Essentials
theDiagonal is a personal blog by Mike Gerra, skeptic, technologist, psychologist, artist, humanist, collector of grand, eclectic ideas.theDiagonal blog connects the dots across multiple disciplines for inquisitive, objective and critical thinkers, exploring the vertices of big science, disruptive innovation, global sustainability, illuminating literature and leftfield art. It is on this diagonal that creativity thrives, big ideas take flight and reason triumphs.
Tag Archives: cosmology
Monday, April 29, 2013
General Relativity Lives on For Now
Since Einstein first published his elegant theory of General Relativity almost 100 years ago it has proved to be one of most powerful and enduring cornerstones of modern science. Yet theorists and researchers the world over know that it cannot possibly remain the sole answer to our cosmological questions. It answers questions about the very, very large — galaxies, stars and planets and the gravitational relationship between them. But it fails to tackle the science of the very, very small — atoms, their constituents and the forces that unite and repel them, which is addressed by the elegant and complex, but mutually incompatible Quantum Theory.
So, scientists continue to push their measurements to ever greater levels of precision across both greater and smaller distances with one aim in mind — to test the limits of each theory and to see which one breaks down first.
...read more
Posted in BigBang
Tagged cosmology, Einstein, General Relativity theory, gravity, pulsar, Quantum Theory
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Sunday, April 7, 2013
Shedding Light on Dark Matter
Scientists are cautiously optimistic that results from a particle experiment circling the Earth onboard the International Space Station (ISS) hint at the existence of dark matter.
From Symmetry:
The space-based Alpha Magnetic Spectrometer experiment could be building toward evidence of dark matter, judging by its first result.
The AMS detector does its work more than 200 miles above Earth, latched to the side of the International Space Station. It detects charged cosmic rays, high-energy particles that for the most part originate outside our solar system.
The experiment’s first result, released today, showed an excess of antimatter particles—over the number expected to come from cosmic-ray collisions—in a certain energy range.
...read more
Posted in BigBang
Tagged AMS, cosmology, dark matter, ISS, NASA, particle physics, spectrometer
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Monday, March 25, 2013
MondayMap: Quiet News Day = Map of the Universe
It was surely a quiet news day on March 21 2013 — most major online news outlets showed a fresh map of the Cosmic Microwave Background (CMB) on the front page. It was taken by the Planck Telescope, operated by the European Space Agency, over a period of 15 months. The image shows a landscape of primordial cosmic microwaves from when the universe was only around 380,000 years old, and is often referred to as “first light”.
From ESA:
Acquired by ESA’s Planck space telescope, the most detailed map ever created of the cosmic microwave background – the relic radiation from the Big Bang – was released today revealing the existence of features that challenge the foundations of our current understanding of the Universe.
The image is based on the initial 15.5 months of data from Planck and is the mission’s first all-sky picture of the oldest light in our Universe, imprinted on the sky when it was just 380 000 years old.
...read more
Posted in BigBang
Tagged big bang, CMB, cosmology, ESA, first light, map, MondayMap, NASA
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Thursday, January 10, 2013
Shedding Some Light On Dark Matter
Cosmologists theorized the need for dark matter to account for hidden mass in our universe. Yet, as the name implies, it is proving rather hard to find. Now astronomers believe they see hints of it in ancient galactic collisions.
From New Scientist:
Colliding clusters of galaxies may hold clues to a mysterious dark force at work in the universe. This force would act only on invisible dark matter, the enigmatic stuff that makes up 86 per cent of the mass in the universe.
Dark matter famously refuses to interact with ordinary matter except via gravity, so theorists had assumed that its particles would be just as aloof with each other. But new observations suggest that dark matter interacts significantly with itself, while leaving regular matter out of the conversation.
...read moreMonday, October 1, 2012
Engage the Warp Engines
According to Star Trek fictional history warp engines were invented in 2063. That gives us just over 50 years. While very unlikely based on our current technological prowess and general lack of understanding of the cosmos, warp engines are perhaps becoming just a little closer to being realized. But, please, no photon torpedoes!
From Wired:
NASA scientists now think that the famous warp drive concept is a realistic possibility, and that in the far future humans could regularly travel faster than the speed of light.
A warp drive would work by “warping” spacetime around any spaceship, which physicist Miguel Alcubierre showed was theoretically possible in 1994, albeit well beyond the current technical capabilities of humanity. However, any such Alcubierre drive was assumed to require more energy — equivalent to the mass-energy of the whole planet of Jupiter – than could ever possibly be supplied, rendering it impossible to build.
