(Roughly) Daily

Posts Tagged ‘Cosmology

“If you think this Universe is bad, you should see some of the others”*…

 

copernicus

FIRST OF FOUR?: The first Copernican revolution moved the Earth out of the center of the solar system. The second recognized that there are many planets in our galaxy, and the third that there are many galaxies in the observable universe. Proving that our universe is one among many would represent a fourth Copernican revolution.

 

A challenge for 21st-century physics is to answer two questions. First, are there many “big bangs” rather than just one? Second—and this is even more interesting—if there are many, are they all governed by the same physics?

If we’re in a multiverse, it would imply a fourth and grandest Copernican revolution; we’ve had the Copernican revolution itself, then the realization that there are billions of planetary systems in our galaxy; then that there are billions of galaxies in our observable universe. But now that’s not all. The entire panorama that astronomers can observe could be a tiny part of the aftermath of “our” big bang, which is itself just one bang among a perhaps infinite ensemble.

At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes…

Cambridge physicist and Astronomer Royal Martin Rees suspects that our universe is one island in an archipelago: “The Fourth Copernican Revolution.”

* Philip K. Dick

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As we find our place, we might recall that it was on this date in 1884 that 41 delegates from 25 nations, meeting in Washington, DC for the International Meridian Conference, adopted Greenwich as the universal meridian.  They also established that all longitude would be calculated both east and west from this meridian up to 180°.

PrimeMeridianThm source

 

Written by LW

October 13, 2018 at 1:01 am

“The truth is not always beautiful, nor beautiful words the truth.”*…

 

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Does anyone who follows physics doubt it is in trouble? When I say physics, I don’t mean applied physics, material science or what Murray-Gell-Mann called “squalid-state physics.” I mean physics at its grandest, the effort to figure out reality. Where did the universe come from? What is it made of? What laws govern its behavior? And how probable is the universe? Are we here through sheer luck, or was our existence somehow inevitable?

In the 1980s Stephen Hawking and other big shots claimed that physics was on the verge of a “final theory,” or “theory of everything,” that could answer these big questions and solve the riddle of reality. I became a science writer in part because I believed their claims, but by the early 1990s I had become a skeptic. The leading contender for a theory of everything held that all of nature’s particles and forces, including gravity, stem from infinitesimal, stringy particles wriggling in nine or more dimensions.

The problem is that no conceivable experiment can detect the strings or extra dimensions…

John Horgan examines physicist Sabine Hossenfelder‘s claim that desire for beauty and other subjective biases have led physicists astray: “How Physics Lost Its Way.”

* Lao Tzu, Tao Te Ching

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As we contemplate certainty, we might recall that it was on this date in 1595 that Johann Kepler (and here) published Mysterium cosmographicum (Mystery of the Cosmos), in which he described an invisible underlying structure determining the six known planets in their orbits.  Kepler thought as a mathematician, devising a structure based on only five convex regular solids; the path of each planet lay on a sphere separated from its neighbors by touching an inscribed polyhedron.

It was a beautiful, an elegant model– and one that fit the orbital data available at the time.  It was, nonetheless, wrong.

Detailed view of Kepler’s inner sphere

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Written by LW

July 9, 2018 at 1:01 am

“We cannot get behind consciousness. Everything that we talk about, everything that we regard as existing, postulates consciousness”*…

 

Ockham’s razor is the principle that, all things being equal, more parsimonious theories – that is to say, theories with relatively few postulations – are to be preferred. Is it not a great cost in terms of parsimony to ascribe fundamental consciousness to the Universe? Not at all. The physical world must have some nature, and physics leaves us completely in the dark as to what it is. It is no less parsimonious to suppose that the Universe has a consciousness-involving nature than that it has some non-consciousness-involving nature. If anything, the former proposal is more parsimonious insofar as it is continuous with the only thing we really know about the nature of matter: that brains have consciousness…

One of the thinkers quoted in (Roughly) Daily’s recent piece on panpsychismPhilip Goff, has elaborated on his argument that the Universe and everything in it is conscious.  Cosmopsychism, as he now calls the notion, might seem crazy; but as he explains, it provides a robust explanatory model for how the Universe became fine-tuned for life: “Is the Universe a conscious mind?

