Posts Tagged ‘Universe’
“Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist.”*…
Our environment…
This map shows a slice of our Universe. It was created from astronomical data taken night after night over a period of 15 years using a telescope in New Mexico, USA. We are located at the bottom. At the top is the actual edge of the observable Universe. In between, we see about 200,000 galaxies.
Each tiny dot is a galaxy. About 200,000 are shown with their actual position and color. Each galaxy contains billions of stars and planets. We are located at the bottom. Our galaxy, the Milky Way, is just a dot. Looking up, we see that space is filled with galaxies forming a global filamentary structure. Far away from us (higher up in the map), the filaments become harder to see…
For a (much crisper, more vivid, and interactive) version: “The Map of the Observable Universe.”
* Stephen Hawking
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As we explore, we might recall that it was on this date in 1616 that The Minutes of the Roman Inquisition recorded the conclusion that Galileo’s writings in support of Copernicus’ heliocentric view of the solar system were “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture.” The next day, Galileo was called before Cardinal Bellarmine, who (on Pope Paul V’s instruction) ordered Galileo to abandon the teaching. Shortly thereafter, Copernicus’s De Revolutionibus and other heliocentric works were banned (entered onto the Index Librorum Prohibitorum) “until correction.”
Sixteen years later, Galileo “published” Dialogue Concerning the Two Chief World Systems (Dialogo sopra i due massimi sistemi del mondo)– that’s to say, he presented the first copy to his patron, Ferdinando II de’ Medici, Grand Duke of Tuscany. Dialogue, which compared the heliocentric Copernican and the traditional geo-centric Ptolemaic systems, was an immediate best-seller.
While there was no copyright available to Galileo, his book was printed and distributed under a license from the Inquisition. Still, the following year it was deemed heretical– and he joined Copernicus on the Index Librorum Prohibitorum: the publication of anything else Galileo had written or ever might write was also banned… a ban that remained in effect until 1835.
“It is difficult to fully appreciate how much our picture of the universe has changed in the span of a single human lifetime”*…
… and it continues to change…
Our universe could be the mirror image of an antimatter universe extending backwards in time before the Big Bang. So claim physicists in Canada, who have devised a new cosmological model positing the existence of an “antiuniverse” which, paired to our own, preserves a fundamental rule of physics called CPT symmetry. The researchers still need to work out many details of their theory, but they say it naturally explains the existence of dark matter.
Standard cosmological models tell us that the universe – space, time and mass/energy – exploded into existence some 14 billion years ago and has since expanded and cooled, leading to the progressive formation of subatomic particles, atoms, stars and planets.
However, Neil Turok of the Perimeter Institute for Theoretical Physics in Ontario reckons that these models’ reliance on ad-hoc parameters means they increasingly resemble Ptolemy’s description of the solar system. One such parameter, he says, is the brief period of rapid expansion known as inflation that can account for the universe’s large-scale uniformity. “There is this frame of mind that you explain a new phenomenon by inventing a new particle or field,” he says. “I think that may turn out to be misguided.”
nstead, Turok and his Perimeter Institute colleague Latham Boyle set out to develop a model of the universe that can explain all observable phenomena based only on the known particles and fields. They asked themselves whether there is a natural way to extend the universe beyond the Big Bang – a singularity where general relativity breaks down – and then out the other side. “We found that there was,” he says.
The answer was to assume that the universe as a whole obeys CPT symmetry. This fundamental principle requires that any physical process remains the same if time is reversed, space inverted and particles replaced by antiparticles. Turok says that this is not the case for the universe that we see around us, where time runs forward as space expands, and there’s more matter than antimatter.
Instead, says Turok, the entity that respects the symmetry is a universe–antiuniverse pair. The antiuniverse would stretch back in time from the Big Bang, getting bigger as it does so, and would be dominated by antimatter as well as having its spatial properties inverted compared to those in our universe [as per the illustration above]…
More at “Our universe has antimatter partner on the other side of the Big Bang, say physicists,” in @PhysicsWorld.
Apposite: “The Big Bang no longer means what it used to.”
* Lawrence M. Krauss, A Universe from Nothing: Why There Is Something Rather Than Nothing
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As we debate doppelgangers, we might send chronologically-accurate birthday greetings to Louis Essen; he was born on this date in 1908. A physicist, he is best remembered for his measurements of time– he invented the quartz crystal ring clock and the first practical atomic clock. His cesium-beam atomic clock ultimately changed the way time is measured: the cesium atom’s natural frequency was formally recognized as the new international unit of time in 1967; the second was defined as exactly 9,192,631,770 oscillations or cycles of the cesium atom’s resonant frequency, replacing the old “second” which had been defined in terms of the Earth’s motion.
