Posts by HDE 226868
Look at Earth's biomes! When it comes to life and everything that comes along with it, we only have one data point, our own planet. Climate modeling is . . . hard. Really hard. When we're talking ...
For waves that have small heights relative to the water depth ($H\ll a$), we can use Airy wave theory. This works well for waves that are far out at sea, and can include tsunamis, in deep water. I ...
The Moon can appear to be different colors, as seen from Earth: A red, orange, or yellow moon can appear when the moon is near the horizon, and light has to travel through more of the atmosphere,...
Optical depth Let's start by looking at the idea of optical depth. Optical depth is a quantity that describes how light is attenuated as it travels through a medium. There are two commonly used eq...
Coboglobin is one of the main iron- and copper- free proteins that can be used for oxygen transport. It was first synthesized by humans in 1970, where cobalt was intentionally substituted for iron ...
I actually figured this out shortly after beginning the story, and I'm going to therefore post a self-answer, because it might be useful to others. Obviously, I'm still open to more ideas if this o...
About 5 billion years from now, the Sun will begin to swell into a red giant. This will cause some problems, because life on a planet orbiting a red giant is hard. Even if Earth isn't engulfed by t...
Yes. You want a hornet-like platypus in the rainforest. Hear me out. Water conducts electricity substantially better than air, salt water in particular. Therefore, electroreception - the ability ...
First, I suppose I should define what a "theory of everything" actually is. I'd describe it as a mathematical model that predicts the behavior of any object under any given set of conditions. It sh...
Temperature and luminosity Let's start with some calculations. For the sake of argument, I'll assume that we're talking about a planet that's identical to Earth orbiting a star that's identical to...
Robots can do jobs humans can't. In fact, they can do a lot of jobs humans can't. They can Explore and clean up after a nuclear accident Go into a volcano to explore Travel the universe without w...
The redness of Mars' surface comes from the large quantities of iron in its crust. Other terrestrial planets in the Solar System also contain iron, but not at their surfaces. Mars in particular has...
Avoid helicopters and airships. Try the WC-130 or WP-3D. First, airships are not fantastic choices for maneuvering in high winds. Helicopters are bad enough, but airships are large and slow, meani...
Let's assume that the Moon is roughly a black body. Therefore, its luminosity can be approximated by the Stefan-Boltzmann law: $$L=4\pi\sigma R^2T^4$$ As you've said, $T=1100^\circ\text{ C}=1373\te...
Yes, and the planets can orbit in the habitable zones. This page gives a long list of planets in these S-type orbits, and states For a few systems (2 so far), there are planets orbiting each m...
The answer to your question, regrettably, is no, and the counterargument is a classic one. The pole is composed of atoms and molecules and particles; it isn't one giant indivisible object. Those ...
1. Orbit a high-mass planet In the Solar System, two moons are covered with ice and have subsurface oceans: Europa and Enceladus. Europa orbits Jupiter; Enceladus orbits Saturn. In the case of the...
Building from scratch weather.gov gives three cases where lightning can suddenly become more intense or common in an area: "High instability" release: In this case, there is a large negative ver...
Probably not. After some more consideration, I'm less confident that the proposal could work. There are two reasons: No guarantee of focusing at any one point, and an inability to control the para...
Interesting question. I'm reasonably certain that the answer boils down to a property of matter called the equation of state. An equation of state is a relation between several thermodynamic varia...
I'm reasonably sure that the $5\text{ G}$ there refers to $5$ Gauss. The Gauss is a unit of magnetic flux (named, of course, after Carl Friedrich Gauss). The $5\text{ G}$ figure makes sense, too; i...
Yes, it's been tried. Hashizume et al. attempted to use semiconductors (variants of which are also used in normal solar cells) which were subjected to gamma radiation from a radioactive isotope of...
As you've stated, the paper you cited gives the rate of atmospheric mass loss as approximately $\dot{M}=10^9\text{-}10^{11}\text{ g/s}=10^{6}\text{-}10^8\text{ kg/s}$ of hydrogen. We can convert th...
You want a cold disk. Mercury is an example of a volatile, which, for our purposes, means that it exists as a solid only at very low temperatures. One thesis (Funk (2015)) classifies it as "modera...
Short answer You have the two equations you need on the linked page under the heading "Stage two": $$r_i=\sqrt{\frac{L_{\text{star}}}{1.1}},\quad r_o=\sqrt{\frac{L_{\text{star}}}{0.53}}$$ where $r...
