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Comment Re:the main legit use i can see (Score 1) 223

I presume that this would be integrated with some kind of app on the receiver end. When the truck is dispatched (or, if the depot is in range, when the parcel is ready for direct dispatch), you'd get a message telling you the time window when it will be available. You then signal that you're ready to receive it and give some GPS coordinates. It's then dispatched and sends another message when it's a few hundred metres away. You then go outside (or stand on a balcony) and wait for it to be delivered directly to you. Once it's very close, it can use WiFi from your phone (send your MAC address to the drone and the SSID that you're associated with - or create an ad-hoc network if you're out of range and it can home in on you) to check that it's actually landing by the correct person. Then just tap the 'delivery received' button and it will fly away.

Comment Re:How does space elevator save energy? (Score 2) 111

No space elevator designs that are even vaguely plausible include a moving cable. To understand why, consider the mass of such a cable: the energy required to accelerate it and then decelerate it for the cars to start and stop would be phenomenal. You could potentially have a loop that would continuously move in a circle, but you'd still have problems starting it. Just dropping things from the top wouldn't be enough, because you'd need to get them a fair way down before they'd stop orbiting and actually provide force in the correct direction. I don't even want to think about the lateral forces that such a structure would have to endure.

Comment Re:"Failed" push for renewables? (Score 1) 334

Speaking as someone who, back in the late 80's, out of my own fear due to ignorance and a lack of foresight, voted to shut down Rancho Seco, [...]

If it's any consolation, you were probably right at the time. We can only talk about how good nuclear power is now because of the moratorium on new plants which let us skip a generation of reactor design. If the US had been building nuclear plants in the 80s, your electricity bill today would still mostly be paying off the capital costs.

Comment Re:Hydro = from the sun (Score 1) 187

Direct solar may sound nice and work fine in small scale, but collectors would have to cover great areas to be effective

The total world energy consumption is somewhere around 100PWh/year. That's around 274TWh/day. The sunlight hitting the Earth is around 1kW/m^2, so 8kWh/m^2 assuming 8 hours of sunlight. If you assume 100% efficiency in conversion (totally impossible, but we'll start there and refine later), then that means that you need about 3.45E10 m^2 of land devoted to solar power. That's a square about 185km on each side. If you assume 10% efficiency (mass produced photovoltaics are 12-25% these days), then you need an area about 342000km^2, or about the area of Germany, to power the entire world. Now, given the efficiency of power distribution, you probably wouldn't want to put it all in one place, but you could easily fit solar panels enough that, even with transmission losses, you could power all of North America in Utah or Texas without anyone noticing. The difficulty is not the generation, it's the storage.

Comment Re:Litigious Much (Score 1) 815

I don't want to get into an argument about biblical exegesis (reading ancient texts with our post-Enlightenment mindset is fraught with difficulty at the best of times). My point is that what Ussher did wasn't at all stupid. Actually it was remarkably smart and scientific by the standards of his day, and given what little he had to work with.

Comment Re:Litigious Much (Score 1) 815

Some bishop interpreting the old testament came to that conclusion, [...]

James Ussher gets a lot of crap for this, and I think it's quite unfair. He didn't just use the Hebrew sacred texts, he actually used all ancient texts at his disposal, such as Greek mythological texts, and found that they all stopped at around the same point. When you consider the constraints that he was working with, this is actually quite a scientific approach. Moreover, 4000 BCE is probably close to the limit of human cultural memory, given that writing wasn't developed until about 3000 BCE.

Ussher was neither the first nor the last person to try this and come up with a similar figure. We probably wouldn't remember Ussher's chronology today if it weren't for some idiot adding it to annotations in the King James Bible.

We're living in a golden age. All you need is gold. -- D.W. Robertson.