Black-eyed Angels

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I jumped in the river, what did I see?
Black-eyed angels swam with me
A moon full of stars and astral cars
And all the figures I used to see

All my lovers were there with me
All my past and futures
And we all went to heaven in a little row boat
There was nothing to fear and nothing to doubt

Text: Pyramid Song, Radiohead.

Image: What the world would look like if all the ice melted, National Geographic.

Snakes & Trains

Gefter: But how can seeing a false reality be beneficial to an organism’s survival?

Hoffman: There’s a metaphor that’s only been available to us in the past 30 or 40 years, and that’s the desktop interface. Suppose there’s a blue rectangular icon on the lower right corner of your computer’s desktop — does that mean that the file itself is blue and rectangular and lives in the lower right corner of your computer? Of course not. But those are the only things that can be asserted about anything on the desktop — it has color, position, and shape. Those are the only categories available to you, and yet none of them are true about the file itself or anything in the computer. They couldn’t possibly be true. That’s an interesting thing. You could not form a true description of the innards of the computer if your entire view of reality was confined to the desktop. And yet the desktop is useful. That blue rectangular icon guides my behavior, and it hides a complex reality that I don’t need to know. That’s the key idea. Evolution has shaped us with perceptions that allow us to survive. They guide adaptive behaviors. But part of that involves hiding from us the stuff we don’t need to know. And that’s pretty much all of reality, whatever reality might be. If you had to spend all that time figuring it out, the tiger would eat you.

Gefter: So everything we see is one big illusion?

Hoffman: We’ve been shaped to have perceptions that keep us alive, so we have to take them seriously. If I see something that I think of as a snake, I don’t pick it up. If I see a train, I don’t step in front of it. I’ve evolved these symbols to keep me alive, so I have to take them seriously. But it’s a logical flaw to think that if we have to take it seriously, we also have to take it literally.

Gefter: If snakes aren’t snakes and trains aren’t trains, what are they?

Hoffman: Snakes and trains, like the particles of physics, have no objective, observer-independent features. The snake I see is a description created by my sensory system to inform me of the fitness consequences of my actions. Evolution shapes acceptable solutions, not optimal ones. A snake is an acceptable solution to the problem of telling me how to act in a situation. My snakes and trains are my mental representations; your snakes and trains are your mental representations.

Text: Amanda Geftner, The Case Against Reality, The Atlantic. 

Image: Huang Yong Ping, Ressort 2012

Bizarre Features

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“According to the team’s modeling, the waves near the point where the asteroid struck would have been approximately 300 metres tall. When they hit the coast they wouldn’t be quite that big, but would still have reached 75 or 80 metres, Costard says.

“The most probable source of the tsunami, the scientists concluded, is a 60-kilometre impact crater located about 1000 kilometres off the putative coast. But it is also possible that the deposits could have been produced by the combined results of two independent impacts, represented by smaller craters closer to the shore.

“The new research also explains bizarre features known as thumbprint terrain, on the seaward ends of some of the tsunami deposits. Composed of curving, concentric ridges 10 to 20 metres high, these look for all the world like the ridges in a fingerprint.

“The explanation, Clifford says, starts with the fact that the tsunami would have come in two pulses. The first would have been produced when the asteroid hit, shoving tremendous amounts of water out of its way. The second would have occurred when water rushed back into the resulting depression from all sides.

“The onrushing water would have crashed together in the centre of the impact depression in a giant splash, then rebounded outward in a second tsunami, even larger than the first.

“And that’s just the beginning of the story. When the first wave, a few minutes ahead of the second, hit the shoreline, part of it would have been reflected back out to sea. There, it would have met the oncoming second wave, where the turbulence would have caused sediment to be dropped in patterns exactly like the enigmatic thumbprint terrains.”

Text: Mars may have experienced a giant tsunamiCosmos Magazine.

Image: The Great Wave Off Kanagawa By Hokusai, Supercoloring version.

A Hole in the Atmosphere

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“Obviously, something […] big hitting the Earth is going to hit with a lot of energy. […] This is the energy one million tons of dynamite would release if it was exploded and is the energy unit used for nuclear explosions. The largest yield of a thermonuclear warhead is around 50–100 megatons. The kinetic energy of the falling object is converted to the explosion when it hits. The 10-kilometer object produces an explosion of 6 × 107 megatons of TNT (equivalent to an earthquake of magnitude 12.4 on the Richter scale). The 1-kilometer object produces a milder explosion of “only” 6 × 104 megatons (equivalent to an earthquake of magnitude 9.4 on the Richter scale).

“On its way to the impact, the asteroid pushes aside the air in front of it creating a hole in the atmosphere. The atmosphere above the impact site is removed for several tens of seconds. Before the surrounding air can rush back in to fill the gap, material from the impact: vaporized asteroid, crustal material, and ocean water (if it lands in the ocean), escapes through the hole and follows a ballistic flight back down. Within two minutes after impact, about 105 cubic kilometers of ejecta (1013 tons) is lofted to about 100 kilometers. If the asteroid hits the ocean, the surrounding water returning over the the hot crater floor is vaporized (a large enough impact will break through to the hot lithosphere and maybe the even hotter asthenosphere), sending more water vapor into the air as well as causing huge steam explosions that greatly compound the effect of the initial impact explosion.

“There will be a crater regardless of where it lands. The diameter of the crater in kilometers is = 0.765 × (energy of impact in megatons TNT). Plugging in the typical impact values, you get a 150-kilometer diameter crater for the 10-kilometer asteroid and a 20-kilometer diameter crater for the 1-kilometer asteroid. The initial blast would also produce shifting of the crust along fault lines.

The oceans cover about 75% of the Earth’s surface, so it is likely the asteroid will hit an ocean. The amount of water in the ocean is nowhere near large enough to “cushion” the asteroid. The asteroid will push the water aside and hit the ocean floor to create a large crater. The water pushed aside will form a huge tidal wave, a tsunami. […] What this means is that a 10-km asteroid hitting any deep point in the Pacific (the largest ocean) produces a megatsunami along the entire Pacific Rim.

“Some values for the height of the tsunami at different distances from the impact site are given in the following table. The heights are given for the two typical asteroids, a 10-kilometer and a 1-kilometer asteroid.

Distance (in km) 10 km asteroid 1 km asteroid
300 1.3 km 42 m
1000 540 m 18 m
3000 250 m 8 m
10000 100 m 3 m

“The steam blasts from the water at the crater site rushing back over the hot crater floor will also produce tsunamis following the initial impact tsunami and crustal shifting as a result of the initial impact would produce other tsunamis—a complex train of tsunamis would be created from the initial impact (something not usually shown in disaster movies).”

Text: Nick Strobel, Effects of an Asteroid Impact on Earth, Astronomynotes.com

Image: “The Chelyabinsk event of 15 Feb. 2013, having an energy equivalent to 500 kilotons of TNT, was the largest well-documented meteor event since the Tunguska event of 1908. Analysis of the Chelyabinsk object’s in-atmosphere trajectory from video records has found that its orbit was similar to the orbit of the 2-km-diameter Near-Earth Asteroid 86039 (1999 NC43).There is a possibility that the Chelyabinsk object was created through a collision between asteroid 86039 and another asteroid. It is also very interesting that the Cheyabinsk Asteroid approached from the Sun’s direction, making it essentially undetectable in telescopes” – Analysis of Chelyabinsk meteor and resultant air burst appears in Nature

The Largest Collective Organism Ever to Live

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“It is hard to overestimate how unusual the situation of bananas in the middle of the last century was—unusual not just in the history of humanity but also in the history of life. There is a patch of aspen trees in the Wasatch Mountains of Utah that many argue is the largest living organism on earth. It comprises some thirty-seven thousand trees, each of which is genetically the same as the other, and the argument goes that the trees, collectively, represent a single organism because they are identical and connected by their roots. But requiring pieces of an organism to be connected in order to be considered part of a collective is arbitrary. The ants in an ant colony, for example, are clearly part of the colony, even when they’re not physically in the nest. All this is to say that an argument can be made that large groups of genetically identical plants, even if not connected, may reasonably be considered a single organism. If one makes such an argument, the banana plantations of Central America in the 1950s were not only the largest collective organism alive at that point, they also may well have been the largest collective organism ever to live.”

