Albert Einstein

Scientists Prove a Key Part of Einstein’s Theory of Relativity

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Albert Einstein’s theory of general relativity predicted that the gravity of stars could brighten and bend the light coming from other stars like a magnifying lens. Yet this is something Einstein did not think we could ever see due to the great distance between stars, writing in a 1936 article that “there is no hope of observing this phenomenon directly.”

Yet, as science persists, this phenomenon, called “gravitational microlensing”, has now been observed by an international team of researchers, led by Kailash C. Sahu, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland.

Writing in an accompanying paper, Terry D. Oswalt from the Embry-Riddle Aeronautical University, says that Einstein would be proud of this accomplishment because “one of his key predictions has passed a very rigorous observational test.”

Gravitational microlensing was initially observed in 1919 by measuring starlight that curbed around the total eclipse of the Sun. This is the first time, however, that the effect was seen involving stars other…

Key Einstein principle survives quantum test

warping space
EINSTEIN ENDURES According to Einstein’s general theory of relativity, massive objects warp space (illustrated above), producing gravitational attraction. Scientists don’t understand how general relativity interfaces with quantum mechanics, but a pillar of general relativity, the equivalence principle, has withstood a new quantum test.

Particles with mind-bending quantum properties still follow a standard gravitational rule, at least as far as scientists can tell.

The equivalence principle — one of the central tenets of Einstein’s theory of gravity — survived a quantum test, scientists report online April 7 at

In Einstein’s gravity theory — the general theory of relativity — gravity and acceleration are two sides of the same coin. According to the equivalence principle, the gravitational mass of an object, which determines the strength of gravity’s pull, is the same as its inertial mass, which determines how much an object accelerates when given a push (SN: 10/17/15, p. 16). As a result, two objects dropped on Earth’s surface should accelerate at the same rate (neglecting air resistance), even if they have different masses or are made of different materials.

One of the first reported tests of the equivalence principle — well before it was understood in the framework of general relativity — was Galileo’s apocryphal experiment in which he is said to have dropped weights from the Leaning Tower of Pisa. Scientists have since adapted that test to smaller scales, swapping out the weights for atoms. In the new study, physicists went a step further, putting atoms into…

You Can Chat With Albert Einstein’s Facebook Bot Alter-Ego

Albert Einstein is on Facebook, and he’s ready to chat. As a promotion for its new show, Genius, the National Geographic Channel has created an Albert Einstein bot for Facebook Messenger. You can banter back and forth with the theoretical version of the theoretical physicist about life, love, and science—although he’s quick to warn that “I become absent-minded during light conversations that do not involve the physical properties of light.”

Nevertheless, he will tell you all about his long list of lovers and send you plenty of GIFs from the show. The bot is more fun than most—full of puns and pithy…

Einstein’s latest anniversary marks the birth of modern cosmology

Andromeda galaxy
Edwin Hubble’s observations of stars in the Andromeda galaxy (shown) demonstrated that the universe was vastly bigger than Albert Einstein realized. Nevertheless, Einstein’s paper applying his general theory of relativity, published a century ago, became the foundation for the modern science of cosmology.

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Sometimes it seems like every year offers an occasion to celebrate some sort of Einstein anniversary.

In 2015, everybody lauded the 100th anniversary of his general theory of relativity. Last year, scientists celebrated the centennial of his prediction of gravitational waves — by reporting the discovery of gravitational waves. And this year marks the centennial of Einstein’s paper establishing the birth of modern cosmology.

Before Einstein, cosmology was not very modern at all. Most scientists shunned it. It was regarded as a matter for philosophers or possibly theologians. You could do cosmology without even knowing any math.

But Einstein showed how the math of general relativity could be applied to the task of describing the cosmos. His theory offered a way to study cosmology precisely, with a firm physical and mathematical basis. Einstein provided the recipe for transforming cosmology from speculation to a field of scientific study.

