modern cosmology

The Wheel of the Year

The Wheel of the Year is an annual cycle of seasonal festivals, observed by many modern Pagans. It consists of either four or eight festivals: either the solstices and equinoxes, known as the “quarter days”, or the four midpoints between, known as the “cross quarter days”.

The festivals celebrated by differing sects of modern Paganism can vary considerably in name and date. Observing the cycle of the seasons has been important to many people, both ancient and modern, and many contemporary Pagan festivals are based to varying degrees on folk traditions.

In many traditions of modern Pagan cosmology, all things are considered to be cyclical, with time as a perpetual cycle of growth and retreat tied to the Sun’s annual death and rebirth.

Yule/Winter Solstice: a festival observed by the historical Germanic peoples, later undergoing Christian reformulation resulting in the now better-known Christmastide. A celebration the beginning of longer days, as this is the shortest day of the year in terms of sunlight. 

Imbolc: the first cross-quarter day following Midwinter this day falls on the first of February and traditionally marks the first stirrings of spring. It is time for purification and spring cleaning in anticipation of the year’s new life. 

For Celtic pagans, the festival is dedicated to the goddess Brigid, daughter of The Dagda and one of the Tuatha Dé Danann.

Among witches reclaiming tradition, this is the  time for pledges and dedications for the coming year.

Ostara/Spring Equinox: from this point on, days are longer than the nights. Many mythologies, regard this as the time of rebirth or return for vegetation gods and celebrate the spring equinox as a time of great fertility.

Germanic pagans dedicate the holiday to their fertility goddess, Ostara. She is notably associated with the symbols of the hare and egg. Her Teutonic name may be etymological ancestor of the words east and Easter.

Beltrane: traditionally the first day of summer in Ireland, in Rome the earliest celebrations appeared in pre-Christian times with the festival of Flora, the Roman goddess of flowers, and the Walpurgis Night celebrations of the Germanic countries. 

Since the Christianization of Europe, a more secular version of the festival has continued in Europe and America. In this form, it is well known for maypole dancing and the crowning of the Queen of the May.

Litha/Summer Solstice: one of the four solar holidays, and is considered the turning point at which summer reaches its height and the sun shines longest.

Luchnassad/Lammas: It is marked the holiday by baking a figure of the god in bread and eating it, to symbolize the sanctity and importance of the harvest. Celebrations vary, as not all Pagans are Wiccans.  

The name Lammas (contraction of loaf mass) implies it is an agrarian-based festival and feast of thanksgiving for grain and bread, which symbolizes the first fruits of the harvest. Christian festivals may incorporate elements from the Pagan Ritual.

Mabon/Autumn Equinox: a Pagan ritual of thanksgiving for the fruits of the earth and a recognition of the need to share them to secure the blessings of the Goddess and the God during the coming winter months. The name Mabon was coined by Aidan Kelly around 1970 as a reference to Mabon ap Modron, a character from Welsh mythology. Among the sabbats, it is the second of the three Pagan harvest festivals, preceded by Lammas / Lughnasadh and followed by Samhain.

Samhain: considered by some as a time to celebrate the lives of those who have passed on, and it often involves paying respect to ancestors, family members, elders of the faith, friends, pets, and other loved ones who have died. In some rituals the spirits of the departed are invited to attend the festivities. It is seen as a festival of darkness, which is balanced at the opposite point of the wheel by the festival of Beltane, which is celebrated as a festival of light and fertility.

9

Dark Matter Theory Triumphs In Sweeping New Study

“It’s a revolutionary breakthrough that dark matter can reproduce both the relationships between luminosity and galactic speeds and the stellar mass function in galaxies simultaneously, as this new study accomplishes for the first time. By incorporating advanced techniques and more detailed physical models and the interplay between different components, relations that has only been observed, never explained, are finally seen to emerge. If we can throw our cosmic ingredients into a simulation and get out the Universe exactly as we observe it, that’s as big a success for our theories and models as one can ask for.”

