Ralathon

Scroll through this site. If you can disprove those graphs with actual arguments as opposed to "These guys are morons" you'll likely win a nobel prize and a boatload of money.

Per distance unit traveled maybe. But 17 deaths out of 536 people is a deathrate per flight of about 3%. If I had a 3% chance of dieing every time I used my car, I would probably stop driving my car.

Was there ever a working scientific probe that did not get a mission extension? Especially on something as exclusive as up close KBO research? They'd be stupid not to fund a mission extension, it would take decades to get another probe in the area.

In that case it depends on the geographic distribution of those people. You need farmland to grow crops while your workforce rebuilds the world. You need mines to gather resources etc. But if we go with an optimistic scenario I reckon we could rebuild in 0.5 to 2 centuries. I'm basing this number mostly on the speed of the industrial revolution while taking into account all the needed knowledge is already present. As soon as you have a lathe you should be capable of building most modern machines. If you're interested in this stuff, You could try the book "The Knowledge: How to rebuild our world from scratch". It explains a lot about how to rebuild modern machines from scrap.

The growth of russia isn't a very good approximation due to its ability to import goods from outside. If Russia wanted to increase steel production they didn't have to build the foundries from dirt and rocks, they could just import them. As for a time estimate, it depends entirely on the population you've got. If you dump 1 billion people on a virgin earth it will go much MUCH faster than when you send 10 guys.

That would be silly to simulate. The spaceship is a closed system, it can't generate a net force that alters the orbit. Best you can do is shift the spaceship around the center of mass, which won't do a damn thing to the orbit.

The ISS panels are getting rather worn down. Their efficiency decays over time and they get hit by micrometeorites etc. Not to mention that with current technology we could build much better solar panels. All in all, it's better to just build new ones instead of retooling old hardware that wasn't designed to be used that way.

The neck of that suit is smaller than the head of the occupant. If it had a rotary seal you would never be able to fit your head through it.

No he shouldn't, because that Star Trek series was by far the worst of the bunch. Anyway, I really doubt that suit is how the final product will look. The design decisions just don't make much sense. Dark colors? partial padding? No rotary joint for the helmet? This might work as a biker outfit, but it won't do as a spacesuit.

Innovation is great. Until people start to die when things don't work as intended. Suppose you're stuck on a desert island without water. You can pick between a 5 decades old, intensively tested and trusted desalination plant. Or you can pick a sleek new model that runs on solar power and is 20% more efficient due to state of the art nanomaterials, but nobody knows if it'll last more than 2 weeks. What one do you pick, knowing that you'll die a painful death if your desalinator breaks. If people's lives are on the line you use tried and tested technology. If they build a new space suit I want to see half a decade of intensive testing before I'll even consider putting it on.

Yea yea, we get it. Graphene is amazing stuff. The problem is that we can't mass produce high quality sheets yet. The fact your smartphone doesn't have graphene batteries yet is the proof of that. It is a very common joke that Graphene can do anything except leave the laboratory. Stop riding the hype train until someone figures out how to make large batches of the stuff.

If some region of the universe is made of antimatter the boundary would light up like a christmas tree. We would easily notice it. You would also have to propose some kind of mechanism to separate particles and antiparticles during the big bang, which is pretty damn hard to do considering the light cones. Besides, we know that there's a CP violation during the decay of kaons. So we got a good lead on the lack of antimatter.

That's not really how superconductivity via cooper pairs works. The creation of cooper pairs that allow for superconductivity depend on the material used. If you want a higher temperature you can't just toss more science at it, you need to find a different material. 6K is pretty bad for a superconductor, simple lead becomes a superconductor at 7.2K. Also, you can't pump 3 amps through a monoatomic layer. Superconductivity is a fragile beast and it will collapse if you try to push too much current. High currents means high magnetic fields and high magnetic fields kill superconductivity. A very low temperature means you don't have much leeway in your critical field. So this graphene lithium superconductor will probably suck at conducting high amps.

