CaptainPanic

Judging by our own atmosphere, yes, there should be a little scattering. I would be surprised if there isn't any. But absorption of certain wavelengths can be quite severe too. Here's a picture (wikipedia) about the difference in the intensity of the sun at the top of the atmosphere and at sea level. I read (in the link in the 1st post) that the gas is probably mostly hydrogen and oxygen, but that they're not entirely sure. Those will be plasmas, I am assuming: single atoms and possibly free electrons. I don't know what those absorb. I am just wondering if it is relevant for our measurements. Enthalpy, I don't understand your post. I am wondering whether there might be a chance that we got the luminosity of distant galaxies wrong, due to a halo. The Hertzsprung-Russell diagram deals with individual stars, not whole galaxies. If we use that diagram to conclude how far other galaxies are from us, that would mean they conclude a distance based on a measurement of luminosity. So, if the luminosity measurement is wrong due to a halo, the distance estimate is wrong too. But maybe your post implied a lot more - I am not too familiar with the Hertzsprung-Russell diagram, actually. (I just looked it up, to be honest).

In my opening post I expressed a second worry: what if our measurements are wrongly interpreted, because we don't correct for the interference of a gas cloud which surrounds us? I'm no expert, but just interested, so some of my questions might be silly. Here is my worry, explained a little better: We measure distances in the universe by the brightness of a type Ia supernova: If there is a halo surrounding us, don't we misjudge the distance, because part of the light is absorbed by that halo? Just like your visibility is reduced in fog? Which wavelengths are recorded from those supernovas? And can they be absorbed by a could of (very) hot basic gases such as hydrogen and oxygen?

So, according to your logic, slaves are the biggest bastards, because they pay no tax (no income, no tax). And the millionaires are the nicest people, because they pay the most tax. Weird logic. It may be off topic a little bit, but did you know that most European countries have a progressive tax system? Higher income means you pay more tax. Our highest percentage is nearly 50%, and some propose to lift it to 60%. So, multi-millionaires will pay over half their income in tax. Why is that good? Because they're rich enough as it is. This is yet another thing that I really don't understand about Republicans. Some of the republican voters are quite poor, yet they defend the regressive tax system as if it's beneficial to them.

Yes. The "You didn't build that" refers to the fact that nobody can achieve anything all by themselves. You need a functioning country around you. It makes perfect sense to me, whereas having windows in jet airliners that actually open makes zero sense to me, as the inevitable decompression would kill all passengers. Even in case of a fire at ground level, the oxygen would only make the fire burn faster. Acknowledging every company needs a good infrastructure around it: makes sense Wanting windows to open in jetliners: makes no sense

! Moderator Note After review by multiple mods (4 in total), we decided to leave this thread closed. Our forum rules, section 2.3b state: The substance mentioned here is considered too dangerous by staff. We warn everybody to study the dangers and required safety measures first, or better: just stay away from it. chilled_fluorine, frankly, we don't think you're mature or experienced enough to work with dangerous materials like this. You are too casual about safety issues.

According the the 1st definition I found in google: An idiot, dolt, or dullard is a mentally deficient person, or someone who acts in a self-defeating or significantly counterproductive way. Sounds a lot like saying that jet airliners should have windows that open, and trying to get yourself elected most powerful man on the planet. It's certainly "self-defeating" and "counterproductive". I'm sorry, rigney, but I have to conclude he's an idiot. It's not just a strong word I chose to use. He just fits the definition.

! Moderator Note If other people misbehave, report it. Do not take any action yourself, certainly not if you cannot do it politely. By the way, saying that people behave as if they're 12 is still considered impolite. Correcting people is the the job of the moderators, and since you seem to struggle to keep it polite, I would suggest you keep strictly to the science. Also, I hope you checked out the etiquette guide. You still fail to use capital letters and punctuation. Finally, we all wonder why you insist on changing the font of all your posts, when our etiquette guide suggests that you do that only to emphasize things. Emphasizing your entire post does not make sense. Now, stop responding to mod notes (that goes for everybody). Please carry on, nothing more to see here.

Would it then not make more sense to vote for a republican senate and house of representatives, but still vote for Obama because he is not an idiot? You do have a separate vote for the president, don't you? What baffles me is that republicans knowingly vote for a complete idiot, just because he's the only republican on the list of options.

As stated before: insulation should (theoretically) be sufficient. Your body produces 150 W of heat, on average, so if your heat loss is that same value, you will not heat up or cool down. It's gonna be a very thick coat, but nothing too special. However, in order to breathe, you may want to have some kind of heat exchanger that pre-heats the air you breathe in, and uses the air you breathe out to do that. That heat exchanger would need a way to collect all the water which will condense (or freeze!) from your breath. Alternatively to ordinary insulation, you could add a little heating inside the suit. It would be heavier, but not rocketscience. I would think of something like a battery-powered electric blanket. Those might even already exist, and will do the job if combined with some additional insulation.

! Moderator Note To all posting: We have removed several posts that link to some online shops for RC toys. This thread is not a place to advertise. If you're a member with sufficient posts and reputation (and we'll be the judge of that), you may link to a website if you think it is particularly good. If you are a new member, and this is one of your first posts here: don't bother including a link. We will either remove the link, or ban you as a spammer. Probably both.

What Ophiolite probably means is that if you miss the target area, and hit a city instead, the costs are huge. I agree with md65536 that asteroid mining only makes sense if you need your materials in space anyway.

! Moderator Note dmaiski, We do not tolerate offensive language at this forum. Calling anyone a moron is a sure way to get banned. Don't ever do it again on our forum. If you cannot deal with a disagreement in a discussion in a polite way, then please do not post at all. For more information, read the rules, especially the bit about being civil. Also, I would like to refer to our etiquette guide, regarding the use of punctuation and emphasis features. Thanks for your cooperation. Do not reply to this moderator note. If you have an issue with it, use the report button at the bottom left corner of this post.