...read more
Posted in BigBang
Tagged cosmology, Miguel Alcubierre, NASA, physics, speed of light, Star Trek, warp drive
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Sunday, July 1, 2012
CDM: Cosmic Discovery Machine
We think CDM sounds much more fun than LHC, a rather dry acronym for Large Hadron Collider.
Researchers at the LHC are set to announce the latest findings in early July from the record-breaking particle smasher buried below the French and Swiss borders. Rumors point towards the discovery of the so-called Higgs boson, the particle theorized to give mass to all the other fundamental building blocks of matter. So, while this would be another exciting discovery from CERN and yet another confirmation of the fundamental and elegant Standard Model of particle physics, perhaps there is yet more to uncover, such as the exotically named “inflaton”.
From Scientific American:
Wednesday, June 20, 2012
The 100 Million Year Collision
Four billion, or so, years from now, our very own Milky Way galaxy is expected to begin a slow but enormous collision with its galactic sibling, the Andromeda galaxy. Cosmologists predict the ensuing galactic smash will take around 100 million years to complete. It’s a shame we’ll not be around to witness the spectacle.
From Scientific American:
Sunday, June 10, 2012
Mutant Gravity and Dark Magnetism
Scientific consensus states that our universe is not only expanding, but expanding at an ever-increasing rate. So, sometime in the very distant future (tens of billions of years) our Milky Way galaxy will be mostly alone, accompanied only by its close galactic neighbors, such as Andromeda. All else in the universe will have receded beyond the horizon of visible light. And, yet for all the experimental evidence, no one knows the precise cause(s) of this acceleration or even of the expansion itself. But, there is no shortage of bold new theories.
From New Scientist:
WE WILL be lonely in the late days of the cosmos. Its glittering vastness will slowly fade as countless galaxies retreat beyond the horizon of our vision. Tens of billions of years from now, only a dense huddle of nearby galaxies will be left, gazing out into otherwise blank space.
...read moreThursday, May 24, 2012
Something Out of Nothing
The debate on how the universe came to be rages on. Perhaps, however, we are a little closer to understanding why there is “something”, including us, rather than “nothing”.
From Scientific American:
Why is there something rather than nothing? This is one of those profound questions that is easy to ask but difficult to answer. For millennia humans simply said, “God did it”: a creator existed before the universe and brought it into existence out of nothing. But this just begs the question of what created God—and if God does not need a creator, logic dictates that neither does the universe. Science deals with natural (not supernatural) causes and, as such, has several ways of exploring where the “something” came from.
...read moreWednesday, May 2, 2012
Spacetime as an Emergent Phenomenon
A small, but growing, idea in theoretical physics and cosmology is that spacetime may be emergent. That is, spacetime emerges from something much more fundamental, in much the same way that our perception of temperature emerges from the motion and characteristics of underlying particles.
More on this new front in our quest to answer the most basic of questions from FQXi:
Imagine if nothing around you was real. And, no, not in a science-fiction Matrix sense, but in an actual science-fact way.
...read moreTuesday, April 3, 2012
So Where Is Everybody?
Astrobiologist Caleb Scharf brings us up to date on Fermi’s Paradox — which asks why, given that our galaxy is so old, haven’t other sentient intergalactic travelers found us. The answer may come from a video game.
From Scientific American:
Right now, all across the planet, millions of people are engaged in a struggle with enormous implications for the very nature of life itself. Making sophisticated tactical decisions and wrestling with chilling and complex moral puzzles, they are quite literally deciding the fate of our existence.
Or at least they are pretending to.
...read more
Posted in BigBang
Tagged astrobiology, cosmology, extraterrestrial life, Fermi, galaxy
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Saturday, February 4, 2012
The More Things Stay the Same, the More They Change?
From Scientific American:
Some things never change. physicists call them the constants of nature. Such quantities as the velocity of light, c, Newton’s constant of gravitation, G, and the mass of the electron, me, are assumed to be the same at all places and times in the universe. They form the scaffolding around which the theories of physics are erected, and they define the fabric of our universe. Physics has progressed by making ever more accurate measurements of their values.
...read moreWednesday, February 1, 2012
A Theory of Everything? Nah
A peer-reviewed journal recently published a 100-page scientific paper describing a theory of everything that unifies quantum theory and relativity (a long sought-after goal) with the origin of life, evolution and cosmology. And, best of all the paper contains no mathematics.
