swansont

In 1D, it should be easy to see that there are discrete wavelengths, since you will get destructive interference if the path length is not a multiple of the half-wavelength. So other wavelengths will not persist. If you consider 3D, there are more paths available and you have more options that avoid destructive interference, but you will still have wavelengths that are excluded from possibility.

! Moderator Note Please establish the truthfulness of your premise(s) before proceeding with arguments that assume they are true

https://www.nasa.gov/feature/goddard/2017/how-hardy-is-webb-a-qa-about-the-toughness-of-nasa-s-webb-telescope We know Webb will get struck by micrometeoroids during its lifetime, and we have taken that into account in its design and construction. We sized Webb’s main mirror so that even after years of little impacts it will still have the reflective surface area and quality necessary to do the science. We even did tests on the ground that emulated micrometeoroid impacts to demonstrate what will happen to the mirrors in space. Similarly, part of the reason the sunshield has five layers is so it can tolerate more than the number of expected small holes, and even some tears, and still work as it should. Also, almost all of Webb’s sensitive components (besides the mirrors and sunshield) are protected behind “micrometeoroid armor.” When micrometeoroids do strike, most are so small that they totally disintegrate upon impact, even when they hit something thin like thermal blankets or a sunshield membrane. Critical wires and electronics are shielded behind even more robust metal “armor” or inside metal boxes

What if it’s just lorem ipsum?

! Moderator Note You need to share what you’ve done to answer this. Moved to HW help

One trick I’ve heard about is to put a clear container filled with water, then frozen, and a coin placed in top. If the ice melts and refreezes (e.g. while you are away and you have a power outage) the coin will drop to the bottom. But if it’s still on top or only part way down, you know the ice didn’t fully melt. Filling up space with ice in the freezer is a good strategy because it has a higher heat capacity than air, so things will stay colder, longer.

! Moderator Note It’s not really an issue of common sense, or being dumb/smart, it’s one of knowledge vs ignorance. There was a point in time where you didn’t know the extent of the Mongolian empire, or when Marco Polo visited the east. You learned these things, and became better informed. You did not transition from being dumb to smart when this happened. So: 1. Don’t call people dumb 2. Proper referencing would include a link to a wikipedia article, rather than just mentioning that the information is available there 3. This is a discussion board, not your blog.

! Moderator Note The energy released in a chemical vs nuclear reaction has nothing to do with logic, and the ONLY reason you weren’t immediately banned for yet another sockpuppet account was that you actually asked a science question instead of your usual nonsense, but here we are.

They get halfway into the article, and all the way through the section on the US, before mentioning vaccination rates. And it ignores booster rates entirely. "Just over 63% of the US population is fully vaccinated, much lower than in the UK (71%) as well as Italy and France (both 75%). In Canada, almost 79% of the population is fully protected." The US lags these other countries in booster rates, too. https://ourworldindata.org/grapher/covid-vaccine-booster-doses-per-capita?country=CHL~RUS~USA~URY~OWID_WRL~GBR~FRA~CAN~ITA We already know that vaccination, and boosting, lowers the chance of hospitalization. But yeah, this is is puzzle. </s>

One thing that gives me pause is the phrasing "acquire mass" If you have a charge, the field is already there. Nothing is "acquired" If you are creating a field by rearranging a charge configuration that has no field into one that does, you are doing work. In that sense mass is "acquired" because you are adding energy, and thus mass, which is stored in that new configuration.

The youngest astronaut in this year's class is 32 https://en.wikipedia.org/wiki/NASA_Astronaut_Corps Astronaut candidates have ranged between the ages of 26 and 46, with the average age being 34. So your observation becomes "we don't have any younger than average astronaut candidates" and it's all much ado about nothing. The reason is that people need time to gain the requisite experience and education, and you're focusing on people who haven't had time to do that yet, and conjuring up a conspiracy.

You also want the gradient to be acceptable as you move toward the rim, or you'd end up with a situation where you had 1g at your feet but significantly less at your head. (consider a 2m radius, for example)

Why would storage space be limitless on a space station?

I'm not sure what you mean here. Uranium density is not lower, or smaller. Logic sequence? That has nothing to do with the energy released in a reaction. Also, I didn't hide any article.

Chemical reaction are in general much lower in energy than nuclear (eV vs MeV scales, i.e. a factor of a million). I know of no batteries, or any electrochemical reactions, that convert grams of mass into energy. As you point out, 1 kg is almost 10^17 Joules, or 25 billion kWh. So a gram is 25 million kWh. A battery might give you a couple of amp-hours at 1.25V, or something of that order of magnitude, which is just a few Watt-hours of energy. That would be around a billionth of a gram. Uranium (U-235 in particular) is used because it readily undergoes fission and can be controlled under the right circumstances. It gives you this energy at the nuclear, rather than chemical, scale.

What is ideological about this?

The GAIA mission encountered more micrometeoroids than expected. “the spacecraft is being peppered by far more micrometeoroids – tiny specks of space dust – than had been anticipated” https://www.newscientist.com/article/dn25925-galaxy-mappers-first-discovery-surprise-space-debris/

! Moderator Note Let’s stick with the topic, which is Mars and the problem that low gravity presents

! Moderator Note did lordofscience read the rules they agreed to upon joining? (specifically 2.7, which says not to make posts advertising your website)

No. The geometry is curved; gravity exists even with no body to experience it.

That would work, if you could do it. But there's no way of "collapsing" the water, since it's already a liquid. My point was that if you were lugging around extra mass, then you will always be lugging around extra mass, regardless of its density.

There is the additional caveat of going directly downwind. A sail won't do this.

Mass-wise this is a non-starter. It's basically conserved at this scale. The density issue is another thing. You want the opposite of a submarine filling the ballast tanks from the compressed air tank. The problem is that you are starting with a positive buoyancy, so you will always need that extra mass, regardless of the density, unless you can figure out a way for the human body itself to become more dense.

I think the first reaction is thinking the propeller is driven by the wind, and powers the wheels. Such a device would not go to faster than the wind, because the thrust would drop to zero when the vehicle speed and wind speed are equal. I think that's the initial reaction of the people saying it's impossible. These are losses and would initially be ignored. The first-order questions are what is the energy of the cart, and what is the energy extracted from the wind? At the point where you are going downwind at the speed of the wind, the speeds are equal. So the mass of the air involved must exceed the mass of the vehicle, which suggest you need a big propeller, since you want to maximize that mass difference. A big propeller means the "column" of air has a large volume.

Do you worry about this when eating food with your hands? Assuming that you wash your hands with soap, that it. The rinsing effort is similar, as is the risk of ingesting soap.