On the largest scales, dark matter has been undoubtedly the most successful theory in modern cosmology for explaining a huge variety of observations. From the motions of galaxies in clusters to the separation of mass and light when they collide, from the correlations between galactic positions to the fluctuations in the CMB, from the bending of starlight to the formation of large-scale structure, it’s clear that the Universe needs dark matter. But individual galaxies have always been the most difficult test for dark matter. In particular, there have been empirical correlations – or relationships between two different observables – that have never had an underlying explanation successfully presented. One of the most difficult has been the Tully-Fisher relation, which relates the luminosity to the rotational speed of spiral galaxies. But a new simulation, at long last, has finally cracked that nut by incorporating not only gravitation and dark matter, but the relationship between baryons and dark matter.

The way a galaxy forms stars over its history matters tremendously for what we get today, and by simulating it all together, it adds up to one stunning conclusion: success for dark matter in an entirely new way!

“The Hindu religion is the only one of the world’s great faiths dedicated to the idea that the Cosmos itself undergoes an immense, indeed an infinite, number of deaths and rebirths.
It is the only religion in which the time scales correspond to those of modern scientific cosmology. Its cycles run from our ordinary day and night to a day and night of Brahma, 8.64 billion years long. Longer than the age of the Earth or the Sun and about half the time since the Big Bang.”

—-

Carl Sagan, Cosmos

—-

Graphic - Giampaolo Bianchi

lovingnaniya  asked:

Can I ask for a top 5 or 10 books (or other resources) on the Orisa?

Sure! So, this is not a book religion, as I’m sure you know, and it can’t be learned from books. It has to be learned in person, in ceremony, as an oral tradition. However, books can be a helpful supplement, especially around history and for getting a general sense.

Santeria by Joseph Murphy
This is a widely available introductory look at a Babalawo-centric Lucumi house. I really love it, and it’s usually my go-to for new people, even though I’m not part of a Babalawo-centric house myself.

Santeria: From Africa to the New World by George Brandon
This is a wonderful history of the religion, including its introduction to the United States following the Cuban Revolution. It’s pretty short, too, so not super intimidating.

Santeria Enthroned by David Brown
This is hands-down the most comprehensive and insightful book on the religion - but it is a giant tome and very academic. It took me six months to read the first time! But there’s nothing else like it available. Part history, part art history, and written by a Santero, this is the most highly esteemed book on the religion in the English language.

Olodumare: God in Yoruba Belief by E. Bolaji Idowu
Hard to find but a really great text on (modern) Yoruba cosmology, particularly about the Orisha.

I’d also recommend the website aboutsanteria.com. This is run by a priest of Oshun who is part of an ilé (a cabildo, actually) in the eastern part of Cuba. Brimming with information and also an interesting contrast to the mostly western Cuban lineages detailed in other places.

A mere two years after completing his daring General Theory of Relativity in 1915 — where gravity is interpreted as resulting from the curvature of space and time around a massive body — Albert Einstein wrote a daring article, taking on the whole universe under his new lens.

Given that mass tells space how to bend, he reasoned, if he knew the mass contained in the entire universe, he could derive its geometry as a whole. For the first time in history, a single mind attempted to derive the shape of the cosmos not from theological or philosophical arguments, as so many had before, but as the result of solid physical and mathematical reasoning.

As an intellectual move, it took a lot of courage. In what follows, I’ll attempt to take you through Einstein’s reasoning, as close as possible to the famous 1917 paper.

How would someone apply equations that worked very well for solar-system-scale problems to a much grander scale?

Modern Cosmology Turns 100

Image: ESO/INAF-VST/OmegaCAM

9

How Big Was The Universe At The Moment Of Its Creation?

“We like to extrapolate our Universe back to a singularity, but inflation takes the need for that completely away. Instead, it replaces it with a period of exponential expansion of indeterminate length to the past, and it comes to an end by giving rise to a hot, dense, expanding state we identify as the start of the Universe we know. We are connected to the last tiny fraction of a second of inflation, somewhere between 10^(-30) and 10^(-35) seconds worth of it. Whenever that time happens to be, where inflation ends and the Big Bang begins, that’s when we need to know the size of the Universe.”

13.8 billion years ago, the Universe as we know it came into existence. Today, the part we can observe is 46 billion light years in radius, having grown tremendously thanks to the expansion of the Universe. But if we extrapolate that backwards, we find that the Universe couldn’t have been infinitely small at the moment of its birth, but rather was a finite size at all finite times. We know an awful lot about the moment the Universe can first be described by the hot Big Bang thanks to the last 50 years of modern cosmology. People used to think the Universe could be contained in a volume no bigger than a marble, or that the part accessible to us could have been the size of the Solar System at birth. No more!