“There is little doubt that Einstein’s 1917 paper … set the foundations of modern theoretical cosmology,” Irish physicist Cormac O’Raifeartaigh and colleagues write in a new analysis of that paper.

Einstein had pondered the implications of his new theory for cosmology even before he had finished it. General relativity was, after all, a theory of space and time — all of it. Einstein’s showed that gravity — the driving force sculpting the cosmic architecture — was simply the distortion of spacetime geometry generated by the presence of mass and energy. (He constructed an equation to show how spacetime geometry, on the left side of the equation, was determined by the density of mass-energy, the right side.) Since spacetime and mass-energy account for basically everything, the entire cosmos ought to behave as general relativity’s equation required.

Newton’s law of gravity had posed problems in that regard. If every mass attracted every other mass, as Newton had proclaimed, then all the matter in the universe ought to have just collapsed itself into one big blob. Newton suggested that the universe was infinite, filled with matter, so that attraction inward was balanced by the attraction of matter farther out. Nobody really bought that explanation, though. For one thing, it required a really precise arrangement: One star out of place, and the balance of attractions disappears and the universe collapses. It also required an infinity of stars, making it impossible to explain why it’s dark at night. (There would be a star out there along every line of sight at all times.)

Einstein hoped his theory of gravity would resolve the cosmic paradoxes of Newtonian gravity. So in early 1917, less than a year after his complete paper on the general theory was published, he delivered a short paper to the Prussian Academy of Sciences outlining the implications of his theory for cosmology.

In that…

Discovery of Speeding Galaxies May Challenge Einstein’s Gravity and Dark Matter

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A present-day near-miss of two spiral galaxies NGC 5426 and NGC 5427, which is possibly comparable to the early flyby of the Andromeda Galaxy past our own Milky Way. Courtesy of © Gemini Image Gallery.

A discovery of fast-moving galaxies, 10 million light years wide, may cause physicists to re-examine Einstein’s theory of relativity. A team from University of St. Andrews in Scotland found the enormous ring of galaxies speeding away from our galaxy much faster than existing physics modeling predicts. In fact, the scientists believe the galaxies are moving so quickly that they are calling this expansion “a mini Big Bang”.

Dr. Hongsheng Zhao and PhD student Indranil Banik co-authored the study, which came from investigating 54 galaxies in what’s called “the Local Group” of the Universe. The scientists explain the unexpected conclusions by proposing that at some point 7 to 11 billion years ago the neighboring Andromeda Galaxy came so close to our own Milky Way Galaxy that they created a “tsunami-like wake,” scattering smaller galaxies with a sling-shot-like effect.

“If Einstein’s Gravity were correct, our Galaxy would never come close enough to Andromeda to scatter anything that fast,”

Atom, Archetype, and the Invention of Synchronicity: How Iconic Psychiatrist Carl Jung and Nobel-Winning Physicist Wolfgang Pauli Bridged Mind and Matter

Two of humanity’s greatest minds explore the parallels between spacetime and the psyche, the atomic nucleus and the self.

Atom, Archetype, and the Invention of Synchronicity: How Iconic Psychiatrist Carl Jung and Nobel-Winning Physicist Wolfgang Pauli Bridged Mind and Matter

“Every true theorist is a kind of tamed metaphysicist,” Einstein wrote as he contemplated the human passion for comprehension in the final years of his life. He may well have been thinking about the great Austrian-Swiss theoretical physicist Wolfgang Pauli (April 25, 1900–December 15, 1958), who first postulated the neutrino and was awarded the Nobel Prize for his discovery of the Pauli exclusion principle — a monumental leap in our understanding of the structure of matter. Decades earlier, 21-year-old Pauli had published a critique of Einstein’s groundbreaking theory of general relativity. It greatly impressed the elder physicist, who wrote in astonishment:

No one studying this mature, grandly conceived work could believe that the author is a man of 21. One wonders what to admire most, the psychological understanding for the development of ideas, the sureness of mathematical deduction, the profound physical insight, the capacity for lucid systematic presentation, the complete treatment of the subject matter, or the sureness of critical appraisal.

