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Comment: Re:This is fine in theory (Score 2) 113

by ceoyoyo (#48916543) Attached to: Proposed Space Telescope Uses Huge Opaque Disk To Surpass Hubble

I don't think it's an interferometer. It's a standard diffraction lens, just like the Canon one you linked, that produces a real image, not an interference pattern. You could stand at the focal point and see an image.

It would be an interferometer if you put a ring of telescopes on the rim instead of at the focus.

Comment: Re:Bless you. (Score 1) 113

by ceoyoyo (#48916365) Attached to: Proposed Space Telescope Uses Huge Opaque Disk To Surpass Hubble

So long as you're not looking at something really close, the little bit of parallax you get by going around the planet isn't going to cause too many problems. And if you're looking at something where it does matter, you just take shorter exposures and stack them. As a bonus you get 3D measurements.

Comment: Re:Bullshit (Score 4, Informative) 210

by ceoyoyo (#48893811) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

Action potentials are a bit funny. They're not actually movements of electrons down a wire like we're used to thinking about, but rather propagating waves of changes in the way cellular pumps move heavy ions through the cell membrane. Action potentials provide essentially no long-distance current, for example.

If you applied 15 mV across the SA node (the heart's built in pacemaker) at just the right time in the cardiac sequence you might be able to interfere enough to stop the organized contraction. There's a lab at my university that's been looking at analyzing chaotic heart contractions in order to use very small, very well-timed pacemaker signals, to correct them.

You would absolutely have to do it internally though ("applied directly to the heart"). The human body is basically a bag of salt water, which conducts quite well (about 300 Ohm from head to toe IIRC) surrounded by skin, which is a pretty good insulator. So if you want to electrocute someone, stab the electrodes in first.

Comment: Re:Hold your horses (Score 1) 210

by ceoyoyo (#48893639) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

You missed his point. 1 nA per ring, second, hour, whatever, makes no sense. An amp is already of measurement of charge per unit time. If the current measurement is correct, which I believe it is, then the GP's formula is correct. Multiplying a current (charge / unit time) by a time gives you a measure of total charge. Multiplying by the voltage then gives you total energy.

Comment: Re:Interstellar missions... (Score 2) 210

by ceoyoyo (#48893329) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

The previous posters are correct - the clear, low humidity air over deserts is more transparent to infrared light and radiative loss is the major reason for fast cooling at night. I've spent the night out in the Sahara. When the air cools off and you dig into the sand you realize that not only is the sand a decent insulator, just below the surface it's also much warmer than the air.

Comment: Re:Interstellar missions... (Score 1) 210

by ceoyoyo (#48893279) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

Dry batteries don't work well in the cold because chemical reactions slow down the colder it gets. Wet batteries don't *survive* the cold because things freeze. I say this both as someone whose camera batteries often needed to be hand warmed, and as someone who's had to change a car battery at -40 because it discharged, froze and cracked it's case.

Comment: Re:Bullshit (Score 1) 210

by ceoyoyo (#48893209) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

You probably could stop someone's heart with 15 mV. But it would have to be applied directly to the heart, and at just the right time.

For external application (i.e. without the open heart surgery) it's going to take rather more than that. You generally need a current of around 100 mA through the heart to stop it. If you're not standing in a puddle of salt water or gripping a water pipe, it's going to take quite a bit more voltage to achieve that.

110 V household current can kill, if you manage to get a good connection hand to hand. I think the lowest voltages observed to kill someone were around 40 V, but that requires some fairly exceptional circumstances.

Comment: Re:The "what?!" is reaction time (Score 1) 304

by ceoyoyo (#48893035) Attached to: Government Recommends Cars With Smarter Brakes

Crashes have been getting much more survivable, but the number of collisions per car-kilometre has also been flat or dropping. Texting in North America took off in a fairly short period of time. If it were actually responsible for as many crashes as it gets blamed for there would have been a big spike in the collision rate. There wasn't. That supports the idea that the ultimate cause is bad drivers, and texting is just the latest thing they can be distracted by. Texting while driving is undoubtedly dangerous, but so are a lot of other things people do in cars.

Comment: Re:Extradition? (Score 1) 299

by ceoyoyo (#48827301) Attached to: Uber Suspends Australian Transport Inspector Accounts To Block Stings

I imagine the laws governing cars are much like those for boats, but less enforced for individuals. If you're the skipper of a boat you can share costs with guests/crew/passengers but those costs cannot be more than the consumables used on the trip and they cannot pay you for your time. As soon as you accept payment for your services you need commercial permits, your boat has to meet more stringent standards, etc.

Comment: Re:Of course it's good for society (Score 1) 227

by ceoyoyo (#48811645) Attached to: Lawrence Krauss On Scientists As Celebrities: Good For Science?

If publishing a paper is the requirement to be a scientist, it's not surprising that stuff like what Wakefield pulled gets by. Wakefield was trained as a physician, not a scientist. His "research" was conducted unethically, on children, without approval. It's generally believed now that the whole thing was a fraud perpetrated to boost his interest in a competing vaccine company.

Wakefield was trained as a physician and operated as a con man. He wasn't a scientist. I agree with you that scientist-celebrities aren't necessarily the best scientists. Especially the "scientist"-celebrities. Part of the problem is that many of them aren't scientists at all, but are perceived that way because people have the strangest criteria for dubbing someone a scientist.

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