Between the size of a soccer ball and a skyscraper-filled city block is the only range left, and the more we learn about inflation, the smaller that range will get. Find out the science behind it today!

duckandorpenguin  asked:

The anthropic principle, like much of modern cosmology, is actually a prank. I mean, they all get together at conferences, Kip Thorne and John Preskill and Stephen Hawking and that lot, and giggle behind their hands at some of the ridiculous shit they come up with and about which Scientific American publishes straight-faced articles. Of course this can backfire; Higgs's surprise at the discovery of his eponymous boson was entirely sincere because the whole idea was fake.

They’re all full of shit mostly and so is Donald Hoffman, except always. Do you know him? He’s the one who says quantum physics are wrong because Darwin was wrong and we evolved not to perceive reality more accurately, but to fool ourselves more completely about what reality is, and that gap is why our physics get weird at the limit. Then he says “no one has proved me wrong yet!” because he doesn’t know how falsifiability works. Dude learned everything he knows about cognitive science  and philosophy from Guns-n-Roses album titles, and the ones that sucked after Axl got lazy to boot. Fucken guy. 

“The Hindu religion is the only one of the world’s great faiths dedicated to the idea that the Cosmos itself undergoes an immense, indeed an infinite, number of deaths and rebirths.
It is the only religion in which the time scales correspond to those of modern scientific cosmology. Its cycles run from our ordinary day and night to a day and night of Brahma, 8.64 billion years long. Longer than the age of the Earth or the Sun and about half the time since the Big Bang.”

—-

Carl Sagan, Cosmos

—-

Graphic - Kenny Scharf

The Kamea

Over the next few weeks — now that they’re finally done — I’m going to be uploading the kamea of the seven planets, and their two principal sigils (proofing them has been a bit of a nightmare, frankly; and if you find a mistake, please let me know).  These are newly assembled.

I’m choosing to begin with Mercury.

Mercury

Mercury is the swiftest planet.  In the old Ptolemaic cosmos, it was next out from earth after the Moon; in modern cosmology, it is the second planet out from the Sun.  The ancients identified its close relationship with the Sun, noting that he was never far from the greater light, and that it took keen vision and determination to separate Mercury out from the light of the Sun.  

Mercury’s number is eight.  Hence, his square has eight columns of eight rows.  His sigil suggests the doubled-square, and four spheres (coins or disks or spheres? It’s hard to say.)  Its shorthand or astrological sign suggests the caduceus, the staff of intertwined snakes.  His color is orange (and why I wear an orange tie on Wednesdays, his day).  The sigil can be used for generating passwords, sigils, and other symbolism.

Mercury’s “portfolio” has to do with business, communication, symbols, language, journeys, travel, science, alchemy, trade, thievery, and all such similar aspects.  (Jason Miller has said that if Jupiter is like a savings account in financial matters {growth of wealth}, Mercury is like a checking account {assurance of quality cash flow}.)  Light and quick and fleet of feet, he is associated with Raphael (in some Judeo-Christian systems of magic; others associate Mercury with Gabriel or with Michael), with the planet Mercury, and with the sphere of Hod on the Tree of Life.  In metals, he is usually identified with quicksilver (Hg on the periodic table), but also with mixed metals, i.e., bronze and brass and other alloys.  When burning incense or in practice of vegetable alchemy, I associate him with lavender.

10

Could a new type of supernova eliminate dark energy?

“Imagine you had a box of candles that you thought were all identical to one another: you could light them up, put them all at different distances, and immediately, just from measuring the brightness you saw, know how far away they are. That’s the idea behind a standard candle in astronomy, and why type Ia supernovae are so powerful.

But now, imagine that these candle flames aren’t all the same brightness! Suddenly, some are a little brighter and some are a little dimmer; you have two classes of candles, and while you might have more of the brighter ones close by, you might have more of the dimmer ones far away. That’s what we think we’ve just discovered with supernovae: there are actually two separate classes of them, where one’s a little brighter in the blue/UV, and one’s a little brighter in the red/IR, and the light curves they follow are slightly different. This might mean that, at high redshifts (large distances), the supernovae themselves are actually intrinsically fainter, and not that they’re farther away.”

