(Roughly) Daily

Posts Tagged ‘Cosmology

“Everything we know and love about the universe and all the laws of physics as they apply, apply to four percent of the universe”*…

 

dark matter

 

In 1969, the American astronomer Vera Rubin puzzled over her observations of the sprawling Andromeda Galaxy, the Milky Way’s biggest neighbour. As she mapped out the rotating spiral arms of stars through spectra carefully measured at the Kitt Peak National Observatory and the Lowell Observatory, both in Arizona, she noticed something strange: the stars in the galaxy’s outskirts seemed to be orbiting far too fast. So fast that she’d expect them to escape Andromeda and fling out into the heavens beyond. Yet the whirling stars stayed in place.

Rubin’s research, which she expanded to dozens of other spiral galaxies, led to a dramatic dilemma: either there was much more matter out there, dark and hidden from sight but holding the galaxies together with its gravitational pull, or gravity somehow works very differently on the vast scale of a galaxy than scientists previously thought.

Her influential discovery never earned Rubin a Nobel Prize, but scientists began looking for signs of dark matter everywhere, around stars and gas clouds and among the largest structures in the galaxies in the Universe. By the 1970s, the astrophysicist Simon White at the University of Cambridge argued that he could explain the conglomerations of galaxies with a model in which most of the Universe’s matter is dark, far outnumbering all the atoms in all the stars in the sky. In the following decade, White and others built on that research by simulating the dynamics of hypothetical dark matter particles on the not-so-userfriendly computers of the day.

But despite those advances, over the past half century, no one has ever directly detected a single particle of dark matter. Over and over again, dark matter has resisted being pinned down, like a fleeting shadow in the woods. Every time physicists have searched for dark matter particles with powerful and sensitive experiments in abandoned mines and in Antarctica, and whenever they’ve tried to produce them in particle accelerators, they’ve come back empty-handed. For a while, physicists hoped to find a theoretical type of matter called weakly interacting massive particles (WIMPs), but searches for them have repeatedly turned up nothing…

Dark matter is the most ubiquitous thing physicists have never found. Is it time to consider alternative explanations? “Does dark matter exist?

[image above: source]

* Neil deGrasse Tyson

###

As we interrogate the invisible, we might recall that it was on this date in 1944 that one of the worst fire disasters in U.S. history occurred; the blaze broke out during an afternoon performance of the Ringling Bros. and Barnum & Bailey Circus that was attended by an estimated 7,000 people.  It killed 167 people; more than 700 were injured.

240px-Htfdcircusfire

Because of the paraffin wax waterproofing of the tent, the flames spread rapidly

hartfordcircusfire-1024x762

Emmett Kelly holding a water bucket on what became known as “the day the clowns cried

 

Written by LW

July 6, 2020 at 1:01 am

“Deep in the fundamental heart of mind and Universe there is a reason”*…

 

darkenergy

 

Why does the Universe exist? There are two questions here. First, why is there a Universe at all? It might have been true that nothing ever existed: no living beings, no stars, no atoms, not even space or time. When we think about this possibility, it can seem astonishing that anything exists. Second, why does this Universe exist? Things might have been, in countless ways, different. So why is the Universe as it is?…

Derek Parfit explores the most fundamental questions of all: “Why anything? Why this?”  Part 2 here.

For a 3-D tour of the subject in question– the universe– see here (the source of the image above).

* Douglas Adams, Life, the Universe and Everything

###

As we explore existence, we might recall that today– and every June 16– is Bloomsday, a commemoration and celebration of the life of Irish writer James Joyce, during which the events of his novel Ulysses (which is set on 16 June 1904) are relived: Leopold Bloom goes about Dublin, James Joyce’s immortalization of his first outing with Nora Barnacle, the woman who would eventually become his wife.

