Posts by HDE 226868
I decided to start answering this question by building a galaxy (well, a model of a galaxy, but it sounds cooler the first way). A lot of research has already been done in this area, specifically, ...
I went about this a bit differently than kingledion, and got a different answer (off by $\sim6$ orders of magnitude!). The difference is that I assumed that there would be accretion no matter what ...
The setup and the equation Let's look at the geometry involved here. I created two diagrams: On the left, we have the star of radius $R$. On the right, we have a cross-section of the ring. The ...
Yes, it can happen. For this to be possible, you first have to put the planet far enough away that it can become totally icy. Then, after the temperature rises as the red dwarf transitions into a ...
Your main problem is that the planets will comprise a chaotic system. This is why the stability of the Solar System is so difficult (possibly impossible) to determine. Our best models are valid for...
Models of such planets exist, courtesy of Unterborn et al. (2014). They discuss planets of similar composition to yours - looking at the value of the mass fraction given by $(\text{Mg}+2\text{Si}+\...
Apparently, this was investigated by NASA in the early 2000s in what became known as The Caves of Mars Project. Its goal was to find possible places for humans to live over extended periods of time...
Wikipedia gives the formula for the tidal heating $\dot{E}$ as $$\dot{E}=-\text{Im}(k_2)\frac{21}{2}\frac{R^5n^5e^2}{G}\tag{1}$$ where $R$ is the radius of the satellite, $n$ is something weird cal...
First, let's look at the different types of trajectories a solar sail can take. They differ mainly based on something called the lightness number, $\beta$, which depends on the composition and stru...
Using Kepler's third law, I get $$a=\sqrt[3]{\frac{P^2G\times(M+M)}{4\pi^2}}=5.32\times10^4\text{ kilometers}$$ where $a$ is the semi-major axis, $P$ is the time it takes the planets to orbit each ...
This is essentially a partial answer, insofar as it's a series of loosely chained together critiques. Sometime in the future, I'll revise it so it's more organized, but for now, it's a work in prog...
I agree with Tim B's assessment that this is a complicated question. However, I disagree on just why this is the case. The characteristics of the star are well defined, given that it's a solar anal...
Is it possible? Absolutely. Pluto and Charon are tidally locked, and yet Pluto has four other moons1. Charon is relatively massive in comparison to Pluto - about one twelfth its mass. Indeed, the c...
I suppose I'll address the solar flares angle, since nobody appears to have tried that yet. My main objection here is that an external source will have a very hard time causing solar flares. Solar...
Jim2B beat me to the best answer, but there are more solutions. Analyzing a system like this is called the three-body problem, a case of the n-body problem. There are not many stable solutions to ...
Note: If anyone can double-check my numbers and result at the end of this answer, that would be much appreciated. This looks like a question that can be broken down as per your bullet points, so I...
$2.55\times10^{45}\text{ Joules}$. But it probably won't work. There are a few things we need to get straight here, namely, the differences between brown dwarfs and giant planets. Here are two of ...
I'm incredibly embarrassed to be chasing the bounty here, but I can't resist the challenge. Besides, drones are cool. Okay, to start with this, we need to know just what developments have been mad...
Flywheels The method[3]: Generate electricity normally. Use the electricity to accelerate a flywheel to very high speeds. Capture the kinetic energy of the flywheel when needed. The benefits ...
This question is a sort of follow-up to Samuel's previous world map question, Creating a realistic world(s) map - planetary systems. Lots of science fiction stories involve journeying to nearby st...
1.Could any planetary orbit sustain life long-term without an imported energy source? I believe that black holes emit Hawking energy. Could that be of use to living creatures? The power emitte...
Stars generate their energy by fusing lighter elements into heavier elements. The most common reaction in Sun-like stars is the conversion of hydrogen to helium via the proton-proton chain, but hea...
As a first approximation, we treat the rod as a one-dimensional rod of length $L$. On each end is a heat source (the mantles of each of the two "Earths". We can begin to model the system as followi...
Ordering of planets (mass and type) Can I start out by jokingly complaining that you picked a rather complex system? We've found a lot of exoplanets, but there are not many that reside in complex ...
The Sun has nowhere near enough mass to enter the branch of stellar evolution that would lead to a supernova, fortunately for us. However, there are planets that orbit stars that are destined to go...
