CaptainPanic

How about stars orbiting a gas nebula, on a very long orbit (a nebula which may ultimately form a more massive star, but has not yet)? I'm no expert in this field either, btw. Btw, Didymus, I don't think that black holes would have reported your post... but it never hurts to be friendly.

! Moderator Note I've moved this from Science News to The Lounge, because a comment about a person who lived about 900 years ago is not considered 'news', but may instead be considered 'olds'. On a sidenote, if swimming in a bath of lettuce would reduce sexual desires... shouldn't manatees be extinct by now?

! Moderator Note zorro, Please do not lower yourself to personal insults. This is a scientific discussion, and we will not accept any personal attacks. Calling somebody 'sir', and then insulting them does not make it any better. John, please don't bother to reply to any insults.

Agreed. It was a poor choice of words. I never proposed to generate electricity with a fission (or fusion) reactor to power an ion thruster. My proposal was to use either an ion thruster (using whatever to power it... solar power?) or, alternatively, use fusion or fission. We are discussing some "technologically advanced interstellar species", who may just have a life expectancy (and the necessary patience) that is required for space travel. Who knows, they just may think that 5000 years is a short time.

Judging simply by our own experiences, then they may have some ion thrusters, and fusion/fission technology. The rest seems a little speculative.

I think the one feature that almost all animals have in common is that we're all essentially a tube, where food goes in at one end, and shit comes out the other end. I don't see why alien life would even have that in common.

It is quite funny that on earth, another group of creatures seems to have developed a complex brain (although not as complex as us): the octopus and squid family. It just shows that there is not 1 formula for the perfect intelligent being.

In the case of hydrogen, they mean the "heat of combustion". And it is 123 MJ/kg hydrogen (you have to add the units, or else it means nothing!!). I'm not gonna list all the elements... but if you look for "enthalpy of combustion", or "enthalpy of formation", then you can probably find quite a few of them. I have no idea about titanium densities.

The air purifiers should themselves be neutral, and grounded. (If this is not the case, and if you get an electric shock when you touch the outside of such a device, unplug it immediately, and take it back to the shop). Those devices should not be able to charge any other devices, certainly not a computer (which itself should be grounded or earthed through its power supply). The reason you're supposed to be careful when opening the computer, it that the computer itself can carry charges (some components inside, mostly within the actual power supply). Some capacitors will build up some charges during normal usage of the computer, and they are not immediately dissipated when you switch off the computer. If your power supply to the computer is not earthed, then charges can also build up, especially if the air is very dry (dry winter days). To be safe, just unplug all the cables from a computer, (and if there is a main on/off switch, turn that off first). After that, it is generally safe to open the main casing of a desktop computer, for example to plug in additional RAM or a new harddrive. Mobile racks and docking stations are just more practical. Delbert, that story about the pull cord of your bathroom light carrying charge is very frightening. I recommend that you have it checked out by a trained and certified electrician.

"To need something" is just the sudden realization that you want to have something, and that you somehow have to acquire this, isn't it? I think it is not difficult at all to learn a robot to go plug itself into the grid when its battery runs low, for example. It requires just a few lines of code. It becomes more difficult when you want to teach a robot the human concept of materialism: the desire to constantly get newer things, and more of them too. And it becomes more difficult still to teach a robot to "need" very abstract things, like a feeling of accomplishment. However, you can argue whether humans really "need" that.

! Moderator Note roger4464, Stop hijacking this thread with your own theories. You already have other places on this forum to discuss your own theories. Please note that you were warned before, and we will not keep warning you indefinitely. Failing to listen to these moderator notes will have consequences. If you have any comments about this warning, take it up with the staff by using the report function at the bottom of each post.

Well, you filled out more fields than most people, so perhaps the extra information attracts the search engines more? But people can be curious too. Maybe you write more provocative, and people just want to know who you are? I checked a couple of other seniors, and their views also number many thousands.

Heh. It's probably Google, Bing and a bunch of other search engines. They visit everything online frequently. I don't think that the NSA's search will show up on our page view counter. The NSA just have a complete copy of the entire forum on their server.

! Moderator Note krash661, Please keep that discussion in the other thread, or if you really have to, open a new one (please make sure it is original, and not just a repetition of things said before). This thread is about server issues, which, thanks to dave's hard work seem all sorted now.

The SFN staff is aware of the problem, and is working on it.

We actually share that hill with Belgium and Germany. The three borders meet there.

You should ask this question at your university, because it depends. Not every Bachelor in chemical engineering is the same. Also, please don't use ALL CAPS. There is no need to shout.

You may claim with all your science that the Earth may be round, but the Netherlands is flat as a pancake. Extrapolate a bit, and the earth is flat. I say we vote!

