ZetaX

Are you a scientist yourself¿ Because he is, and I am (from a different field), and I can only agree with him on this. Yes, this part of the approach, but not at the level of free roaming creativity you mention. It is actually quite directed. Maybe some metaphors help: imagine yourself drawing a picture of a tree; you can choose the details, colors, forms, background, but you are still drawing a tree, not a wolf. That's not a fallacy from auhority, as the argument is that a scientist knows almost by definition what science is, as science is defined (!) and also practiced by them. What anyone else thinks science _should_ be is irrelevant. The point of that fallacy is that someones status is not sufficent proof, but with added knowledge that this persons is an expert on the topic and gives further arguments (the examples from history, and the how science defines itself), this dwindles. Sorry, but that looks more ad hominem then any previous comments to me. He mentioned a lot of real content (that long post on how relativity grew, for example) which you ignored.

But using meters makes it easier to order useful tools for that online ;-)

While I won't deny genetical or otherwisely hard to influence dispositions, a lot of these intuitions and connection finding skills can be learned and taught.

Those differences between hindsight and foresight are only superficious. A better "knowing" of what to come spares you the time to find out the correct formulations, yes, but that's mostly work and not genius that solves this part. The ordering happens often much later only and is often done by completely different people.

O rly! That's still not the same as saying a liters is x meters. You haven't looked at the relevant post at all, did you¿

You will die.

He also got the units wrong, by the way. At least, last time I checked liters were not measured in meters...

My 2 ¢ as a scientist* on the above debate: Most of the development is actually quite expected, but not linear. Branching occurs a lot without fabulous new ideas just from digging deeper. Somebody sometimes creates a new theory, but this is always based on tons of development and insights gained before, thus calling them geniusses feels sometimes disrespectful to all those that also contributed to it. A standard example: special relativity was not that special or new from a scientific point of view, physics "had it comming"; general relativity has more interesting new insights by Einstein itself, but in some way is also simply "going one or two steps further"; this is not to decrease or disrespect Einstein's contribution to science, but just to point out that things are to some degree automatic and just a matter of time. A good scientist is one that shortens the time needed and figures out the key aspects or concepts of things, like for example the underlying nature of curved space, and a breakthrough is such a new idea/concept/aspect that creates deeper understanding. *: but a formal, not a physical one

On the Lorentz factor and special relativity, there is a neat way to very easily calculate some things: You don't need the Lorentz factor to do some types of computations at all. The Lorentz factors cancel when calculating flight time from the space ships own frame of reference, thus everything behaves like in the classical scenario as long as no interaction with other objects is considered. Therefore, investing 4 times as much energy into velocity will get you there exactly two times as fast, i.e. in half the time, from your point of view. And if you travel to anywhere outside your current solar system in comfortable flight times (own frame again) of at most months, then your speed relative to the stars is rather close to c, letting you expect a year per lightyear to happen in the frame of the stars/the galaxy.

The "instant" (a.k.a.: much faster than the other processes involved) closing is no problem at all.

@ SFJackBauer: Sorry for the long response time, the forum software failed to send my first version, which made me write everything again. Note that the comment on lifes saved is purely to give other hypothetical reasons of similiar basis than the one critizied by it. I think money is well spent on research in a lot of cases, even if that research has no obvious goal and/or might never give anything useful in return. Science often does not work in this directed way, but more like evolution. A lot of things that were thought to be useless or be done for the fun of it turned out to be important in the long run, and there is no obvious reason why this trend should not continue. This is also half of my answer to your question on the System/360 (of which I only know a little): in hindsight, it was probably good by IBM to go that way as it should have helped towards modern computers (but one could also make up a scenario were waiting ten more years might cause even better computers today), but it was in no way clear that this would come out of it, nor do I find that necessary to legitimate it. You can justify it if that was expected to go this way beforehand, that's all. And on the exact question itself, I am indeed lacking enough information whether it was expected to be worth the investment (but, being capitalistic driven, likely was). There is nonetheless some difference to the case of the shuttle I think: the shuttle was developed (i.e. the science by the project itself, especially the research on the semi-reusable starting and airplane-like landing, was already done) and it was then very expensive to launch, so creating cheaper replacement afterwards might have been a better choice and if executed correctly maybe had no disadvantages. It's understansable that justifying a complete restart to congress and public would be hard, but assuming the above would still been the correct choice, making it a sunken-cost-fallacy. True, but how much of that mass was really needed¿ You could bring back the data and samples only, and burn the rest by deorbiting it. If you spend 500 million less each mission, which is less than half of the shuttles launch costs, on bringing the lab into orbit, then the cost of the lab itself might not be that relevant anymore. Is disrespectful for those who have lost their lives both on Soyuz and the Shuttle program? We are talking about people here. I don't find that disrespectful but see it as a comment that is true, despite it's snarkyness. If I had to choose how to get back to earth safely and my options are a broken leg with probability of 50% or death with a probability of 5%, I would gladly choose the former. Such decisions might seem disrespectful towards humans if mentioned explicitely, but they happen a lot in real life, be them often more subtle or not. There are many cases that turn down to "do we save 100 or 1000 people¿", or any other version of the trolley problem (http://en.wikipedia.org/wiki/Trolley_problem). For example, we put more money into cancer research than e.g. into HIV or Ebola, as the former is the greater problem in the countries most of us first worlders live in.

Being decelerated, while sounding like a trivial and intuitive notion, should also be defined carefully; you can also create a lot of paradoxes otherwise. Wikipedia had a short list of such and length-contraction related paradoxes I think. In general, there essentially can be no contradictions in special relativity: Its axioms are consistent, i.e. can not cause a contradiction by themselves, if one assumes that the so-called axioms of ZFC (Zermelo-Fraenkel & choice) are consistent. The latter has survived many much harder beatings by mathematician so far (but the consistency is provably impossible to prove, see Gödel's incompleteness theorem). This obviously only implies that pure thought experiments cannot contradict it and says nothing about its applicability to real life.

