Activity for celtschk
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #286609 |
Post edited: |
— | almost 2 years ago |
| Edit | Post #286609 |
Post edited: |
— | almost 2 years ago |
| Edit | Post #286609 | Initial revision | — | almost 2 years ago |
| Answer | — |
A: If this earth were cube shaped would it be possible during Magellanic era using a float ship to figure out that the earth is cube shaped? While the other posts did already explain the issues with the cube-formed Earth, I just want to give a feeling of the dimensions we are speaking of. Imagine that the centre of the cube's faces are at Earth's radius, about 6300 kilometres above the cube's centre (that is, the cube is sized so that ... (more) |
— | almost 2 years ago |
| Comment | Post #286461 |
I see how having a presence on Facebook would increase visibility. But I don't see how it would increase trust. I certainly wouldn't trust a site more just because they are on Facebook.
The same of course is true for other social media. (more) |
— | almost 2 years ago |
| Edit | Post #283595 | Initial revision | — | over 2 years ago |
| Answer | — |
A: How would an interstellar spaceship's speedometer work if everything else is moving? The first question is: What is instantaneous speed measured against (that is, what is the “ground” relative to which the speed is measured)? Remember that there is no such thing as absolute speed. The closest to an absolute speed would be the speed relatively to the cosmic microwave background. Th... (more) |
— | over 2 years ago |
| Edit | Post #282198 |
Post edited: Fixed a stupid exponent error |
— | almost 3 years ago |
| Edit | Post #282198 |
Post edited: Fixed intended link to actually be linked |
— | almost 3 years ago |
| Edit | Post #282198 | Initial revision | — | almost 3 years ago |
| Answer | — |
A: Natural ways to acquire gravity and heat for a colony on earth's moon Gravity You seem to assume that the Moon's mass is mostly concentrated in its core. While I didn't find detailed data on the Moon's density distribution, this Wikipedia page tells that the density of the outer core is about $5\\,\rm g/cm^3$ (unfortunately that value is not referenced), while the a... (more) |
— | almost 3 years ago |
| Comment | Post #281984 |
Since I was talking about a planet in the void, I don't see the relevance of the particle density near sol (which isn't even intergalactic space, let alone a void). The other points are clearly relevant, though; +1. (more) |
— | almost 3 years ago |
| Edit | Post #206265 |
Post edited: Added a few more considerations about flammable substances and ignition mechanisms, a few reformulations |
— | almost 3 years ago |
| Edit | Post #281763 |
Post edited: Fixed a typo |
— | almost 3 years ago |
| Edit | Post #281763 | Initial revision | — | almost 3 years ago |
| Question | — |
Could a habitable planet lit by the cosmic microwave background plausibly exist? I've got this idea of a rogue planet that is moving that fast through the intergalactic void that the cosmic microwave radiation, thanks to the Doppler effect, actually provides enough heat that it is habitable (and of course, it should be actually inhabited). Thanks to the searchlight effect, I thin... (more) |
— | almost 3 years ago |
| Comment | Post #281056 |
From [Wikipedia,](https://en.wikipedia.org/wiki/Caspian_Sea#Environmental_degradation) emphasis by me: “The **rising level** of the Caspian Sea between 1994 and 1996 reduced the number of habitats for rare species of aquatic vegetation.” Now that doesn't actually answer your question (it could be an ... (more) |
— | about 3 years ago |
| Edit | Post #213131 |
Post edited: Fixed some obvious typos |
— | over 3 years ago |
| Comment | Post #279725 |
(Note that those measures would not stop/delay the growing up process, only the ageing process; you'd need an independent change to stop the growing-up, which may have any sort of specific consequences.) (more) |
— | over 3 years ago |
| Comment | Post #279725 |
@Matthew: Sure. For example, I could imagine that the process simply doubles the reserves of adult stem cells. Now I'm not a biologist, but my guess would be that this would delay ageing because you simply take longer to use up your reserves. Or maybe your treatment doubles the number of times a cell... (more) |
— | over 3 years ago |
| Suggested Edit | Post #213131 |
Suggested edit: Fixed some obvious typos (more) |
helpful | over 3 years ago |
| Comment | Post #279503 |
Is there a deeper reason why you didn't link to https://scientific-speculation.codidact.com/questions/213114 for the old question? (more) |
— | over 3 years ago |
| Edit | Post #279617 | Initial revision | — | over 3 years ago |
| Answer | — |