What is all this nonsense about? First of all, in 2002, there was no 'pro sharia party' in France. And there still isn't. During the elections, which you could have looked up on wikipedia, the extreme right wing were larger than ever, but Le Pen (their leader) did not stand any real chance to become president. It sounds to me that you've heard some vague rumors one time when you were having some beers in the pub. You cannot really remember the details, but you all had a good laugh. And now you're trying to piece together the awesomeness of what you heard, but you forgot which parts were real, and which parts were just made up by one of your friends. Am I close?

It is pretty clear that we suffer from a very standard type of spammers, and I am sure that this issue will be resolved soon. We should have some software to kill spam, but it seems it is not working properly at the moment. We kindly ask for a little patience. And keep reporting the spam posts if you think a moderator has missed it. (You don't have to report the newest ones yet, which only a few minutes old).

There is a risk that your comments here on SFN would flood the Google results when people search for your name. I am not sure you'd like that. Personally, I want people to see what I do professionally, not what I write about on SFN. My professional work has gone through some screenings and peer reviews. The stuff I write here has not. It is not a matter of "having something to hide", or a "fear of being prosecuted". It's more a matter of what I want on display.

Here's a link to a nice TED talk, about the development of the language of texting (called: "Txtng is killing language. JK!!!"). It's quite on topic, because it uses all the abbreviations that the OP seems to be disgusted by, and it also introduces new words.

The world spends 1600 billion per year (that is 32 times as much as this guy asks for) on military/defense/weapons. I think that if the whole world would spend 3% less on weapons, we would still be able to kill each other quite dead, and we would have a shot at building a starship. The thing is, that we waste a lot of money already. If we would be able to allocate that waste of money on another waste of money then we at least don't waste any additional money. By the way, it's my opinion that we'd be better off spending those 50 billion on multiple missions. Spread out the money, spread the risk. But I wouldn't object to spend it on spacecraft to travel to other planets.

Assuming you want an airco of about 1 kW, and assuming you can lose that heat by increasing the water temperature by 10 C, you'd have a water flow of about 0.024 liter/s, or about 2 m3 per day. (I hope I calculated that correctly, it was quick). That's an insane amount of water. I think nobody sells those things, because nobody wants them? Maybe there are systems that evaporate water to cool air? I do seem to find something called an evaporative cooler. But in the end, you're gonna have to dump the heat somewhere. Where does the fresh air come in and out of the room?

Alright, I'm gonna give it a shot too. Firstly, I'll make a list of what I'd like to have to 'live sustainably'. In my opinion, this requires a little luxury too, or you'll go insane in your tin can. Then I'll guestimate the weight of that. And then we can add a price tag, which will consist only of launch costs, and will not include development costs. We would need: 1. Living quarters for at least 2 people (alone is boring, want someone else there too), including a bathroom, toilet, lounge with view, air lock, bedroom, kitchen, storage. 2. A sizable greenhouse for food and oxygen production. Made of light-weight plastics. You probably want to super-size this (1 hectare per person), and burn off excess plants that you don't want to eat. Better too much than too little. Needs to be able to shield sunlight to imitate earth's day/night cycle, and light it during the long night. I'm assuming you cannot grow food with a monthly 2-week-long night. 3. Electricity production, including a huge battery pack to provide power during the 2-week-night. 4. An oxygen buffer that can last 1 month (2 weeks darkness, 2 weeks extra buffer just in case). 5. Waste water treatment and recycling facility. 6. Some means of transportation (on solar power). That would weight a guestimated: 1. Living quarters: 400 tons. I just took the weight of the ISS. Meh. 2. Greenhouse: 200 tons. Soil excluded. Foundation excluded too, we'll use lunar soil, and somehow make sure our water doesn't leak away. 3. Solar cells: negligible. Battery: 500 tons. (20 Watts of light for the greenhouse, for 12 hrs per day, for 30 days in a row, at 265 Wh/kg). 4. I guestimate you'd need about 60 m3 of pure oxygen in a month. Multiply by 100 to make sure you do not notice a drop in oxygen level during the night, and you need 6,000 m3 of oxygen. Add nitrogen (80%), and you need approximately 30,000 m3, so (rounded off) 30 tons of 'atmosphere'. That inconveniently makes your greenhouse volume 30,000 m3 too, making its height about 1.5 meters high. So, we'll take 50 tons of atmosperic gas, so we can have a 2 hectare greenhouse at 1 bar, and 2.5 meters high. 5. Water needs 30 days to be cleaned (rough guess), so let's say we need 5 tons of water for the inhabitants. And we'll get all the rest from our ice-mines on the Moon itself. 6. Our Moon-rover will be 3 tons. Grand total: about 1150 tons of material. Let's just round that up to 1,200 tons. Costs are based on the 200 $/kg to LEO mentioned earlier. So, to the moon it's perhaps 2000 $/kg (we'll need fuel to land it safely too). Total costs: 2.4 billion. Sounds like a bargain.