Follow Slashdot stories on Twitter


Forgot your password?

Comment Re:Extraordinary claims (Score 1) 254

The last point is arguable. The nanorobotics would be permanent nanoscale fixtures built into a large machine, they would not wander around freely like in science fiction. Given that micromachined parts work today (a common example is the mirror array in certain kinds of projectors), nanomachined parts seem probable in the future.

Furthermore, your brain has an awful lot of redundant circuits and connections. If you were rebuilt atom by atom, it is possible that the person revived would be "close enough" to the original to satisfy people who knew the original.

Comment Re:Slashvertisement (Score 1) 254

To some extent, experiments have been done that provide some fairly convincing evidence for #1-4.

1. Electrical measurements of brain activity during anesthesia pretty much disprove this one. During heavy anesthetic, the neurons stop communicating and become fairly quite electrically. They become even quieter if you cool the blood.

2. This is a mostly guess, based on electron micrographs of frozen specimens. When the freezing is done perfectly, the details seem to still be visible. Also, an experiment has been done where a slice of brain tissue was frozen under exotic conditions (by exotic, I mean conditions that can't be reached for an entire brain with existing tech), and the cells came back online and started communicating again upon thawing the slice.

3. This one is a major problem. It is hoped that the current procedures are fast enough, but faster would be better.

4. This is based upon a set of assumptions that are fairly solid. Assuming no civilization ending catastrophes, the tools that will be capable of fixing you are almost certainly possible in a technical sense. One caution : the kind of tools that will probably work would be able to "fix" your body from a technical level, but philosophically it is hard to argue if you survived. See, the way to fix it is to slice your brain into many small slices, and to scan these slices at extremely high resolution. Software would reverse most of the freezing damage, and construct a graph in memory of the state of your neural network at death. A hardware emulator would be loaded with this graph, and that's what you'd be - a very good emulation.

5. This one's just a gamble. No one can predict the future with certainty. One thing that IS absolute, however, is your fate if you don't pay the $100k. Not a penny of that money will do you any good anyway, so...

Comment Re:DOA (Score 1) 240

6 kps is faster than escape velocity for Mars. So if you don't have a way to slow down, won't the spacecraft just hurtle past Mars (or slam into it at high speed)

I understand sorta what you're talking about regarding an elliptical orbit, it makes sense via conservation of energy, and it works that way in KSP. :)

In any case, from an engineering prospective, to land on Mars with a big heavy lander full of people and supplies is a difficult problem. I *think* that a similar approach to that used by the MSL may work, that a capsule the size of SpaceX dragon can slow down using it's heat shield, then deploy parachutes, then use rocket engines for a soft touchdown.

But it's by no means guaranteed and is extremely dangerous. Also, there doesn't seem like there is any room at all for aborts or error. When the spacecraft comes screaming in at 6kps towards Mars, they gotta either land or die, right? No way to go into orbit around Mars without it costing a lot of fuel.

Comment Re:Magnetic fields for passengers (Score 1) 533

Yeah, it's supposed to either use "reaction thrusters" (basically it would send out little puffs of compressed air from the same onboard supply the skis use) or control moment gyroscopes.

What I'm proposing is you embed some magnets in the walls of the tunnel a mile or so before the stator slot to force the stator into the correct position.

OR, you could have a "guide" made of light plastic a few thousand meters before the actual metal stator. The capsule control systems try to line up the rotor with the stator slot, such that it fits within this plastic "guide". If it fails to do this, the jerk as the rotor cuts through the plastic would trigger an emergency breaking.

Comment Re:How do you breathe in it? (Score 2) 533

The actual PDF with his plans does mention this briefly. It has a massive air compressor in the front, and the air that's in the hyperloop tubes is just ordinary air that leaked in. There's compressed air tanks inside the front of the car, and so basically some of that compressed air gets injected through tiny holes in the skies, and some of that air is pumped into the cabin, with the exhaust air pumped out the back.

If the car loses pressure, those exact same plastic masks that fall from the ceiling they use on airliners would come down, and the oxygen would come from those chemical oxygen generators that they also use on airliners.

Comment Re:Magnetic fields for passengers (Score 1) 533

If you read the actual article, you'll find out that the "rotor" of the linear electric motors is an aluminum blade that sticks out below the capsule. This is one tricky bit - it has to neatly slide into narrow track of the the stators of the linear motor when it reaches that part of the track at 800 mph. I'm thinking that external stabilizing electromagnets located in the tube itself might be needed to make sure this happens even if the capsule has system failures.

In any case, I don't think the magnetic fields impinging on the cabin should be any worse than if you sat a few feet above a conventional electric motor. (admittedly a several thousand horsepower motor, but still)

Comment Sigh, this is why NASA doesn't get anything done (Score 1) 545

"tall order" to build it in 150 years. Does this NASA director know what the world was like 150 years ago? Virtually all of the technology and all of the thing we have built today did not exist then, nor did the people to build them.

