Quantum Gravity Could Reverse Cause and Effect



Quantum Gravity Could Reverse Cause and Effect

You’ve probably heard of Schrödinger’s cat, the unfortunate feline in a box that is simultaneously alive and dead until the box is opened to reveal its actual state. Well, now wrap your mind around Schrödinger’s time, a situation in which one event can simultaneously be the cause and effect of another event.

Such a scenario may be inevitable in any theory of quantum gravity, a still-murky area of physics that seeks to combine Albert Einstein’s theory of general relativity with the workings of quantum mechanics. In a new paper, scientists create a mashup of the two by imagining starships near an enormous planet whose mass slows time. They conclude that the starships could find themselves in a state where causation is reversed: One event could end up causing another event that happened before it.

“One can devise this kind of scenario where temporal order or cause and effect are in superposition of being reversed or not reversed,” said study co-author Igor Pikovski, a physicist at the Center for Quantum Science and Engineering at Stevens Institute of Technology in New Jersey. “This is something we expect should take place once we have a full theory of quantum gravity.”

Related: 8 Ways You Can See Einstein’s Theory of Relativity in Real Life

All Quantum Gravity Theories Suck – Here’s Why
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Quantum time

The famous Schrödinger’s cat thought experiment asks a viewer to imagine a box holding a cat and a radioactive particle, which, once decayed, will kill the unfortunate feline. By the principle of quantum superposition, the cat’s survival or death is equally likely until measured — so until the box is opened, the cat is simultaneously alive and dead. In quantum mechanics, superposition means that a particle can exist in multiple states at the same time, just like Schrödinger’s cat.

The new thought experiment, published Aug. 21 in the journal Nature Communications, combines the principle of quantum superposition with Einstein’s theory of general relativity. General relativity says that the mass of a giant object can slow down time. This is well established as true and measurable, Pikovski said; an astronaut orbiting Earth will experience time just a smidge faster than his or her twin back on the planet. (This is also why falling into a black hole would be a very gradual experience.)

Thus, if a futuristic spacecraft were near a massive planet, its crew would experience time as a little bit slower than would people in a fellow spacecraft stationed farther away. Now, throw in a little quantum mechanics, and you can imagine a situation in which that planet is superpositioned simultaneously near to and far away from the two spacecraft.

Time gets weird

In this superpositioned scenario of two ships experiencing time on different timelines, cause and effect could get wonky. For example, say the ships are asked to conduct a training mission in which they fire at each other and dodge each other’s fire, knowing full well the time the missiles will launch and intercept their positions. If there’s no massive planet nearby messing with time’s flow, this is a simple exercise. On the other hand, if that massive planet were present and the ship’s captain didn’t take the slowing of time into account, the crew might dodge too late and be destroyed.

With the planet in superposition, simultaneously near and far, it would be impossible to know whether the ships would dodge too late and destroy each other or whether they would move aside and survive. What’s more, cause and effect could be reversed, Pikovski said. Imagine two events, A and B, that are causally related.

“A and B can influence each other, but in one case A is before B, while in the other case B is before A” in a superposition state, Pikovski said. That means that both A and B are simultaneously the cause and effect of each other. Fortunately for the likely-confused crews of these imaginary spacecraft, Pikovski said, they would have a mathematical way to analyze each other’s transmissions to confirm that they were in a superpositioned state.

Obviously, in real life, planets don’t move around the galaxy willy-nilly. But the thought experiment could have practical implications for quantum computing, even without working out an entire theory of quantum gravity, Pikovski said. By using superpositions in computations, a quantum-computing system could simultaneously evaluate a process as a cause and as an effect.

“Quantum computers may be able to use this for more efficient computation,” he said.

Originally published on Live Science.

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5 things apples have been used for throughout history



5 things apples have been used for throughout history

Apples have always been a popular fruit all over the world. While they were not originally from America (the first country to make apples a sought-after food was Persia), they have become an extremely “American” fruit, being used in everything from apple pie, to savory dishes like pork roast. Apples have had many different uses in different places throughout the centuries, though, some of which may surprise you.

Planting orchards

Credit: S847 / iStock

The first American apple orchard was planted in 1625 by a man named William Blackstone. He created this orchard by planting apples/apple seeds from Europe on Beacon Hill in Boston in order to bring the beloved fruit to America. Many other Americans followed suit, planting their own apple orchards on American soil. The first governor of Massachusetts, for instance, wrote all about his own orchard in his account book, where he also mentioned that his children set fire to part of it and burned down 500 of his trees. Founding Fathers George Washington and Thomas Jefferson were orchardists as well, although their orchards fared much better than the governor’s.