Back in the 1990s, scientists were quite surprised to find that when they measured the brightness and redshifts of distant supernovae, they appeared fainter than one would expect, leading us to conclude that the Universe was expanding at an accelerating rate to push them farther away. But a 2015 study put forth a possibility that many scientists dreaded: that perhaps these distant supernovae were intrinsically different from the ones we had observed nearby. Would that potentially eliminate the need for dark energy altogether? Or would it simply change ever-so-slightly the amount and properties of dark energy we required to explain modern cosmology? A full analysis shows that dark energy is here to stay, regardless of the supernova data.

My History of Science Was Wrong
  • Back when Venus passed between Earth and the Sun, a conversation with a local astronomer got me interested in reading just a little bit about the history of astronomy. I was completely surprised by how reasonable old-timey theories like Aristotle's levity/gravity and a geocentric Earth are--IF you drop your presentist knowledge in favour of the tools that were around at the time.
  • I learned a lot of things from reading just one (long) online comment-thread
  • Part of the understanding is just how crazy our modern cosmology is. Of course none of us question it because there were astronauts on the moon on TV and besides our teachers told us so and they have a higher social position and education than we do. (Bacon) This really hit home for me when I read that some ancient Greek natural-philosophers had measured how fast the Earth would have to spin to validate heliocentricity and concluded the number (~10,000 mph) was ludicrous. It sure feels like I'm standing still and not being blown by a 10,000 mph wind!
  • One ancient natural-philosopher speculated: If only there were some kind of ... ENVELOPE, or SHEATH, that would protect everything from spinning off and keep the air still on the Earth as the Earth whirled at its . Speaking of ad-hoc theories that fail Ockham's Razor....
  • (But wait ... how could they make that calculation if they thought the Earth was Flat because no Colón/Magellan...? I think that's another misconception I'll have to remedy later.)
  • Also interesting is that the concept of relativistic frames shows up in the 14th century. To say whether the celestial sphere or the Earthly sphere is rotating (what the stars can be observed to do at night) ... well, it's all just a matter of perspective, innit? Neither one "is really" rotating, it's just that the "other" is rotating -- considered from wherever "you" are standing.
  • I was also reminded, in imagining the astronomers working with their epicycles to predict -- quantitatively, not necessarily knowing the underlying mechanism -- the motions of the stars and planets, of quantitative finance. Particularly the machine-learning side. We just try to figure out *a* formula that works. If it has lower Vapnik-Chervonenkis dimension, great, but all we're really trying to do is predict what will happen or, more often, the risk of X happening. I can imagine future economists looking back on what fools we are, with our neural nets trained on the wrong data and overfitting the wrong functional forms. All for the sake of making a dollar and getting that social approval.
  • Have you ever tried explaining why inertia is right and things all fall at the same speed to a kid? Because things don't all fall at the same speed, and smoke in fact goes up. Not only that, but (if you have chosen to live far enough away from artificial light or regularly venture there at night) the sky is obviously still and even with great precision we can't measure parallax. Not to mention
  • Also -- that whole "Humans have over time come to see themselves as less and less special or privileged in the order of the universe"? Who said that, Sagan? I oughtta put a different book in front of his face before he promulgated all that stuff. The ancients and medievals didn't see humans as special or privileged by the Earth being at the centre of the Universe. They saw us as being at the bottom (which we obviously are. all the Heavens are above us. "up" is defined as the normal to the manifold surface of the Earth) of the natural order. This is totally consistent with the Fallen post-Eden state -- the Earth getting older and decaying, Man living shorter and shorter lifespans and falling deeper into Sin, the great civilisations of the past crumbling and decaying.
  • Anyway, there are way too many informative things said by different people to do "Quote" posts and I want these to be tied together. So I'm using the "Chat" Format instead.
  • if heliocentrism is so blatantly obvious and only the stupid Catholics didn’t get it because of their “blind faith”, why did the Chinese, who were unencumbered by both Aristotle and the Bible, have to wait until the Jesuits – of all people – came, rather than vice versa? It’s funny how all these clamorous indictments against the Catholic Church for holding back science somehow amount to a big insult to non-European civilizations, who didn’t have the evil Church to hold them back and somehow still didn’t make it, despite being given a 1000-year headstart.