However, I do agree with you. If we pick up some signal it's probably something unintentional, we haven't been around long enough to be particularly noticable. Also, if we can detect it from such huge distances it has to be a really powerful energy source. So some kind of advanced drive system or a long distance radio bounce would be very likely sources. The radio bounces that we use to measure the planets in the solar system should be detectable for dozens of lightyears. If they do the same trick with asteroids and exoplanets they should be visible through much of the galaxy.

I fully agree here. Human level AI is definitely possible (We're the living proof) and it's probably possible to engineer something smarter and faster than ourselves. But the way I always understood the singularity is that this AI would proceed to self improve at an exponential rate until it is many orders of magnitude more intelligent than ourselves. This superintelligent AI would then proceed to create godlike technology that grant it (and hopefully us) immense power. This power is then used to convert all nearby matter into intelligence and infrastructure (depending on the person talking this 'nearby' is either the solar system or the entire universe). It's this line of thinking that I disagree with. A superintelligent AI is still bound by the laws of physics. If those types of technology are impossible within physics then so is the singularity as envisioned by people like Ray Kurzweil etc.

The problem I always have with the singularity is the assumption that technology can be improved nearly indefinitely. I've never really seen any justification for that assumption. For all we know we're very close to the practical limits of technology: a few more major breakthroughs and then stagnation until our extinction. Not because we stop trying, but because there is simply no way to improve technology within the current limitations of physics.

Erm dude, we are discussing this subject by sending 1's and 0's over an worldwide information network of billions of computers. Each of these computers is trillions of times more advanced than anything designed by any other species in the history of the planet. Our technological networks allow us to live like gods compared to other species. It is kinda hard to argue that humans are not intelligent. The problems you're summing up are a result of greed, conflicts of interrests, lack of resources and other things that wouldn't change even if we were a thousand times smarter.

Remember that they can't quickly pop over and replace the wheels. They want to keep this rover alive and rolling as long as possible. So if the wheels show visible damage after just 3 years that's a cause for major concern.

Nobody is saying that we shouldn't do anything to prevent the collapse of our civilization. The argument is whether Mars is a cost effective way of doing so. We will have to leave the earth at some point in the future. In the end the sun will go nova, and our distant descendants will have to gtfo. But we aren't in a hurry to do so. As you said, it's unlikely that anything really unsurvivably bad is going to happen in the next few thousand years. So we can afford to wait a century or 2 before colonizing Mars.

If our resources were limitless and opportunity cost wasn't a thing I'd agree with you. However, we live in a world where a lot of resources are needed for a lot of projects, and colonizing Mars now means losing a lot of other things we need. Especially when new technology can make colonization a lot easier and safer in the future. It's kinda like cavemen in europe saying "We should cross the Atlantic ocean! It will be harder for the bears to eat us!". Sure, they could do that. But crossing an ocean with stone age tech is rather difficult and risky. Better to invest in a better cave to fend off the bears and wait till the renaissance to cross the atlantic.

No, global warming won't turn the earth into some venusian hellhole. But comparing the current increase in the greenhouse effect with the one during the paleocene is disingenuous. The current increase is way faster than any natural effect and thus the biospheres of the earth don't have time to respond. If you wait a couple of millenia the planet would be a lush haven. But on the short term (short term being 50-100 years) it means desertification, flooding, more extreme weather, a minor mass extinction and all around bad stuff.

Pretty much. If you have a vault with a self sufficient life support system, enough data storage to hold most of our knowledge and a genetically viable pool of humans that should be enough to rebuild our civilization from scratch. You would need something really apocalyptic to wipe out both the entire surface population and these vaults. So that should be enough to get us safely through the next couple of centuries. Eventually we will need to colonize the solar system, and eventually the galaxy. Either because we need more resources to sustain economic growth or because the sun goes nova. But now we're talking about enormous timescales. So we aren't in a hurry. We could easily afford to wait a few centuries so new advances in material science and fusion power make spaceflight much cheaper and easier.

