sevenperforce

Science fiction gloss: Short-term visitors to Mars acclimated quickly to "Tourist 50-50", the mixture of 50% nitrogen and 50% oxygen at just under half of Earth's atmospheric pressure. For most, it was no different than relocating from a city near sea level to a higher altitude like Denver or La Paz. The lower pressure helped make EVA operations less challenging and also conserved the precious resources of bottled nitrogen carried by Starship from Earth. Colonists who were willing to live at 0.1 Earth atmospheres (or 16 Martian atmospheres) were the "lifers", those who had chosen to spend the rest of their days on the Red Planet. At these pressures, the heart and lungs would last for much longer than those of their tourist counterparts, and they could walk freely across the Martian sands with nothing more than warm clothing and a well-fitted breathing helmet. They aged much more slowly, although a slow death from cancer at 150 or 170 years due to elevated radiation levels was inevitable. But the change to their organs was permanent; they could not transition back to 50-50. If they spent more than a few hours at higher pressures, the atrophy in their organs would lead to rapid hypoxia and death.

First, aren't they in orbit around Earth and just "running up the curved wall?" the whole time? Which I guess would mean your continuously running up a very steep hill that curves toward you. Lot easier than a flag surface, or "downhill" (!!!) Yes, this was my thought. They're in microgravity; they're just using the curvature of the wall to keep themselves moving. Very different from running across the lunar surface. Hmm, yes, I must have dropped an order of magnitude. The lowest oxygen concentration that can sustain human life is 35.1% of the sea level oxygen concentration, and sea level air is 21% oxygen, so the lowest pressure that would be indefinitely survivable with a pure oxygen atmosphere would be 0.073 atm. Quite low, but still over ten times the atmospheric pressure on Mars. That being said, I'm not entirely sure that's a problem. As long as you have warm clothes and a firmly-fitted mask, a difference of 0.067 psi between the inside of your body and the outside isn't going to hurt you. Humans take airplane flights every day where the external pressure drops 0.25 atm over ten minutes and it doesn't hurt them. It's gauge pressure that's the problem, and I don't think that wearing a mask pressurized at 1.067 atm would hurt me. In fact, given that heat transfer in an 0.006 atm environment would be extremely low, I suspect you could even get away with exposed skin, at least for a minute. Only if you're stupid enough to take your mask off. The Armstrong limit only applies to exposed liquids. Skin is quite tough and can hold in pressure very well. If it couldn't then we'd all simultaneously explode; after all, our blood pressure is 16% higher than atmospheric pressure. In a near-future world where people are actually living out their entire lives on Mars, I suspect you would rapidly end up with colonies that used different air pressures. Would make for an interesting science fiction setting.

Interestingly, people can (over time) acclimate to lower oxygen concentrations. And a pure oxygen environment lowers the pressure without lowering the oxygen concentration. In theory, someone who was acclimated to life in the Andes mountains could survive in a pure-oxygen environment with the same atmospheric pressure as Mars. Thus all they would need to go outside would be warm clothing and an oxygen mask. Hybrid suits are definitely the way to go. But I'm still holding out for an Iron Man suit.

The data absolutely do suggest, at this point, that omicron is less deadly than the alpha, beta, or delta variants. But it is still much more deadly than the flu. Excess deaths in South Africa are lower than they were with previous waves, but they are not just "a few" by any means. Of course the flu was never "a few" either. People would always conflate actual influenza with "a stomach flu" or "the 24 hour flu" or random sinus infections. The actual flu kills an average of 36,000 Americans a year...more than three times the annual death toll of drunk driving in this country. It is possible that people who have recovered from omicron and subsequently receive annual boosters are more or less immune. That would be nice. But we don't have the data to support that yet. Dr. Spencer makes a good point. In terms of observation, most people who have been fully vaccinated and recently boosted have minor symptoms. Or if they have only been fully vaccinated but not recently boosted, they're a lot more miserable but they don't need hospitalization. It's the people who are unvaccinated or are trusting "natural" immunity who end up on oxygen. But also I can say from personal experience, having both had the flu subsequent to a flu shot and currently having omicron subsequent to a booster, that you do not f*&#ing want to have omicron if you can possibly avoid it. It really sucks. I just have a strong knee-jerk reaction to anyone who is like "oh well, we'll all get it eventually." I mean, maybe? But I'm telling you, you don't want it. Even if you're fully vaxxed and boosted.

