Weird Science

[Bloopy]

That blows my mind man. Astrophysics and all that shit is amazing. What really brought it home to me is when it was explained that any given star I can see in the sky may have already gone supernova because what you're seeing is an old image of the star because of the distance and we womt know it went nova for years or decades.

I felt relativity was made mysterious and not explained nearly as well at high school as it could've been, even if it was a subject only touched on briefly. One thing that eventually made it click for me is that an orbit's like a straight line in 4D spacetime. It'd seem a lot simpler if introduced that way.

Of course if I then think about it more deeply it becomes mysterious again. Physics theories are pretty much just mathematical models that fit appropriately. Each one opens up yet more questions ("Great, now tell me: what underlying mechanisms cause all the shit that this theory fits?")

 

[Einherjar86]

I feel the exact same way about physics.

I've yet to have a physics major enroll in one of my undergrad writing courses, which I've been waiting for. I've taught "Story of Your Life" (on which the movie Arrival is based) by Ted Chiang a few times; the text goes into differential equations more than the film does (I don't think the film discusses this at all). Anyway, the characters discuss the theoretical reversibility of time in classical physics, but in class I mentioned that the second law of thermodynamics sort of puts the lie to this (complex processes and entropy being irreversible). I still find this apparent irreconcilability between entropy and time symmetry (Loschmidt's paradox) fascinating.

I've been reading lately on chaos and complexity theory, which is giving me a new perspective on physical systems.

 

[Dak]

https://www.quantamagazine.org/the-new-science-of-seeing-around-corners-20180830/

 

[Einherjar86]

https://www.quantamagazine.org/the-new-science-of-seeing-around-corners-20180830/

I just noticed this. Fucking fascinating. I've always been interested in the interplay of photonics that underpins our vision (e.g. I've reminded my students that when they look at themselves in the mirror, they're seeing their body as illuminated by the light reflected off a mirror--it's a largely inconsequential fact, but it drives the point home). This is really cool:

In 2012, realizing an idea he had five years earlier, Raskar and his team pioneered a technique that involves shooting laser pulses at a wall so that a small fraction of the scattered light bounces around a barrier. Moments after each pulse, they use a “streak camera,” which records individual photons at billions of frames per second, to detect the photons that bounce back from the wall. By measuring the times-of-flight of the returning photons, the researchers can tell how far they traveled and thus reconstruct the detailed 3-D geometry of hidden objects the photons scattered off of behind the barrier. One complication is that you must raster-scan the wall with the laser to form a 3-D image. Say, for instance, there’s a hidden person around the corner. “Then light from a particular point on the head, a particular point on the shoulder, and a particular point on the knee might all arrive [at the camera] at the same exact time,” Raskar said. “But if I shine the laser at a slightly different spot, then the light from the three points will not arrive at the same exact time.” You have to combine all the signals and solve what’s known as the “inverse problem” to reconstruct the hidden 3-D geometry.

Love it.

Been reading about extinction lately:

Difficulties surrounding the definition of species are compounded by the fact that the number of species currently inhabiting earth is unknown. About 1.8 million species, about half of them insects, have been identified and scientifically classified, and several large-scale database projects are currently underway to make knowledge about these species accessible on the Internet for researchers and conservationists (cf. chapter 2). Even this much is by no means a simple task, since for historical and political reasons, not all data about already known species are readily available. But estimates of the total number of species of Earth are even more tenuous; they range from a low of 3 million to a high of 100 million, with typical estimates ranging between 10 and 40 millions species. "The median of the estimates is a little over 10 million, but few experts would risk their reputations by insisting on this figure or any other, even to the nearest million," E.O. Wilson observes (2002, 14). The divergence is in part due to very different assessment methods for different geographical areas and taxa. No matter what the definitive number might be, it is clear that humans known only a fraction of existing species, and very likely species are constantly going extinct that humans have not had a chance to encounter and name.

Damn.

https://www.press.uchicago.edu/ucp/books/book/chicago/I/bo23093383.html

 

[Dak]

I just noticed this. Fucking fascinating. I've always been interested in the interplay of photonics that underpins our vision (e.g. I've reminded my students that when they look at themselves in the mirror, they're seeing their body as illuminated by the light reflected off a mirror--it's a largely inconsequential fact, but it drives the point home). This is really cool:

I wonder if it's this along with other things that have yet to be identified that contribute to those "feelings of someone/thing around" that turn out to be accurate; stuff picked up subconsciously.