The first Bloomsday was observed on the 50th anniversary of the events in the novel, in 1954, when John Ryan (artist, critic, publican and founder of Envoy magazine) and the novelist Brian O’Nolan organized what was to be a daylong pilgrimage along the Ulysses route. They were joined by Patrick Kavanagh, Anthony Cronin, Tom Joyce (a dentist who, as Joyce’s cousin, represented the family interest), and AJ Leventhal (a lecturer in French at Trinity College, Dublin).

The crew for the first Bloomsday excursion

source

 

Written by LW

June 16, 2020 at 1:01 am

“Blessed be you, mighty matter”*…

 

anyon

The existence of anyons was inferred from quantum topology — the novel properties of shapes made by quantum systems

 

Every particle in the universe — from a cosmic ray to a quark — is either a fermion or a boson. These categories divide the building blocks of nature into two distinct kingdoms… or so we thought.  Now researchers have discovered the first examples of a third particle kingdom…

Anyons, as they’re known, don’t behave like either fermions or bosons; instead, their behavior is somewhere in the middle. In a recent paper published in Science, physicists have found the first experimental evidence that these particles don’t fit into either kingdom. “We had bosons and fermions, and now we’ve got this third kingdom,” said Frank Wilczek, a Nobel prize–winning physicist at the Massachusetts Institute of Technology. “It’s absolutely a milestone.”…

Rethinking the substance of reality…  More on these newly-identified building blocks at “‘Milestone’ Evidence for Anyons, a Third Kingdom of Particles.”

* “Blessed be you, mighty matter, irresistible march of evolution, reality ever newborn; you who, by constantly shattering our mental categories, force us to go ever further and further in our pursuit of the truth.”   — Pierre Teilhard de Chardin, Hymn of the Universe

###

As we examine existence, we might spare a thought for Roger Bacon; he died on this date in 1292.  A philosopher and Franciscan friar, Bacon was one of the first to propose mathematics and experimentation as appropriate methods of science.  Working in mathematics, astronomy, physics, alchemy, and languages, he was particularly impactful in optics: he elucidated the principles of refraction, reflection, and spherical aberration, and described spectacles, which soon thereafter came into use.  He developed many mathematical results concerning lenses, proposed mechanically propelled ships, carriages, and flying machines, and used a camera obscura to observe eclipses of the Sun.  And he was the first European give a detailed description of the process of making gunpowder.

He began his career at Oxford, then lectured for a time at Paris, where his skills as a pedagogue earned him the title Doctor Mirabilis, or “wonderful teacher.”  He stopped teaching when he became a Franciscan.  But his scientific work continued, despite his Order’s restrictions on activity and publication, as Bacon enjoyed the protection and patronage of Pope Clement…  until, on Clement’s death, he was placed under house arrest in Oxford, where he continued his studies, but was unable to publish and communicate with fellow investigators.

Statue of Roger Bacon in the Oxford University Museum

 source

 

Written by LW

June 11, 2020 at 1:01 am

“That is a very Earthling question to ask, Mr. Pilgrim”*…

 

universe

 

What does it mean to be alive? Science, shockingly, still doesn’t have a consensus. For example, is it fair to say that the novel coronavirus now sweeping the world is alive? The short answer is there isn’t one agreed-upon answer — for something so basic, you’d think life would be easier to define.

The first recorded definition of life came from Aristotle in ancient Greece, around 350 BC. He posited that to be alive, something must grow, maintain itself, and reproduce. In contrast, the most well-known modern definition is probably NASA’s, which says living things must be “a self-sustaining chemical system capable of Darwinian evolution.” Take, for example, great apes: given appropriate resources like food and water, the “machinery” of a great ape — its organs and nervous system — regulates itself, keeping the great ape functioning in most conditions. They are also capable of evolution — just look at us. But this isn’t the only accepted definition of life. There are actually over 100 published definitions!

A lot of the debate comes down to the fact that the various fields of science approach the topic quite differently. A geneticist, whose focus is on known organisms and their genomes, will very likely have a different view on what constitutes life than an astrophysicist, who considers a more expansive, universal definition.

