-Velocity-

I agree, but maybe not for the same reason that you do. I know lots of otherwise not-so-bright people who actually make reasonably bright decisions simply because they KNOW they are not-so-bright, and they rely on the advice, wisdom and intelligence of others. This self-knowledge of their own fallibility actually makes them quite wise. As I like to say, The dumb man thinks himself smart. The smart man knows himself to be dumb. The favorite words of the ignorant are "I know". It's the people who think themselves to be so clever that they do not need to listen or consider the ideas of others that are the major cause of human stupidity. You can have just about any IQ and fall into this category, as the only requirement is arrogance and overconfidence in your own abilities. So, I think it's not necessarily how clever you are that matters, so much as how willing you are to admit your own fallibility, critically assess your own intellectual abilities, and consider the ideas of others. Sure, being smart HELPS, quite a lot in fact, but it is far from the whole picture, and you can be pretty wise without being very smart- just admit to yourself that you DON'T know everything, and listen to the advice and ideas of others. Two things that are vital for a person who wishes to be wise- 1) Admit your own fallibility. If you think you're so much smarter than everyone else, it's only because you are too arrogant and stupid to realize your own failings. 2) Believe that which is supported by EVIDENCE, and not only what you WANT to believe. Most people believe what they want to believe, to hell with the facts (ahem... religion... ahem... politics...), but wisdom only comes if you put your own wants and desires out of the equation and try to look at a issue without bias. The world doesn't base itself on how you want it to work, it just is. If you actually want to understand it, remove your desires from the equation.

I actually found out recently that the engine (NK-33) that the Soviets developed to power their failed moon rocket (the N1), is actually being considered for use as part of NASA's SLS. Also, if I remember correctly, the F1 rocket engine developed for the first stage of the Saturn V is also under consideration as an upgrade for the SLS, the idea being replacing the SRBs with F1-powered liquid fueled boosters... as we know from KSP, liquid fueled rockets are more efficient than solid Cool stuff. It really goes to illustrate, that apart from making materials advances in rocket engines (such as making 3D printable rocket engines), chemical rocket engines are a very mature technology. It's also comforting to know that some good came from the Soviet N1 project.

Can you explain this? Yes, you would still have the same problem. The whole point is that there is no such thing as simultaneity, and different observers can observe spatially-separated events occurring in different orders. If the train stops the instant the beams are reflected, there is still a mis-match between the two observer's observations using the instantaneous communicator experimental set-up. Now, if you have the train stop, it is no longer an inertial reference frame, it is an accelerating reference frame. You have to use different parts of Relativity that I am not very familiar with to predict how light will behave. Rest assured though, in the original set-up, using just light beams and no impossible devices, the two observers still agree on the same events taking place.

Did you even read the thought experiment? If a warp drive lets you get a signal or ship or anything that contains information from point A to point B faster than the speed of light, THAT IS A CAUSALITY VIOLATION no matter how you try to frame it, and it will lead to impossible stuff like I describe in the thought experiment I posted. The fact is, Relativity is not a complete description of the universe. Because we think we found a loophole in it that allows us to go faster than light does not mean that we actually found a loophole in the universe. FTL travel/communication is prohibited by two separate things- 1) It takes infinite energy to accelerate to the speed of light 2) If you communicate faster than the speed of light, you set up causality violations, independent observers observe different things, impossible scenarios, etc. Point 1) is what warp drives "find a work-around" for. They do not accelerate at all. Obviously. I knew that when I first read about them in the mid 90's. It's written in EVERY SINGLE article and paper about them, and that part of them is not in contention here. If you've heard of warp drives at all, you KNOW they don't accelerate, so please don't bring that up here as some sort of "trump card". Because it is NOT- Point 2) is not codified in Relativity, per say- at least, as far as I know, Relativity prevents Point 2) only in so much that it says Point 1), and it implies that Point 1) ensures Point 2). However, Point 2) is required to keep reality from... well, existing. We don't have a complete picture of physics yet, but it seems certain that Point 2) will be part of it when or if we do. If you violate causality, if you have two separate observers in the same universe observing different versions of reality... that is CLEARLY impossible. And don't get hung up on "observers", thinking I am implying an observer is an actual thinking, breathing, observing thing. They are not. A hydrogen molecule in interstellar space is an observer. A neutrino is an observer. Heck, everything is an observer. The very nature of reality would break down if FTL communication was possible.

Reposted from like a month and a half ago: Here's something I wrote up somewhere else, I'll repost it here with some modifications: Anyway, please consider the above thought experiment, and you will see why FTL communication would violate the very foundations of the universe and reality.