Almost none of the things given by you require anything to be brought back (Hubble, the probes, etc.), and those that do only are exactly as BlackBicycle says: at most a couple of kilograms. None of the things you mentioned would have been impossible otherwise. And the "being disrespectful" part is, if anything, disrepectful by similiar reasons if you want so (ever dared to check how many lives could be saved with the money wasted on the shuttle¿), or actually, that concept makes no sense at all: Just because some guys put lots of effort or money into something does not make them exempt from criticism, nor does it make it great; and those that actually did a great job, e.g. those scientists, indeed deserve respect for their execution of it, but that does not imply the shuttle as a whole does. They did their job well, but the job itself was at least a bit wrong to begin with.

It is way more crazy to spend three times the amount of money on getting your satellite into orbit than necessary just to have the option of aborting the deploy and bring it back. Unless you assume a rather high probability of failure that is detectable while the object is still close enough to the shuttle, this is not worth it at all. Launching it and building it seem to be in a similiar price range for e.g. broadcasting satellites, so you would need a chance of at least 10% (already if calculated very optimistically towards your claim) to have an error in your satellite that is not detectable/present pre-launch, but detectable before final deployment from the shuttle into an orbit; this seems not to be the case, so I conclude your point to be moot.

The first sentence is just offensive and shows that you haven't really thought about my comment at all. Just think about how much of the experiments really need bringing back in full instead of just bringing back the date and some (not heavy!) material samples. The cost of that equipment is very minor compared to over a billion per shuttle launch, so you could essentially just throw it out of the window (yeah, not literally, obviously, for several reasons). Edit cause of newer post: obviously bringing back stuff is useful, but most of the bringing back is not needed and just convenient; it often does not at all outweight the higher cost of the shuttle.

The ability of returning cargo seems to be mostly useless, though.

What exactly is the reasoning for it to have a nonzero probability to be at the center, while it (seemingly¿) having a zero (or very very close to zero) one in an actual hydrogen atom¿

You know that dinosaurs were egg-laying, right¿

AngelLestat: There can't be a microscopic black hole inside a neutron star because nothing in there is dense enough (the density of a microscopic BH is extreme even compared to a neutron star; at least if calculated classically/relativistically). What is dense enough is the star as a whole, and maybe a slightly slower volume, but still a very makroscopic one (some kilometers in diamater, probably). I am repeating myself, and you ignored it the last two times already: A black hole is some (spherical) volume with enough mass inside it to form an event horizon. For a given radius, there is either enough mass inside it or not, and the required density inside the volume is lower the larger the radius gets. Therefore, some smaller part around the center may not have enough mass to be a BH by itself, but the larger volume of the exact same density can. (Fun fact: by most estimates the whole universe is one, still you and I are not).

Please you think a min before answering: is there a tiny event horizon within you¿ If yes, you have gotten a lot of things wrong. If no, then where does one come form if you are pressed into a sufficiently small volume, if not by "simply appearing"¿ Things get a bit more complocated if seen relativistically, so lets just use something at your/the hydrogen sphere's surface as an observer, just to avoid nitpicking; or just think semi-classically on those matters.

This still makes no sense and is no consistent argument at all. Something is either a black hole or not. You can't be 70% BH and 30% non-BH. This has absolutely nothing to do with quickness (unless you wait some days/months/millenia for that hydrogen cloud to contract to a star or more likely a smaller BH by shrinking its volume; both are not what this is about). The Schwarzschild radius is a function of mass, and it is indeed continuous, but being a BH means that to have all that mass inside it. It's the same for a supernova, the BH formed by them is also not just microscopic and then grows, but is large to begin with.

It doesn't. If you think it does, you will have to give more reasoning.

I'm not K^2, but: This somewhat feels like some futuristic version of Xeno's paradox to me. One way to resolve it: You don't create a much too small BH, but instead you make it about the size you want (and then feed some more matter into it or wait a couple of centuries). To do this, note that your problems only start after you get an event horizon or are at least close to creating one. But such a thing doesn't grow from inside out, but just "is there". It is the fact that inside some volume there is enough mass, and this can easily happen without it happening in any smaller volume because smaller BH would require higher density of energy/matter. You can build a BH of enormous size directly without building a smaller one by just putting hydrogen into a huge sphere, but just with the density of earth's atmosphere. Do that big enough (to laze to do the calculations to get the diameter) and it will be a BH. Yet it won't be one if you use a smaller sphere of that density.

No it isn't. They outnumber your cells, but your mass is mostly yours. Quoting Wikipedia: "The mass of microorganisms are estimated to account for 1-3% total body mass." and "Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 10^14 versus 10^13)".

They might not be completely correct regarding the actual size and get problematic for very small BHs, but they are somewhat a necessity. You are completely ignoring how to get antimatter and how to make that sustainable and ideally without needing a refueling station every 100 light years. The antimatter one has actually no advantage over a BH as it is inherently more dangerous, harder to refuel, probably a lot less energy efficient due to losses of energy in antimatter creation, and, most of all, would probably use energy to create antimatter to create energy, i.e. no energy gain here, too. Adding to what K^2 already said: even at a horribly inefficient accelerator you could still use its waste heat as an energy source, and the energy stored in the particles isn't lost at all. See the linked paper, section III.D. At about 4·10^11 g or 0.6 attometers you get about a year and equation (11) gives you a rough estimate on more general things. The one they propose has a lifetime of 10-100 years, so this is not that critical as long as you don't somehow loose your particle accelerator.