The paper written by a faculty member at Case Western Reserve University raises interesting issues about the peer review process and the viral spread of information, whether it’s correct or not.
From Ars Technica:
Physicists have been working for decades on a “theory of everything,” one that unites quantum mechanics and relativity. Apparently, they were being too modest. Yesterday saw publication of a press release claiming a biologist had just published a theory accounting for all of that—and handling the origin of life and the creation of the Moon in the bargain. Better yet, no math!
...read more
Posted in BigBang
Tagged cosmology, grand unified theory, particle physics, peer review, science
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Friday, January 6, 2012
From Nine Dimensions to Three
Over the last 40 years or so physicists and cosmologists have sought to construct a single grand theory that describes our entire universe from the subatomic soup that makes up particles and describes all forces to the vast constructs of our galaxies, and all in between and beyond. Yet a major stumbling block has been how to bring together the quantum theories that have so successfully described, and predicted, the microscopic with our current understanding of gravity. String theory is one such attempt to develop a unified theory of everything, but it remains jumbled with many possible solutions and, currently, is beyond experimental verification.
Recently however, theorists in Japan announced a computer simulation which shows how our current 3-dimensional universe may have evolved from a 9-dimensional space hypothesized by string theory.
From Interactions:
Saturday, December 31, 2011
Pulsars Signal the Beat
Cosmology meets music. German band Reimhaus samples the regular pulse of pulsars in its music. A pulsar is the rapidly spinning remains of an exploded star — as the pulsar spins it emits a detectable beam of energy that has a very regular beat, sometimes sub-second.
From Discover:
Some pulsars spin hundreds of times per second, some take several seconds to spin once. If you take that pulse of light and translate it into sound, you get a very steady thumping beat with very precise timing. So making it into a song is a natural thought.
But we certainly didn’t take it as far as the German band Reimhaus did, making a music video out of it! They used several pulsars for their song “Echoes, Silence, Pulses & Waves”. So here’s the cosmic beat:
Send to KindleMonday, December 12, 2011
A Great Mind Behind the Big Bang
Davide Castelvecchi over at Degrees of Freedom visits with one of the founding fathers of modern cosmology, Alan Guth.
Now professor of physics at MIT, Guth originated the now widely accepted theory of the inflationary universe. Guth’s idea, with subsequent supporting mathematics, was that the nascent universe passed through a phase of exponential expansion. In 2009, he was awarded the 2009 Isaac Newton Medal by the British Institute of Physics.
From Scientific American:
On the night of December 6, 1979–32 years ago today–Alan Guth had the “spectacular realization” that would soon turn cosmology on its head. He imagined a mind-bogglingly brief event, at the very beginning of the big bang, during which the entire universe expanded exponentially, going from microscopic to cosmic size. That night was the birth of the concept of cosmic inflation.
...read moreSaturday, September 17, 2011
The Universe and Determinism
General scientific consensus suggests that our universe has no pre-defined destiny. While a number of current theories propose anything from a final Big Crush to an accelerating expansion into cold nothingness the future plan for the universe is not pre-determined. Unfortunately, our increasingly sophisticated scientific tools are still to meager to test and answer these questions definitively. So, theorists currently seem to have the upper hand. And, now yet another theory puts current cosmological thinking on its head by proposing that the future is pre-destined and that it may even reach back into the past to shape the present. Confused? Read on!
From FQXi:
Thursday, September 8, 2011
Science: A Contest of Ideas
From Project Syndicate:
It was recently discovered that the universe’s expansion is accelerating, not slowing, as was previously thought. Light from distant exploding stars revealed that an unknown force (dubbed “dark energy”) more than outweighs gravity on cosmological scales.
Unexpected by researchers, such a force had nevertheless been predicted in 1915 by a modification that Albert Einstein proposed to his own theory of gravity, the general theory of relativity. But he later dropped the modification, known as the “cosmological term,” calling it the “biggest blunder” of his life.
So the headlines proclaim: “Einstein was right after all,” as though scientists should be compared as one would clairvoyants: Who is distinguished from the common herd by knowing the unknowable – such as the outcome of experiments that have yet to be conceived, let alone conducted? Who, with hindsight, has prophesied correctly?
...read moreFriday, September 2, 2011
Dark Matter: An Illusion?
