Except if it's one of these.

You could put on three spheres, so that any objects are always visible by at least two of them. Then you can do some processing (quite a lot of processing, actually) to synthesize the images that would have been seen by two cameras at a fixed distance from each other pointing in any particular direction. I'm not saying it's easy, but certainly feasible with today's processing power. And it would result in less lag than actually having to physically move the cameras. Also, multiple people could use the same feed like popo suggested.

There are obviously some disadvantages, one of them being the much higher bandwidth required to capture 360 degree vision from three cameras in sufficiently high resolution so that a relatively small view window still keeps enough pixels to look good.

But lag is an extremely important issue if you don't want people to get seasick within minutes of using the device.

Yes, because articles on the internet and in newspapers always only contain exactly correct details, no information ever gets lost, misunderstood, or altered in transmission. So if they say the screen was black, it couldn't possibly have been any other shade, and certainly could not have had any text on it, like an error message or something like that. Because journalists never get this kind of thing wrong.

OK, back to reality. Since both the captain's and first officer's iPad "went black" (?) at the same time, and this in multiple airplanes, even after many months without this problem ever occuring in a rather large fleet of airplanes, I imagine this is probably some configuration error related to some sort of DRM, licence expiration or other kind of protection. I doubt multiple iPads would all "crash" at the same time. Maybe the database had an incorrect expiration date, for example. Must not let pilots fly with out of date charts, better give them no charts at all. That sort of thing. Wouldn't be the first time, I've had a few experiences like that in different airline companies.

We've had an airbus grounded because a student pilot had messed with the on board clock, for example. The computers decided that the deadline for flap inspection had passed (based on the incorrect date set by the student) and refused to extend the flaps for take-off. Maintenance action was required before the plane could take off again.

I've never understood the rationale behind a holographic universe. I'm not saying it's impossible, but Occam's razor would seem to suggest it's unlikely.

If I understood correctly, the theory goes something like this: Information cannot be destroyed, yet the actions of a black hole on its surroundings (i.e. what we can observe from outside) are completely determined by its twodimensional event horizon, therefore a volume of that size can only contain as much information as what is present on that surface area. Since you can imagine any area of the universe collapsing into a black hole, and again no information can be lost there, the entire universe can only contain as much information as a twodimensional sphere, so the universe really only has two dimensions.

But why is everyone so sure information cannot be "destroyed" (rendered inaccessible) in a black hole? Many laws of physics break down in black holes, what makes you so sure the second law of thermodynamics will hold?

And it's not like this second law is really a "law" in the strictest sense. Mathematicians would never call this a law. It's like people observing a box with red and blue marbles in it. When they shake the box and then look inside, the marbles are all mixed up. Therefore, they introduce the "law" that the marbles will always be mixed up after shaking the box, and it will be impossible for all the blue marbles to be on one side and the red ones on the other.

Now this second law does turn out to be very practical. Because for all intents and purposes, given enough particles, you may reasonably expect to never see a violation of the second law. And certainly on the scale of the universe, it would be... well... "impossible".

But black holes are not like the rest of the universe. Extrapolating the second law, which isn't even really a real law but kind of a quasi-law, to black holes (which we know little about, apart from speculation) and then jumping to the conclusion that this must mean that the whole universe is twodimensional, is just silly. It's people performing "logical deductions" without asking themselves if that particular step actually makes sense.

Also, the fact that we can only see a certain amount of information from outside the black hole, does not mean that more information could not be present inside. What if you drop into the black hole? Of course you wouldn't survive, but if you disregard that detail, couldn't you find all the "lost" information inside? Applied to the universe, this might mean that you could replace a chunk of the universe with a sphere of that size, and you could calculate the effect of that chunk on its surroundings based on that twodimensional sphere, but that doesn't mean the information inside does not exist.

Also, if gravity inside a black hole is so strong that our usual laws of physics break down, it doesn't seem outrageous to assume that information could indeed really be lost there. Why not? Which is more likely? Information getting lost in a singularity, or our threedimensional world being only twodimensional? I would say Occam's razor favors the former.

Information gets lost all the time anyway, in the expanding universe. There are plenty of galaxies that are moving away from us so quickly that we will never be able to see their light. We are "losing" information all the time, yet this doesn't seem to bother anyone.

Really, maybe I'm missing something, and by all means feel free to enlighten me, but I fail to see a compelling reason to assume the universe has only two dimensions, it seems to be an unlikely solution looking for a problem.

Holograms or it didn't happen!

I'm not an expert, but I thought string theory had dozens of dimensions while the holographic universe has only three (including time)? Looks like a pretty big difference to me.

You mean the ice age that comes after the eruption?

Keep saying that until, a few millennia from now, pretty much every newborn needs immediate medical attention to fix all sorts of life-threatening problems, breast feeding humans can only be found in history books, everyone needs eye surgery to be able to see normally, we can no longer smell anything, babies can only be conceived using IVF because natural fertility is about zero, and so on, and so on. Hey, we can fix all of that with medical procedures, so they are not serious defects anymore, are they?

