weight of evidence from the newly invented telescope.

Then Newton came along to explain that gravity is why the planets orbit the sun. He said all objects with mass have a gravitational attraction towards each other. According to his ideas we orbit the sun because it is pulling on us, the moon orbits Earth because we are pulling on it. Newton ruled for two-and-a-half centuries before Albert Einstein turned up in 1915 to usurp him with his General Theory of Relativity. This new picture neatly explained inconsistencies in Mercury's orbit, and was famously confirmed by observations of a solar eclipse off the coast of Africa in 1919.

Instead of a pull, Einstein saw gravity as the result of curved space. He said that all objects in the universe sit in a smooth, four-dimensional fabric called space-time. Massive objects such as the sun warp the space-time around them, and so Earth's orbit is simply the result of our planet following this curvature. To us that looks like a Newtonian gravitational pull. This space-time picture has now been on the throne for over 100 years, and has so far vanquished all pretenders to its crown. The discovery of gravitational waves in 2015 was a decisive victory, but, like its predecessors, it too might be about to fall. That's because it is fundamentally incompatible with the other big beast in the physics zoo: Quantum theory.

The quantum world is notoriously weird. Single particles can be in two places at once, for example. Only by making an observation do we force it to 'choose'. Before an observation we can only assign probabilities to the likely outcomes. In the 1930s, Erwin Schrödinger devised a famous way to expose how perverse this idea is. He imagined a cat in a sealed box accompanied by a vial of poison attached to a hammer. The hammer is hooked up to a device that measures the quantum state of a particle. Whether or not the hammer smashes the vial and kills the cat hinges on that measurement, but quantum physics says that until such a measurement is made, the particle is simultaneously in both states, which means the vial is both broken and unbroken and the cat is alive and dead.  TO READ MORE, CLICK HERE...

Spacetime

In physics, spacetime is any mathematical model which fuses the three dimensions of space and the one dimension of time into a single four-dimensional manifold. The fabric of space-time is a conceptual model combining the three dimensions of space with the fourth dimension of time.  Source:  Wikipedia

But, to the ordinary person who lives in a 3 dimensional world, time simply moves forward in a straight line, and one's age increase each day, each week, each month, each year until one day that same person is no longer alive...  and, in their death, time continues.

To the ordinary person, life is seen to possess height, width, and depth and while height and depth seems to go on forever, width is constrained by one's environment; for example, if one is in one's home then the three dimensions are fixed and somewhat finite, however, if one is on the coast of let's say the Atlantic Ocean, then those same 3 dimensions seem to be endless and yet, we intuitively know that there are, in fact, limits.

Time is not seen so easily other than in the passing years, the body always changes sometimes that changes happens faster on some people than others but time is a concept of which everyone is aware even though like the dimensions is hardly ever discussed.

Similarly, hardly anyone talks about the atoms that are found in all matter and that because of the arrangement of these atoms we have different types of matter.  Likewise, hardly anyone talks about the breakdown of atoms into sub-atomic particles and that some of those particles are composed of even smaller particles to the point that the smallest imagined particle is a vibrating string of energy that has no probability of movement...  and, because of that lack of probability, we might have different dimensional realities in some sort of parallel but unseen universe.

Spacetime is a concept that is rarely imagined by the general public nor is it a topic of discussion at get togethers that meet social distancing guidelines...

There Is No Beginning or End Just a Present

EINSTEIN'S THEORY OF RELATIVITY

To understand special relativity you must first familiarize yourself with the speed equation: 

speed (s) = distance (d)/time (t)

The speed of light is the same for all observers, and this is known as 

“c” for constant (as in c in E=mc2)

where is E is energy and M is the mass of an object). So the speed of light for any observer is constant regardless of the speed the observer is going. For the speed of light to remain constant, something in the speed equation has to give way, that something is time. It turns out time slows down when you travel faster and faster, nearing the speed of light. What could be 10 minutes for the object could be 20 minutes for the observer. So what’s the future for the fast-moving object could be the past for the slow-moving observer, and vice versa. 

This relativistic effect is called time dilation. So the faster an object travels, the slower the time passes. That’s why moving clocks are slower than stationary ones. For example, observer A is on a slow-moving train called "train A". She measures time using her wristwatch. Observer B, passing train A at high speed, has the exact copy of A’s wristwatch. Yet, from the point of view of A, B’s wristwatch runs more slowly than her own. And this is why Einstein said “time is an illusion”.

According to Merrian-Webster’s definition, spacetime is “a system of one temporal and three spatial coordinates by which any physical object or event can be located”. So if spacetime isn’t constant, then what is? The spacetime interval. The spacetime interval is the spacetime difference between two separate events. The equation:

(Spacetime interval)2 =

 (the distance between two events)2 – (speed of light)2 x (the time between two events)2

Let's reach out to a physics professor for an explanation of what this means...  physicist Professor Brian Cox of Manchester University gives an example: "The Sun is eight light-minutes away – it takes light eight minutes to get from the Sun to the Earth. If the Sun exploded now, it will take me eight minutes to notice. So let's say the Sun explodes, and from my point of view, four minutes elapsed. I still don't know it's exploded, so there's nothing the Sun can do to cause something to happen on the Earth – it's completely disconnected from it for eight minutes".

Can the events of time be reversed?  Let's say I throw a ball and knock you off the chair on which you are standing...  and we all agree that it was the ball hitting you that knocked you off the chair...  now, can those events be reversed in that can you fall off the chair before I throw the ball?  Obviously, the answer is no.

Now...  what if time was not created...  what if it has always been there from the getgo?  If it had no beginning, then it will have no end...  and the resulting concept is that we are always living in the PRESENT...  all as it is.

QUANTUM MECHANICS

Quantum Mechanics or QM, describes how the Universe works at the level smaller than atoms. It is also called "quantum physics" or "quantum theory". A quantum of energy is a specific amount of energy, and Quantum Mechanics describes how that energy moves and interacts at the sub-atomic level.

The new theory ignored the fact that electrons are particles and treated them as waves. By 1926 physicists had developed the laws of quantum mechanics, also called wave mechanics, to explain atomic and subatomic phenomena.  When X-rays are scattered, their momentum is partially transferred to the electrons.

The world as we know it has three dimensions of space—length, width and depth—and one dimension of time. But there's the mind-bending possibility that many more dimensions exist out there. According to string theory, one of the leading physics model of the last half century, the universe operates with 10 dimensions.

String theory is a set of attempts to model the four known fundamental interactions—gravitation, electromagnetism, strong nuclear force, weak nuclear force—together in one theory.  Einstein had sought a unified field theory, a single model to explain the fundamental interactions or mechanics of the universe.

One notable feature of string theories is that these theories require extra dimensions of spacetime for their mathematical consistency. In bosonic string theory, spacetime is 26-dimensional, while in superstring theory it is 10-dimensional, and in M-theory it is 11-dimensional.

M-theory is a new idea in small-particle physics that is part of superstring theory that was initially proposed by Edward Witten. The idea, or theory, often causes arguments among scientists, because there is no way to test it to see if it is true.

A type of spacetime symmetry, supersymmetry is a possible candidate for undiscovered particle physics, and seen by some physicists as an elegant solution to many current problems in particle physics if confirmed correct, which could resolve various areas where current theories are believed to be incomplete.

LOOSE ENDS