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Comment Re:How does space elevator save energy? (Score 1) 95

It's a lot more fundamental than that. Even with 120 GPa unobtanium they still can't support themselves over those sorts of distances - any cable has to have a large taper factor (the lower the breaking strength, the larger the taper factor is needed). Which makes moving cables impossible, because as soon as you rotate it, the taper is structured all wrong - it has to constantly be thickest at the top and thinnest at the bottom or it will break.

Comment Re:Missing the point a bit? (Score 1) 115

I'm not really in the target audience; but I know that sage, at least, can optionally use sage as a frontend to mathematica. I don't know how the feature sets compare; but if you are using the sage web interface it is pretty painless to interact with a copy of mathematica installed on the sage server; instead of, or in addition to, the OSS tools that it works with.

It may just be added complexity, there may be something that mathematica handles particularly brilliantly that the parent poster has in mind; but it shouldn't be terribly unpleasant done over the network unless your problem is computationally expensive enough that it would crush the rPi whether done locally or remotely.

Comment Re:How does space elevator save energy? (Score 2) 95

Solar cells may produce - on a clear day - 200W/m^2, if they're sun-tracking and unshadowed. A climber climbing over the course of two weeks (more on that in just a second, you need to climb far faster) has to climb 35,5 meters per second. A small 1 tonne climber with 2 tonnes of cargo requires 1 megawatt of power, meaning 5000 square meters. Think you can fit 5000 square meters of sun-tracking solar cells on a climber that only weighs one tonne?

Speed is important because it defines throughput, and your cables - even if you have some mythical unobtanium 100-120 Gpa diamond filament tether - are still very massive objects with very tiny objects climbing them, meaning you need high throughput to make them economically justifiable.

I don't think most people discussing space elevators realize how tiny the margins on these things have to be even with a cable made of unobtanium. Inside the atmosphere is irrelevant. It's the tiniest fraction of your 43000 kilometer trip, you have no margin to make a special case for in-atmosphere propulsion. It's only relevant for the additional problems it causes your cable, such as wind, lightning, ice, oxidation, etc.

Space elevators really aren't a good design. They're just totally impractical even when made of unobtanium. But science fiction has locked a generation onto this concept when there are far better concepts available.

Comment Re:Free Publicity For Amazon! Yay! (Score 1) 215

I'm guessing that Amazon plans to mail these out to customers when they sign up to a premium delivery service.

Or you could just print a QR code and staple or tape it down someplace. Maybe slip it into a plastic envelope. Then you could have one-time-markers that would help prevent spoofing.

Comment Re:Noise pollution (Score 1) 215

They may not even be using LiPos. The energy density of Li-Ions is very good these days. Lots of people are apparently powering their 250-size quads with LiIons, and maybe even some 450s. I aim to try powering my 450 with a 3S2P Li-Ion pack, but I haven't come up with a replacement for my USB power bank yet and there's where all my 18650s are right now. The ESCs will support it, and I think I can get enough current out of it. If I can come up with three more cells and two more servos I'll have everything I need to build another foam plane, too... save for the $11 motor/esc/prop combo

Comment Re:The treaty says no such thing. (Score 1) 199

I'm not really sure how much staking-out of high ground is even possible until one gets closer to economic realization. Even if some treaty said that "Any touching of the asteroids is forbidden forever, with utter seriousness", one could safely enough do the R&D necessary to make grabbing them and chopping them up more practical; basically all the capabilities you'd need for asteroid mining can also be used for satellite launch, automation/robotics, improved astronomy and telescopes, and similar warm and fuzzy applications. The astronomy stuff would mostly fall under 'pure science', unless you can convince somebody that it will help detect ICBMs; but launch capabilities and improved robotics and remotely automated process research have a variety of plausible commercial applications even if the asteroids are off the table.

On the other side of the coin, highflown expressions of legal principle are usually given a great deal of latitude until they actually conflict with the interests of the nations that you need to sign and obey them. So long as the prospect is sufficiently science-fiction, anyone willing to spend a lot of time hounding UN delegates is more or less free to write whatever they want. Were somebody to step up to the table with a vaguely plausible plan, however, it's hard to imagine that they'd have much trouble finding a country large enough to be able to ignore the consequences and more than willing to do so in exchange for a cut of the take.

