pavelcherepan

I'm straying off-topic here but from what I've seen they aren't feasible at the moment largely due to structural limits of current technology. For example, this graph from wiki article shows that SSTO is only capable of getting to LEO (9.1 km/s delta-v, payload 4500 kg) with a specific impulse of 450 s, which we can't achieve (at sea level) with current fuels based on this data. Of the currently used drives only the ion drives can achieve that sort of SI but their thrust is far too low to use them to launch from the surface.

metaman, when you post links to some resources you have to explain, at least briefly, what those resources are for. Link provided leads to a website describing various 'experimental technologies that can be replicated at home by anyone'. In reality what it talks about is how ancient people harvested energy and electricity (sic!) from pyramids and how to re-create this technology, without providing any scientific evidence. Also talks about UFO's and aether drives (whatever this is) with the same lack of physical explanations. From what I've seen it's just another pseudoscience resource. Feel free to skip. EDIT: Even the first sentence of the first passage contains factual errors: While other sources say that the word pyramid originates from greek 'pyramis' - 'wheat cake' or

Latex (while similar to rubber latex is natural) Ore Coal Chondrite (one of material types of meteorites but specifically is important for understanding of Solar System formation) Bolide (Not Formula 1 bolide. It's similar to meteorite again, but it doesn't reach the surface and so is different) Air (I know you have gas already, but air is very specific and keep us alive so I'd include it too) Asteroid EDIT: Just went out for a smoke and thought of these things that I was inhaling: Tar Ash

We can use stars to change the momentum of the craft in the Galaxy rest frame, but we can't use the Sun, for example, to change our momentum within Solar system because this frame Sun is pretty much stationary and thus has next to 0 momentum. On the other hand we can use stars in binary and more complicated systems to travel faster within such system, because in this case stars would be moving around the common barycenter and will have momentum to share. Also it's been proposed that in an imaginary system with two black holes we can accelerate close to the speed of light by jumping back and forth from one to another. This extreme case requires black holes to be pretty big so that tidal forces are still bearable even right next to the event horizon. The other issue is that once you have accelerated to a significant portion of c using this method you will be going through gravity wells so quickly that you won't have time for the momentum to change appreciably.

Actually a good idea Next time I find one I'll keep it and feed with some roots from the backyard. Let's see what it's going to become.

Yeah, I have read that one but can't perform an experiment now because my better half had banished my subjects from the house

Thanks StringJunky! This one looks very similar!

Just to clarify some confusion I'm having. So if every observer in the Universe has its own observable Universe (I'm on fire with tautologies today!) would those be the same size from the perspective of such an observer? I mean right now for us on the Earth the observable Universe is some 46 bly and then for another observer somewhere in Andromeda galaxy it is the same since the age of the Universe should be the same for both. And another observer in NGC4696 at 150 mly will have the same size of observable Universe too. With that in mind can we constrain the size of the entire Universe in any way or should it be deemed infinite?

Even if it's a skin cell travelling in bloodstream?

I've seen a few larvae like in the picture below a few times in the last few days. I live in Melbourne, Australia and so far looking through various websites I think it must be the larva form of Darkling beetle. What do you guys think?

Nouns: Bose-Einstein condensate Neutrino Solution Mineral Gunpowder Atom Nucleus Isotope Flint Foam Leaf Adjectives: Soluble Crystalline Amorphous Atomic Molecular Toxic

No bacon in the list?

Didn't see water in the list. That one is quite amazing. Sorry, my bad. See it now How about wax then?

Actually, I've read that for the next launch they will try and land the first stage on land ( EDIT: I checked, this is not a tautology ) Thanks for that. I've been also wondering for a long time why no one ever tried to land first stage on parachutes? We do drop tanks from planes on chutes so it shouldn't be impossible to do with a first stage. I've never thought of paraglider though, this is new to me.Do you know if any tests for systems like this have been attempted? Seems much easier than using engines for a controlled landing. I agree. All of these are highly detrimental, unless SSTO design is developed (which AFAIK is near impossible on Earth). But then another question: some planes utilize variable wing geometry. Could this design be of any use for re-usable space vehicles?

I agree with studiot, but also like to note that there are a lot of variables in this situation. Firstly, there is the particular crystal structure you're dealing with. For example, phyllosilicates (such as clay minerals) have relatively big gaps between adjacent sheets which cations of impurity can populate. Since these gaps are quite big a whole range of cations can sit there and these wouldn't cause any significant change to overall energy levels of the structure and as a result melting point won't change appreciably. Secondly, it depends a lot on what position an impurity will take in the crystal structure. It can take empty gaps, like in the example above, but also it can replace some of the atoms in their positions. Then, depending on the size of the atom of impurity compared to the original atom the total energy configuration of the structure can increase. This will result in lowering of the melting point. Generally speaking, crystal structure is supposed to be the lowest energy state for the set of atoms that comprise it and any change will most likely result in an increase of the total energy and thus will lower the melting point so the answer is most likely no. That is unless you're talking about alloys or solid solutions.