Step 0 to build something like the Elysium is to build large scale, fully automated factories that can churn out the parts to build such a station. Bonus points if those factories can also build many of the components used to build more factories, because you're going to need a lot of them.

Step 1 is to build a set of superconducting quench guns that you would use to actually put those parts into space.

Step 2 is to build more of these automated factories on the moon, since there's no environmental laws against strip mining, and plenty of real estate. Also no atmosphere to slow down your quench gun launches, and a fraction of the velocity needed.

Step 3 is to assemble all that shit together in space.

Now, building a single monolithic ring that rotates for centrifugal pseudo-gravity - THAT's hard to do and probably a bad idea (since if the ring fails, you lose the whole station). I'd much rather see several thousand smaller "hab modules" that spin opposite one another on big cables. You'd take transit cars or small spacecraft to move between the hubs of different modules (and ride an elevator down the cable to each distinct module)

If a cable snaps, you can send a recovery spacecraft to recovery them individual modules - if they didn't crash into anything, the occupants would probably be uninjured.

Comment Re:DOA (Score 1) 240

Not true. At the end of the trip using a transfer orbit, you're still going about 6 kps. That's what the MSL mission control video mentioned on reentry.

The expensive (and completely impractical way) to slow down from 6 kps to under 1 is to bring enough rocket fuel and an engine to make that kind of velocity change. However, you'd need to have a lander almost as big as the rocket that launched the mission.

Or you can try to skim the atmosphere and use a really great heat-shield. That's what MSL did. I understand there's problems with bigger spacecraft doing this, however. That's why landing methods are in doubt.

Comment Re:You're ignorant (Score 1) 285

That's fine, but consider the relative mass ratios of human crew mass to space station mass. The ISS weighs 419,455 kilograms, while it only has maybe 300 kilograms of crewmembers onboard. That means that more than 99.9% of the mass is things that might be able to withstand the acceleration you mentioned.

Now, of course this is optimistic, none of the ISS's assembled modules can withstand 360G of acceleration. But all kinds of raw materials, basic components, supplies, and so forth can. If we had a big quenchgun launcher we could probably send at least 90% of the stuff needed in space as disassembled components that can survive the Gs.

Comment You're ignorant (Score 3, Insightful) 285

The drawbacks you mention apply to rail guns, not Gaus guns. Gaus guns have serious problems of their own (most of the prototype designs aren't powerful enough, the only design I've read about that would probably have truly useful velocities requires superconducting magnets. If you read the wiki article, apparently there's serious problems with iron projectiles.)

On Page 6 it has an interesting table of the actual mass and physical dimensions of the accelerator. Note that muzzle energies far greater than proposed for the Navy's railgun project are possible (the smallest one is 1820 megajoule's, the navy wants a 64 megajoule railgun) but also notice the huge size and bulk of the launcher : 147 meters long.

But there's no arcing problem, and the proposed design is supposed to be reusable.

Comment Yep (Score 5, Funny) 122

In the long run (read : I mean the next 30 years), every job in existence has a programmer involved.

Manual Labor? In the long run, it'll be robots that do nearly all of it, and software is the only real obstacle that stops us from automating more tasks.

Manufacturing? Software problem. Healthcare? Most of a doctor's thinking could be automated with existing software techniques. (sure, not the physical procedures part, but that's only a portion)

Of course, in the LONG, LONG run, someone will advance the art of software to the point that we have software that can write itself, and then we're all out of work...

Comment Reads like an apple ad (Score 1) 238

Apple charges a premium for their products of about 30%. However, they have a very large and dedicated team of developers, and only one major product to work on at a time. Furthermore, as a firm, they are aware that their survival and profits depend on Getting It Right. If they cut corners, maybe skip some testing, don't support their products the day after it ships, it lowers the public perception of their brand, and they will no longer be able to consistently charge that 30% markup.

Shoulda bought an iphone. With the subsidized carrier model, it wouldn't have cost any more than you are already paying.

Comment Economics 101 (Score 2) 52

I think the business lesson here is clear. Whenever you're trying to evaluate the likely success of a business, ask yourself if the business is efficient for the market it covers or not. In the case of facebook games, a bigger company is less efficient, because there's no benefit to throwing dozens of developers at a tiny browser game for casual players. 2-3 people can develop a top tier game in this market, the trick is coming up with the right mechanics.

There's also no natural monopoly in browser games, unlike, say, a connection network like facebook.

Zynga should have stayed small, and just enjoyed it's huge profits from the early hits.

Comment This is great news! (Score 5, Interesting) 104

25-35% less file size for the same quality is an incredible advance. Obviously the task of improving compression algorithms is going to ratchet up enormously as the file sizes get smaller with higher entropy. I'm in fact amazed that an advance this big is even possible, apparently, x264 is nowhere near the theoretical limits for (lossy) video compression.

Slashdot Top Deals

13. ... r-q1