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Comment Re:#BlackLivesMatter (Score 3, Interesting) 983

You are drawing a false equality/similarity. The majority of police shooting are NOT directed at homicide suspects. So it would not be surprising to find that if one broke down the distributions of citizens killed by police to find a racial disparity in homicide suspects being killed and, as you point out, this wouldn't be surprising. However since the majority of police do not involve homicide suspects it is hard to say. It is even harder to say because the Republican controlled Congress has blocked funding to study police violence.

Comment Re:Galactic North... (Score 1) 268

...and this is why I don't like the balloon analogy -- people point to the way in which the analogy is completely unlike the analogous system, and then assume that there is a comparable property in reality.

Think of the universe as the dolly zoom in the movie Vertigo. No matter where Jimmy Stewart is, as he climbs up the tower, when he looks down you see the bottom of the tower stretching away from him. There is no real center point -- it's not like the center of expansion suddenly moves up the tower with him. And it's not as if the bottom of the tower is expanding into the ground below. It's just that the space between him and the bottom appears to stretch away.

Comment Re:Getting close to design sensitivity (Score 1) 220

Actually, let me rephrase that -- it's not counter-intuitive at all that amplitude goes as 1/r, but what's odd is that with gravitational waves, you directly detect the wave amplitude, so detectability falls off as 1/r. For most waves, you detect the wave intensity, which goes as amplitude squared and therefore 1/r^2.

Comment Re:'10 times more efficient' and xenon gas (Score 4, Insightful) 52

It's all about delta-v, not about the occurence of said gasses on Earth.

Rockets work, whether we like it our not, according to the Tsiolkovsky rocket equation: the delta-v you can obtain it only logarithmic in your start mass / payload fraction, but linear in your exhaust velocity. That velocity is in ~3 km/s for chemical rockets, but 20-50 km/s for ion engines. That allows you to push a probe/ship from LEO into a transfer orbit using a massively lighter ship, which in turn allow you to launch that into orbit using a massively smaller launch vehicle.

Comment Re:Public-key cryptography is the death of freedom (Score 2) 55

I don't like locked-down computers any more than you do. I hate ransomware even more; it's the single most despicable use of public key cryptography there is. But consider that without public key cryptography Apple wouldn't even be in a position to stop the FBI from hacking the iPhone. Individuals wouldn't even have the option to secure their personal communications, at least not in practice. (Yes, I know all about one-time pads. That's why I said "in practice"). Nor would we have the Internet, or at least anything like the one we have now. And without the Internet, computers of all kinds (secure or non-secure boot) wouldn't be nearly as capable and available as they are now because the volume and demand would be vastly less.

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"Necessity is the mother of invention" is a silly proverb. "Necessity is the mother of futile dodges" is much nearer the truth. -- Alfred North Whitehead