Thanks. I didn't know that it was hosted in the US before. Yeah, I'm watching it too. In fact I was more interested in manufacturing phophine gas for... rats extermination. Yeah, that's what it would be for

Below is the link to Youtube video on unsuccessful (yet again) landing of the first stage of SpaceX's Falcon 9 rocket. The craft managed to successfully approach the landing pad but in final moments of landing sequence excess horizontal velocity resulted in it falling on its side and exploding. In the very final moments you can see the RCS thrusters on the top of the vehicle working hard, but still they couldn't stop it from falling: https://youtu.be/GbYQQE5LZ2E Anyway, I'm generally really supportive of what Mr. Musk and his team are doing and this technology seems like a very important advancement in attempting to make space flights cheaper. Obviously I don't have the required information (which only SpaceX has) but still gets me thinking of how big are the chances of successful landing this way. It seems to be easier for spaceplanes (although they are generally much less cost-efficient) to perform automated landing since they have some reasonable amount of lift. For example, Space Shuttle on approach has lift/drag ratio of 4.5, which is actually more than Concorde has. This allows them to possibly make more than one attempt to land if conditions are unfavorable. I think I read somewhere the Buran shuttle on its first and only flight landed automatically on second attempt due to strong cross-winds (it's claimed to have L/D of 6.5). Do you think that this technology is here to stay or it will be temporary and will be abandoned soon?

I've browsed through the entire thread to check your evidence and so far you have linked 4 sources. Two of those I have discussed in the previous posts and the rest is popular science pages, but even those seem to contradict what you say. Just for your reference, this is all the evidence you have posted so far: http://www.ncbi.nlm.nih.gov/pubmed/20334900 http://link.springer.com/article/10.2478%2Fs13545-011-0023-6#page-2%C2%A0 http://www.whoi.edu/oceanus/feature/how-is-fukushimas-fallout-affecting-marine-life http://www.cfact.org/2014/01/07/true-facts-about-ocean-radiation-and-the-fukushima-disaster/ Only two of those are real science papers and even those seem to contradict what you say as discussed previously. None of these seem to explicitly support your claims. I have no idea why you re-iterate that. Do you want to keep your argumentum ad ignorantiam going? If you want to prove you position find proper evidence because that's how science works. I'm not saying "There will be no ecological consequences", do I? I'm just saying that "Based on scientific peer-reviewed evidence the likelihood of major damage is low". Oh, well, maybe so, but if organisms in the middle of the food chain accumulate radiocaesium and it doesn't lead to increased concentrations along the food chain then it's not a damage to the entire ecosystem, but just to several specific organisms. Again, argumentum ad ignorantiam. How many of those do you have stocked? Science doesn't work like that, it's approximation by default. No scientific theory ever claimed to have 100% of related phenomena investigated. And how in the world are you ever supposed to know that you've studied them all? Are you expecting a giant sign to appear in the sky saying "Well done, mate! You've studied them all!"? That's why theories are mean to be updated as new evidence arrives. You should look up Scientific Method. Again? You're on fire today! By the way, I have provided you with links on Cs accumulation in phytoplankton and it doesn't seem all that bad. Do you even read what people wrote about background radiation levels? Allow me to continue your line of thought. I think I'm pretty good with it now: 7) Due to the lack of relevant data... 8) Because not all organisms have been studied... 9) Since we don't know enough... 10) We can't conclude this based on limited evidence we have... ....

That's a logical fallacy you're using, an argument from ignorance. If you want to prove your point please provide relevant evidence to support it, but instead what you're trying to do is to say that "Since we don't know for certain, you must be wrong". Attempting to shift the burden of proof is also lame. If you want to prove something then do it, if you claim that research I've linked is rudimentary then provide some that is not. Random hand-waiving and logical fallacies never helped any scientific discussions and won't do any good now either. Also, I'm not a marine biologist or a biologist at all for that matter but it seems quite reasonable to me that if we analyse both the top and the bottom of the food chain and see that there's no significant bioaccumulation of radiocaesium in either of these then we can infer that middle bits of the chain don't accumulate it to a large extent. I think you need to: 1) watch your language, 2) finally try and properly acknowledge and try to dispute the evidence that you've been provided, 3) provide evidence to support your position.

I was reading the 'Hazmat policy' sticker at Chemistry forums and one line really sounded weird: Was the second instance meant to say "UK"?

OK, you've balanced the reaction and it's all good. But these coefficients in front of compounds are for ideal-case scenario when 1 mol of aluminium hydroxide reacts with 3 moles of hydrochloric acid. But what you have is 0.128 moles of Al(OH)3 so then you multiply this number by stoichiometric coefficients for each of the compounds and you will find the actual number of moles of H2O. Then you multiply this actual number of moles by molecular weight that you already know and the result will be the number of grams of H2O.

How about this: http://www.sciencedirect.com/science/article/pii/S0306452213007550

I wasn't trying to discuss suffocation, I haven't seen any evidence so far to support it. I'll search a bit more to make sure. Just attempting to answer this:

Sudden pressure change? EDIT: For example Labyrinthitis

Not sure I follow that thought. Why would on a non-rotating body equator be further away from center of mass than poles? Non-rotating planet should be ideally spherical (or very close to it). EDIT: Sorry, didn't notice the 'shape' bit initially. In that case you're right, but then there's the question of why the shape is the same.