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Einstein's general theory of relativity predicts the existence of black holes, formed when giant stars collapse. But that same theory predicts that their centers are singularities, which are points of infinite density. Since we know that infinite densities cannot actually happen in the universe, we take this as a sign that Einstein's theory is incomplete. But after nearly a century of searching for extensions, we have not yet confirmed a better theory of gravity.But we do have candidates, including string theory. In string theory all the particles of the universe are actually microscopic vibrating loops of string. In order to...

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. Such a picture cannot be reconciled with a smooth, continuous fabric of space-time. According to Einstein, space-time is warped by matter and energy, but quantum physics says matter and energy exist in multiple states simultaneously — they can be both here and over there. According to Einstein, space-time is like a stage that remains in place whether actors are treading...

Embrace the flow, says a duo of mechanical engineers at North Carolina State University—the flow of energy, that is. The mantra you might normally hear from your yoga instructor could be an entirely new way of looking at the universe. 🌌The universe is badass. Let's explore it together. The two theorists, Larry Silverberg and Jeffrey Eischen, suggest that fragments of energy, rather than waves or particles, may be the fundamental building blocks of the universe. The bedrock of their theory is the foundational idea that energy is always flowing through space and time. The authors suggest thinking of energy as...

What is the fundamental nature of reality? Is space-time — the four-dimensional fabric of our universe — ultimately smooth at the tiniest of scales, or something else? It seems impossible to measure, but with the power of advanced telescopes peering through billions of light-years of distance, researchers are beginning to look down. Deep down.

The way the fabric of space and time swirls in a cosmic whirlpool around a dead star has confirmed yet another prediction from Einstein's theory of general relativity, a new study finds. That prediction is a phenomenon known as frame dragging, or the Lense-Thirring effect. It states that space-time will churn around a massive, rotating body. For example, imagine Earth were submerged in honey. As the planet rotated, the honey around it would swirl — and the same holds true with space-time. Satellite experiments have detected frame dragging in the gravitational field of rotating Earth, but the effect is extraordinarily...

Cracks in the universe: the search for cosmic strings Galaxy-sized filaments of raw energy may be threaded through spacetime, according to some theories. Will we ever find traces of them? Cathal O’Connell takes up the hunt. Share Tweet Tatyun / Getty Images Our universe exploded into being, expanded at a fantastic speed and cooled. Perhaps too quickly. Some physicists believe the rapid cooling might have cracked the fabric of the universe.These hairline fractures may still be threaded through space-time. Dubbed cosmic strings, mathematical models see them as invisible threads of pure energy, thinner than an atom but light-years long. The...

Although for five decades, the Big Bang theory has been the best known and most accepted explanation for the beginning and evolution of the Universe, it is hardly a consensus among scientists. Brazilian physicist Juliano Cesar Silva Neves part of a group of researchers who dare to imagine a different origin. In a study recently published in the journal General Relativity and Gravitation, Neves suggests the elimination of a key aspect of the standard cosmological model: the need for a spacetime singularity known as the Big Bang. In raising this possibility, Neves challenges the idea that time had a beginning...

For decades astronomers tried to prove Albert Einstein right by doing what Einstein thought was impossible: detecting the faint ripples in the universe called gravitational waves. They failed repeatedly until two years ago when they finally spotted one. Then another. And another. And another. Three American scientists — including one who initially flunked out of MIT — won the Nobel Prize in physics Tuesday that launched a whole new way to observe the cosmos. Sweden’s Royal Academy of Sciences cited the combination of highly advanced theory and ingenious equipment design in awarding Rainer Weiss of the Massachusetts Institute of Technology...

Microsoft researchers have teamed up with physicists from the University of California, Santa Barbara, to show how time crystals might be possible. First proposed by Nobel-prize winning theoretical physicist Frank Wilczek, time crystals are hypothetical systems that spontaneously break time-translational symmetry (TTS) – a fundamental symmetry in physics. In plain language, they exhibit tiny movements without using energy. Crystals have a rigid arrangement of atoms that break translational symmetry. Their structure is not symmetrical in space, unlike a sphere, which looks the same from all directions. Time crystals break the symmetry of space and time. Wilczek considered a group of...

The story starts in the 1980s, when astronomers found that small (stellar-mass) black holes emit X-ray light that flickers in a curious pattern. At first, this flickering occurs every few seconds; however, the time between each flicker shortens over the course of a few months, eventually stopping completely. This "quasi-periodic oscillation" (QPO) was thought to be a result of a phenomenon predicted by Albert Einstein's theory of general relativity — that any object with enough mass, like a black hole, will twist space-time as it spins. Later, scientists calculated that these gravitational vortices will cause the orbits of particles around...