That would be a better outcome than what the data shows right now, yes.

Unless Kryptonians are substantially denser than humans, yes. I don't believe they are. Superman is supposed to be about 225 lbs. So it would be much easier for Kryptonians to stop on a dime on Krypton than it would on Earth. Of course, that means that if Kryptonians ever came to Earth, it would take them a long time to acclimate because they'd be slipping and sliding and falling over every time they tried to move faster than a snail's pace. As for air and sea, friction in a fluid is independent of gravity, and so inertia would be unchanged. Buoyancy might be a little different, though, but I can't remember. It might be the same. Powered flight based on aerodynamic lift would be impossible. You'd need legit antigrav (or zeppelins) for any sort of aerial vehicle.

For the Starlink launches, they are jettisoning the fairings almost immediately after SES-1. I wonder if they could jettison the fairing prior to stage separation but simply don't need the extra margin.

Supersonic.

LOX load complete. Weird that water is spewing out of the top of that water tower. Those darkened, worn fairings have a very ancient-future feel.

I imagine the challenge is changing direction at speed. You need friction to change direction. Low gravity means low normal force, and since friction is proportional to the normal force, you have much less of an ability to change direction.

Yep. Now, many vaccinations prevent "catastrophically bad disease" by preventing infection/transmission in the first place. When Pfizer and Moderna first created the mRNA vaccines, they didn't know whether the vaccines would actually prevent infection/transmission or if they would merely reduce symptom severity and duration. That's why there was a lot of uncertainty at the beginning about who should get the vaccine first. If the vaccines prevented infection/transmission, then young healthy people who were most likely to be super-spreaders should have gotten it first. If the vaccines only prevented severe illness, then the most vulnerable should have gotten it first. With past variants, the vaccines did both: they significantly reduced the risk of infection and they also significantly reduced the severity and duration of symptoms. With omicron, it appears that the vaccines only moderately reduce the risk of infection, but they still reduce the severity and duration of symptoms. Keep in mind that by shortening the duration of symptoms, you also reduce the risk of transmission, because even if vaccinated people with breakthrough infections have the same peak viral load, that peak doesn't last nearly as long and so they don't have as much of a chance to infect other people. There are some vaccines which don't actually attempt to prevent infection at all. The tetanus vaccine (and the booster that you need every 10 years) doesn't produce antibodies against Clostridium tetani, the bacteria that causes tetanus; it only produces antibodies against the toxin that C. tetani creates. So if you step on a rusty nail, C. tetani will still infect you just the same, but your body will quickly destroy the toxin that makes it harmful, and then your general immune system will eventually get rid of the bacteria. The same is true for diphtheria; the vaccine creates antibodies to the toxin created by Corynebacterium diphtheriae, not to the bacteria itself. Well, I hope that works. The problem is that SARS-CoV-2 mutates very rapidly, and people who are previously infected with one variant have little to no protection against the next. And so even if Omicron sweeps through the population rapidly and everyone ends up with hybrid immunity to Omicron (like I now have), we could still see another variant emerge that escapes that immunity and puts us back to where we were when Omicron emerged.

World War II carriers all used catapults. Most were hydraulic but some used gunpowder charges or even solid-fueled rockets.

Unrelated to extraterrestrial life, I would like to note that all of those people who were saying "omicron is more contagious but less severe" were full of it. This sucks. I mean, I'm not in the hospital -- but then again I was double vaxxed and boosted, so maybe that's why. It really, really sucks.