Cosmologists and particle physicists have over the last decade or so proposed the existence of Dark Matter. It’s so called because it cannot be seen or sensed directly. It is inferred from gravitational effects on visible matter. Together with it’s theoretical cousin, Dark Energy, the two were hypothesized to make up most of the universe. In fact, the regular star-stuff — matter and energy — of which we, our planet, solar system and the visible universe are made, consists of only a paltry 4 percent.
Dark Matter and Dark Energy were originally proposed to account for discrepancies in calculations of the mass of large objects such as galaxies and galaxy clusters, and calculations derived from the mass of smaller visible objects such as stars, nebulae and interstellar gas.
The problem with Dark Matter is that it remains elusive and for the most part a theoretical construct. And, now a new group of theories suggest that the dark stuff may in fact be an illusion.
...read moreSaturday, August 13, 2011
So the Universe is Flat?
Having just posted an article that described the universe in terms of holographic principles – a 3-D projection on a two dimensional surface, it’s timely to put the theory in context, of other theories of course. There’s a theory that posits that the universe is a bubble wrought from the collision of high-dimensional branes (membrane that is). There’s a theory that suggests that our universe is one of many in a soup of multi-verses. Other theories suggest that the universe is made up of 9, 10 or 11 dimensions.
There’s another theory that the universe is flat, and that’s where Davide Castelvecchi (mathematician, science editor at Scientific American and blogger) over at Degrees of Freedom describes the current thinking.
What Do You Mean, The Universe Is Flat? (Part I), from Degrees of Freedom:
Wednesday, August 10, 2011
Are You Real, Or Are You a Hologram?
The principle of a holographic universe, not to be confused with the Holographic Universe, an album by swedish death metal rock band Scar Symmetry, continues to hold serious sway among a not insignificant group of even more serious cosmologists.
Originally proposed by noted physicists Gerard ‘t Hooft, and Leonard Susskind in the mid-1990s, the holographic theory of the universe suggests that our entire universe can described as a informational 3-D projection painted in two dimensions on a cosmological boundary. This is analogous to the flat hologram printed on a credit card creating the illusion of a 3-D object.
While current mathematical theory and experimental verification is lagging, the theory has garnered much interest and forward momentum — so this area warrants a brief status check, courtesy of the New Scientist.
From the New Scientist:
Sunday, July 17, 2011
When the multiverse and many-worlds collide
From the New Scientist:
TWO of the strangest ideas in modern physics – that the cosmos constantly splits into parallel universes in which every conceivable outcome of every event happens, and the notion that our universe is part of a larger multiverse – have been unified into a single theory. This solves a bizarre but fundamental problem in cosmology and has set physics circles buzzing with excitement, as well as some bewilderment.
The problem is the observability of our universe. While most of us simply take it for granted that we should be able to observe our universe, it is a different story for cosmologists. When they apply quantum mechanics – which successfully describes the behaviour of very small objects like atoms – to the entire cosmos, the equations imply that it must exist in many different states simultaneously, a phenomenon called a superposition. Yet that is clearly not what we observe.
...read moreSaturday, July 16, 2011
Dark energy spotted in the cosmic microwave background
From Institute of Physics:
Astronomers studying the cosmic microwave background (CMB) have uncovered new direct evidence for dark energy – the mysterious substance that appears to be accelerating the expansion of the universe. Their findings could also help map the structure of dark matter on the universe’s largest length scales.
The CMB is the faint afterglow of the universe’s birth in the Big Bang. Around 400,000 years after its creation, the universe had cooled sufficiently to allow electrons to bind to atomic nuclei. This “recombination” set the CMB radiation free from the dense fog of plasma that was containing it. Space telescopes such as WMAP and Planck have charted the CMB and found its presence in all parts of the sky, with a temperature of 2.7 K. However, measurements also show tiny fluctuations in this temperature on the scale of one part in a million. These fluctuations follow a Gaussian distribution.
...read moreFriday, July 1, 2011
Brilliant, but Distant: Most Far-Flung Known Quasar Offers Glimpse into Early Universe
From Scientific American:
Peering far across space and time, astronomers have located a luminous beacon aglow when the universe was still in its infancy. That beacon, a bright astrophysical object known as a quasar, shines with the luminosity of 63 trillion suns as gas falling into a supermassive black holes compresses, heats up and radiates brightly. It is farther from Earth than any other known quasar—so distant that its light, emitted 13 billion years ago, is only now reaching Earth. Because of its extreme luminosity and record-setting distance, the quasar offers a unique opportunity to study the conditions of the universe as it underwent an important transition early in cosmic history.