To explain gravity

Credit: lucentius / iStock

While most of us remember the story about Isaac Newton getting bopped on the head by an apple in the 17th century and suddenly coming up with the concept of gravity, that is most likely not exactly how it happened. Newton, a college student at the time, really was in his family’s orchard in England when he saw an apple fall from a tree, but it probably didn’t hit him on the head. The way that it fell straight down to the ground instead of to the side or in another direction got him to thinking, which eventually led to his developing the universal law of gravitation.


Credit: nata_vkusidey / iStock

According to some legends, apples have a connection to the “fairy world.” The tradition of bobbing for apples at Halloween is related to the idea that both apples and water have a supernatural link to other worlds beyond our own. Some other Halloween traditions say that taking a bite out of an apple and sleeping with it under your pillow will make you have a dream about the person who will be your true love. It is also said that falling asleep in an apple orchard could make you wake up years later, and that burying treasure under an apple tree will ensure that it will never decompose or be discovered by anyone else.


Credit: docent / Shutterstock.com

Everyone has heard the story of the Garden of Eden, in which Eve is tempted to eat the fruit from the Tree of Knowledge of Good and Evil, and she does it, dooming her companion Adam and the rest of the human race that came after them. For centuries, people have believed that the fruit that is referred to in this story is the apple, but this is actually not true. The type of fruit is never specified, meaning it could have been anything from a fig to an olive to a banana. Early artists, though, depicted this fruit as being an apple, perhaps because in Latin the word “malus” means both “evil” and “apple.” This associated the Forbidden Fruit with an apple in everyone’s mind, and the symbolism has hung on for hundreds of years.


Credit: RomoloTavani / iStock

You knew we couldn’t get through an article about apples without reciting the compulsory phrase: “An apple a day keeps the doctor away.” This idea has been around for thousands of years, with some cultures believing that apples could make them immune to sickness, or even immortal. Today, apples have been scientifically proven to help reduce allergic reactions by slowing down the body’s secretion of histamine, as well as to shorten the length and severity of migraines. They have also been shown to help with digestion by slowing down the process and making you feel fuller and more satisfied longer.

Dark Matter And Black Holes



WHEN IT COMES to the nature of dark matter, astronomers are still largely, well, in the dark. The existence of this mysterious substance was hypothesized more than 40 years ago to explain discrepancies between the calculations of how galaxies ought to behave, based on their mass, and what was actually observed. In short, it seemed like mass was missing. So Vera Rubin, the astronomer who first discovered this discrepancy, conjured an invisible substance that is far more abundant than “normal” matter and acts as the scaffolding for the large-scale structure of the universe. Today we call it dark matter.

Yet decades of hunting for the elusive dark matter particle still have not yielded direct evidence of its existence. Most cosmologists still believe that dark matter must exist, but some have splintered off to propose other explanations that explain away dark matter by modifying our understanding of gravity.

But two findings are now casting doubt on the modified gravity explanation. In March, a team of astronomers led by Yale professor Pieter van Dokkum and his graduate student Shany Danieli published two papers, one confirming the existence of a galaxy that appears to have almost no dark matter and the other announcing the discovery of a second galaxy of this type. The irony, the researchers say, is that the seeming lack of dark matter in these galaxies is strong evidence that it exists.

The reason they believe these galaxies have no dark matter is that their dynamics can be predicted using our traditional theories of gravity. The discrepancy of the “missing mass” that’s seen in most galaxies isn’t present here, meaning there’s no need for dark matter to explain their behavior. And it means that the modified version of gravity proposed by some cosmologists doesn’t predict these galaxies’ movements as cleanly as good old Newtonian physics.

The discovery of these dark-matter-free galaxies traces back to 2014, when van Dokkum and his colleagues finished building Dragonfly, a new kind of telescope, made of off-the-shelf telephoto camera lenses, that specializes in observing extremely faint celestial objects. Only a year after its first light, Dragonfly discovered a new galaxy characterized by an extreme lack of stars relative to its size. Known as an ultra-diffuse galaxy, this ghostly celestial object had roughly the same mass as our Milky Way, but only one hundredth of one percent of that mass could be attributed to “normal” matter like stars. In other words, van Dokkum and his colleagues had discovered a galaxy made of 99.99 percent dark matter.

While this galaxy was unique, its existence isn’t entirely surprising. Most cosmologists think that dense collections of dark matter act as a sort of seed for the formation of large celestial objects like galaxies. The general idea, says Anže Slosar, an astrophysicist at Brookhaven National Laboratory, is that once a collection of dark matter reaches a critical density, it collapses under its own gravity and forms a so-called “dark matter halo.” This halo, in turn, gravitationally attracts hydrogen gas to its center, where it begins to form stars and, eventually, galaxies. The mass of a dark matter halo varies from galaxy to galaxy, but it seemed like every galaxy must have at least some dark matter to keep its form. Indeed, this assumption was precisely what made Dragonfly’s next discovery so surprising.