That is certainly one possibility - in fact a quite likely possibility. When you look more closely at DNA, it seems even more unlikely that independent abiogenesis would produce a polymeric nucleotide acid that was even remotely comparable to DNA. After all, DNA doesn't code for proteins directly; the four DNA bases code in triplets called codons for the 20 amino acids which make up life. Those 20 are a tiny subset of the 500+ amino acids which exist. Now, 43 = 64, so many amino acids have two or even three codons which will produce them. But even so, this means that for an independently-evolved virus to have any compatibility with terrestrial life (such that our ribosomes could translate their alien viral code and produce their alien proteins), that independently-evolved life would need to: Use most of the same 20 amino acids as life on Earth, rather than the 480+ other options. Otherwise it would be like trying to assemble a Lego spaceship out of Lincoln Logs. Use a double-helix rather than a single-helix or triple-helix nucleotide polymer. Otherwise it would be like trying to play a cassette tape with a record player. Use phosphate as the nucleotide polymer backbone, rather than the many other possible backbones like aminoethylglycine. Otherwise it would be like trying to play an audio cassette tape in a VHS player. Use the same four nucleobases as life on Earth, rather than the hundreds of other possible nucleobases. Otherwise it would be like trying to create words in English using Hebrew letters. Have the same codon correspondence between most those nucleobases and most of the amino acids. Otherwise it would be like trying to write Spanish words if you only knew English.

I would say that polymeric nucleotide acids like RNA and DNA are fairly simple, and I do think that given the right conditions their emergence is almost inevitable, but I think that it is very very unlikely that an independent abiogenesis event would produce a polymeric nucleotide acid that has any substantial correspondence to RNA or DNA. Sort of how the evolution of a phoneme-based written language is almost inevitable, but independently-evolved alphabets aren't going to look even remotely similar. It's one of the reasons that anyone who knew anything about computers tore their optical nerves rolling their eyes at the alien computer virus in Independence Day. In other news, I had symptoms last night and my rapid test came back negative; my symptoms were worse this morning and I tested again and the rapid test came back positive. And I am double-vaxxed, recently boosted, and probably previously-infected before my first vaccine. Just goes to show how strong omicron's immune escape is.

