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Comment Re:Maybe now, but (Score 2) 358

No, those places are accelerating away from us much faster than 1G. Well, depening on the coordinate system you use to calculate that acceleration, obviously. But with cosmological coordinates, yes, way more than 1G and faster than the speed of light. In any case, you will never reach their speed no matter how fast you accelerate, since you can't go faster than (local) light and even light will never catch up with them. Even if you shine a strong laser at them, that light will never get there.

(Assuming our current theories about the inflation of the universe are correct)

Comment Re:FTL or Wormhole Travel (Score 1) 358

I'm just using the term "never" to mean that, with that particular coordinate system, the event does not have a real time coordinate. Maybe an imaginary or infinite one, but not a real one. But if you apply the right coordinate transformation, all of a sudden it's as real as ever. The question whether or not the event is something that will actually exist, is a philosophical one. We will certainly never see it happen, that's all we can really say.

Comment Re:FTL or Wormhole Travel (Score 1) 358

From our pov, it will appear as if time is moving very slowly in their part of space. You might as well have said we don't exist because time is moving slowly here from their pov. Just because the light from the Jurassic is just now reaching some other place, doesn't negate history. The Universe still has a history. It's just the vast majority of it is unknown to us. It's not frozen in a bottle because of inflation.

There is no absolute measure of time in the universe. Depending on your choice of coordinates (special relativistic with us at the center, with some other point at the center, cosmological model, or any other model), distant events can happen in the past, future, present or even never at all. The only thing that matters is interactions between objects. But if events are separated far enough so they cannot possibly have had any causal impact on each other, it's completely meaningless to say one happened before the other or vice versa. Hell, I can make the Andromeda nebula move several years into the future or past simply by getting out of my seat (using a coordinate system tied to my body). That's the beauty of relativity: coordinates are just a way for us to stick numbers onto things and do calculations, but the universe itself doesn't care. That's also why we have such a hard time with general relativity and quantum mechanics.

Comment Re:FTL or Wormhole Travel (Score 2) 358

There's no real center (as far as we know). You can pick any spot and consider that to be "the center" with everything moving away from that spot, but you can just as well pick some different spot.

Of course that's just one theory, with a truly infinite universe. It's perfectly possible that the universe is finite after all, or that it wraps around at some point. It certainly is very big.

Comment Re:FTL or Wormhole Travel (Score 5, Interesting) 358

It's a bit more complicated than that. General relativity allows you to pick any reference frame, even one that is bent, stretched or distorted in some other way, and do your calculations in that reference frame.

You could pick a "normal" reference frame that obeys the special theory of relativity: speed of light constant everywhere, nothing can go faster, etcetera. Nothing wrong with that, but this turns out to be impractical: we have to pick some place to consider as the center of the universe (for example some place in our immediate neighborhood), and then find that the rest of the universe is moving away at very high speeds, approaching (but not exceeding) the speed of light. This means those galaxies are shrunk in the direction of their motion (Lorentz contraction) and time passes more slowly for them (time dilation). The further you "look" (the infinitely quick kind of looking which you can only do inside a theoretical model, not having to wait for light to get here so we can actually see stuff), the more things are shrunk and the slower time is ticking. At a distance of the speed of light ("c") times the age of the universe, things approach the speed of light and time is passing so slowly that the Big Bang is only just happening right now. In this way of describing the universe, with these coordinates the universe actually fits in a finite sphere around us.

That's a perfectly valid set of coordinates, but I think you'll agree it's not very practical. So physicists invented the cosmological model: imagine a bunch of clocks everywhere in the universe, flying at the same speed as the expansion of the universe (i.e. the same speed as average galaxies in that neighborhood) and ticking at whatever rate the local clocks are ticking at (not synchronized to ours). We define time at any place in the universe as being whatever is indicated by those clocks, not ours. So in effect we change the very definition of simultaneity, moving things from the future into today simply by changing the labeling. Also, imagine measuring sticks available everywhere in the universe, but just like the clocks flying at the same speed as the local expanding universe. To measure distances, we use those sticks instead of our own.

If we now measure everything using local (Lorentz-contracted) sticks and local (time-dilated) clocks, the universe looks completely different. It is truly infinite, the same age everywhere, and distant objects are no longer flat Lorentz-contracted pancakes but look the same as objects in our neighbourhood. Note that this is not a different universe, it's the same one but with different labels stuck onto objects.

Now, with this set of coordinates, it turns out that rays of light don't travel at a fixed speed "c" relative to us, but relative to the local clocks and sticks we used to define the coordinate system. It is still true that nothing can go faster than (local) light, i.e. you cannot overtake a ray of light, but a distant object certainly can move away from us faster than the speed of a ray of light in our neighbourhood. And if some alien over there were to try and shoot a laser beam our way, that light would never reach us because it is traveling towards us at the speed of light relative to the local "space" which is moving away from us faster, like a cosmic conveyor belt. Note that this conveyor belt is not real, it's just a product of our mathematical trickery refefining distances and times.

Of course you might wonder what happens to that alien laser beam in the first coordinate system, where rays of light all travel at the same speed relative to us. Well, in that system, the aliens don't exist yet because time in that part of space is moving very slowly (and has been moving slowly ever since the big bang). And since that part of space is still accelerating away from us ever faster and closer to the speed of light, local time comes to an asymptotic halt before the aliens ever get a chance to shoot that laser.