Eagles have excellent eyesight because their life depends on being able to spot a mouse from high up in the sky. Moles have nearly zero eyesight because they rarely come out of the dark. Yet moles probably evolved from some other animal that did have good eyes. Evolution is a constant balance between natural selection and random degeneration from mutations. It's not black and white, things just evolve to the point where the two "pressures" match. If some quality no longer makes a difference for your ability to reproduce, random mutations over the course of millennia will slowly erode it away. And this random degeneration happens much more quickly than positive evolution, because it's much easier for a random mutation to mess something up rather than improving it.

Of course this does not mean we should re-introduce natural selection by letting people die or prevent them from reproducing, as certain societies have done in the past. But genetic techniques offer a humane way of achieving the same goal. It's already starting to be used to weed out obvious and serious genetic defects, by selecting embryos not carrying the defect, and we'll slowly get better at it so we'll be able to at least stabilize, and possibly improve our genome. If done responsibly, this needn't result in dystopian future societies with rich superhumans and poor degenerates. Just randomly weeding out some bad genes and introducing a sprinkle of good ones is enough to keep things going in the right direction, they will spread out naturally to the benefit of all mankind, while keeping enough diversity.

Or, due to a strange quirk in the space-time continuum, we are actually looking at a future version of our own planet exploding. Don't worry about paradoxes ripping the universe apart, though. The fact that we can see it, means that there's no way to avoid it so there won't be a contradiction. Moving right along.

Well, that's exactly the opposite of what I remember from that study I mentioned, but then again, you can probably find studies either way depending on what the researchers were trying to prove. I can't find the link for mine, but would be interested to read more. (Actual articles and papers, not just opinions).

Fortunately that doesn't appear to be true. Sure, quite a few geniuses with a 150 IQ have trouble finding a mate, but there are just as many people (by definition) with an IQ of only 50. How likely are they to find someone and have kids?

Closer to the average, higher intelligence definitely makes people more attractive, not less. Girls don't want to marry someone who's dumb if they can get a smarter partner. I remember reading a study demonstrating a positive correlation between IQ and procreation, but it was a few years ago and I can't find the link. Anyway, it seems to make sense, notwithstanding trailer trash with dozens of kids and business women running out of time to start a family. Apparently we're still doing OK on average.

There are plenty of other areas, especially health-related, where our genome is slowly degenerating for lack of selection since we can fix so many defects with medical procedures (or simply don't need high quality senses anymore to survive), but fortunately the evolution of intelligence appears to still be going in the right direction.

For all those other qualities that are degenerating, we'll need some kind of genetic manipulation or selection at some point, but we'll be OK for quite a while before it really becomes a problem, and by then we will have gotten over our ethical objections (apparently the Chinese are well on the way).

They did not demonstrate CPU cache snooping. The only thing the app can see, is whether or not certain cache lines have been used (and therefore, some of a whole lot of different possible memory locations may have been accessed). So, for example, if you can figure out that certain cache lines are used every time the user presses a key, you can watch those cache lines to have a rough idea of whether the user is typing or not. You don't know what's in those cache lines, just that they have been used. But since a cache line corresponds to a multitude of possible address ranges, you're not even sure which memory addresses were accessed. It could very well be some totally unrelated process doing totally unrelated things that happen to use the same cache line. But statistically, you get a better than average guess about what kind of activity is occurring on the other end.

The part you need two apps for, is where they demonstrated sending actual data from one VM to another. The app on one side (a keylogger, perhaps) accesses specific memory locations corresponding to specific cache lines. The app on the other side watches those cache lines by reading from them and timing how long it takes. If the location is read instantly, the process on the other side has not accessed that cache line, so that's a zero. If it takes slightly longer, the other side may have accessed it (or some totally unrelated process has), so that's a "probably one". Throw in some error correction, and you can slowly send data from one VM to the other.

There. Still scared?

Those attacks are about as similar as the matchbox car and the high speed train in my example above.

The kind of attacks that could extract bitcoin keys were monitoring certain system parameters like energy consumption with a very high resolution.

This attack can just say whether certain groups of memory locations that correspond to certain cache lines (which is a many-to-one relationship) have been accessed during a certain (rather long) time frame. We're talking a few hundred Hz resolution here. Good luck finding that bitcoin key. Or even a simple web address. OK, maybe visiting certain specific websites would show a specific memory usage pattern that might be recognized. So you'll know that the victim might have visited FaceBook. That's about the best you can do, and even that is pushing it. You're not going to find much more detailed data than that, the method is just too coarse.

They can't even do that. All they can see is whether or not certain areas of memory have been accessed. They write something to a specific location to use a line in the cache and thereby invalidate it for other apps. Then, some small amount of time later, they read from that same location and time how long it takes for the data to arrive. If it takes longer, that means the cache line has been invalidated and therefore some other process must have accessed the memory that uses the same cache line. That gives them a very rough idea about which parts of memory could have been accessed. Very rough, since the same cache line corresponds to many different memory locations.