It took a century, but the theory from Albert Einstein handwritten neatly on paper that is now yellowing has finally been vindicated. Israeli officials on Thursday offered a rare look at the documents where Einstein presented his ideas on gravitational waves, a display that coincided with the historic announcement that scientists had glimpsed the first direct evidence of his theory. [...] In a landmark discovery for physics and astronomy, international scientists announced in Washington on Thursday that they had glimpsed the first direct evidence of gravitational waves, or ripples in space-time. Einstein's theory states that mass warps space and time,...

Physics is built out of philosophically fascinating ideas. Or, at least, ideas that fascinate us as physicists. We are often moved to reverentially proclaim the beauty of various concepts and theories. Sometimes this beauty makes sense to other people (we're made of star stuff) and other times it's opaque (Frobenius manifolds in psuedo-Euclidean spaces). I have my own personal favorite idea. It arises from the philosophically fantastic (but mathematically moderate) workings of Einstein's relativity theory. The theory of special relativity holds that time and space are not separate entities, each operating on its own; rather they are intimately and inextricably...

Okay, but what exactly is a gravitational wave and how could they help us crack the conundrum of the black hole code? A gravitational wave is akin to a ripple in space-time. Albert Einstein predicted that massive bodies changing speed or direction generate these gravitational waves. Picture bodies like a pair of black holes orbiting each other. This then creates a gravitational wave that ripples outwards, like a disturbance in a still pool of water after a leaf has dropped onto its surface and ripples are sent across the surface. Like star-crossed lovers, the black holes of two merging galaxies...

Nobody knows how the universe’s biggest black holes grow so large. Now one astrophysicist says it’s because they feed on the quantum foam that makes up the fabric of spacetime One of the more fascinating astrophysical discoveries in recent years is that almost all galaxies hide supermassive black holes at their cores. Indeed, astronomers believe that galaxies and black holes have a kind of symbiotic relationship so that one cannot form or grow without the other. The evidence comes from observations of galaxies both near and far—almost all contain huge black holes. But that raises an interesting question. We see...

Ever wondered what would happen if the dimension of time came to a sudden end? A new experiment reveals all One of the most exciting areas of science is the emerging field of spacetime analogues. This is the discipline in which physicists play around with systems that have a formal mathematical link with general relativity. For example, changes in the way electrons move in graphene as it is cooled are identical to the changes that may have occurred in the universe soon after the big bang. So physicists can use cool graph to test theories about the universe's earliest behaviour....

Was Newton right and Einstein wrong? It seems that unzipping the fabric of spacetime and harking back to 19th-century notions of time could lead to a theory of quantum gravity. Physicists have struggled to marry quantum mechanics with gravity for decades. In contrast, the other forces of nature have obediently fallen into line. For instance, the electromagnetic force can be described quantum-mechanically by the motion of photons. Try and work out the gravitational force between two objects in terms of a quantum graviton, however, and you quickly run into trouble—the answer to every calculation is infinity. But now Petr Hořava,...

God’s mighty expanse by D. Russell HumphreysPublished: 26 February 2009(GMT+10) Psalm 150:1, the first verse of the last psalm, contains a phrase that has always intrigued me: … Praise Him in his mighty expanse. (NAS), or… praise him in the firmament of his power. (KJV) God made the expanse (firmament) on the second day and called it “heavens” (Genesis 1:8, plural from literal Hebrew). Later, on the fourth day, He populated the expanse with the sun, moon and stars (Genesis 1:14-19). So the expanse is not the heavenly bodies, but rather the space that contains the heavenly bodies. Normally people...

Three different trends in physics each suggest that our universe is just one of many.We usually think of the universe as being “everything there is.” But many astronomers and physicists now suspect that the universe we observe is just a small part of an unbelievably larger and richer cosmic structure, often called the “multiverse.” This mind-bending notion – that our universe may be just one of many, perhaps an infinite number, of real, physical universes – was front and center at a three-day conference entitled "A Debate in Cosmology — The Multiverse," held at the Perimeter Institute for Theoretical Physics...

Author - Alexander Mayer: This book is going to change the course of the 21st Century. Many old ideas (and inflated reputations) will die. Inevitably, some people will resist that. Science is about ideas that work. The only thing that matters in science is accurate predictions of empirical phenomena. Just read the book. Partial Abstract: The concept of geometric cosmic time is introduced, which allows astrophysical observations to be interpreted without concluding that an unknown force is accelerating the expansion of the Universe. This relativistic temporal model yields a redshift-distance relationship based on simple geometric rules that involves no free...

TIME BEFORE TIME An event like the Big Bang is about as likely as billions of coin tosses all coming up heads. Explaining why that is might take us from empty space to other universes--and through the mirror of time. by Sean Carroll • Posted August 28, 2006 11:53 AM From the SEPTEMBER issue of Seed:    The nature of time is such that the influence of the very beginning of the universe stretches all the way into your kitchen—you can make an omelet out of an egg, but you can't make an egg out of an omelet. Time, unlike...