  • Don’t forget, heliocentrism had been falsified in good Popperian fashion by the absence of the predicted stellar parallax and the lack of eastward deflection in falling bodies. (Good evidence why Popper is inadequate.) The latter was not empirically settled until the 1790s when Gugliemini dropped weights down the inside of the spiral staircase of the tower of the Univ. of Bologna. The former was apparently settled when Calandrelli observed parallax in a-Lyrae. (“Apparently” because some have contended that he could not have actually observed it. However, it was reported in the literature in 1803.)
  • the Jesuits were half-way convinced. Grienberger was reported to have said that Scheiner was on board and even Clavius was not far from the Copernican system. Then GG had to get into a flame war with Grassi over the comets of 1618, where Grassi had made meticulous telescopic observations and was clearly right on the science while GG had not even bothered to observe them, and so the Jesuits, who had earlier celebrated Galileo, sat on their hands when he went on trial.
  • Galileo declared that the comets of 1618 were emanations in the earth’s atmosphere; whereas the Jesuit astronomers claimed they were bodies in highly eccentric orbits that had come from somewhere beyond the moon. In the Dialogo, Galileo had claimed the ocean tides were sloshing caused by the earth’s rotation and so conclusive proof. But centuries before, Aquinas had written that the tides were caused somehow by the moon.
  • Somebody else pointed out that the Catholics have had the longest-running astronomical observatory in the world. Elsewhere that Aquinas wrote that there are multiple possible interpretations of the Bible and we shouldn't settle on THE official one until we know it's true (however false interpretations can be ruled out)
  • Apparently the future Pope told Galileo in 1611 that the theologians needed a little time to go over his work. He pushed them on the issue and said they needed to reinterpret the Bible based on his work of natural philosophy, That was a no-no because only the Church can interpret the Bible (this is before Martin Luther) and that is in fact where all of their political power comes from. So rather than being anti-science, the Church was forced, politically, into taking GG head on when, for intellectual reasons, they woudl have preferred to continue their centuries-long project of squaring science with religion.
  • (In the discussion it coes clear that science and religion as we think of them today are misleading terms, because science as we understand it didn't exist and neither did religion as we understand it. Natural philosophy, astronomy, geometry, and theology are better terms.
  • here's what the other guy said:
  • The Catholic Church has one of the oldest operating observatories in the world. During the time the Catholic Church was ascendant, Europe experienced one of the greatest scientific booms in world history.
  • The conflict thesis about Galileo and Bruno are basically urban legends that have little connection to what actually happened. It always disappoints atheists when they find out that Galileo was actually kind of a dick, and Bruno wasn't executed in the slightest for his support of heliocentrism, but I try to always attack urban legends whenever they crop up.
  • Geocentricity was not seen to support humanity’s “specialness”. The centre of the universe was the bottom of the universe – everywhere you looked was up. That we occupy the place of least dignity in the universe was a commonplace of classical & medieval poetry. --Andrew Brew
  • "Anachronistically, we tend to think the Church's great problem was negotiating the difference between dogma and emerging science. But the Galileo debate was superimposed on a much older struggle to assimilate Greek thought (Aristotle) w Church teaching." —Jim Harrison
  • "Immutability of the heavens is not & never was prerequisite to geocentricity. Stoics rejected immutability & accepted geo."—@rmathematicus
  • "There is an obsession with suggesting that X was wrong, and that the 'truth' came along and bulldozed all previous lies."—Pete Langman
  • "contrary to popular opinion, Copernicus’ De revolutionibus was not on the Librorum Prohibitorum but only referred there until corrected."
  • "Kepler worried about having his book on the Librorum Prohibitorum but friends pointed out that it became more attractive, forbidden fruit."
  • "All the ban meant was that scholars could not find the book on open shelves but had to apply…duly delivered from the poison cabinet."
  • attributed as a chat
  • presentist ... fuels debate
  • W
  • Jim Harrison: What really ended the debate was not a decision on which system had fewer epicycles and assumptions, but the emergence of a persuasive dynamic explanation. So long as it’s just a matter of geometry, Tycho’s system works as well as a heliocentric system even if you consider the phases of Venus. Once you develop laws of motion and a theory of gravity, however, it becomes pretty hard to think that the itty bitty Earth is lording it over the enormous sun. It seems there was this guy named Newton…
  • Came across a historian of science who is tearing apart the story we were all told about the Catholic Church and Galileo.
  • https: //thonyc.wordpress.com/2011/06/22/but-it-doesn%e2%80%99t-move/
  • A few choice quotes:
  • @rmathematicus: if heliocentrism is so blatantly obvious and only the stupid Catholics didn’t get it because of their “blind faith”, why did the Chinese, who were unencumbered by both Aristotle and the Bible, have to wait until the Jesuits – of all people – came, rather than vice versa? It’s funny how all these clamorous indictments against the Catholic Church for holding back science somehow amount to a big insult to non-European civilizations, who didn’t have the evil Church to hold them back and somehow still didn’t make it, despite being given a 1000-year headstart.