1) Diving in Europa's oceans 2) See the geyers on Enceladus 3) Liquid hydrocarbon skiing on Titan 4) Blimp ride on Titan 5) Spelunking on Mars- if you don't know what I'm talking about, see these- We've found more than just those, too. Anyway, those would be on my "bucket list" if we had cheap tourism to the solar system bodies.

This is an incorrect assumption. You are assuming that the bureaucrats who assign funding to research projects actually know what they are doing. I am in academia right now, and I've seen a fair share of useless, hopeless research projects. I mean, the money isn't wholly wasted, sometimes some topic or concept that appears useless turns out not to be, or it has an unexpected alternative function/use. Using a warp drive to exceed the speed of light, allowing for FTL communcation is wholly against the underpinnings of the universe (such as causality), and you can make contradictory impossible situations with FTL communcation. So, it seems that warp drive FTL must be impossible, and we just haven't figured out why yet (however, some researchers have recently claimed that FTL warp drives would be nearly instantly destroyed by Hawking radiation, so maybe that's at least part of why they can't exist). But who knows, maybe there's some small possibility that a warp drive is possible, but you just have to use it to go less than light speed. That would still be very useful. It's important to be open-minded, but not so open-minded that your brain falls out In more exact terms, be open minded, but use reason to eliminate the impossible and highly unlikely. Honestly, I'd like to see two options of KSP interstellar travel, a "realistic" mode using very high time compression and things like pulsed fusion drives, and a non-realistic mode using warp drives. That should satisfy everyone and end this silly debate.

Wow, thanks. None of the ideas are really mine though, the struggle against racism and xenophobia is a central theme in a very large percentage of sci-fi literature. Anyway, xenophobia isn't really a problem yet, so don't worry. However, giving proper respect to the rights and welfare of the most intelligent of the non-human animals on this planet is a problem we still need to properly address, IMO.

Honestly, given the history of let-downs, setbacks, and shattered hopes, it's probably not a good idea to place any bets at all on when or if commercial fusion plants will become a reality. Technological progress cannot be carried on to infinity, and it is not beyond the realm of possibility that even with the best technology, fusion ends up being possible but just too expensive compared to other, simpler energy sources. Maybe building commercial fusion plants ends up being roughly analogous to powering a well pump on farm with a nuclear reactor instead of just using a windpump. Maybe more efficient energy usage plus alternative sources like wind and solar are good enough. I HIGHLY DOUBT THAT THOUGH.

Maybe Jeb, Bill, and Bob are like the endlessly cloned lunar miner in the movie Moon. Maybe underneath the Kerbonaut training center there is a secret underground lab where hundreds of Jebs, Bills, and Bobs lie in cryo-preservation, waiting to be thawed out after your next big rocket failure.

I've got an even better question- why does it matter whether they are human or not? What is "human" anyway? Are we going to be nothing but xenophobic racists that only care for whatever we arbitrarily decide to call "human"? If there are one day things around that are unequivocally non-human, does that mean that we should not care what their feelings and desires are? If so, then humans are most definitely the enemy of all other intelligent life forms, and we will be probably be eradicated, and GOOD RIDDANCE. We would be nothing more than 3rd millennium Nazis, the superior "Aryan" race redefined to be only slightly more inclusive. What happens in nature is that life forms evolve into better adapted, new forms. Why should humans be any different? Are we going to archaically cling to some obsolete form of "humanity" until we are so poorly adapted to a rapidly changing technological world that we become extinct entirely? Or are we willing to embrace the fact that evolution, whether by natural selection or intelligent design (where the intelligent designer is US), applies to all life forms, INCLUDING HUMANS. The genus Homo won't be gone, we'll just be something newer and BETTER than the current Homo sapiens. The new human life forms will be our descendants, our legacy, and something we should EAGERLY embrace.

Honestly, it seems to me, that the only way to keep humans viable might be to meld man and machine, perhaps in combination with genetic engineering/tailoring. Like, what if it were possible to supplement our intelligence with implanted bioelectronics? I do think that if we aren't willing to modify ourselves, we will end up being extremely obsolete eventually. This is another area where religion becomes a major pain in the side, this idiotic notion that "man should not exceed his bounds". Hopefully, this idea becomes obsolete before humans are obsolete. But if humans DO become obsolete, as long as there is something better than us (morally and intellectually) to take over, I wouldn't be sad. I just don't want to see the spark of intelligence leave the universe; as far as we know (it's unlikely, but possible), we're the first pieces of matter to know itself. What is the point of the universe if there is no one around to appreciate it?