Indeed, this uncommon fusion of psychological acumen and scientific rigor only intensified as Pauli grew older. Around the time he wrote the paper that spurred Einstein’s praise, Pauli became enchanted with the work of pioneering psychologist William James. After a three-decade immersion in it, and several years after the won the Nobel Prize in Physics, Pauli met the great psychiatrist Carl Jung (July 26, 1875–June 6, 1961), who in turn was deeply influenced by Einstein’s ideas about space and time.

Jung and Pauli struck an unusual friendship, which lasted a quarter century until Pauli’s death and resulted in the invention of synchronicity — acausally connected events, which the observer experiences as having a meaningful connection on the basis of his or her subjective situation, a meeting point of internal and external reality.

Although rooted in Pauli’s interest in dream analysis, their conversations and correspondence went on to explore fundamental questions regarding the nature of reality through the dual lens of physics and psychology. Each used the tools of his expertise to shift the shoreline between the known and the unknown, and together they found common ground in the analogy between the atom, with its nucleus and orbiting electrons, and the self, with its central conscious ego and its ambient unconscious.

Both men were deeply imprinted by this intellectual cross-pollination. In his posthumously published final work, Jung would write:

We do not know whether what we on the empirical plane regard as physical may not, in the Unknown beyond our experience, be identical with what on this side of the border we distinguish from the physical as psychic. Though we know from experience that psychic processes are related to material ones, we are not in a position to say in what this relationship consists or how it is possible at all. Precisely because the psychic and the physical are mutually dependent it has often been conjectured that they may be identical somewhere beyond our present experience, though this certainly does not justify the arbitrary hypothesis of either materialism or spiritualism.

Pauli’s parallel curiosity about mind and matter is perhaps best articulated in by his friend and collaborator Werner Heisenberg — he of uncertainty principle fame — who would later write:

Behind [Pauli’s] outward display of criticism and skepticism lay concealed a deep philosophical interest even in those dark areas of reality of the human mind which elude the grasp of reason. And while the power of fascination emanating from Pauli’s analyses of physical problems was admittedly due in some measure to the detailed and penetrating clarity of his formulations, the rest was derived from a constant contact with the field of creative processes, for which no rational formulation as yet exists.

In their conceptually daring correspondence, collected in Atom and Archetype: The Pauli/Jung Letters, 1932–1958 (public library), the two delve into these parallels between the physical and psychic dimensions of reality. In one of his early letters, Jung considers the analogy Pauli had proposed between the atomic nucleus and the self. He writes in the autumn of 1935:

Generally speaking, the unconscious is thought of as psychic matter in an individual. However, the self-representation drawn up by the unconscious of its central structure does not accord with this view, for everything points to the fact that the central structure of the collective unconscious cannot be fixed locally but is an ubiquitous existence identical to itself; it must not be seen in spatial terms and consequently, when projected onto space, is to be found everywhere in that space. I even have the feeling that this peculiarity applies to time as well as space… A biological analogy would be the functional structure of a termite colony, possessing only unconscious performing organs, whereas the center, to which all the functions of the parts are related, is invisible and not empirically demonstrable.

The radioactive nucleus is an excellent symbol for the source of energy of the collective unconscious, the ultimate external stratum of which appears an individual consciousness. As a symbol, it indicates that consciousness does not grow out of any activity that is inherent to it; rather, it is constantly being produced by an energy that comes from the depths of the unconscious and has thus been depicted in the form of rays since time immemorial.


The center, or the nucleus, has always been for me a symbol of the totality of the psychic, as the conscious plus the unconscious, the center of which does not coincide with the ego as the center of consciousness, and consequently has always been perceived as being external.

Carl Jung on the cover of TIME magazine, February 1955

Over the following few years, their correspondence focuses primarily on dream analysis — which both Jung and Pauli saw as…