...read moreWednesday, June 29, 2011
Largest cosmic structures ‘too big’ for theories
From New Scientist:
Space is festooned with vast “hyperclusters” of galaxies, a new cosmic map suggests. It could mean that gravity or dark energy – or perhaps something completely unknown – is behaving very strangely indeed.
We know that the universe was smooth just after its birth. Measurements of the cosmic microwave background radiation (CMB), the light emitted 370,000 years after the big bang, reveal only very slight variations in density from place to place. Gravity then took hold and amplified these variations into today’s galaxies and galaxy clusters, which in turn are arranged into big strings and knots called superclusters, with relatively empty voids in between.
On even larger scales, though, cosmological models say that the expansion of the universe should trump the clumping effect of gravity. That means there should be very little structure on scales larger than a few hundred million light years across.
...read moreFriday, June 24, 2011
Nick Risinger’s Photopic Sky Survey
Big science covering scales from the microscopic to the vastness of the universe continues to deliver stunning new insights, now on a daily basis. I takes huge machines such as the Tevatron at Fermilab, CERN’s Large Hadron Collider, NASA’s Hubble Telescope and the myriad other detectors, arrays, spectrometers, particle smashers to probe some of our ultimate questions. The results from these machines bring us fantastic new perspectives and often show us remarkable pictures of the very small and very large.
Then there is Nick Risinger’s Photopic Sky Survey. No big science, no vast machines — just Nick Risinger, accompanied by retired father, camera equipment and 45,000 miles of travels capturing our beautiful night sky as never before.
From Nick Risinger:
Tuesday, June 21, 2011
Cosmic Smoothness
From American Physical Society, Michael J. Hudson:
The universe is expected to be very nearly homogeneous in density on large scales. In Physical Review Letters, Shaun Thomas and colleagues from University College London analyze measurements of the density of galaxies on the largest spatial scales so far—billions of light years—and find that the universe is less smooth than expected. If it holds up, this result will have important implications for our understanding of dark matter, dark energy, and perhaps gravity itself.
In the current standard cosmological model, the average mass-energy density of the observable universe consists of 5% normal matter (most of which is hydrogen and helium), 23% dark matter, and 72% dark energy. The dark energy is assumed to be uniform, but the normal and dark matter are not. The balance between matter and dark energy determines both how the universe expands and how regions of unusually high or low matter density evolve with time.
Wednesday, March 10, 2010
The Real Rules for Time Travelers
From Discover:
People all have their own ideas of what a time machine would look like. If you are a fan of the 1960 movie version of H. G. Wells’s classic novel, it would be a steampunk sled with a red velvet chair, flashing lights, and a giant spinning wheel on the back. For those whose notions of time travel were formed in the 1980s, it would be a souped-up stainless steel sports car. Details of operation vary from model to model, but they all have one thing in common: When someone actually travels through time, the machine ostentatiously dematerializes, only to reappear many years in the past or future. And most people could tell you that such a time machine would never work, even if it looked like a DeLorean.
...read moreThursday, January 7, 2010
Are Black Holes the Architects of the Universe?
From Discover:
Black holes are finally winning some respect. After long regarding them as agents of destruction or dismissing them as mere by-products of galaxies and stars, scientists are recalibrating their thinking. Now it seems that black holes debuted in a constructive role and appeared unexpectedly soon after the Big Bang. “Several years ago, nobody imagined that there were such monsters in the early universe,” says Penn State astrophysicist Yuexing Li. “Now we see that black holes were essential in creating the universe’s modern structure.”
...read moreSaturday, November 7, 2009
Will Our Universe Collide With a Neighboring One?
From Discover:
Relaxing on an idyllic beach on Grand Cayman Island in the Caribbean, Anthony Aguirre vividly describes the worst natural disaster he can imagine. It is, in fact, probably the worst natural disaster that anyone could imagine. An asteroid impact would be small potatoes compared with this kind of event: a catastrophic encounter with an entire other universe.
As an alien cosmos came crashing into ours, its outer boundary would look like a wall racing forward at nearly the speed of light; behind that wall would lie a set of physical laws totally different from ours that would wreck everything they touched in our universe. “If we could see things in ultraslow motion, we’d see a big mirror in the sky rushing toward us because light would be reflected by the wall,” says Aguirre, a youthful physicist at the University of California at Santa Cruz. “After that we wouldn’t see anything—because we’d all be dead.”
...read more