Perhaps unsurprisingly, given Essen’s punctilious dedication to accuracy, he was a critic of Einstein’s theory of relativity, particularly as it related to time dilation. Moreover, we note (with an eye to the item above) that Essen’s clocks measured time in only one direction…
“Horror vacui”*…
Recently, (Roughly) Daily took a look at nothing– and the perplexing philosophical questions that it raises. Today, Charlie Wood examines nothing’s physical manifestation, the vacuum, and the similarly perplexing questions it raises for physicists…
Millennia ago, Aristotle asserted that nature abhors a vacuum, reasoning that objects would fly through truly empty space at impossible speeds. In 1277, the French bishop Etienne Tempier shot back, declaring that God could do anything, even create a vacuum.
Then a mere scientist pulled it off. Otto von Guericke invented a pump to suck the air from within a hollow copper sphere, establishing perhaps the first high-quality vacuum on Earth. In a theatrical demonstration in 1654, he showed that not even two teams of horses straining to rip apart the watermelon-size ball could overcome the suction of nothing. [See illustration above.]
Since then, the vacuum has become a bedrock concept in physics, the foundation of any theory of something. Von Guericke’s vacuum was an absence of air. The electromagnetic vacuum is the absence of a medium that can slow down light. And a gravitational vacuum lacks any matter or energy capable of bending space. In each case the specific variety of nothing depends on what sort of something physicists intend to describe. “Sometimes, it’s the way we define a theory,” said Patrick Draper, a theoretical physicist at the University of Illinois.
As modern physicists have grappled with more sophisticated candidates for the ultimate theory of nature, they have encountered a growing multitude of types of nothing. Each has its own behavior, as if it’s a different phase of a substance. Increasingly, it seems that the key to understanding the origin and fate of the universe may be a careful accounting of these proliferating varieties of absence.
“We’re learning there’s a lot more to learn about nothing than we thought,” said Isabel Garcia Garcia, a particle physicist at the Kavli Institute for Theoretical Physics in California. “How much more are we missing?”
So far, such studies have led to a dramatic conclusion: Our universe may sit on a platform of shoddy construction, a “metastable” vacuum that is doomed — in the distant future — to transform into another sort of nothing, destroying everything in the process.
Nothing started to seem like something in the 20th century, as physicists came to view reality as a collection of fields: objects that fill space with a value at each point (the electric field, for instance, tells you how much force an electron will feel in different places). In classical physics, a field’s value can be zero everywhere so that it has no influence and contains no energy. “Classically, the vacuum is boring,” said Daniel Harlow, a theoretical physicist at the Massachusetts Institute of Technology. “Nothing is happening.”
But physicists learned that the universe’s fields are quantum, not classical, which means they are inherently uncertain. You’ll never catch a quantum field with exactly zero energy…
For an explanation of how key to understanding the origin and fate of the universe may be a more complete understanding of the vacuum: “How the Physics of Nothing Underlies Everything,” from @walkingthedot in @QuantaMagazine.
* attributed to Aristitole, and usually “translated,” as above, “Nature abhors a vacuum”
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As we noodle on nought, we might spare a thought for Hugo Gernsback, a Luxemborgian-American inventor, broadcast pioneer, writer, and publisher; he died on this date in 1967 at the age of 83.
Gernsback held 80 patents at the time of his death; he founded radio station WRNY, was involved in the first television broadcasts and is considered a pioneer in amateur radio. But it was a writer and publisher that he probably left his most lasting mark: In 1926, as owner/publisher of the magazine Modern Electrics, he filled a blank spot in his publication by dashing off the first chapter of a series called “Ralph 124C 41+.” The twelve installments of “Ralph” were filled with inventions unknown in 1926, including “television” (Gernsback is credited with introducing the word), fluorescent lighting, juke boxes, solar energy, television, microfilm, vending machines, and the device we now call radar.
The “Ralph” series was an astounding success with readers; and later that year Gernsback founded the first magazine devoted to science fiction, Amazing Stories. Believing that the perfect sci-fi story is “75 percent literature interwoven with 25 percent science,” he coined the term “science fiction.”
Gernsback was a “careful” businessman, who was tight with the fees that he paid his writers– so tight that H. P. Lovecraft and Clark Ashton Smith referred to him as “Hugo the Rat.”
Still, his contributions to the genre as publisher were so significant that, along with H.G. Wells and Jules Verne, he is sometimes called “The Father of Science Fiction”; in his honor, the annual Science Fiction Achievement awards are called the “Hugos.”
