I was reading about the production of calcium carbide, and that it involves mixing lime and coal in an arc furnace. Is there something unique about arc furnace heating that, say, an induction furnace could not provide?

What are the consequences of not severing it? I imagine you'd have the weirdest bellybutton on earth if nothing else.

Cheers!

Assuming we are talking about an era when Sol has a thriving space industry and the Solar system is broadly colonized. Current materials science supports structures up to 8 kilometers in diameter, and if large scale graphene production is possible, up to 100km in diameter, at least according to Isaac Arthor.

I am wondering what resources would be difficult for a colony ship to reproduce in-situ on an one way trip to the first interstellar expansions of humanity. I picture a true generation ship might be primarily designed around the transport of some of the largest prefabricated sections of a future centrifugal spin gravity habitat.

1. Using hard science to speculate, what types of materials and components would only be available with the massive industry present in humanity's original home?

I picture the main outer ring frame structure of an O'Neil cylinder, like some kind of curved beam, would be prefabricated and sent in a few pieces for later assembly. If the O'Neil cylinder was to be 8km in diameter, 3 pieces would make the generation ship at least 5.7km long.

2. What is practical to transport assuming fusion is in the cards, as are self replicating drones for resource extraction in a region like the astroid belt, and assuming planets are resource poor gravity prisons we avoid in favor of mobility?

3. How might carbon get utilized for large structure fabrication in space as far as processes?

4. What about metals and space based fabrication. How can you picture the production happening in ways that would only be possible in a highly advanced space based economy?

I know this is highly speculative and I hope the mods will let it fly to ask this. I know most nerds are curious about this kind of thing. I'm only interested in the most conservatively realistic of hard science fiction/futurism.

This is something I always wondered because some people have a bunch of theories about whether your head should face north or south or whatever, because of the earth magnetic field. Is there any science in this or just "superstition"?

Also, would it be better to have the head towards a window or away from a window, even if closed (e.g. in winter)?

I'm basically asking whether there exist "recommendations" on how to structure a bedroom backed by science.

I feel like we are ways out from seeing anything like it. From what I've seen non-Newtonian fluids typically take a decent amount of energy to stop something and sound wouldn't have much energy compared to something like a bullet.

On a sidenote does Decibullz own a patent on percussive hearing protection or am I looking up the wrong term? I feel like there must be other hearing protection out there that is effective against sudden loud sounds.

After reading the abstract of the paper mentioned here I started wondering, why did human groups migrate away from southerner (warmer) places towards the north which is far colder and has less possibilities to grow crops and wild animals to hunt?

Was the population density too high?

And after they migrated, what did they mostly survive on? Were they hunters-gatherers? Did they cultivate? Was it not more difficult to survive in colder climates?

People talk of potential human flight on planets. Somewhere in the recesses of my mind I still wear my inner 5 year old's caped Superman pajamas, stressing over how many stairs one must jump from to take flight. So is it possible to flappy bird a flying monkey?

I don't care about the math and statistics. I went looking for visual comparisons, where image exposure is adjusted to show how a sunny day on both planets really compares, but I didn't find anything.

During the last partial solar eclipse in SoCal, I thought, "I wonder how close this really is to how Mars feels." It was eerie (as always) with a clear sky, and sun near noon, but feeling colder than I should (obviously Mars is FAR colder), and with dimmer light.

Our eyes have an enormous dynamic range. That is not exactly intuitive to most people. Still, I was hoping to find some way or reference that captures the experience of the sun on Mars, and really the emotional impact of what it means to stand on Mars at solar noon with human eyes.

Our pictures of Mars are all adjusted for optimal exposure, but that makes it intuitively seem very Earth like when in reality it is like a next level Neo Exo-Antarctic, even under the warmest of days under direct sunlight. What is that really like?

I'm trying to wrap my head around something that appears far more complex than I first thought. I don't understand the explosive elements and chemistry that drives ash production and the heat to create the eruption column. I'm aware of how molten metal behaves in a foundry crucible with flux and degassing required. So I understand how magmas can have a tremendous amount of dissolved elements that can release like CO2 from a shaken soda bottle being opened. I can picture this kind of pyroclastic flow easily; the "shaken soda bottle" type.

I don't have a very good grasp of how the ash column can reach enormous heights and then collapse, or how composition impacts this kind of collapse. I just can't picture in my mind how this type of collapse results in a flow, like some kind of avalanche or pronounced river of material as opposed to more of a micro-regional rain like ash fall event that is very intense and superheated. What is the trigger and how does it overcome any hotter material lower in the column?

https://en.m.wikipedia.org/wiki/Pyroclastic_flow

I bought a torch that has a 365nm UV light, which I believe is UV-A?

When doing a poke around my house to see what I could see with UV, I noticed that my freshwater fish tanks looked "cloudy" / "milky" under UV, yet they are crystal clear under normal light.

I checked tap water and bottled water with the same torch and they do not react and look perfectly clear under both UV and normal light

I also have an auto top off for one of the tanks which is full of ~50L of a mix of RO water and tap water treated with dechlorinator and this also does not react.