A: How do you establish identity when people can change their appearance at will? Since manipulation of the brain is prohibited and illegal modifications are assumed to be reliably caught, the obvious way to check someone's identity with biometry would be by checking their brain. One thing I could imagine is that there are recognisable patterns in the EEG that allow identificat... (more) |
— | over 3 years ago |
| Edit | Post #214808 |
Post edited: Fixed a typo |
— | over 3 years ago |
| Edit | Post #279296 | Initial revision | — | over 3 years ago |
| Question | — |
Is it realistic to see satellites moving across the sky centuries after humans stopped space activity? After an age of highly developed technology, including many different satellites in various Earth orbits, humanity loses the technology needed to control those satellites. After many centuries, how realistic is it that you can still occasionally see a satellite moving across the sky (say, at least on... (more) |
— | over 3 years ago |
| Edit | Post #279088 |
Post edited: |
— | over 3 years ago |
| Edit | Post #279088 |
Post edited: Thinking again, the efficiency will likely be lower |
— | over 3 years ago |
| Edit | Post #279088 | Initial revision | — | over 3 years ago |
| Answer | — |
A: How efficient can a Dyson sphere be? I think a reasonable assumption is that you don't want to accumulate entropy from the Dyson sphere. That is, the entropy you get from the star must not be lower than the entropy you send to outer space (indeed, you'll have to send out more entropy because on one hand you have other sources of entropy... (more) |
— | over 3 years ago |
| Answer | — |
A: Quantum Based AI getting around Isaac Asimov's "Three Laws of Robotics" Quantum computers operate differently than classical computers, and most importantly, doing measurements in the middle of a quantum computation process will disturb the process, and possibly lead to unpredictable behaviour. So maybe the three-rule-enforcement unit monitors the quantum computer, by l... (more) |
— | over 6 years ago |
| Answer | — |
A: Generation ships: Over coming agoraphobia when you land Actually I don't think you'll have that problem, for a simple reason: It is very unlikely that the planet will be a perfect match before doing some serious terraforming. Therefore after landing, people will likely mostly stay in the space ship and in new buildings on the planet that "extend" the spac... (more) |
— | over 6 years ago |
| Answer | — |
A: How does a species with three "sexes", where only two needed are at a time, determine the sex of its offspring? Here's another option: There are three genes: The X gene, the Y gene, and the Z gene. And there are three sex chromosomes: The XY chromosome, the XZ chromosome and the YZ chromosome. Each sex chromosome has exactly the two genes found in its name. Just as with humans, each individual has two sex chr... (more) |
— | over 6 years ago |
| Answer | — |
A: Making a lethal, hard to cure virus? A possible way to have the virus spread quickly yet be deadly is to have a double effect. Shortly after infection, it basically acts like the common cold. The common cold spreads quite effectively every winter, but is neither feared much nor do people take too strict measures to avoid it. So if in th... (more) |
— | almost 7 years ago |
| Answer | — |
A: What could cause the Earth to be so endangered that mankind needs to relocate to another system? When the sun started to behave strangely, astronomers were confused: The accepted solar model didn't at all predict this behaviour. Indeed, based on the new data it could quickly be shown that their model of the sun was wrong due to some previously unknown factor (maybe the sun contained a considerab... (more) |
— | about 7 years ago |
| Answer | — |
A: Stopping time, by speeding it up inside a bubble Well, let's see how such a field would work. The Hamiltonian equations are $$\frac{\mathrm d xk}{\mathrm d t} = \frac{\partial H}{\partial pk} \quad \frac{\mathrm d pk}{\mathrm d t} = -\frac{\partial H}{\partial xk}$$ Now we want the field to affect the speed of things happening, so a natural assumpt... (more) |
— | over 7 years ago |
| Answer | — |
A: When will uploaded minds be a reality? Never. The problem is not being able to simulate a human brain; that one I consider possible, and probably even achievable on affordable hardware at some time in the future. The problem is taking an existing brain and reading out the full state. Since the properties of the person are not just in the... (more) |
— | over 7 years ago |
| Answer | — |
A: Why do people in Cryogenic sleep not wear clothes? The main function of clothing is to hinder the flow of heat. The last thing you want to do when putting people into cryogenic sleep is to hinder the flow of heat. Quite the opposite: You want to have perfect control of the temperature on the skin. So, you say, why not put on some special clothing th... (more) |
