Yes, but I thought he was saying it was dangerous because a nuclear engine could fail, not because a regular chemical rocket launch could fail. If a nuclear engine fails in space, big deal (except for the crew....). But to keep things low-risk, you launch everything dangerous with highly reliable and proven rockets from the earth. It's not going to be risk-free; nothing in life is. But we do have some very reliable rocket engines now, and by the time we're ready to build a nuclear-powered ship to Mars, we should have even more reliable rockets (or, we'll use the same ones we have now, but by that time they'll be even more proven and have more bugs worked out).

The other things we could try are 1) building the nuclear engine here on Earth, but obtaining nuclear fuel from the Moon or an asteroid. I'm not sure how plentiful such fuel would be up there though; didn't they detect thorium or something on the moon? I dunno. 2) This is farther off, but if we could build working fusion engines, there's plenty of He3 on the Moon to power them.

Well, it will work in London, England, where there are several million people living. It works in many European cities already.

Europe has an extremely different climate than North America; it's far more mild. Europe doesn't get brutal winters (well, inland it does, but London and various western European cities are not inland like, say, Moscow), and it never gets very hot (people there seem to think 90F is hot....). Europe's climate is pretty similar to Portland's and the rest of the west coast.

And it works in New York City, where there are lots of Class 1 Bikeways

I live right next to NYC. Not very many people use bikes there, and only in Manhattan, which is only a fraction of the city. There aren't very many bikeways, and the traffic is still brutal. Cyclists regularly get hit by cars and cab drivers (I've seen it myself). You're taking your life into your hands riding a bike in Manhattan, unless you stick to the bikeways that are totally segregated from roads (there's not many of these, mainly in the tourist areas). And again, that's only Manhattan; the other boroughs are not as bike-friendly at all. There has been a push to get people to use "CityBikes", a rental bike system, with some success. If they really want it to be more successful, they need to close down a bunch of the streets and make them bike-only, but I have a hard time seeing that because of the taxi lobby.

including for several of the reasons you cite (eg our roads date back a lot further than colonial times) and we're managing

You've also done things like close off lots of streets, institute tolls for driving in the city at certain times, etc. Those things can't be done here; they're too unpopular both with car drivers and with the taxi companies. London also has an effective subway system, something that only a few US cities have. The US has a far stronger car culture than anyplace in Europe, so it's easier over there to do things which make things difficult for car drivers to the benefit of others; not here.

The only good "Christian" music I've heard is by artists who are musicians foremost, and happen to be Christian and wove some of that into their lyrics, just like every lyric-writing musicians puts some of themselves into their lyrics. But I wouldn't call this "Christian music", because it's not overtly Christian, isn't played on Christian Radio or in churches, and isn't explicitly designed for Christian audiences. "Christian music" is its own genre, and it's just like what you said: it's made by people who chose the medium to create the message, it has an agenda, which is to spread and reinforce Christianity.

I'm not an Uruk-hai, those are a different breed. I'm an orc captain. I enjoy slaughtering men! But I really hate Ents...

The point is, I don't know many places offhand where it would work. Phoenix AZ is an exception; in most built-up places, the roads were not master-planned, and are not sufficiently wide for the traffic they already have. Most places here do not have 3-lane wide roads crisscrossing the metro area. Taking away lanes will just make traffic much worse (and the slight reduction in traffic due to increased cycling isn't going to compensate), and in very many places, there aren't any lanes to take away in the first place. Again, Phoenix is an exception, and is not at all typical of the USA at large. New Jersey is: 2/3 of the population lives on the eastern side of the country, where the local roads were probably laid out in colonial times. Furthermore, even in Phoenix this idea wouldn't work at all, because the city is simply too spread out and sprawling. Even in good weather, no one is going to ride 30 miles each way to work (that's a typical commute there). At least here in NJ, things are generally closer together, but that also means there's no room left over to build proper bike roads; there isn't even any room to build decent car roads, so the traffic is atrocious anywhere near peak times, and the roads are entirely chaotic in their design.