But beyond that, most of these definitions of life fall short in another, very subtle way: They are based on the origins of life on our planet. This means our hypotheses for what sentient and conscious aliens look like almost always reflect humankind. You only have to look at a Star Trek episode to see it — humanity likes to make the world in our image, which is partially why in sci-fi and fantasy a lot of the “aliens” look a lot like ourselves. (Okay, and because it’s easier to dress a human up as a humanoid alien)…

Cal Tech scientist (and published poet) Alison Koontz explains why none of the 100 definitions of life we have may be accurate away from “home”: “Our concept of life is too Earth-centric — alien life might look totally different.”

* Kurt Vonnegut Jr., Slaughterhouse-Five

###

As we confront our chauvinism, we might send speculative birthday greetings to Harlan Jay Ellison; he was born on this date in 1934.  A member (with Philip K. Dick, Samuel Delany, Thomas Disch, Ursula K. LeGuin, and Roger Zelazny) of the American “new wave” science fiction vanguard, Ellison wrote more than 1,700 short stories, novellas, screenplays, comic book scripts, teleplays, essays, and a wide range of criticism covering literature, film, television, and print media.  Some of his best-known work includes the Star Trek episode “The City on the Edge of Forever“, his A Boy and His Dog cycle, and his short stories “I Have No Mouth, and I Must Scream” and “‘Repent, Harlequin!’ Said the Ticktockman“… for which he won many, many awards, including multiple Hugos, Nebulas, and Edgars.

Ellison is also remembered for his outspoken, sometimes combative personality, of which Robert Bloch (the author of Psycho) said “[Ellison is] the only living organism I know whose natural habitat is hot water.”

200px-Harlan_Ellison_at_the_LA_Press_Club_19860712_(cropped_portrait)

source

 

 

 

Written by LW

May 27, 2020 at 1:01 am

“Once we introduce the possibility of applying the quantum principle to the universe, we are forced to consider parallel universes”*…

 

antiverse

 

In the Antarctic, things happen at a glacial pace. Just ask Peter Gorham. For a month at a time, he and his colleagues would watch a giant balloon carrying a collection of antennas float high above the ice, scanning over a million square kilometres of the frozen landscape for evidence of high-energy particles arriving from space.

When the experiment returned to the ground after its first flight, it had nothing to show for itself, bar the odd flash of background noise. It was the same story after the second flight more than a year later.

While the balloon was in the sky for the third time, the researchers decided to go over the past data again, particularly those signals dismissed as noise. It was lucky they did. Examined more carefully, one signal seemed to be the signature of a high-energy particle. But it wasn’t what they were looking for. Moreover, it seemed impossible. Rather than bearing down from above, this particle was exploding out of the ground.

That strange finding was made in 2016. Since then, all sorts of suggestions rooted in known physics have been put forward to account for the perplexing signal, and all have been ruled out. What’s left is shocking in its implications. Explaining this signal requires the existence of a topsy-turvy universe created in the same big bang as our own and existing in parallel with it. In this mirror world, positive is negative, left is right and time runs backwards. It is perhaps the most mind-melting idea ever to have emerged from the Antarctic ice ­­– but it might just be true…

Strange particles observed by an experiment in Antarctica could be evidence of an alternative reality where everything is upside down: “We may have spotted a parallel universe going backwards in time.”

* Michio Kaku

###

As we consider our alternatives, we might recall that it was on this date in 1912, in his “Manuscript on the Special Theory of Relativity,” that Einstein first identified the fourth dimension as time… or so it is widely accepted.  Some physicists believe that Einstein was making a subtler– and much more complicated– suggestion, “x4 = ict”: that the fourth dimension, not “physical” like the other three, but emergent (in a way “understandable” as time) as the fourth dimension expands from the other three at the rate of “c.”

Screen Shot 2020-04-12 at 1.59.50 PM source

 

 

Written by LW

April 15, 2020 at 1:01 am

%d bloggers like this: