It’s a bit of optics, a bit of eye physiology, and a bit of how the brain works.
Optics: Your lens focuses light on a focal point. For a sharp image, this point in space should be on the retina surface. Both lens and retina are not ideal geometric objects, so directions and angles can matter.
Eye: As others said, the retina has different regions, with different amounts and types of photoreceptors. Some regions are good for a high resolution image of whatever is in focus, others are mostly used for peripheral vision.
Brain: Your brain still gets all the data, from in and out of focus photoreceptors.
Maybe it would be possible in terms of optics to focus on more than one thing at the same time. But retina composition and brain architecture are adapted to the optics which we have: One way to focus, and peripheral vision around it.
With a bit of training it should be possible to mentally focus on image parts out of physical focus; mentally focus on something in your peripheral vision. You would mentally concentrate on a physically low resolution image (lower receptor density), it might be distorted (lens optics), and your brain might not be used to use data from these receptors for this task. So the result probably still feels like “I can’t focus on that”.
Here's a video from Dr. David Barker, who leads the Rosetta@Home project, describing how that project's computing has helped COVID research. https://www.youtube.com/watch?v=ODEIN5V3yLg
I hadn’t seen that video before, but it’s not quite what I’m looking for; it seems that video was made while they were still working on the project, and they were looking for a way to “get it out into the world”. Is there a sort of post-mortem analysis of what the project achieved / is still achieving now?
Ultimately, what distributed computing projects provide is processing of data to facilitate scientific research. Most projects publicize scientific papers that make use of their data, like this blog post and the paper linked therein. In terms of post-mortem, that's difficult to have while COVID is still an ongoing field of research.
Here's a video from Dr. David Barker, who leads the Rosetta@Home project, describing how that project's computing has helped COVID research. https://www.youtube.com/watch?v=ODEIN5V3yLg
How did I completely miss this, the video linked in another comment does a decent job of explaining. Is there anything like this currently going on for other research elsewhere? Would love to get involved.
Thanks, will check that one out. I do like things that are a little more on the technical side, but it’s a fine balance between going deep and keeping it understandable. Especially when it’s outside of your field of study.
I am not aware of any community where you could have these sorts of discussions. But, while I cant vouch for its quality, your question reminded me of a service I read about called Curiosity Stream. Maybe check them out.
I tried curiosity stream for a while and it was decent. I think my major complaint was that it didn’t do the technical deep dives as well. PBS space time does a great job of that. I didn’t feel like I fully understood entropy until their videos.
I have also seen ads for Magellan tv which also calls itself a streaming platform for documentaries. I know very little about it beyond the ads though.
The youngest at any given time is probably a diatom, I’d think. They just exist in such great numbers, that’s all. They’re even harvested up and sold as diatomaceous earth.
Oldest bone is a 400 million year old fishbone, apparently. I had to google it.
Continental drift or just the idea that the continents move. And it makes sense, looking at a map of the earth, you can clearly see that some landmasses look like they fit together like puzzle pieces. Combined with the fossil record with also supported this, it seems obvious to us now, the continents were once all one landmass. However, back then, the issue was Alfred Wegener, who came up with continental drift, didn’t have an adequate mechanism for how it worked. The question on everyone’s mind was, if the continents moved, HOW did they move? There wasn’t a good answer. It was suggested at one point that the continents maybe just plowed through the ocean crust. But that idea doesn’t work because the ocean crust is too rigid. So without any mechanism to get it to work, many geologists simply dismissed the idea. And to be fair to them, most of what Wegener claimed was indeed wrong.
Further advancements in geology and technology allowed for a better understanding of the earth. A key finding was paleomagnetic stripes on the ocean floor which proved that the earth’s crust, and the continents must be moving. This, combined with other evidence helped construct the modern theory of plate tectonics.
The rule of thumb among paleontologists says that fossilization takes about 10.000 years, so that would be your youngest age. It should be noted, however, that there are many different mechanisms that lead to fossilization. The Lloyds Bank coprolite, for example, is generally described as a fossilized Viking poop despite being ‘only’ about 1200 years old.
You don’t have to wait for it to cool. As water evaporates the dissolved solids in it reach a higher concentration. If the concentration becomes greater than the molecule’s solubility it will precipitate and fall to the bottom.
If you have pieces of metal that you can filter out. Metals in water are usually in ionic form, they are “chelated” by water in solutions. Unless some salt is created and precipitate, solved metals distribuite over the solution to avoid concentration gradients.
So the answer is: what metal are you talking about? What is its form and concentration? Most likely, if you couldn’t see depositions before boiling it, metal ions will likely stay in solution.
Boiling water is used to kill biological organisms. If you want to get “pure” water you need to distillate it or filter it with material that can capture ions
They stay in the water when you boil it, what you need is a good filter. Most filters you find in the shop don’t do much tbf, but I cannot suggest anything, I am not an expert on commercial products.
I don’t think that is how it works. You could buy an air still, but you really don’t want to drink distilled water unless you add some minerals to it like calcium or fluoride. Water in nature always has dissolved minerals in it, and your body is designed with the assumption that those minerals are there.