After a number of unfortunate remarks from Romney (e.g. insulting 47% of the voters), this latest remark surprised me a lot. Why would Romney risk so much by making remarks about airplane design? Does he really think he knows better than numerous safety engineers in the aircraft industry? Or is he just not particularly concerned with making any sense? I know that the Republicans take on the scientific ideas, and prefer their own, less scientific explanations. But really, take on the aviation industry? I hope he makes it a law to have windows that open on jetliners. It would certainly make flying an "experience" again. I would expect any person above 18 years old to know why airplane windows don't open. There is actually more than 1 good answer.

H2SO4 exists. I have never heard of H2SO5. ! Moderator Note I have also temporarily removed the link to your blog. We don't allow advertising here, and we don't want people to make a post specifically to advertise their blog. The post only contained a picture of the periodic table anyway. It can easily be found through any search engine. Please check our forum rules, section 2.7.

Online expert support enhances the quality of life in general. So, yes. Also, welcome to the forum.

How can we be certain about the mass of the universe, when only recently the Chandra observatory found a halo of gas surrounding our own Milky way? Although the mass is unknown, it is huge: the estimates range between the mass of 10 and 60 billion suns (comparison: the milky way itself contains between 100 and 400 billion stars). That's a lot of mass we hadn't noticed until now. And related, have we now found some of the missing dark matter? Why are we trying to invent new science to explain some missing mass in the universe, when it might just be thinly dispersed around the galaxies? I read this as: we just found out that our galaxy is perhaps up to 20% heavier than we originally thought, and we have no way to say whether other galaxies are also surrounded by such a gas cloud. Also, wouldn't such a huge gas cloud interfere with all our measurements of other galaxies, just like the atmosphere interferes? Should any instuments be recalibrated and/or should results be recalculated?

I found this map of the world, which shows wind speed in January and July (source: NASA). It clearly shows that in winter, wind speeds are higher than in summer, both on the northern and southern hemispheres. To me, this seems counter intuitive. During summer, I would expect that there is more energy in the atmosphere, due to more energy from the sun. More energy -> higher wind speeds. Apparently, the opposite is true. Does anyone know why this is, or does anyone feel like taking a guess?

I have a few issues with this: 1. If you have balloons, you will get very little sunlight for your small farms. Your own balloon will block the light. 2. You cannot avoid the weather. You just go where the wind takes you. All you can do is change your altitude. 3. The airspace above a country is legally owned by that country and they can legally deny you access. 4. You need seriously huge balloons to do this. The cost of the construction, as well as the helium would be astronomical.

Now, there's your problem. Rail networks should be state owned, just like road networks.

After a quick look around on the internet, I think that it's safe to say that colored smoke bombs are not for camp fires. But they do work. They just don't require a camp fire. But there does not seem to be that magical cheap material. However, if you want to make a lot of normal smoke with your camp fire, all you need is some wet plant material. Green leaves are excellent for making smoke.

Regarding the livestock, the bottleneck is not the maximum velocity, but loading times and waiting times at depots. There is no point in using a high speed rail system if the cargo is gonna spend a couple of hours standing at a depot afterwards. I would only connect main cities with high speed trains. And you're gonna have to buy new trains anyway. Take the European high speed network as an example, and put it in a tube, and add some airplane technology to allow passengers to stay conscious. Simpler = high speed trains like in Europe, Japan, China. If you're gonna go Maglev anyway, you might as well take it a step further. To be honest, I don't really believe in large Maglev networks. Too complicated. Changing tracks is as complicated as moving a house. But I think you were questioning the investment costs of these tunnels... and I agree. It's likely to be far too expensive to contemplate.

Please just go see a professional. Even though I love this forum, I wouldn't trust us with such an important thing.

We can calculate this with some rough back of the envelope calculations. A modern train uses something like 5 MW of power (ballpark figure). By going to a vacuum, this power consumption should become less, so you can use a certain percentage of that power for creating a vacuum. Now it's just a matter is calculating what a vacuum pump requires (and I'm too busy today to do that), and looking into leakage into tunnels. Btw, I think you're likely pumping water vapor, not air. At some point all the air has been pumped out, and only water leaks into the (underground) tunnel. You might therefore achieve your vacuum by cryogenic cooling too. I'm not really sure which is more efficient. Would there be any data on how much water seeps into the Channel tunnel? Then you have a flow of water (mass/time), and you can calculate how much power (depending on the level of vacuum) you need to have to get it out.

Go see a psychiatrist. Sounds like your issues go a little deeper than just a dislike of your brother in law.

The approach of the Mythbusters is the best approach. And perhaps people come to our forum looking to get the same kind of help. But at SFN, we are volunteers with jobs and lives who spend some minutes per day online to talk about what we think is interesting. That's a huge difference with the multi-million dollar TV show that is broadcast worldwide. Also, the Mythbusters, by the nature of their TV show, are interested in things that are not likely to work. So, while the Mythbusters say: "Ok, let's test it" (after dismissing many ideas, which they don't show on TV), on SFN we answer: "Ok, if we can test it from behind our computers, within a few minutes, let's do it, otherwise you test it, and show us". We cannot do anything else. No budget. No time. I am sure that if someone would actually design a test, and show some results, interest would increase a lot. If we can investigate something within a reasonable amount of time (i.e. some minutes), we often do it. But if actual physical experiments need to be designed, you can forget about it. People come here with a nice idea. They do not test it themselves. And when we also don't test it for them, they get upset. It's weird. What other response do they expect from us? Of course we tell them to prove it. The only scientific alternative is that we prove it, and we don't have time or money to do that. Of course we bounce it back to the owner of the idea.