And, once again, overpopulation is not just about running out of food or natural resources. Clean energy wouldn't be such an urgent problem if we only had like 1/5th the current population, and hence, 1/5th the current pollution. Overpopulation = pollution + destruction of forests/land for farmland/housing. We bemoan invasive species and try to fight their spread, when we are by far the worst invasive species on the planet. I'm not saying we shouldn't live on every continent, I'm saying we should live responsibly, in better controlled numbers with better environmental stewardship. We're not like some dumb pythons invading the Everglades; we're smart enough to know better, but too damn apathetic to care. Honestly, if we don't get our act together, we deserve to be wiped out. Hopefully, one day another intelligent race would arise on Earth and learn from our mistakes. At least they'd have a hard time finding enough left over oil and coal to !@#$ up the atmosphere. However, even if we were to totally wreck the environment, it's unlikely the human species would become extinct. Humans are the most adaptable animals on the planet, and the most adaptable animals are always the ones to survive the mass extinctions. ---------- I'm actually surprised how few mentions of nuclear weapons there are. The nuclear threat still hangs over our heads today, it's greatly reduced but it's still there, and given enough time, a nuclear war is very likely to break out. But maybe the threat of nuclear war can be filed under the heading of "human stupidity", since it is ultimately stupid humans who press the button. Again though, I find the possibility of a nuclear war completely driving humans to extinction unlikely.

RTGs were used for civilian use, at least very small RTGs, in pacemakers. Given the current concerns with radiological weapons, and scarcity of Pu-238, it's pretty safe to assume that large RTGs will never be cleared for civilian use, at least, not until/unless the very nature of humanity changes. Pu-238 is an alpha emitter IIRC, so I think that means it's fairly "safe" unless you breathe it in (it should just give you skin burns otherwise), but that's exactly what the chemical explosive is good for- dispersing it in the air so people breathe it in.

I'll check the article out, but I thought that the Sun orbited at a distance where the spiral arm density waves travel at about the same speed as a star in a circular orbit? Wasn't that like, half the idea behind the "galactic habitable zone" concept (the other half being high enough metalicy for terrestrial planets)?

I'm currently at about 750 tons (maybe 550, 600 tons payload) with this thing. The top third of the rocket is the payload, in this case, the rear half of an interplanetary "supertanker/carrier". The rocket uses a combination of vertical and asparagus staging. It can get a 500 ton payload into orbit with 3000 tons of rocket. That's a pretty good payload fraction... I think... I get it by using a bunch of smaller, more efficient engines instead of fewer big but less efficient engines. At launch, this sucker initially starts with 210 engines burning like 25 or 30 tons of fuel per second. I've tried to go bigger, but between incredibly low frame rates, constant memory overflows/leaks and subsequent crashes (mostly caused by the 32 bit inexcusatable), and the rocket falling apart on the pad, it's too painful of a process for too little gain... as I don't really have a use for anything larger anyway.

I've seen it mentioned but never seen an example. I've done forum searches, advanced and normal, to no avail. Anyone care to explain how a "decoupler-based suspension" works, and how to build one? Put the wheels on decouplers? What kind of decouplers? Please post pics... I want to create this insane stunt spacecraft, but it needs a very good suspension to... well, if it works, you'll see

Yup. Polywells may be the best chance outside of laser (inertial) confinement and big tokamak magnetic confinement, and would be MUCH cheaper and more practical than either of the two, and unlike cold fusion, polywells at least seem to have a chance at actually working. Oh and finally, you might even be able to build a polywell in your garage too.

Why do you need to attach your rover to a lander at all? Just make the lander and the rover the same thing. It's not like it's hard to build a rocket rover. Or For the life of me, I can't understand why so few people do this!!! Wheels weigh about as much as landing legs, and even for Tylo, you can make a fully reusable rover that is capable of landing and taking off back into orbit (though, the accommodations on board a fully reusable single-stage Tylo rover are rather spartan... it's pretty much fuel tanks and rocket engines, with a couple wheels and a chairs attached ).

I certainly would agree that, at least right now, we don't know for sure, and starting such a project NOW would certainly be ill-advised and premature. However, we very well might have a much better handle and understanding of how a reduction in sunlight would affect the planet and plant life in 100 or 200 years. I think it very likely that we will have a very good understanding of how climate works in just a few more decades, as ever more powerful supercomputers come online that run ever more detailed climate simulations. And, I cite again the evidence that it doesn't look like sunlight is a limiting factor in plant growth. BUT, considering the consequences of being wrong on an issue like this, I would whole-heartedly agree that extreme caution is definitely advised, and the negative effects of global warming would have to be pretty substantial to justify a project like this. Unfortunately, solar shades will do nothing to stem the tide of ocean acidification caused by high CO2 levels.