Where did you read this? Unfortunately it doesn’t work like that, unless you have concentration so high that a deposit is created. But, in that case, I wouldn’t absolutely drink that water
Having done some pilot scale experiments (60 l barrels), I’ve noticed that mixers are absolutely essential. At that scale, metals really do form notable concentration gradients.
solid metals are a separate phase, they create a deposit
salts over a certain concentration, part create a deposit, so they slowly create a powder at the bottom, part stay in solution as ions
Ionic metal in solutions spreads all over, as any concentration difference (gradient) generates an excess of free energy that the system naturally releases. You need to add external energy to maintain the gradient, such as a external electric potential gradient (an anode and a cathode)
Generally speaking, the experiments should follow the third category, but the system didn’t have enough time to reach equilibrium.
If you have infinite time at your disposal, you can rely on diffusion to do its job. Unfortunately, the project had a finite amount of time allocated to it, and 60 l barrels are large enough that significant concentration gradients can exist. Found that out the hard way.
LPT: Don’t start your experiments until all the mixers have arrived.
Never heard of this channel, but either of those two claims would be a huge advancement in multiple fields, so the fact that it’s not being reported or published anywhere else is a pretty big indication that his claims are bunk.
Like I said, I don’t know that for sure and I haven’t watched the videos, but I do keep current on most big advancements and I’ve heard nothing about either of these.
Roche limit is not really relevant here. That’s for orbiting bodies, like a satellite around a Jupiter-like planet whose orbit spirals inward due to tidal forces, and eventually crosses the Roche limit, whereby the moon disintegrates into a cloud of rocks that spreads out and forms a ring. Yes, the hyperbolic orbit of the collision trajectory here is a “type” of orbit, but really the video is about the collision itself. There is not enough time for the planet to meaningfully disintegrate under the neutron star’s gravity. “What’s that? The ground is kinda shaking. Could that be the tidal force from that neutron st-ACK!!!”.
In the video you can see the surface of the Earth bulge out towards the star under its gravity in the last second, but most of the kinetic energy of the explosion is imparted by direct physical interaction (i.e. electromagnetic) between the matter of the earth and the matter of the star, and in particular between the matter of the earth that has already been accelerated and the matter of the earth lying farther out.
Or at least it would be if the impactor really was just a chunk of iron with the density slider cranked up. This fluid simulator can’t imagine anything else of course, but you are right that it remains a question of whether a neutron star or a black hole could impart any kinetic energy onto the greater earth at all. Maybe it will just pass through and leave a circular hole, sweeping the material in front of it onto itself. The tunnel would immediately collapse, and the crust would be messed up from tidal sloshing, but maybe the ball of the earth itself will remain intact.
The hard x-rays I believe is a reference to thermal radiation of infalling matter. Just like a bullet that hits a wall while staying intact is hot to the touch because its kinetic energy got 100% converted into heat, or a meteoroid that hits the Moon creates a flash of light visible from Earth because for a second the cloud of collision debris is as hot as the filament of a lamp, the earth material impacting the surface of the star gets really hot. The impact velocity is at minimum the escape velocity of the star, which is thousands of km/s, which means the peak of thermal radiation is in the x-ray range.
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<span style="color:#323232;">E = 3/2 k_B T
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Say we imagine that the entire kinetic energy of bulk material from Earth (let’s say iron) impacting the star at 10000km/s is converted into thermal kinetic energy of individual iron atoms (atomic weight 56).
You might be interested in Tomasello’s “The Evolution of Agency” where he kind of addresses this very question. It really depends on how you define “making decisions” and “purely chemical reactions” doesn’t it - all life is chemical reactions, including when we make decisions, and it’s easy for us to apply decision-making language even to systems that are simple enough that we can see them as “purely chemical reactions”.
Tomasello defines the notion of “agents” as “feedback-control systems” that he distinguishes from pure stimulus-response systems. In his examples a nematode for example is “stimulus-response”; its behavior is very directly related to its immediate environment. If it runs into food it eats, otherwise it doesn’t, and there isn’t really a notion of it seeking out food when it’s hungry and not when it’s not. In contrast and “agent” is a feedback-control system with goals, a perceptual system that checks whether the goal is accomplished at any given time and a behavioral repertoire aimed at accomplishing the goal. In our lineage he sets the appearance of this agency around the evolution of vertebrates, and uses lizards as an example of the most basic level. (he doesn’t address other lineages other than to say that various levels of agency clearly evolved convergently a few times; so octopuses and social insects for example would also have these systems). So where a nematode has feeding behavior that’s triggered by running into food and other behaviors when food isn’t present, a lizard’s behavior depends not only on the immediate stimulus but on more abstract goals - in a given environment it might be currently hungry and looking for food, or sated and looking for shade or sun to rest or hide or thermoregulate, or looking to reproduce, etc, and its behavior will depend on and be directed towards accomplishing that goal.
It’s interesting that you say “thinks through and makes decisions” as if they’re on the same level but the book actually claims that human agency is actually the result of the evolution of several successive layers of feedback-control mechanisms that each allow more flexibility and responsiveness - so for example lizards have a feedback systems that adjusts behavior to achieve goals, and mammals have that and also a higher-level feedback system above that to adjust the goal-seeking behavior itself, mentally “playing out” different ways of accomplishing the goal in order to pick the best one. He describes four such levels for humans and it suggests a variety of ways we could define “think through and make decisions”, with different species qualifying or not depending on which we choose.
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