  • @rmathematicus: Don’t forget, heliocentrism had been falsified in good Popperian fashion by the absence of the predicted stellar parallax and the lack of eastward deflection in falling bodies. (Good evidence why Popper is inadequate.) The latter was not empirically settled until the 1790s when Gugliemini dropped weights down the inside of the spiral staircase of the tower of the Univ. of Bologna. The former was apparently settled when Calandrelli observed parallax in a-Lyrae. (“Apparently” because some have contended that he could not have actually observed it. However, it was reported in the literature in 1803.)
  • @rmathematicus: the Jesuits were half-way convinced. Grienberger was reported to have said that Scheiner was on board and even Clavius was not far from the Copernican system. Then GG had to get into a flame war with Grassi over the comets of 1618, where Grassi had made meticulous telescopic observations and was clearly right on the science while GG had not even bothered to observe them, and so the Jesuits, who had earlier celebrated Galileo, sat on their hands when he went on trial.
  • @rmathematics: Galileo declared that the comets of 1618 were emanations in the earth’s atmosphere; whereas the Jesuit astronomers claimed they were bodies in highly eccentric orbits that had come from somewhere beyond the moon. In the Dialogo, Galileo had claimed the ocean tides were sloshing caused by the earth’s rotation and so conclusive proof. But centuries before, Aquinas had written that the tides were caused somehow by the moon.
  • @rmathematicus: Somebody else pointed out that the Catholics have had the longest-running astronomical observatory in the world. Elsewhere that Aquinas wrote that there are multiple possible interpretations of the Bible and we shouldn't settle on THE official one until we know it's true (however false interpretations can be ruled out)
  • @rmathematicus: Apparently the future Pope told Galileo in 1611 that the theologians needed a little time to go over his work. He pushed them on the issue and said they needed to reinterpret the Bible based on his work of natural philosophy, That was a no-no because only the Church can interpret the Bible (this is before Martin Luther) and that is in fact where all of their political power comes from. So rather than being anti-science, the Church was forced, politically, into taking GG head on when, for intellectual reasons, they woudl have preferred to continue their centuries-long project of squaring science with religion.
  • @isomorphisms: (In the discussion it coes clear that science and religion as we think of them today are misleading terms, because science as we understand it didn't exist and neither did religion as we understand it. Natural philosophy, astronomy, geometry, and theology are better terms.
  • here's what the other guy said:
  • The Catholic Church has one of the oldest operating observatories in the world. During the time the Catholic Church was ascendant, Europe experienced one of the greatest scientific booms in world history.
  • The conflict thesis about Galileo and Bruno are basically urban legends that have little connection to what actually happened. It always disappoints atheists when they find out that Galileo was actually kind of a dick, and Bruno wasn't executed in the slightest for his support of heliocentrism, but I try to always attack urban legends whenever they crop up.
  • Andrew Brew: Geocentricity was not seen to support humanity’s “specialness”. The centre of the universe was the bottom of the universe – everywhere you looked was up. That we occupy the place of least dignity in the universe was a commonplace of classical & medieval poetry.
  • Jim Harrison: Anachronistically, we tend to think the Church's great problem was negotiating the difference between dogma and emerging science. But the Galileo debate was superimposed on a much older struggle to assimilate Greek thought (Aristotle) w Church teaching.
  • @rmathematicus: Immutability of the heavens is not & never was prerequisite to geocentricity. The Stoics, for example, rejected immutability & accepted geocentricity.
  • Pete Langman: There is an obsession with suggesting that X was wrong, and that the 'truth' came along and bulldozed all previous lies.
  • "contrary to popular opinion, Copernicus’ De revolutionibus was not on the Librorum Prohibitorum but only referred there until corrected."
  • "Kepler worried about having his book on the Librorum Prohibitorum but friends pointed out that it became more attractive, forbidden fruit."
  • "All the ban meant was that scholars could not find the book on open shelves but had to apply…duly delivered from the poison cabinet."
The Hindu religion is the only one of the world’s great faiths dedicated to the idea that the Cosmos itself undergoes an immense, indeed an infinite, number of deaths and rebirths.
It is the only religion in which the time scales correspond to those of modern scientific cosmology. Its cycles run from our ordinary day and night to a day and night of Brahma, 8.64 billion years long. Longer than the age of the Earth or the Sun and about half the time since the Big Bang.
—  Carl Sagan, Cosmos
8