Yep. A lot of people will make the argument "well prove it wasn't created in a lab" and that is very silly because you cannot prove a negative. However, you can still make a very good argument that if it had been created in a lab, then one of the many, many smart people examining it would have found traces, and since they haven't, it almost certainly wasn't. This part I completely disagree with. Even if an alien virus is capable of reproducing in terrestrial hosts, it's not adapted to them. There is such a multitude of viruses on this planet that while certain organisms have specific defenses against specific types of viruses, if we had no generic defenses that have to be bypassed with very specific attacks, all cellular life would be doomed. Human immune system specifically is exctremely good at detecting pathogens it cannot possibly be familiar with. Response to these isn't as rapid or reliable as against known pathogens, but it is still very, very good. And it's only because terrestrial viruses are specifically evolved to combat immune system of the host that they ever get by. An alien virus wouldn't have that advantage and would, in all likelihood, be easily picked up by our immune systems. Well, honestly I misspoke -- I said virus but I was thinking of pathogens generally. I also was thinking of a non-DNA/RNA-based pathogen, simply because I don't find panspermia to be particularly likely. I find it more probable that abiogenesis occurs independently across the universe. I don't think an alien virus would have any chance of reproducing using its ordinary infection route in terrestrial hosts, because I am assuming the code would be incompatible. What I was picturing was more like a grey goo scenario with an alien fungus or bacteria. You can imagine a type of extraterrestrial microbe for which any terrestrial cellular life is a rich source of nutrients, simply because of some unique chemical interaction. Life on earth typically uses proteins like keratin, chitin, or cellulose as its primary barrier, in part because DNA-based life does not readily and rapidly break those down. But if the alien ecosystem where this pathogen originated was not DNA-based, those proteins very well might look less like a barrier and more like a tasty snack. This will be great if it works, but it is not a wonder-drug. It is simply a more complex vaccine which includes multiple spike proteins on the same substrate. They added the omicron spike protein to this one, but when there is a future variant with a significant departure from omicron, they will have to go back and add its spike protein too. Also, this would not elicit any different type of immunity than what existing mRNA vaccines (or convalescent immunity) already provides. It wouldn't necessarily be longer-lasting or more robust immunity. You would still need two shots plus at least one booster; it is not one-and-done. With some viruses, our immune system needs only one exposure and it will be immune forever (measles, mumps, smallpox), whereas with some the immunity lasts for a few decades (varicella, tetanus, diptheria) and with others only a few months or years at most (influenza, rhinoviruses, coronaviruses). And there are some viruses for which you never develop any immunity, like norovirus. And for each of those, immunity is not a constant or an on-off switch, but is a deterrent to infection that wanes slowly over time. Even with something like measles, vaccination or prior exposure doesn't magically make all your cells completely impervious to the virus. If you are re-exposed, the virus will still be able to penetrate the cell walls of the macrophages and dendritic cells it targets through the CD150 receptor. However, your antibody count is high enough that you will fight off that infection before it becomes significant, and your viral load will never grow high enough to spread it to someone else. We don't know exactly why some diseases produce longer-lasting immunity than others. Part of it is the mutation rate; a virus that mutates quickly will be less susceptible to antibodies. Another part is severity; more serious diseases typically produce a stronger immune response and thus you have more antibodies. But that is not always the case. Norovirus can be quite serious but you never get immune; Hepatitis A is often very mild and doesn't produce much of an immune response but once you've had it you can't get it again, even if it was a mild infection. Polio is a weird one. Most cases are asymptomatic, and you don't have any significant immune response, and you don't develop immunity. But in the very small percentage of cases that are symptomatic, it can be very serious, crippling, or life-threatening...but at least those people end up immune. And so children need 3-4 polio shots over a period of years in order to convince the body that it is serious enough to build up that lifelong immunity. Fortunately, polio has a low mutation rate. SARS-CoV-2 just happens to have a nasty mix of a high mutation rate, a large number of asymptomatic or mild infections, and a dangerously high morbidity rate among those who do have serious illness. Plus, it's a coronavirus, which the immune system tends not to worry about because so many of them are harmless. The people who have mild infections don't develop many antibodies at all, and the antibodies that are produced (even from serious infections) wane more quickly than most. This is incorrect. Vaccines are not particularly expensive, and drug companies do not make a lot of money off of them. Drug companies make money off of licensing new drugs they develop; the more they innovate and develop new drugs, the higher their stock value becomes. If a drug company figured out a way to make a one-and-done COVID vaccine that never needed a booster, their stock would soar through the roof and their stockholders would be very happy, and they would be able to hire even more scientists to work on even bigger problems. Yep, that was the point I was trying (and failing) to make above. For independently-evolved life, either it won't be able to infect at all, or will be through something like a bacterial or fungal path.

Yes, we originally believed that there must be a super-earth outside the orbit of Neptune due to wobbles in the orbits of Neptune and Uranus. So we were looking for a super-earth out there when we found Pluto in 1930, and assumed it must be the super-earth causing Neptune and Uranus to wobble. We didn't figure out we were wrong until 1976, when we calculated the albedo of Pluto and realized its surface was covered in super-reflective methane ice, meaning it had to be much smaller than it looked. But we soon realized that our initial estimates of Neptune's mass had been off; once the mass of Neptune was corrected, the wobbles finally matched the interactions expected between Uranus and Neptune, and so we realized there never had been a planet in the spot where we were looking. Even if we did find a dwarf planet there by mistake.