Text: Rob Dunn, Humans Made the Banana Perfect—But Soon, It’ll Be Gone, Wired.

Pic: Banana X-Ray

New Safe Confinement

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“World leaders jostle with global executives and anonymous men dressed in full camouflage as platters of shrimp, foie gras and cheesecake are passed around by white-gloved staff. It would all seem quite normal were it not for the fact that we’re just 100m (330ft) away from the site of the worst nuclear disaster in history.

“A hospitality tent has been erected just inside the gates of the Chernobyl nuclear power plant near Pripyat in Ukraine. The tent has many windows, to ensure everyone gets a good view of what’s about to happen.

“These guests are here to witness the final stage of a 30-year clean-up job that has been underway, on and off, since one of the plant’s reactors exploded in 1986. The Chernobyl disaster still casts a pall over nuclear power. And other serious accidents, such as that at Fukushima in Japan in 2011 – the only other incident to be classified a maximum Level 7 in the seven-point International Nuclear Event Scale – are weighed against it.

“It also set in train a series of measures to ensure nuclear safety around the world. Now the whole site is about to be encased inside a vast structure known as the sarcophagus, sealing in some of the most dangerous waste material in the world for at least 100 years.

“The behemoth 35,000 tonne structure beside us has spent the past few days inching along a set of purpose built tracks towards its final destination. This sarcophagus – or New Safe Confinement (NSC) – is taller than the Statue of Liberty and larger than Wembley stadium. But what it resembles most is a very large metal shed.

“Its appearance belies its historic importance, however. The NSC is not only the largest object people have ever moved, it’s also a symbol of what we can achieve when the stakes are highest.”

Text: A Vast New Tomb for the Most Dangerous Waste In The World, BBC.com

Pic: Field of Thorns, “But what if the day in question is not today, not tomorrow, but 24,000 years from now, when no known languages are spoken? What if the enemy is not some foreign power, but an ancient civilization? And what if the great threat to human life is no longer a bomb dropping down from above but waste creeping up from below? Will art come to our rescue then?” -WILL ART SAVE OUR DESCENDANTS FROM RADIOACTIVE WASTE?, JSTOR Daily

To Remember, We Must Forget

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“In order to remember, we must forget. Recent research shows that when your brain retrieves newly encoded information, it suppresses older related information so that it does not interfere with the process of recall. Now a team of European researchers has identified a neural pathway that induces forgetting by actively erasing memories. The findings could eventually lead to novel treatments for conditions such as post-traumatic stress disorder (PTSD).

“We’ve known since the early 1950s that a brain structure called the hippocampus is critical for memory formation and retrieval, and subsequent work using modern techniques has revealed a great deal of information about the underlying cellular mechanisms. The hippocampus contains neural circuits that loop through three of its sub-regions – the dentate gyrus and the CA3 and CA1 areas – and it’s widely believed that memories form by the strengthening and weakening of synaptic connections within these circuits.

[…]

“This is the first time that a pathway in the brain has been linked to forgetting, to actively erasing memories,” said Gross, a co-senior author of the study. “One explanation for [our findings] is that there is limited space in the brain, so when you’re learning, you have to weaken some connections to make room for others. To learn new things, you have to forget things you’ve learned before.”

“The finding that memory loss can be induced by Npy1 receptor activation alone could one day help researchers to treat conditions involving intrusive traumatic memories. “A patient suffering from intrusive traumatic memories would take a pill containing a drug that would enter the brain and activate Npy1 receptors and then be exposed to a virtual experience of the trauma,” says Gross, “and we predict that the combination of receptor activation and trauma exposure and recall would promote the selective erasure of the relevant memory.”

Text:  A neural pathway that erases memories, The Guardian.

Pic: Total Recall, 1990.