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Comment Re:Would D-Wave Take That Risk? (Score 4, Interesting) 224

Chances are, they don't know themselves exactly how "quantum" the system is. It's unlikely to be an outright fraud --- there's something other than a Core 2 Duo on the inside faking quantum results --- but a system working on the hairy edge of current technical understanding. They've built something that has a bunch of cryogenic doodads and performs annealing, but the technical understanding isn't all there. That said, they have demonstrated signs of acting in bad faith --- being very cagey about offering real details, and performing poorly-done comparisons against sub-optimal classical systems. So, they know that even they don't know whether the system they have lives up to claims, and are acting like a for-profit corporation rather than researchers with integrity about it.

Comment Re:Dark Matter is only a filler (Score 1) 62

The reason that the dark matter separates is the same reason that it follows a different distribution from visible matter in other galaxies (a diffuse blob instead of a galactic plane): whatever the stuff is, it's very weakly interacting with everything else (including other dark matter). Normal matter experiences "drag" as you push one cloud of it through another --- from the particles interacting and bouncing off of each other (or, at least, more gently being pushed by electromagnetic radiation from other particles). These interactions, as particles clump and stick and drag, are what allow a galaxy to collapse into a flat disc (instead of a big, amorphous gas cloud). But Dark Matter hardly feels this "drag" at all --- it's extremely "slippery," so two clouds will pass through each other virtually undisturbed. The lack of interactions also makes it really hard (impossible, so far) to catch DM in the lab.

Comment Re:A Marble mountain? A mountain made of marble? (Score 2) 62

Same reason that these kinds of experiments often use "ancient lead" [aspera-eu.org] that has been buried under the seas for thousands of years: Stuff that has been underground for thousands or millions of years is vastly less likely to have been made radiative from the sun or other cosmic sources.

Newly-mined lead is not radioactive due to the sun or cosmogenic sources, but because of isotopes of lead which are produced from decays of uranium and thorium (which already existed from the supernova remnants that formed our current solar system) --- see here. So, you don't want lead that you've just mined from millions of years deep underground --- that stuff is still pretty hot. What you want is stuff that was mined by the Romans two millenia ago, separated from the underground crud full of uranium/thorium, and left to cool off since then.

Comment Re:A Marble mountain? A mountain made of marble? (Score 3, Informative) 62

Just about every kind of rock has background radiation of its own, which must be dealt with (some more than others). However, radiation from rocks is typically easier to deal with than cosmic rays from space --- it's lower energy stuff that can be blocked by a few extra layers of extra lead/copper shielding (carefully screened for even lower radioactivity), instead of energetic particles that go through hundreds of meters of material unhindered. You have to worry about things like radon (radioactive gas) seeping out of the rocks and getting into the equipment; but, these are known effects to watch out for deal with by proper ventilation/sealing.

Comment Re:Dark Matter is only a filler (Score 3, Informative) 62

We can make estimates of the amount of dust out there based on the light we see from distant stars. Where there is dust, it will scatter light passing through it (and modify the spectrum). There are lots of open questions about how much and what kind of dust is out there --- this isn't a "solved" problem --- however, best estimates plus known uncertainties don't put this within range of explaining dark matter. So, we still need dark matter to "make the math work out."

Comment Re:Foam/warpage (Score 2) 62

What collider experiments do look for is "missing mass" --- if the amount of stuff coming out doesn't add up to the stuff going in, minus known detector inefficiencies (indicating some new "invisible" particle being produced). So, people are looking for dark matter production --- anything that results in mass/energy being converted to unknown/undetectable forms --- in a systematic manner. You may not specifically be looking for "spacetime foam," but anything that doesn't mimic "ordinary" particles in firing detectors (thus would already be visible in existing DM searches) in sufficient quantities will be found.

Comment Re:Foam/warpage (Score 1) 62

Who assumes matter-antimatter collisions are "nullfiications"? They don't produce "nothing," but spit out particles with the "combined" properties of the inputs --- i.e, back-to-back photons carrying the energy and momentum of the initial particle/anti-particle pair. Also, if DM is some localized warpage in space-time, why does it appear gravitationally bound to visible masses (i.e. accumulating in galactic halos)? Space-time wiggles (like gravity waves) don't behave that way in known theories. unless you're just stringing together random words with no meaning to sound smart.

Comment Re:Chinese Mountain, Italian Mountain... (Score 3, Insightful) 62

We just had a story about "people doing something on a computer" last week. Not much has changed about the existence of computers since last week. No need to post articles bothering with the trivial details between one computer system and another --- it's all the same, once you've seen one. Only alert me when something new happens in the world.

Comment Re:California (Score 1) 374

Personally, I'd consider the best defense to include the communal societal infrastructure to prevent death-squads commanded by the ultra-rich from roaming the streets, rather than individual approaches like a gun under my pillow and hoping I can shoot faster than a hired goon squad. I'd greatly prefer the freedom to not constantly worry about being gunned down to the freedom to maintain an effective personal arsenal (which might not turn out to be as good as the personal arsenal commanded by a hostile oligarch).

Comment Re:Dark Matter is only a filler (Score 4, Informative) 62

We're talking about that one decimal place before the decimal point: current observations indicate more than five times as much dark matter as known matter. It's not just a little bit of round-off error in how much dust there is between stars, but apparently most of the stuff in the universe (at least, before you get to "dark energy," which is "twice as big" again, but far more poorly understood).

Comment Re:Ridiculous premise (Score 1) 267

Who said all cars would be driverless? More likely, drivered cars will go the way of the horse-ful carriage: a specialty item for enthusiasts off the major highways. And, why do you assume there's anything that will limit driverless cars to the 0.01%? In mass-production mode, there's nothing overly expensive needed for a driverless car --- a few cameras and scanners (which are mainly pricey now due to low production, rather than fundamental materials/manufacturing barriers), plus some clever software (which has zero marginal cost to reproduce). If you can fit enough computers in a car today to drive it, then you'll have enough computers in every telephone in another decade or two (the timescale needed for legislative updates plus people replacing old cars).

Comment Re:Ridiculous premise (Score 2) 267

So, the horseless carriage was never invented, because the motor is the horse? Rather, "driver" has, in common meaning, indicated the person controlling the car; and, if you see a car coming down the street towards you without a person at the wheel, you think "holy shit, that car has no driver!" (just like someone might have thought "holy shit, that carriage has no horse!").

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