Damn.

https://www.press.uchicago.edu/ucp/books/book/chicago/I/bo23093383.html

Given basic evolutionary principles, wouldn't we expect this though? That new species pop up constantly and mostly fail to effectively compete?

 

[Einherjar86]

I wonder if it's this along with other things that have yet to be identified that contribute to those "feelings of someone/thing around" that turn out to be accurate; stuff picked up subconsciously.

The brain picks up on things the conscious mind is totally blind to. So I wouldn't be surprised.

Given basic evolutionary principles, wouldn't we expect this though? That new species pop up constantly and mostly fail to effectively compete?

Yes, but I just had no idea of the sheer numbers. It's incredible.

 

[CiG]

Not sure if this really fits the thread's theme but I randomly came across this:



This bird impersonates all other birds around them to try and attract mates, but because it lives in an area where humans encroach, it also impersonates cameras, car alarms and even chainsaws. Fucking amazing!

 

[The Ozzman]

Dude that is insane. I audibly said 'Holy shit' when the bird did the alarm sound

 

[Einherjar86]

Not sure if this really fits the thread's theme but I randomly came across this:



This bird impersonates all other birds around them to try and attract mates, but because it lives in an area where humans encroach, it also impersonates cameras, car alarms and even chainsaws. Fucking amazing!

Awesome. This reminds me of something I read online yesterday:

https://aeon.co/essays/why-does-keeping-a-bird-in-a-cage-make-people-happy

Serious funding for parrot cognitive research is fairly recent, and its findings have met with pockets of resistance, partly because earlier research centred on less impressive birds such as pigeons. But parrots offer great insights into the parallel evolution of intelligence in animals and humans, and the impact of ecology and social conditions on higher degrees of intelligence.

The most famous investigation into parrot intelligence was the eye-popping research of Irene Pepperberg, adjunct professor of psychology now at Brandeis University, into the psychology of Alex the African Grey Parrot, a bird described as having the cognition-levels of a dolphin, or the intelligence of a five-year-old child. Alex had an extraordinary ability to communicate and reason using sophisticated human language and a vocabulary of 150 words. He had the ability to understand, in his own way, the very advanced conceptual idea of nothing. ‘Alex has a zero-like concept; it’s not identical to ours but he repeatedly showed us that he understands an absence of quantity,’ wrote Pepperberg in 2005 in an email in the journal LiveScience.

 

[CiG]

That's amazing. I went ahead and looked up Alex the African Grey Parrot and found these:





Mind blown.

 

[rms]

https://www.theguardian.com/science...t-the-goblin-discovery-planet-nine-oort-cloud

 

[The Ozzman]

https://www.theguardian.com/science...t-the-goblin-discovery-planet-nine-oort-cloud

Wait until people say this is a sign of Nibiru coming lol

 

[rms]

never heard of that until now hah

 

[The Ozzman]

never heard of that until now hah

Nibiru/Planet X/etc. Astronomers get more questions about that than actual space related shit lmao.

 

[Einherjar86]

I get shivers thinking about the Oort. Lot of uncharted shit out there.

 

[Einherjar86]

https://www.quantamagazine.org/famo...ve-alternative-to-quantum-weirdness-20181011/

De Broglie’s pilot-wave vision of the quantum world was little remembered 78 years later, when the Paris droplets started bouncing. Suddenly, Couder and his colleagues had an “analogue system” for experimentally exploring de Broglie’s idea.

Straightaway, they saw the droplets exhibit surprisingly quantum-like behaviors — only traversing certain “quantized” orbits around the center of their liquid baths, for instance, and sometimes randomly jumping between orbits, as electrons do in atoms. There and in bouncing-droplet labs that soon sprang up at the Massachusetts Institute of Technology and elsewhere, droplets were seen to tunnel through barriers and perform other acts previously thought to be uniquely quantum. In reproducing quantum phenomena without any of the mystery, the bouncing-droplet experiments rekindled in some physicists de Broglie’s old dream of a reality at the quantum scale that consists of pilot waves and particles instead of probability waves and conundrums.