— | over 7 years ago |
| Answer | — |
A: How could a vampire pathogen operate in hard science fiction? A remark at the beginning: In a world where real-life vampires existed, there would certainly also grow a lot of myths about them. So we would have to distinguish between in-world real traits and in-world myths (that is, things that are commonly ascribed to vampires in that world, but are not true, o... (more) |
— | over 7 years ago |
| Answer | — |
A: Ways to "kill" an AI? Hostile takeover. The other AI has lots of useful routines that your AI doesn't want to simply erase or leave unused. Instead it takes over the other AI, that is, incorporates all its routines, so that while the routines, data, etc. are all there, the other AI as an independent being no longer is; i... (more) |
— | over 7 years ago |
| Answer | — |
A: How could the air be stopped from falling off of a flat world? The whole universe could be filled with air. That would also explain why the world isn't just in free-fall (and thus effectively gravitation-free): It is going at the limit speed where air resistance equals gravitational pull. Of course it would still not explain why the air doesn't fall as well. No... (more) |
— | over 7 years ago |
| Answer | — |
A: How would we see the world if we could see polarized light? With many more than three colour receptors, our colour TVs, using just three colours for display, would not come even close to showing all the colours of the world. Moreover, LDCs inherently work with polarized light; as is, they would probably look very unnatural. However, in principle this could be... (more) |
— | over 7 years ago |
| Answer | — |
A: Why would a civilisation choose to inhabit a single enormous vessel instead of maintaining interstellar colonies? The ship started out as a generational ship to colonize some far-away planet. However, when approaching that planet, nobody wanted to be a colonist. They lived on the ship, their parents lived on the ship, their grandparents lived on the ship. Indeed, some even doubted the historical record and claim... (more) |
— | almost 8 years ago |
| Answer | — |
A: Is Cancer Biologically Universal? Assuming the alien life form is multicellular, it should definitively know cancer. Cancer is basically a defect in the mechanism that controls the cell division. Cell division is absolutely essential for growth and reproduction. Also, the multicellular life will have evolved from single-cellular life... (more) |
— | almost 8 years ago |
| Answer | — |
A: Speeding up time? There's no way to achieve this in the known laws of physics. However given that near a mass the time "goes slower". I guess if you could create a negative mass, near it time should "go faster". So if you assume there's a way to create a large negative mass, then you could do that near that mass. O... (more) |
— | almost 8 years ago |
| Answer | — |
A: Can a planet have 10x Earth mass, 4x Earth gravity and support intelligent life? If $R$ is the planet's radius and $\rho$ is the planet's average density, then its surface gravity is $\propto \rho R$ and its mass is $\propto \rho R^3$. Let's measure in units where the Earth's radius and average density are both 1. Then for Dekuuna we have $\rho R=4$ and $\rho R^3=10$. Therefore ... (more) |
— | almost 8 years ago |
| Answer | — |
A: Space Age to Bronze Age The space age civilisation has heavily computerized systems. That is, all important aspects of the space ships, factories, and whatever else advanced technology they use is completely controlled by software. People don't know how to make things because they don't need to; "the system" provides them w... (more) |
— | almost 8 years ago |
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A: Dead bodies on a partially terraformed planet : Would they rot or dry? tl;dr: The corpses would still decay, but probably much slower. From the Wikipedia article about decomposition: Decomposition begins at the moment of death, caused by two factors: autolysis, the breaking down of tissues by the body's own internal chemicals and enzymes, and putrefaction, the brea... (more) |
— | almost 8 years ago |
| Answer | — |
A: How large could a planet be yet still approach 1 Earth gravity and support life as we know it? For a spherically symmetric planet, surface gravitation is determined by just two quantities: The average density, $\rho$, and the radius, $R$. In particular, due to spherical symmetry you can consider the whole planet's mass to be concentrated in the center, and then you get for the gravitational ac... (more) |
— | almost 8 years ago |