Why are dark matter and modified gravity in such conflict?

“Most in the dark matter camp are convinced that the full suite of their successes to date mean that a better understanding of the nature of dark matter and improved computational power will lead to galaxy rotation falling into line. Similarly, most in the modified gravity camp are equally convinced that the failure of dark matter on these small scales is a catastrophe, and that the correlations they’ve discovered are a natural law that’s a precursor to a revolution even bigger than Einstein’s was 100 years ago. The great challenge for modified gravity is to reproduce the successes on large-scales of modern cosmology; the challenge for dark matter is to reproduce the details of the smallest scales correctly.”

The past month has seen a slew of papers out highlighting the tension between modified gravity and dark matter. Both recognize the same puzzles and problems with the Universe, and both ideas recognize that either one could be valid. In fact, if you look at the two greatest “crises” in gravity in the 19th century, it’s arguable that dark matter (Neptune) solved one, the Uranus problem, while modifying gravity (with Einstein’s general relativity) solved the other. Now in the 21st century, we have a whole Universe to explain, and while dark matter is definitely the leading theory, the idea of modifying gravity isn’t crazy. Moreover, it has a success that dark matter can’t match: on galaxy-scales and below. In the end, it will take a big step forward for a true victor to emerge, but here’s where the science stands right now.

calebgoodfellow  asked:

How do you feel about the idea that our universe exists inside a black hole? And that each black hole contains a universe?

I like that theory. It actually makes sense if you think about it. All the black holes found so far in our universe—from the microscopic to the supermassive—may be doorways into alternate realities. According to the theory, a black hole is actually a tunnel between universes—a type of wormhole. The matter the black hole attracts doesn’t collapse into a single point, as has been predicted, but rather gushes out a “white hole” at the other end of the black one, the theory goes.

According to the new equations, the matter black holes absorb and seemingly destroy is actually expelled and becomes the building blocks for galaxies, stars, and planets in another reality.

The notion of black holes as wormholes could explain certain mysteries in modern cosmology. For example, the big bang theory says the universe started as a singularity. But scientists have no satisfying explanation for how such a singularity might have formed in the first place.

How do you test that? Some of our universe’s black holes rotate, and if our universe was born inside a similarly revolving black hole, then our universe should have inherited the parent object’s rotation.If future experiments reveal that our universe appears to rotate in a preferred direction, it would be indirect evidence supporting his wormhole theory. 

It is fascinating to think about. If we can figure that out it answers a lot of questions. Another great question! Thank you :)

Sources: National Geographic

6

The Multiverse for non-scientists

“So what is the Multiverse? It could mean one of three things:

1. More “Universe” like our own that came from the same Big Bang, but isn’t observable.
2. Or it could mean more Universes like our own that came from different Big Bangs, but that originated from the same, common inflationary state.
3. Or it could mean a wide variety of Universes — some like our own and some different — with different constants and even laws governing them.

The Multiverse may be finite in size and number of Universes, or it could be infinite. If you accept the Big Bang and modern cosmology, then the first one is definitely true. If you accept cosmic inflation (and there are good reasons to do so), then so is the second one. And if you accept certain models of String Theory or other unification ideas, the third one may be true as well. (But not necessarily!)”

Ever wonder what the Multiverse is, why we think it exists, what the different options are and why some people hate it so much? Find out today!