Posts by celtschk
Let's listen to the head of the colonization movement, who happens to give a speech about this topic right now: Ladies and Gentlemen, thank you for giving me the opportunity to tell you about t...
What I've found out is that Ammonia has (in the relevant temperature/pressure regime) cubic crystal structure. But what would that mean for ammonia snowflakes? Would they have fourfold symmetry? Bu...
First, the good news: You still can have quantum stuff. All the quantum weirdness already exists in non-relativistic quantum mechanics. Without the speed limit, full relativity is, of course, out ...
The situation I'm considering is as follows: A space ship (a transport ship operated by two people) crashes onto a planet on which a swing-by was planned. The crew could escape using an escape cap...
This is somewhat of a follow-up question to my ammonia-based world question. I've found out that the melting point of ammonia is at 25°C at a pressure of about 1 MPa (about 10 times the atmospheri...
First, the deadliness of a virus can vary widely from mostly harmless (Herpes) to very deadly (Ebola). However, note that even for Ebola, there are people who survive without treatment. Indeed, Ebo...
One quite nasty type of bug (which can especially be hard to find, and can give quite inconsistent results) is out-of-range indices, in a language which doesn't range-check indices (likely to be us...
Let me add another point of view. Most answers assume that the large brain evolved in order to gain intelligence. However, I've once read another hypothesis (unfortunately I don't remember where): ...
Well, one obvious effect of cats acquiring flight ability would be that they would be much more effective in catching birds (it of course depends on how well/fast the cats can fly). Probably the nu...
Apart from the obvious difference that liquid ammonia needs a much colder temperature than liquid water (but ammonia-based life forms wouldn't feel that as particularly cold), what would be the mos...
At least the Artemis project thinks it is possible. The process they describe is $$\rm FeTiO_3 + H_2 \to Fe + TiO_2 + H_2O$$ and then split the water to hydrogen and oxygen (note that after splitt...
Their main problem would probably be to find food. Plants don't grow underground/without sunlight. Of course, if they have sufficient supply of canned food to survive until the surface is habitable...
One possibility that has not yet been mentioned (actually inspired from githubphagocyte's comment on how the evolution of plants began in the first place): It could be that the animal doesn't do ph...
As others noted, there's no real physical effect that does this. However let's look at how a fictional effect might work. Water can be supercooled to quite low temperatures, that means, there does...
A quite common idea to provide "gravitation" in space stations is to make them rotate, so the centrifugal force gives an effective gravitation. A possible design is a ring-shaped space station. No...
I think an interesting option could also be that dragons can switch between cold-blooded and warm-blooded metabolism. For example, they could be warm-blooded when young (providing them the needed e...
Apart from the problems of formation and the problems of mechanical stability already mentioned by others, there's also the problem that gravitation cannot preserve that situation. If the sphere w...
A plant chasing humans would be unrealistic, but I think a plant generating a trap for human-sized animals could be possible in principle, given the right circumstances (maybe it evolved from one e...
Plants would be blue if their photosynthesis were based on phycocyanin instead of chlorophyll. Since there are organisms on earth that use this, it's not entirely implausible that it could be used ...
One disadvantage of airplanes is that they need a runway to start/land. So one thing that would discourage airplanes is a geography where you simply have no space for runways (hills/mountains every...
It is not only possible, apparently it actually exists on earth. The abstract of the linked article reads: Two recently discovered cases of genetic caste determination in social insects might p...
The main problem with antimatter would be containment. You cannot simply put it into a normal container, because the normal container would be made of matter, and the antimatter would annihilate wi...
I assume you mean the solar day (determined e.g. as the average time between two sunrises). Although you didn't say it, I also assume that you want a planet in the habitable zone (otherwise you've ...
I'm taking "near ground" as meaning "the height over ground is negligible compared to the radius of the planet". That is, we can as good approximation we can assume that the radius of the geostatio...
What about the sphere being hit by a cosmic string? Some excerpts from the Wikipedia page: Cosmic strings, if they exist, would be extremely thin with diameters of the same order of magnitude ...