I have 3 tanks inside of various volumes (700L, 150L, 20L) and various stocking levels which all show the water as a pale flourescent green colour under UV. The colour is uniform and completely spread out through the water volume, not concentrated on any area or in layers or whatever.

The currently empty 20L tank reacted the least, leading me to believe that it may be some sort of organic material that is causing the UV light to react so much?

I know that sound doesn’t travel in a vacuum, you can hear it muddled in water, and different temperatures of air transmit better. But which is the “best”. Let’s say you had a speaker and a microphone in an enclosed case filled with whatever you wanted, which would be the best medium to ensure the best sound transmission?

Asking this because I've been thinking about resin printing and how a small layer of said liquid could, in theory, be used to make the prints faster and negate any problems regarding the FEP film (which can wrinkle, tear and be a hassle to clean when small pieces are stuck to it). The ideal liquid would have to be:

• Inert to UV light
• Not miscible with the resin
• Denser than 1.25g/cm³

Maybe the liquid doesn't even need to have a small refraction, so long as the light doesn't diffuse too much after going through ~1mm of it. That or doing some compensation on the print.

I came across David Sinclair and his research into reverse aging. Especially, I came across this video by Veritasium with Sinclair. Apparently his team has managed to reverse aging in mice in a lab? Has this been peer reviewed?

I personally want to believe Sinclair, but he just.... seems snake oil salesman-ey for some reason. For one, the channels that he seems to come on are the same channels that host manosphere/pseudoscience/conspiracy related guests. Secondly, he talks a lot of shit about his fellow scientists and just seems a little egoistic? I dunno...

Also, the recommendations that he seems to give (like reducing protein intake) to slow aging just seem to be against conventional wisdom? Also, for the drugs that he recommends taking, wouldn't the FDA approve them if they actually worked? I dunno. This isn't how a man of science behaves, right?

Anyway, aside from Sinclair, how far have we gotten in the reverse aging/stopping aging or whatever science? Should we hope to get drugs/treatment to cure this in the next 10/30/50 years?

I under stand that the lower the air pressure, the lower the boiling point of water. Also, some primitive desalination kits are basically evaporators.

Could you make a really big tank without a bottom and paint it black. Then, submerge it partly in the ocean . Pump the air out of the top. The water would rise up into the tank, a bit, but not all the way.

You wouldn’t need to have a perfect vacuum, just lower the air pressure enough to make boiling easier. Let the sun heat the black tank, and viola, steam.

Collect that steam from the air you are pumping out of the top of your tank, and you’ve got fresh water, right?

Edit: nevermind. Found it on google. Leaving this here to display my shame.

I discovered the "Tromatz" bioelectric wave toothbrush, and it sounds too good to be true, which usually means... it is. However, they do link to some journal articles, so it seems it's somewhat based on fact. There's very, very little else out there aside from their own website that I can find. Thoughts from anyone familiar with the field? Is this the next evolution of oral care?

More at their website.

So, I’ve been reading about the MIT bio suit. It’s basically a pressurized helmet and gloves, and a fancy fabric suit with bands that squeeze you with enough pressure so decompression doesn’t kill you.

However, since the body is not pressurized, would there be an immediate and constant flow out of your private bits the moment you stepped outside the space ship?

This is an abrasive disk, rotating at 1500 rpm. When I shine my flashlight at it, it carries the glow with it, approximately halfway around the disk. What am I seeing happen here?

Can it freeze water?

I tried finding some research and found lots about freezing matter or putting it under extreme pressure, but not trying both.

My thought experiment involved taking a small portion of ideal of matter (not sure what), artificially applying extreme pressure to it and than attempt to lower its temperature and if possible, apply even more pressure before trying to lower its temperature - taking it as low as possible under the highest pressure you could.

I assumed there's likely to be a conflict between pressure - thus increasing vibration/wave properties of the material - and how it would be possible to reduce those energetic wave properties.

Thanks for any insight.

I thought that the frequency of light was directly inverse to the wavelength by a constant. In other words, I assumed that graphing the frequency of light as a function of wavelength would be a straight inverse line. Because of that, the graphs for the distribution of light from the sun as functions of frequency and wavelength would be exactly the same, but reversed. Yet, this is not what is reported in the linked article. Even more confusing to me is that the different functions peak at different light. When as a function of frequency, the light peaks at infrared. When as a function of wavelength, the light peaks at violet.

What am I misunderstanding? Is the frequency of light not directly proportional to it's wavelength? Or is this something to do with the way we are measuring the light from the Sun?

Found this very useful Youtube video about How do Magnets & Magnetic Fields Work? and within it I finally found someone willing to explain greater details about how same poles repel in laymen terms. The link above takes you to the section where the Presenter explains how (as I understand him) potential energy forms between the same poles and that energy ultimately causes the repulsion. I like his thermodynamic(?) description and haven't ever come across a better laymen explanation. That said, I was hoping to get some opinions about them. I've also read about the exchange of virtual photons but even that wasn't intuitively explained.

Thank you for any additional insight.