So no, I disagree with your statement that "it will definitely work in some places", except perhaps for a very few, very select locations where the local climate, city layout, and local culture all coincide to allow it to happen, such as Portland OR. Portland, being on the west coast, is a newer city so it likely wasn't laid out in such a cramped way like colonial-era east coast cities were, the weather is excellent as is characteristic of the west coast on every major northern hemisphere continent due to ocean currents, and it has a local culture where things like environmentalism are favored, unlike most of the rest of the US. These factors simply don't exist in almost any place else in the US.

Remember: malfunctioning rockets have a tendency to EXPLODE, and rockets that do not explode but either place a payload into orbit or fail to properly push it out to escape velocity have put something above everybody's heads that WILL come back down someday and probably in an inplanned location.

Saffaya never suggested using a nuclear rocket to launch cargo from the Earth directly to Mars. He suggested using a nuclear engine to propel a ship to Mars, from Earth orbit. Did you miss the bit about the ship having artificial gravity (with a self-rotating part)? You can't do that with a single mission; that's something you do by launching pieces into orbit or someplace near the Earth, assembling them there, and then sending that ship to Mars. That means you use existing, reliable chemical rockets to lift all these pieces (including a nuclear engine) into high orbit or perhaps a Langrange spot. An actual nuclear rocket launched from Earth would leave behind a trail of radiation in our atmosphere, so that's obviously not politically feasible these days; out in space, who cares about some extra radiation?

This exchange reminds me of people who try to push Christian movies and music: "people don't give it a chance", etc., when everyone else think it's namby-pamby, insipid crap with awful plots/lyrics and dreadful production values.

No, I think the retail release should collect at least as much information, and this should be clearly advertised to users. Let's see just how much BS consumers are willing to put up with.

Many democrats are purposely avoiding backing him up, having Obama campaign for them, etc

That's not what I've seen; somehow I got on some Democrat mailing lists and I've seen nothing but nonstop emails asking for donations to help politicians who want to "back Obama's agenda!!!". The DCCC in particular is really big on Obama promotion.

With the Patriot Act. And who pushed through those laws?

Both parties. Both parties pushed them (Patriot Act and NDAA) through, and both parties have renewed them over and over.

From that point on, *homeland security" (by any means) became the main function of government.

Yep, and what has Obama done about the TSA abuses, about all the military weapons being transferred to local police, etc.? He hasn't reined it in at all, if anything it's become much worse under his watch.

And considering the two trillion spent on an unnecessary occupation of Iraq and Afghanistan, plus the number of innocent lives lost or maimed, I can't imaging how ANYONE could seriously claim that Obama is worse than Bush

Obama stepped up the presence in Afghanistan by a huge amount. He also wanted to stay in Iraq, but was forced out by the Iraqis because they wouldn't agree to give immunity to US soldiers.

Obama merely continued what Bush instituted.

That's a pathetic excuse. No one forced Obama to continue (and worsen) Bush's policies.

Actually, I do have to retract my statement about DO-178 standards: using these standards as-is wouldn't work for general-purpose computing kernels, and one giant reason is that DO-178 doesn't allow you to deallocate memory. Once it's allocated, that's it, it stays allocated forever. So "free" (C) and "delete" (C++) are forbidden. This would make your PC run out of memory pretty quickly. It's done in embedded systems because it provides deterministic behavior, and such embedded systems only do one task (or a small group of tasks), continuously, and unlike, say, a smartphone, aren't repurposed to do other things that use a lot of memory (such as running the Firefox mobile browser, then switching over to the Facebook app, then running Tinder, then playing Angry Birds, etc. There's not enough memory in a phone for all of that staying allocated at once.).