"Space itself" is just whatever we define it to be. By changing coordinates, we can move things from the past into the future or even into "never". It doesn't matter, it's just math(s), the end result is that we will never see that laser and we will never be able to reach that galaxy either.

Comment Re:Maybe now, but (Score 2) 358

The problems are a bit deeper than "we don't have the technology to do it". If we would be able to break these theoretical speed limits, this would automatically imply we would also be able to travel through time or at the very least send messages into the past. That would create a whole bunch of problems for concepts like causality, free will, grandfather paradox, etcetera. Not entirely impossible, I agree, but unlikely nonetheless.

Comment Re:I have just one question, please. (Score 1, Funny) 106

Why does the sound of a Tesla employee farting make a frontpage splash in this site?

What? Did a Tesla employee fart? Where did you read that? I just googled it and couldn't find anything.

Are you just spreading FUD to discredit Tesla? Post a link to a story confirming the fart, or stop spreading these false rumors.

Tesla's stock is slightly up today, by the way, so I assume there's absolutely no truth to what you were saying.

Comment Re:TC developer used hidden message!!! (Score 1) 475

I would assume that, if the NSA had a back door in TrueCrypt, it would be in their best interest for people to keep using it. So in that case, they definitely would not want to have it taken down.

On the other hand, maybe someone discovered the back door, wanted to remove it, was told by the NSA not to, and then decided the project should be scrapped.

The most likely explanation, though, was that the NSA did not have a back door and therefore sent a letter to have it taken down.

Comment Re:You are wrong,, and probably a liar. (Score 1) 437

The only airplanes where a pilot has to do nothing from roll out to landing, are military drones. And they crash frequently. There is no airliner in existence (or even planned right now) that can take off automatically at all, successful tests have been done but it was decided that the decision to abort or continue a take-off was better left to a pilot and he had to be able to react so quickly that he had to be actually at the controls without losing time by having to take over from an autopilot. So the software for automatic take-offs was never installed in any actual passenger aircraft in service. Landing can be done automatically BUT with a pilot giving instructions to the autopilot, and special equipment at the airport. And it's not just a matter of "push a few buttons and the airplane will fly to the proper airport and land itself". You have to give the right instructions at the right time, extend the landing gear and flaps when at the correct speed, etcetera.

Automatic landing systems are indeed required for Cat III, but the vast majority of landings are not Cat III. Whenever visibility is sufficient, we land manually. We only use autoland when visibility is very poor, and in that case we have a special checklist and lots of extra items to continuously check during the approach, with special procedures to react quickly when failures occur (either in ground equipment or the aircraft itself). These procedures have to be trained regularly. If for some reason one of the two pilots is not certified for Cat III, they are allowed to fly but can only land manually.

And trust me, an automatic landing is MORE work, not less.

Comment Re:no (Score 1) 437

Crashes due to pilot error are more common than crashes due to mechanical failures because when the mechanics fail, the pilots can usually rectify the situation and avoid a crash. Those failures simply don't enter the crash statistics. Take the pilots out, and the number of crashes will skyrocket because there's nobody left to correct the many, many failures that occur in an automated aircraft.

I have never crashed a plane, but have experienced plenty of cases where the mechanics failed and the airplane would have crashed if we hadn't been there to take over.

You cite Air France 447 as "a great example" but it's quite the opposite: in that case, the mechanics had already failed. Without pilots, the aircraft would have crashed just the same. Even more, this exact kind of failure had already happened several times to other crews, and they had always managed to rectify the situation. So basically, the success rate for automation for this particular failure was zero while the success rate for pilots was more than 80%.

In the case of Air France 447, automation was actually working against the pilots, giving them false warnings: stall warning combined with overspeed warning, and later the stall warning disappearing and coming back precisely when the pilots were temporarily applying the correct input, making them reverse their correct action again. So the automation did not just give up, it actually created a much more confusing situation for the pilots. Add to that the fact that many Airbus pilots had never even been trained in stall recovery for a large aircraft because Airbus insisted that it was impossible for an Airbus to stall. They thought the automation was so infallible that they could squeeze that extra half hour of training out of the curriculum to save money.

Another example, not long after that Air France crash, another Airbus plane also experienced an airspeed indication problem and the automation decided, incorrectly, that the airplane was stalling so it violently pushed the nose down. It would have crashed if the pilots had not quickly switched off two computers to put the aircraft into a basic direct control law that allowed them to pull the nose back up. Otherwise, the aircraft would have crashed because it refused to obey the pilots' orders to pull the nose up.

However, I still think driving a car is definitely more complex to automate. An airplane can rely on all sorts of electronic signals, GPS, ILS, VOR/DME, etc. It doesn't need to look outside, it has plenty of space to avoid obstacles and other aircraft. A car has to actually analyze visual data, recognize objects and pedestrians, etcetera. That is incredibly more complex and error-prone. Sure, great strides have been made, but compared to "if the signal says you're right of track, correct to the left", analyzing video images is far more demanding. And the margins are a lot smaller, cars have to pass other cars with maybe a meter between them, while airplanes are considered to be in "near collision" if they are still hundreds of meters apart.

Comment Re:no (Score 1) 437

Exactly, all automatic cars still have manual overrides. As long as these overrides are considered necessary, nobody without a license will be allowed to drive them.

Once the technology is so well proven that manual overrides are no longer necessary (and can even be disabled by a parent), it will be safe for a 12 year old to drive. Just like riding one of the many automatic transit systems already in use today.

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