Posts by HDE 226868
In a young planet, oxygen can be produced from water vapor via photodissociation, which occurs along a pathway like $$\text{H}_2\text{O}+h\nu\to\text{H}+\text{OH}$$ $$\text{H}+\text{OH}+h\nu\to2\te...
In general, the problem with hollow-Earth setups is that objects in hydrostatic equilibrium cannot be hollow - and planets must be in hydrostatic equilibrium. Planets form through collisions of sma...
I'm considering a story set about fifty years (2065) in the future. It takes a rather optimistic view; space exploration has led to colonies on the Moon and Mars, as well as several space stations ...
What could be learned? There are so many things you could study by looking at a black hole. There are lots of open or partially unsolved problems that surround them: Does Hawking radiation exist...
Surface gravity Surface gravity is really the most important quantity when it comes to determining many of your planet's properties. It can be used to constrain atmospheric composition, planetary ...
Make it a ruse - an offering to the gods. I'm reminded, strangely, of the Minotaur. Every seven or nine years (accounts differ), seven boys and seven girls were sent from Athens to Crete in tribu...
A recent Snowball Earth period might help. Heavy glaciation can cause enormous changes to the terrain. There are no longer any glaciers where I live, but there once were, during a recent ice age. ...
This has been proposed, believe it or not. Gravity is the weakest of the four fundamental forces, a mystery which has been dubbed the hierarchy problem. Several solutions have been floating around;...
To properly determine the orbital path of the asteroid, you'd need to do a numerical simulation (the three-body problem here likely not having an analytical solution). There are certainly $n$-body ...
Let's think about why a supernova happens in a massive star. You probably know that after a star develops an iron core, further nuclear fusion is not possible on a large scale. Yes, you can produce...
This is just a basic answer, but I used Samuel et al. (2014), who in turn cited the climate model of Léger et al. (2011) for a tidally-locked planet with no atmosphere. They give the formula for s...
Let's determine some basic parameters of the cluster. You say you want the stars to be 1-2 light-years apart. This is a little tricky because star clusters don't necessarily have uniform densities...
Sefa's answer is correct. Due to Newton's shell theorem, the force on any object inside (and due to) a spherically symmetric object of uniform mass density of exactly zero. The exact integration (s...
Yes, it's quite possible for hydrogen sulfide ($\text{H}_2\text{S}$) to replace water as the solvent for life. It already plays a major role in chemosynthesis in hydrothermal vents. The basic react...
We can use something called Kleiber's law (which I originally found here). It states that a power law describes the relationship between metabolic rate $q$ and mass of an animal $M$ (in kilograms):...
It seems like you've generated a chthonian planet, although typically, they're theorized to form when normal solar winds from a star slowly strip away the atmosphere, not the release of a star's ou...
13 square meters BIOS-3, a sealed, underground compound designed to mimic a spacecraft, managed to generate oxygen for humans using algae. Its specifics are outlined in an article by Salisbury et ...
Give it a protoplanetary disk: Image in the public domain. Protoplanetary disks are circumstellar disks that form early on in the life of a planetary system, from the original protoplanetary ne...
My chief reference here is Appendino et al. (2009), though this possibility was first brought to my attention by this National Geographic article. The Joker's real-world substance of choice? Oenan...
I like to use Kasting et al. (1993) when talking about better climate models of planets around main sequence stars, as it evaluates habitable zones in while taking into account atmospheric effects....
Check out the cone snail. Cone snails like to stupefy their victims (see also Safavi-Hemami et al. (2014)) by either Using an extremely fast "harpoon" with venom to stab their prey. Releasing a ...
The major problem with building a space station like a city is that you can't really make it anything like Earth: O'Neill cylinders are big enough that they can have their own weather systems. Th...
I'm currently working on two connected continents for the world I'm building. They've created a convergent boundary where they meet, which has given rise to an east-west mountain range, in addition...
Let's imagine that the organism causing the disease (a virus) has two states, depending on whether or not it's inside its host. State #1: Active In this state, the organism is inside the host. It...
Ever heard of shepherd moons? Shepherd moons are moons (typically not very massive) that orbit in the middle of planetary rings, creating gaps in the material. They also keep the ring material wher...