It seems to me that team lawyer wins more or less by default so long as the implementation isn't worked out(both because it won't actually be happening; and because there will be relatively little resistance to opining against it); but team mining will win more or less by default if they can actually make it cost effective; since laws national and international are bent, broken, or rewritten all the time for markedly less profitable(and much more ghastly) ventures.

Until that time, the posturing is symbolic(either banning the practice or laying claim to rocks you aren't already on course to intercept). If the law says nobody can do it; that will change once somebody concludes that they can turn a profit by doing it; and if I get myself crowned God Emperor of the Kupier belt now; I'll still have to get my tech up and running before somebody else does, or the claim will do me little good.

Comment Re: But (Score 1) 95

Aww, my stalker is back! Hi, stalker!

Don't you have some nutters over at the USGS to argue with? Damned USGS and their pie-in-the-sky analysis that is pretty much exactly what I wrote a couple weeks ago concerning resource availability and work/uncertainties that remain to be resolved! Given that this is what led you to start stalking me, you might want to split your time with stalking them too.

Comment Re:You are all hypocrites (Score 1) 99

when Uber greatly improves the taxi industry

For who? Certainly not the owner-drivers, for them it is an uninsured race to the bottom.

That is a problem that should be fixed. Insurance companies should not be able to deny you coverage while you are on your way to pick up a fare. Uber provides additional insurance while you are transporting them.

As for customers - Uber do not have any "taxis", they are a plain old (illegal) limo company "on a computer".

Oh, so it's better than taxis?

Taxi's can be hailed on the street,

Not in most cities.

taxi's have ranks and other infrastructure to manage street queues at popular locations,

Not in most cities, or at least, they don't function.

you can talk to a human to book a taxi or use an uber style booking app,

Most companies don't have a booking app, and it is not uber style in any case. It's just like making a phone call. It doesn't do any of the things that the Uber app does.

taxi's have appropriate insurance,

You said that already. Having trouble following your own conversation? Are you new?

taxis have regular mechanical inspections,

A problem best solved by demanding mechanical inspections at mileage checkpoints for all vehicles, taxis or not.

and yes, you can legally negotiate an up front price with a taxi driver.

In my experience, they always tell you that they can't do that in the USA. In other countries, I've had more luck.

Uber brings absolutely nothing to the taxi/limo industry that wasn't already illegal 30yrs ago.

having failed to make a valid logical argument you resort to the false idea that legality equals morality

Comment Re:How does space elevator save energy? (Score 1) 95

No, I mean $18k. From your link:

by 2011, the incremental cost per flight of the Space Shuttle was estimated at $450 million,[3] or $18,000 per kilogram (approximately $8,000 per pound) to low Earth orbit (LEO).

The $60k is when you include the cost of the whole program (including the design/development phase) which no figure in my post included. If you want to compare, you need to compare equivalent situations: the incremental cost per launch. And the incremental cost per launch of the Shuttle was an estimated $18k/kg.

Comment Re:Yep, Unions do nothing (Score 1) 99

The Unions did a lot for the average worker. But now they've stopped doing that, and only serve their own ends. Since union workers get paid multiples of the minimum wage, they do campaign to raise it occasionally, but never enough to actually help anyone who is not in a union.

Unions have done a great deal for the average worker. But now we have reached a point where it is difficult to unionize the rest of the workers, yet they still need rights. It is time to move beyond the trade union, and work again to secure rights for all workers.

Comment Re:Not true (Score 2) 383

This post, and many others in this thread have been modded "-1 Troll" just because they don't show Israel as an evil state bent on the destruction of human kind.

No, it's because it's self-serving bullshit posted by an anonymous coward, and therefore should be ignored at best, or alternately modded down as propaganda. Especially the line "The biggest complaint arabs have is checkpoints" when in fact Israel is bulldozing crops, removing water systems, etc.

Comment Re:Here are a couple of more objective news accoun (Score 1) 383

Actually, YouTube removed videos which were encouraging Palestinians to kill Israelis (and were actually faked),

And now they're meeting to talk about removing a whole bunch more content. What do you want to bet that they will only be removing things that should legitimately be removed?

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