* Max Planck

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As we ascribe some level of sentience to absolutely everything, we might send brave birthday greetings to Fang Lizhi; he was born on this date in 1936.

An astrophysicist, vice-president of the University of Science and Technology of China, who published published a paper (in 1972) on a topic central to the argument for cosmopsychism– the Big Bang theory, previously a forbidden topic in China (Marxists claimed that the universe was infinite)– which met condemnation from the Communist Party.  He became an advocate of intellectual freedom and civic reform, whose liberal ideas helped inspire the pro-democracy student movement of 1986–87 and, finally, the Tiananmen Square protests of 1989– and for which he was expelled from the Communist Party and forced into exile.

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Written by LW

February 12, 2018 at 1:01 am

“The missing link in cosmology is the nature of dark matter and dark energy”*…

 

Familiar visible matter can be thought of as the privileged percent—actually more like 15 percent—of matter. In business and politics, the interacting 1 percent dominates decision making and policy, while the remaining 99 percent of the population provides less widely acknowledged infrastructure and support—maintaining buildings, keeping cities operational, and getting food to people’s tables. Similarly, ordinary matter dominates almost everything we notice, whereas dark matter, in its abundance and ubiquity, helped create clusters and galaxies and facilitated star formation, but has only limited influence on our immediate surroundings today…

The common assumption is that dark matter is the “glue” that holds together galaxies and galaxy clusters, but resides only in amorphous clouds around them. But what if this assumption isn’t true and it is only our prejudice—and ignorance, which is after all the root of most prejudice—that led us down this potentially misleading path?…

Indeed,  Harvard theoretical physicist and cosmologist Lisa Randall asks, “Does dark matter harbor life?

* Stephen Hawking

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As we reach reflexively for a flashlight, we might send particular birthday greetings to Abraham Pais; he was born on this date in 1918.  After earning his Ph.D. in physics in Holland five days before a Nazi deadline banning Jews from receiving degrees, he went into hiding– and worked out ideas in quantum electrodynamics (later shared with Niels Bohr) that became the building blocks of the theory of elemental particles.  He was later a colleague of Robert Oppenheimer and Albert Einstein at the Institute for Advanced Studies at Princeton.

Pais was also an widely-respected historian of science.  Among his many works were a biography of Bohr and (the work for which he’s best remembered as a historian) Subtle Is the Lord: The Science and Life of Albert Einstein, which is considered the definitive Einstein biography.

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Written by LW

May 19, 2017 at 1:01 am

“Life could be horrible in the wrong trouser of time”*…

 

The challenge that the multiverse poses for the idea of an all-good, all-powerful God is often focused on fine-tuning. If there are infinite universes, then we don’t need a fine tuner to explain why the conditions of our universe are perfect for life, so the argument goes. But some kinds of multiverse pose a more direct threat. The many-worlds interpretation of quantum physicist Hugh Everett III and the modal realism of cosmologist Max Tegmark include worlds that no sane, good God would ever tolerate. The theories are very different, but each predicts the existence of worlds filled with horror and misery.

Of course, plenty of thoughtful people argue that the Earth alone contains too much pain and suffering to be the work of a good God. But many others have disagreed, finding fairly nuanced things to say about what might justify God’s creation of a world that includes a planet like ours. For example, there is no forgiveness, courage, or fortitude without at least the perception of wrongs, danger, and difficulty. The most impressive human moral achievements seem to require such obstacles.

Still, many horrifying things happen with nothing seemingly gained from them. And, Everett’s many-worlds and Tegmark’s modal realism both seem to imply that there are huge numbers of horrific universes inhabited solely by such unfortunates. Someone like myself, who remains attracted to the traditional picture of God as loving creator, is bound to find such consequences shocking…

How scientific cosmology puts a new twist on the problem of evil.  A theist wrestles with the implications of the “Many World” hypothesis: “Evil Triumphs in These Multiverses, and God Is Powerless.”

* Terry Pratchett

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As we calculate our blessings, we might send carefully-addressed birthday greetings to Infante Henrique of Portugal, Duke of Viseu, better known as Prince Henry the Navigator; he was born on this date in 1394.  A central figure in 15th-century Portuguese politics and in the earliest days of the Portuguese Empire, Henry encouraged Portugal’s expeditions (and colonial conquests) in Africa– and thus is regarded as the main initiator (as a product both of Portugal’s expeditions and of those that they encouraged by example) of what became known as the Age of Discoveries.