But a series of bouncing-droplet findings since 2015 has crushed this dream. The results indicate that Couder’s most striking demonstrationof quantum-like phenomena, back in 2006 — “the experiment that got me hooked on this problem,” the fluid dynamicist Paul Milewskisaid — was in error. Repeat runs of the experiment, called the “double-slit experiment,” have contradicted Couder’s initial results and revealed the double-slit experiment to be the breaking point of both the bouncing-droplet analogy and de Broglie’s pilot-wave vision of quantum mechanics.

 

[Einherjar86]

Just in case you want to read about where symmetry doesn't exist: https://www.quantamagazine.org/a-proof-about-where-symmetries-cant-exist-20181023/

When we think of symmetry, we picture a whole shape being rotated, like a square turned clockwise 90 degrees. At a granular level, though, symmetry is really about moving points. To transform a space by symmetry means to take each point in the space and move it to some other point in the space. In that light, rotating a square clockwise by 90 degrees really means: Take each point on the square and rotate it clockwise 90 degrees so that it ends up on a different edge from where it started.

This business of moving around points can be done in more or less rigid fashion. The most familiar symmetry transformations — reflect a square over its diagonal, or rotate the square 90 degrees — are very rigid. They’re rigid in the sense that they don’t really scramble the points. Points that were vertices before the reflection are still vertices after the reflection (just different vertices) and points that formed straight edges before the reflection still form straight edges after the reflection (just different straight edges).

There are looser, more flexible types of symmetry transformations, though, and these are the ones of interest in Zimmer’s conjecture. In these transformations, points are more thoroughly reorganized; they don’t necessarily maintain their prior relationship with one another after a transformation has been applied. For example, you could move each point on the square three units around the perimeter of the square — that satisfies the basic requirements of a symmetry transformation, that it simply move every point in the space to some new position in the space. Aaron Brown, coauthor of the new proof, described what these looser kinds of transformations could look like in the context of a ball.

“You could take the north and south poles and twist them in opposite directions. Distances and points would get pulled apart,” Brown said.

When you’re talking about a grid, instead of just shifting the grid in the plane, you’re allowed to twist the grid, or stretch it in some places and contract it in others, so that the transformed grid no longer overlays perfectly on the starting grid. These types of transformations are less rigid. They’re called diffeomorphisms.

 

[Dak]

https://www.centauri-dreams.org/2018/10/29/on-oumuamua-thin-films-and-lightsails/

Could ‘Oumuamua be debris from a technological civilization, a discarded lightsail?

A fascinating speculation indeed. From the paper:

Considering an artificial origin, one possibility is a lightsail floating in interstellar space as debris from an advanced technological equipment (Loeb 2018). Lightsails with similar dimensions have been designed and constructed by our own civilization, including the IKAROS project and the Starshot Initiative. The lightsail technology might be abundantly used for transportation of cargos between planets (Guillochon & Loeb 2015) or between stars (Lingam & Loeb 2017). In the former case, dynamical ejection from a planetary system could result in space debris of equipment that is not operational any more (Loeb 2018) and is floating at the characteristic speed of stars relative to each other in the Solar neighborhood.

 

[Einherjar86]

"...a new class of thin interstellar material." Sweet.

The introduction of this one new non-real number — i, the imaginary unit — launched an entirely new mathematical world to explore. It is a strange world, where squares can be negative, but one whose structure is very similar to the real numbers we are so familiar with. And this extension to the real numbers was just the beginning.

In 1843, William Rowan Hamilton imagined a world in which there were many distinct “imaginary units,” and in doing so discovered the quaternions. The quaternions are structured like the complex numbers, but with additional square roots of –1, which Hamilton called j and k. Every quaternion has the form a + bi + cj +dk, where a, b, c and d are real numbers, and i2=j2=k2=−1. You might think anyone can invent a new number system, but it’s important to ask if it will have the structures and properties we want. For instance, will the system be closed under multiplication? Will we be able to divide?

To ensure the quaternions had these properties, Hamilton had to figure out what to do about i × j. All quaternions need to look like a + bi + cj +dk, and i × j doesn’t. We ran into a similar problem when we first multiplied two complex numbers: Our initial result had an i × i term in it, which didn’t seem to fit. Luckily, we could use the fact that i2=−1 to put the number in its proper form. But what can be done with i × j?

Fucking math man.

https://www.quantamagazine.org/the-imaginary-numbers-at-the-edge-of-reality-20181025/

 

[The Ozzman]

Are they implying -1 is not in the set of real numbers?