In 2016, van Dokkum and his colleagues at Yale discovered NGC 1052-DF2, an ultra-diffuse galaxy that appeared to contain little to no dark matter at all. Last year, when the Yale astronomers published their results in the journal Nature, their peers in the cosmological community were incredulous. This was the first galaxy ever discovered that appeared to lack any dark matter, and as Carl Sagan rightly observed, “extraordinary claims require extraordinary evidence”—which is what many cosmologists thought the Yale team was missing.

University of Pennsylvania astrophysicist Robyn Sanderson says the skepticism about DF2 sprang mostly from the limited amount of data used to draw the conclusion. In this case, the Yale team was using data from just 10 star clusters observed over a period of two nights. This meant it was possible they were overlooking key details of the star clusters’ motion, which would distort their estimations of the galaxy’s mass—and undermine their claim that it lacked dark matter.

The Yale researchers recognized this possible source of error themselves when they published their paper on DF2. The only way to resolve this conundrum was to make more detailed measurements or to find another galaxy with characteristics similar to DF2. In March, the Yale team published two papers that did exactly these things.

The first paper offered more refined measurements of stellar velocities within DF2. This time, rather than just measuring the velocities of 10 star clusters, van Dokkum and Danieli used the Keck telescope in Hawaii to observe the velocities of the stars within the star clusters. This approach produced far more data that reinforced the team’s earlier conclusion that the galaxy lacked dark matter.

The other paper announced the discovery of a second galaxy, DF4, which also appears to have little, if any, dark matter. Not only does this increase the odds that the DF2 observations are accurate, it also means such ultra-diffuse galaxies might not be so rare. The fact that two were found in quick succession, Danieli says, was “really reassuring.” Nevertheless, she says “it’s still too early to say whether they are super rare or quite common.” The team will begin observing other nearby ultra-diffuse galaxies next month in an effort to answer this question.

But that won’t resolve the mystery of how these strange galaxies came to exist in the first place. Theoretical cosmologists will have to run simulations to determine how a galaxy can lose its dark matter, she says. One leading theory involves tidal interactions, which is astronomer-speak for when the gravitational forces of two neighboring galaxies pull material from each galaxy and distort them. DF2 and DF4 are both near the galaxy NGC 1052, which makes it a strong candidate for the galaxy that stole their dark matter.

However they came to be, Danieli argues that the existence of these galaxies is a blow to the modified gravityexplanation for why most galaxies don’t behave as we’d expect.

Known as modified Newtonian dynamics, or MOND, this theory recasts gravity such that it has different effects at the galactic scale. Although MOND has successfully predicted the stellar dynamics of hundreds of galaxies, most of which are relatively isolated, it must be able to predict the dynamics of all galaxies to dethrone dark matter as the going cosmological theory.

As Slosar explains it, the discovery of DF2 and DF4 strengthens the case for the existence of a dark matter particle because it means that it can be separated from normal matter. Because these galaxies behave in line with standard gravitational theory, using the equations discovered by Newton and Kepler, they present a challenge to MOND.

“If you find galaxies, some of which have a lot of dark matter and some of which have a little dark matter, you can’t explain it with the loss of gravity unless you’re willing to say that one part of the universe has a different law of gravity than another part, which is just silly,” Slosar says. “The entire point of physics is to find unified laws that are always there. This is why it is an argument for the existence of dark matter.”

So does the existence of galaxies devoid of dark matter pose an existential threat for MOND? Stacy McGaugh, an astronomer at Case Western Reserve University, doesn’t think so. “When DF2 was first discovered, it was portrayed as a huge problem for MOND,” McGaugh says. “On more careful analysis, it turned out that the prediction of MOND was spot-on what was observed.”

The analysis by McGaugh and his colleagues of DF2’s implications for MOND hinges on the galaxy’s proximity to the massive elliptical galaxy NGC1052. Under a set of “reasonable” assumptions, paired with equations from MOND, McGaugh and his colleagues found that NGC1052’s gravitational effects on DF2 would return stellar velocities similar to what van Dokkum and Danieli actually observed. Although he hasn’t had the chance to repeat this analysis for DF4, McGaugh says it also “appears to be consistent with MOND, since it is likely affected by NGC 1052.”

The existence of these galaxies poses a number of vexing problems for the theory of galactic formation, which must account for how a galaxy can come to be violently stripped of its dark matter and still retain the relative order seen, for example, in the presence of star clusters in DF2 and DF4. Will further observations of ultra-diffuse galaxies resolve the dark matter debate? Probably not, but they will, at least, shed some light on the matter.