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“Magnetism, you recall from physics class, is a powerful force that causes certain items to be attracted to refrigerators”*…

 

Concentric incision on a jar handle from Ramat Rahel, in modern-day Israel

Of all the environmental amenities that this hospitable planet provides, the magnetic field is perhaps the strangest and least appreciated. It has existed for more than three and a half billion years but fluctuates daily. It emanates from Earth’s deep interior but extends far out into space. It is intangible and mostly invisible—except when it lights up in ostentatious greens and reds during the auroras—but essential to life. The magnetic field is our protective bubble; it deflects not only the rapacious solar wind, which could otherwise strip away Earth’s atmosphere over time, but also cosmic rays, which dart in from deep space with enough energy to damage living cells. Although sailors have navigated by the magnetic field for a millennium and scientists have monitored it since the eighteen-thirties, it remains a mysterious beast. Albert Einstein himself said that understanding its origin and persistence was one of the great unsolved problems in physics…

Direct measurements of the magnetic field now span almost two hundred years, and iron-rich volcanic rocks on the ocean floor provide a lower-fidelity chronicle of its erratic behavior—including wholesale reversals in polarity—back about a hundred and fifty million years. But reconstructing the field’s behavior between these two extremes has been difficult. The trick is to find an iron-bearing object that locked in a record of the magnetic field at a well-constrained time in the past, in the way that wine of a given vintage preserves an indirect record of that year’s weather conditions…

Last Monday, in a study published in Proceedings of the National Academy of Sciences, a team of Israeli and American archeologists and geophysicists reports the most detailed reconstruction yet of the magnetic field in pre-instrumental times, using a set of ceramic jars from Iron Age Judea…

In the geophysical community, the tales told by the Judean jars may cause unrest. Both the height and the sharpness of the spike they recount push up against the limits of what some geophysicists think Earth’s outer core is capable of doing. If the eighth-century-B.C. geomagnetic jeté is real, models for the generation of the magnetic field need significant revision. Given the importance of a stable magnetic field to our electricity-dependent, communications-obsessed culture, these questions are of more than academic interest…

More on these befuddling fields at “Earth’s mysterious magnetic field, stored in a jar.”

* Dave Barry

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As we look for True North, we might send undulating birthday greetings to George Fitzgerald Smoot III; he was born on this date in 1945.  An astrophysicist and cosmologist, Smoot discovered the signature of gravitational waves– ripples in space-time were first predicted by Albert Einstein– in his study of the cosmic microwave (“background”) radiation that originated with the Big Bang.  He won the Nobel Prize in Physics in 2006; three years later he became the second person to run the board on the quiz show Are You Smarter than a 5th Grader?, and took home the $1 million grand prize.

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“When the going gets weird, the weird turn pro”*…

 

An international study claims to have found first observed evidence that our universe is a hologram.

What is the holographic universe idea? It’s not exactly that we are living in some kind of Star Trekky computer simulation. Rather the idea, first proposed in the 1990s by Leonard Susskind and Gerard ‘t Hooft, says that all the information in our 3-dimensional reality may actually be included in the 2-dimensional surface of its boundaries. It’s like watching a 3D show on a 2D television…

Just when one thought that things couldn’t get any stranger: “Scientists Find First Observed Evidence That Our Universe May Be a Hologram.”

Pair with this piece on recent experimental confirmation of what Albert Einstein called “spooky action at a distance.”

* Hunter S. Thompson

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As we batten down the hatches, we might send shady birthday greetings to Fritz Zwicky; he was born on this date in 1898.  A distinguished astronomer who worked at Cal Tech most of his life, Zwicky is best remembered for being the first to infer the existence of “dark matter“: while examining the Coma galaxy cluster in 1933, he used the virial theorem to deduce the existence of what he then called dunkle Materie. Colleagues knew him as both both a genius and a curmudgeon. One of his favorite insults was to refer to people of whom he didn’t approve as “spherical bastards”– because, he explained, they were bastards no matter which way you looked at them.

[For more on dunkle Materie:Will We Ever Know What Dark Matter Is?“]

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Written by LW

February 14, 2017 at 1:01 am

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