Brotoro

I don't make these kinds of measurements, so I don't know if the lines are saturated. I wouldn't expect them to be because the stuff is pretty thin in most directions. We get information about where the gas doing the absorbing is located by the doppler shift of the lines. If it's gas in another galaxy doing the absorbing, it would exhibit a redshift that matches that of the other galaxy. If it's an intergallactic gas cloud between us and a far away galaxy, the absorption lines due to the cloud exhibit a redshift of something less than that of the distant galaxy. In our own Galaxy, we can use the doppler shift of the 21cm radio emissions from neutral hydrogen clouds (the intensity of which depends on the amount of hydrogen) to map the locations of hydrogen clouds because of the slightly different doppler shifts that we expect to observe from different directions in our rotating Galaxy. A certain fraction of interstellar gas gets ionized by stellar UV (the amount of which is calculable from the known UV flux and the density of the ISM), and the electrons from those ions affect the travel speed of radio waves coming to us from pulsars, so that a pulsar pulse is received at slightly different times for different frequencies.

As I said, normal matter is detectable because of its emission and absorption of various wavelengths of electromagnetic radiation. We can measure how much gas and dust is in the interstellar medium in several ways, such as the strength of the absorption lines, the extinction and reddening of light from distant stars, the dispersion of pulsar pulses of different frequencies, etc. We know how much of that stuff there is from these observations. NFUN mentioned Massive Compact Halo Objects (things like sub-stellar mass objects loose in interstellar space and black holes) that we could not easily observe by their emissions, and which are also made of baryonic matter. But if there were a lot of these things, we would see a lot more gravitational lensing events as they pass between us and distant stars, but we don't...so we have a limit on that stuff as well. When all the things that could be seen were added up, the tally fell well short of the amount of mass needed to keep our Galaxy rotating the way we observe it to rotate.

"Dark“ means that we can't detect this matter by any kinds of electromagnetic emission or absorption (not just that it isn't visibly glowing). We can detect the amount of gas in interstellar space because of its emission (hydrogen, for example, radiates at 21cm radio wavelength...and gets ionized and glows visibly as "HII regions" when excited by UV from nearby hot stars) or absorption (interstellar gas can show up as absirption lines in starlight that passes through it). Whatever dark matter is, it does not radiate in ANY part of the EM spectrum.

I see shadows of an outstretched arm that has obviously be removed.

No. The astronomical observations available at the time Einstein formulated General Relativity indicated that the universe was not expanding. This was simply because the measurements were limited to our own Galaxy (which is not expanding). It wasn't until later on that Hubble got the distance and velocity measurements of external galaxies that showed that the universe is expanding. So Einstein was just trying to make sure his theory matched the then-known observational data.

Oh, I updated the save file, and it seems to work. Hellou and Emilynn are properly female now.

Dead? No. I'm just finding it difficult to get back into things. Version 1.0.4 introduced more changes to the aerodynamics than I expected it would. I thought it would be more of a tweak regarding reentry heating...but a lot of things changed that affected the new vehicles that I had built and tested in 1.0.3, such as the effectiveness of parachutes and air brakes and jet engine thrust. So it required more modifications to the ships than expected. And when I haven't been writing these episodes up for a while, I realize again how much time it takes to do all that...so it's hard to get motivated back into the swing of things.

There is no simple equation for this, but there are stellar models for all of those types of stars that could be looked up. I believe the Sun gets to 1 gram per cc at a little over 50% of its radius, and gets to 150 grams pet cubic centimeter at its center.

All these decades stuck in LEO, and I can't believe we haven't done the experiments to test how well humans tolerate centrifugal force 'gravity.'

One syllable. Same as 'lathe,' the shop machine used to turn wood.

Except that the universe was filled with an opaque gas prior to the Era of Recombination (about 378,000 years after the Big Bang)...so that photosphere, the source of the cosmic background radiation, is as far back as we can currently observe.

I wouldn't expect that you could have liquid droplets as rain at the extremely low gas pressures in what passes as an atmosphere on Pluto.

Ceres, Pallas, Juno, and Vesta were once classified as planets...so our solar system had 11 known planets in 1807 (and then 12 when Neptune was discovered). It was only the discovery of many more asteroids starting in the mid-1840s that got these four demoted to "minor planets" (asteroids) after half a century as planets. I'm sure there were people at the time who were upset about the demotions. But there aren't any of those people left. The same thing will happen with people upset about Pluto being demoted.

What are you talking about? Ida has a perfectly normal elliptical orbit around the Sun, just as Pluto does. - - - Updated - - - Nice plot. I especially like the usage of the technical term 'crap' there.

So all asteroids that have moons would be planets? Welcome to the list of planets, Ida.

Jupiter has a layer of clouds made of water (ice crystals higher up, water droplets lower down) where the temperature of the atmosphere crosses the freezing point of water. That's a substantial amount of liquid water. Jupiter also has organic compounds in its atmosphere...they help provide those interesting colors, and are the result of photochemistry. I wouldn't be surprised if there is life in the clouds...but I don't think I'd bet huge amounts of money on it.

Yumyum?

Good for him. Very clever idea, the crankshaft.

The video seems to indicate that the thrust of the engines comes from the plasma that results from the fusion pulse...but most laser-fusion rocket engine designs I've seen use the energy from the fusion pulses to heat and expell some reaction mass (such as hydrogen) to produce the thrust. I assume in an atmospheric engine, the energy from the fusion pulses would heat air to expel as a reaction mass. But the interesting part of the design is using the Uranium-238 dome to capture part of ths fast neutron flux from the fusion pulse to fission the Uranium and produce heat. Normally, the neutrons you get out of the D-T reaction in a fusion power plant are not only useless for propulsion, but they are are detrimental in that they can make the structure of your fusion reactor radioactive by neutron activation of its materials. But this design turns that problem into an energy source. Of course, most of the neutrons are spraying out the back of the engine (the directions where you aren't catching them in the Uranium blanket), so I wouldn't want to stand off in that direction. And your dome of Uranium is going to fill up with fission fragments over time, making it radioactively nasty like a spent reactor fuel rod. I assume they'd have to replace them often and reprocess them to remove the fission products. But I'm mainly skeptical of the method being able to capture and convert enough energy to power the lasers (which have poor efficiency).

Jinx? Science? Pick one.

What an odd essay question. Power plants don't corrupt countries.

I think you are incorrect (although I suppose it would depend on how you define "modern"). The Savannah River Nuclear Laboratory website claims that they make the high pressure deuterium-tritium gas systems for the W87 warhead

I would think that ALL modern thermonuclear bombs have some tritium in them because they use boosted primaries. The secondaries also contain hydrogen in the form of deuterium in the lithium deuteride. Yes, in theory a multi-stage device the size of an oil tanker should be possible.

I'm sad to hear that. The SAS pointing problem is really bad, and if I were Squad I'd fix such an embarrassment right away.

I don't know where you get that calculation from. The destructive radius of a nuclear explosion scales as the yield to the 2/3 power. A "Doomsday Bomb" would not be a deliverable weapon. It would be a multistage nuclear device of enormous yield that could, supposedly, spread enough radioactive fallout to kill all people on the surface of the planet. Because it isn't designed to be deliverable, it could be built any size needed. Just remember, Dimitiri: the whole point of the doomsday machine...is lost if you keep it a secret! No...The logic of the neutron bomb was to kill an attacking Soviet tank column while minimizing the collateral damage to the infrastructure of the friendly nation that's being invaded. Or, in the case of neutron bombs used as missile interceptors, the logic is to irradiate the fissile material of the incoming warhead, causing fissions that release energy to ruin the incoming warhead.