In my "couple hundred thousand square km" example, I am talking about a reduction in sunlight by 0.25%. A couple hundred thousand square km may be a very realizable goal, especially in a future where we have large space-based asteroid mining and manufacturing operations. After all, right now, the world is producing something on the order of around 40,000 or 50,000 square km of aluminum foil each year. Solar shade material would be MUCH thinner than aluminum foil. Maybe, the bigger and tougher material manufacturing challenge lies in the rigging and support for all those solar sails/shades. Anyway, even if your concerns are legitimate, if global warming does become bad enough, it might very well be the lesser of two evils. HOWEVER, plant life, at least as far as I have seen, and on land at least, is far more limited by the lack of water or nutrients than by any lack of sunlight. Many of the greenest places in the world have the cloudiest and rainiest days. That's why they call them "rain forests" . I would suspect that nutrients and perhaps water conditions are likely to be the limiting factors for phytoplankton growth too. Finally, I note that during the Carboniferous period, the time when perhaps the Earth was the most plant-covered in all its history, the sun was several whole percentage points FAINTER than it is today. So while I'm no botanist, I'll need quite a bit more information before I would believe that a reduction in sunlight would actually result in a reduction in plant life. Obviously, plants need sunlight, but a reduction in sunlight only leads to a reduction in plant life if sunlight is a limiting factor inhibiting plant growth, and it does not appear to be, not at all.

It's just a point of view, I guess. To me, real color is what an eye with a fully dilated 7mm pupil would see if the eye was placed very close to the object so that no telescope was needed at all. So I've seen the Orion nebula in "real color", as I've observed it from an effective distance of 15 light years with a 7mm exit pupil (in a 25" scope). It's not red. It's greenish-whitish, with HINTS at other colors. With the eye, the best way I've found to detect the other colors, at least indirectly, is to view the Orion nebula with a nebula filter, and then compare that to the view without a nebula filter. Without the nebula filter, the color is greenish-whitish, with hints of browns in places, and inexplicably, a few blues, perhaps (I think that the blue is an illusion though). Once you pop the nebula filter in though, the Orion nebula turns a very deep turquoise/stoplight color (the color of H-beta + OIII). That PROVES there are significant, other colors there that your eye is detecting, but your eye just has a hard time picking them out due to the overwhelming green color.

I primarily use space.com, it's got a good mix of science and space flight news, but it seems like they are dumbing their articles down more and more as the years pass... maybe I'm wrong though.

As far as global warming goes, I have yet to figure out why a couple hundred thousand square km of star shades at L1 wouldn't fix a little overheating. We could mass produce a bunch of very thin solar shade material in space, place it directly between Earth and the Sun at the L1 point, and just block enough sunlight to completely null out any global warming. I read an article that said such a scheme would supposedly cool the tropics more than the poles- but I never found out why they were saying that? Maybe due to parallax? The most extreme parallax, at the poles, from a star shade at Earth-Sun L1 would be a little under 15 arc minutes- when the solar disk is 30 arc minutes in diameter- so it would be borderline. However, if you utilized the radiation pressure on the sunward-facing side of the sail to reduce the effective gravity of the Sun by a bit, it ought to move the effective L1 point away from the Earth, reducing the parallax a bit, maybe enough to ensure full shade coverage even at the poles. Even without that though, we'd be talking about full shade coverage of almost all of the Earth. Anyway, that article was based on recent research, and as we know, that can be very much subject to change, especially for something as complicated as the climate.

You completely missed the point. Look over my post... where did I mention running out of resources? Though that is certainly a problem (more like, the resources we need will slowly get more and more expensive to extract), that's not the primary problem I see with overpopulation, at least, not at this point in time. How much carbon dioxide would there be in the atmosphere if our population were just 1/7th of what it is now? (i.e., 1 billion people?) How many species would be driven to extinction by habitat loss if we only used like 1/4th the farm land and residential area that we use today? How much pollution would we be adding to the environment if our population was just 1 billion? How much environmental destruction would be being caused by our mining efforts to supply those 1 billion people? The fact is, in the modern world, our destruction of the environment is almost directly proportional to the population. Just think of how much additional carbon emissions each additional child represents.