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The ‘Gravity’ Of Religion



A couple of hours ago I was contemplating writing an article for this site, yet I was stuck in that I wasn’t settling on a subject matter. I don’t remember where or how the word ‘gravity’ got stuck in my thoughts yet it did. I decided to look up the meaning in the dictionary so I used the website of ‘Dictionary.com’ to see what it had to say. I was also intending to look up the word gravity in the index of my King James Bible to see what it may say about the word gravity, the answer to that question is that my KJV doesn’t say anything about it. I did find out through Dictionary.com that the word gravity has a Latin root from the year span of 1500-1510 A.D.. Even the Gutenberg Bible that was written in the area of 1450 says nothing about gravity, and now I know why, it (the word gravity) hadn’t been invented. The KJV was published in 1611 A.D., basically 100 years after it ‘became a word’ yet it doesn’t mention the word. So, that reality cut off a big portion of what I was planning to write. I am not going to just make things up and say things that I know are not true to you so, I will simply say true things for you to consider please.


In the Dictionary.com definition it gave 7 examples of the meaning. I am going to give you 4 of them as the other 3 didn’t appear to me to be even a little bit relevant with our discussion. First of all it says that gravity, is a noun. 1) The force of attraction by which terrestrial bodies tend to fall toward the center of the Earth. 2) Heaviness of weight 3) Gravitation in general 4) Serious or dignified behavior; dignity: Solemnity.


Some of you may be thinking, well, what has gravity and religion got to do with each other, and that is a fair question so I will now explain why I have put them together. Those of you whom are regular readers of my articles know that my religion is the Christian Faith. I did not say Catholic, Baptist, Methodist, Lutheran excreta. There is only one Christian Faith, it is humans whom have made the splinters, yet this would be a totally different subject for a different article. In this article I am going to be pointing toward the Christian Faith yet folks who believe in other Religions can easily picture in their own minds the parameters of the Religion that you do believe in. Like a lot of my articles this article is simply designed to get us all to think, to dig inside ourselves, to know ourselves better.


The force of attraction, one body gravitating toward another body. Yet I am not speaking of two humans, I am speaking of you, or me, as a human growing closer to a Deity, a God, that we believe in. Can a person really have love for or faith in that which we do not have believe in, or love for? If we humans are to gravitate toward God then we must honestly and urgently seek Him. If we are not pulled together then we will not meet together. If we do not seek God, then we will not find Him. If we do not have faith in Him, if we do not believe Him then we do not love Him. Without faith it is impossible to please God, our own Creator.


The heaviness of the weight of believing in God: For many, in fact, most people who call ourselves Christians know little about what the Scriptures actually say so we are easily deceived even by some sermons within the Churches. For so many people they believe that there is a ‘God’ even though they know almost nothing of Him. Many people, and I am speaking about people who call themselves Christians, feel a weight on their shoulders and their conscience because they still want to do all the ‘Earthly’ things like wild partying, getting drunk regularly and do a little whoring around or even a little bit of stealing once in a while. Many folks who do all of these things will still tell you, if none of their drinking buddies are around, that yes they are a Christian. Many of these same folks who are staying up all night Saturday night will still be sitting in a Church Pew on Sunday morning. The Lord tells us that if we love Him, then we will obey Him. As a person’s faith grows in God, the things of the world mean less and less to us. Folks, the Church, is the ‘Bride of Christ’, it is ‘the Church’ that the Lord will be coming back to get, His Bride. Folks either we gravitate toward God, or we are running away from Him. It is not possible to have the world and God at the same time.


Serious or dignified behavior; dignity: solemnity/oneness. My question for all of us now is, do we have a serious dignified behavior, a oneness with God? Do we believe in God? If we do, do the people around us know that we do? Do they see the love of God within us? Would our neighbors or coworkers be shocked if they happen to see us walking into a Church building one Saturday of Sunday morning? If we truly believe that there is a God, do we act like it? We don’t have to yell from street corners to tell everyone that we are a Christian, the quietness of our actions prove whether we really believe or not. If I were able to give a million dollars to the Red Cross or to a hurricane relief fund but then turn around and blab it to the world about what I had done, then I am seeking the attention of the world, not of God. Gravitating toward God is a matter of our own dignity.  If we are not serious about our love for God, are we so unwise that we think God doesn’t know why we do, or don’t do things? Do we honestly think that God is blind, or ignorant? “If you love me you will do like I ask of you”. Just as if our love is for our spouse, do we act like it each day? Does our spouse know without a doubt that we love them? Do you have doubts that your spouse loves you? The Gravity of our Faith in God is a very serious matter folks, our own Soul lay in the balance. God seeks a oneness with us yet we must seek this same oneness with Him, but, do we?