I read it yesterday evening. It's indeed a good blog post and I recommend everyone who's interested in spaceflight to read it. But I wasn't terribly convinced by the "multi planet colonies = life insurance" argument. The article correctly ascertains that we don't really have to worry about asteroid strikes, gamma ray bursts or supernovae etc. The timescales are just too damn long. The main reason we need life insurance for our species is due to our own actions. Nuclear war, genetically modified diseases, runaway climate change and unforeseen impacts of new technology. But the article never properly explains why we need to go to Mars to protect our species from this. Obviously Mars would be better than the Earth from a safety standpoint, 225 million km is a nice safety distance. But building a few well insulated pockets of humanity deep underground would be orders of magnitude cheaper and be almost as good. It's kinda like buying insurance for your house. For 1k/year you can get fire insurance or for 100k/year you can have fire+asteroid+tsunami insurance. The latter is obviously better from a safety standpoint, but can you justify spending that much money for only marginal safety gains? Obviously we need some kind of insurance, but should we really go with the luxury package? SpaceX is aiming to bring down the cost of fire+asteroid+tsunami insurance, which is really cool. But I'll have to see it before I'll believe it. Sure, you can cut some costs via vertical integration and reusability. And I have no doubt that ULA and other launch companies are overcharging. But I have a hard time seeing costs drop by a factor 100. The fundamental physics of spaceflight just don't add up to cheap orbital access. You're always going to lose some parts of your rocket and you will always need a whole boatload of reaction mass. You can't bend the laws of physics by tossing enough technobabble at them. All in all, the article has the same problem as the AI post on WBW: it is hopelessly optimistic. Both in spaceflight and AI development things look very promising if you only look at the big picture, but once you get down in the nitty gritty you run into a myriad of big problems. The problems aren't necessarily insurmountable, but they'll take time. A lot of time. So his timeline is at least twice as fast as mine. Manned Mars flights in 2030? Rather unlikely, but I reckon we have a good chance at seeing one around 2040.

No, it wouldn't create a paradox if you take the reaction mass into account. Say our gauss rail has a mass of 1kg and a reaction mass of 1kg. You feed it 100 joulles, which is split evenly between the reaction mass and the railgun. So they both move in opposite directions with 10m/s relative to the ground. The initial energy is 0J, the final energy is 2*(0.5*10^2) = 100J, exactly as expected. Now lets do the same thing on a train that moves 1km/s. We know the initial energy of the system is 0.5*2*1e3^2 = 1MJ. We know that we feed the system 100J, so the final energy needs to be 1.0001MJ. So we need to solve 0.5*vreaction^2 + 0.5*vgauss^2 = 1.0001MJ. We also know that the velocity difference is symmetrical. vinit-vreaction = vgauss-vinit = ÃŽâ€v. 0.5*(vinit-ÃŽâ€v)^2 + 0.5*(vinit+ÃŽâ€v)^2 = 1.0001MJ (vinit-ÃŽâ€v)^2 + (vinit+ÃŽâ€v)^2 = 2*1.0001MJ (vinit^2-2*vinit*ÃŽâ€v+ÃŽâ€v^2) + (vinit^2+2*vinit*ÃŽâ€v+ÃŽâ€v^2) = 2*1.0001MJ 2*vinit^2+2*ÃŽâ€v^2 = 2*1.0001MJ vinit^2+ÃŽâ€v^2 = 1.0001MJ vinit = 1000m/s 1MJ + +ÃŽâ€v^2 = 1.0001MJ ÃŽâ€v^2 = 100J ÃŽâ€v = 10m/s So the final velocity of the gauss rifle will be 1010m/s and the final velocity of the reaction mass will be 990m/s. No paradox anywhere, both the guy on the station and the guy on the train see the gauss rifle move 10m/s faster than before. The total energy gained by the gauss rifle is much higher than 100J for the guy on the station, but it is compensated by the decrease in energy of the reaction mass.