Anyway, perhaps a subset of the standards could be used, such as forbidding C++ exceptions. A lot of places I've seen do stuff like this: they use C++, but with a lot of specific rules on which features are and aren't allowed, and exceptions are a big one on the forbidden list. Basically, the main idea is places doing this kind of development like some of the C++ features like object-orientation and inheritance because it lets them avoid doing some of the nasty stuff you see in the Linux kernel, such as all the callbacks and tables used for mapping function pointers; with C++, you can just do that stuff using the standard OO features. Also, templated code: there's a huge pile of #define macros in the kernel which are really just implementing template code, which could easily be done with C++ templates instead. Shifting to C++ would allow eliminating many lines of code this way, and probably making some things safer (not having to worry that you're checking every function pointer for not-null before calling it, for instance), and theoretically this shouldn't affect performance if the compiler works correctly as the generated object code should be the same. It would be an interesting project to rewrite parts of the kernel in C++ and then compare, line-by-line, the object code and verify it's mostly the same and that performance isn't affected, and if it is, fix the compiler or at least identify specifically why it isn't the same.

Yep, I'm a big big fan of PRT like SkyTran. However every time I bring it up, naysayers just tell me how it's "impossible" even though it's just using existing technology and was probably technologically doable back in the 80s or 90s (meaning it's quite easy today with current computing and navigation technology), that "it'd cost too much" even though it's far cheaper than light rail or monorails, etc.

If we had had Slashdot back in the mid 1960s, people there would have gone on and on about how it's utterly impossible to send a manned spacecraft to the Moon.

That still doesn't answer how car traffic is supposed to get around. You're talking about completely removing cars as an option for travel where I live. Voters will never approve that. This approach works in dense cities like Manhattan where walking is normal, there's no driveways (only street parking), and there's lots of streets in a grid, so it's no big deal to shut some of them (the smaller, non-thoroughfare ones) off for pedestrians and cyclists, and let car traffic go around. In a place where ALL the streets are thoroughfares, no matter how small the street, and all the houses have driveways, this approach is impossible.

Or, you can take road space away from autos and dedicate it to bikes. There's a lot of outrage when you do it, but it's possible. Google London super cycle highway debate to see how this is playing out in the UK.

I don't see how you could possibly do that, because now you've made it impossible for cars to get to many homes and businesses, or worse delivery trucks. How do stores get stocked when there's no road for the trucks to bring the goods to the stores to stock them? How do people get from town to town in cars if there's no roads? Taxpayers would never go for a plan like that.

Maybe in some places you could make the streets much narrower to give room for bikes; this would work in Phoenix for example where many streets are 3 lanes wide on each side (good luck convincing people to ride in 120-degree temperatures though). But here in New Jersey, the streets are only 1 lane wide (remember, these roads were laid out a couple hundred years ago most likely); you simply can't narrow them any more than they already are. Traffic between towns is already ridiculous because it's so hard to build highways here, so much of the traffic is carried on narrow streets. This can't be fixed without doing something radical, like bulldozing lots and lots of buildings to build new highways or widen existing roads, or building tunnels (obviously not cost-effective).

You're forgetting the wind chill, and all the extra clothing you have to wear which makes it very difficult to have the proper range of motion necessary on a bicycle. Plus, how do you keep your head from getting too cold? Bike helmets are great for ventilation, but that's exactly what you don't want in very cold temperatures, and they don't cover your ears at all. Back in college when I rode in temperatures like you describe (down to the teens), I wore a thin skullcap under my bike helmet, but that's not nearly sufficient for subzero temps. I guess you could forgo the helmet, and just not worry about a concussion if you have an accident, but that doesn't sound like a very good option to me. If we're going to do that, when why not eliminate all the safety equipment in cars?

I imagine they wear heavy coats and layers of clothing, and don't stay outside for very long, just enough to get from their house to their car.

Walking around for a few minutes in a heavy parka is very different from riding around at 10-20mph on a bike for 30-60 minutes.