(Coincidentally, today is also the birthday– in 1906– of Philo T. Farnsworth, the man who actually did invent television…)
“Eventually everything connects”*…
Long-time readers will know of your correspondent’s fascination with Powers of Ten, a remarkable short film by Charles and Ray Eames, with Philip Morrison, that begins with a couple having a picnic, zooms out by “powers of ten” to the edge of the universe, then zooms in (by those same increments) to a proton.
We’ve looked before at a number of riffs on this meditation on scale: see, e.g., here, here, and here.
Now the BBC has updated the first half of Powers of Ten:
It’s a trip worth taking.
* Charles Eames
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As we wrestle with relationships, we might light a birthday candle for Sir Francis Bacon– English Renaissance philosopher, lawyer, linguist, composer, mathematician, geometer, musician, poet, painter, astronomer, classicist, philosopher, historian, theologian, architect, father of modern science (The Baconian– aka The Scientific– Method), and patron of modern democracy, whom some allege was the illegitimate son of Queen Elizabeth I of England (and others, the actual author of Shakespeare’s plays)… He was in any event born on this date in 1561.
Bacon (whose Essays were, in a fashion, the first “management book” in English) was, in Alexander Pope’s words, “the greatest genius that England, or perhaps any country, ever produced.” He probably did not actually write the plays attributed to Shakespeare (as a thin, but long, line of enthusiasts, including Mark Twain and Friedrich Nietzsche, believed). But Bacon did observe, in a discussion of sedition that’s as timely today as ever, that “the remedy is worse than the disease.”
“It is unnatural in a large field to have only one shaft of wheat, and in the infinite Universe only one living world”*…
NASA’s top scientists have a provocative message for the scientific community: that they need a plan in place for if — or when — we find evidence of extraterrestrial life…
James Green, the agency’s chief scientist, coauthored a new article, published in the journal Nature, urging researchers to create a framework for reporting evidence of aliens. In it, the authors stressed the importance of clearly communicating any findings of extraterrestrial life, as well as establishing clear expectations for the public for when it occurs and accurately expressing ambiguity in early evidence.
“As life-detection objectives become increasingly prominent in space sciences, it is essential to open a community dialogue about how to convey information in a subject matter that is diverse, complicated and has a high potential to be sensationalized,” read the paper.
Green and his co-authors propose a confidence of life detection (CoLD) scale to help evaluate any evidence that might be discovered. The scale itself contains seven different levels like a staircase. Each level is a benchmark that must be met before we can proceed to the next step.
For example, level one would be discovering life signatures such as biological molecules. The second level would be ruling out that the sign of life is the result of contamination from Earth. Eventually, the CoLD scale ends with the final step: scientists declaring that they’ve confidently discovered evidence of extraterrestrial life.
“Having a scale like this will help us understand where we are in terms of the search for life in particular locations, and in terms of the capabilities of missions and technologies that help us in that quest,” Green said in a NASA news release.
The paper’s authors stress that the scale is merely a starting point for a larger conversation with scientists and science communicators about the best ways to proceed if and when we discover evidence of alien life.
It also comes in the context of the upcoming launch of the powerful James Webb telescope, along with the Perseverance Mars rover searching for life on the Red Planet, meaning that such a finding might become a reality sooner rather than later.
“The search for life beyond Earth requires broad participation from the scientific community and many kinds of observations and experiments,” Mary Voltek, co-author of the study and head of NASA’s Astrobiology Program, said in the release. “Together, we can be stronger in our efforts to look for hints that we are not alone.”
“NASA Says We Need a Plan for When We Discover Alien Life,” from @futurism.
As to what we’ll do with that knowledge, a complicating factor: “94% of the universe’s galaxies are permanently beyond our reach” (if the speed of light remains an upper limit on travel).
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As we search far and wide, we might send enduring birthday greetings to Sir Hermann Bondi; he was born on this date in 1919. A mathematician and cosmologist, he is best remembered for developing the steady state model of the universe with Fred Hoyle and Thomas Gold as an alternative to the Big Bang theory. In an attempt to explain the paradox: how can the stars continually recede, yet without disappearing, they audaciously proposed an unproven hypothesis: that the universe has an eternal existence, with no beginning and without an end. Further, they argued, the universe is continuously expanding, maintaining a constant density by continually creating new matter from energy. Their model was rendered obsolete when, in 1965, Arno Penzias and Robert Wilson detected a background microwave radiation from all directions in space, as predicted by the “Big Bang” theory of creation that is now accepted. [See here for more on Penzias’ and Wilson’s discovery.)
Bondi also contributed to the theory of general relativity; was the first to analyze the inertial and gravitational interaction of negative mass; and the first to explicate correctly the nature of gravitational waves.
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