Bingo. It literally only took a single weekend -- three days -- for the Moderna vaccine to be synthesized, because they already had so much experience creating mRNA vaccines for SARS/MERS. We never needed those vaccines because neither SARS nor MERS were particularly contagious, but it gave us practice with coronaviruses. And so it was very nearly plug-and-play with the SARS-CoV-2 vaccines. An extraterrestrial alien virus would either wipe out literally all DNA-based life in a matter of weeks or it would never infect a single host. There would be no middle ground.

Nitrous is good for hobbyists because it is self-pressurizing but it has a poor mass fraction for the same reason.

Understand that by "accursed" I meant "some sort of magical wizardry maximal-gravity-assist voodoo that I could never hope to achieve."

To be honest, I am exactly as concerned about contamination of investigation of past life as I am about contamination of existing life. Manifest destiny and all.

I just wrapped this up in a...smol...vehicle. 37.6 tonnes is more than that accursed Moho SSTO above, but I told myself I was going to do this WITHOUT gravity assists, so... Dropping my landing gear because, contrary to expectations, this is NOT an SSTO. Can your SSTO do this? I mean, I suppose it could, but it would not be by design. TWR on the way in was.....really, really bad. At least Jeb had a landspeeder to play with. The return vehicle was spartan. Very spartan. Also, toasty. 1/10, do not recommend. Welll......some parts of the vehicle made it back! Anyway I got all possible points, other than the Mohole exploration. Gotta leave that to someone else.

That's really disappointing. And also not unexpected. I'm sure SpaceX will do a sample return before they send people. Unsure whether they will do it via Starship+ISRU or something else. Starship could deploy a MAV via crane readily enough.

You have proposed a battery with theoretically infinite specific energy but a thermally-limited charge/discharge rate. From a semi-turgid science fiction perspective, this is actually a pretty reasonable idea. It would not be hard to conceive some sort of futuristic organometallic nanocapacitor bank which could hold effectively limitless amounts of energy. The fact that it has a limited charge/discharge rate keeps it from being as physics-breaking as most of your ideas. What type of discharge rate are you thinking of? These things are typically measured in specific power, i.e., the amount of power that the battery is able to receive or produce per unit mass. This is also referred to as "power to weight ratio." You would want to get units of W/kg (that is, watts per kilogram). Some examples of specific power, for reference: Household rechargeable nickel-cadmium battery: 200 W/kg Tesla PowerWall battery: 43.9 W/kg ISS Solar Array Wing (each of the solar panels on the ISS): 28.5 W/kg TOPAZ nuclear reactor (used on Russian spacecraft): 15.6 W/kg MMRTG (the radiothermal generator on Perseverance): 2.4 W/kg So if you want your ordinary discharge rate to be reasonable, you would want it to be higher than the power-to-weight ratio of a solar panel, but probably lower than the power-to-weight ratio of a household battery. Antimatter is normal mass. Antimatter does not have negative weight or negative inertia. However, I doubt you'd need to worry about this. If you converted all the chemical energy in the entire first stage of the Saturn V into electricity, and you stored that electricity in batteries, the total mass of all those batteries would increase by only around 0.14 grams. No need for liquid hydrogen. You'd just use water as your coolant. The energy required to convert water into liquid hydrogen is pointless when you can just use more water. On the flip side, if you need coolant for increased use -- well, now you've got a handy-dandy propellant source. The actual challenge here is going to be the thrust-to-weight ratio of your reactionless drive. You'd need a reactionless drive which can actually get itself off the ground.

I wish I remembered enough from my undergraduate optics class to calculate the size of the largest possible telescope that could fit inside a custom Starship. Hubble's primary mirror is 2.4 meters with a gross area of 4.52 m2. Webb's primary mirror is 6.5 meters with a gross area of 26.8 m2. A 9-meter telescope would have a gross area of 63.6 m2, more than double that of JWST, but if you tilted it sideways inside the Starship payload bay it could be oval-shaped and thus even larger. This would result in some aberration but nothing that couldn't be corrected.