> SpaceX want to remove the parachutes, too?

No, they are not removing the parachutes, they'll be kept as a backup system in case the landing thrusters fail.

It'll be a while before we start towing asteroids into Earth orbit. Earth-Moon Lagrange points will be the first destinations, then after we get good at that we'll gradually allow more and bigger rocks closer to Earth.

As for kinetic bombardment from orbit, the energy budget is not promising for this scenario. The amount of reaction mass needed to de-orbit a large boulder is "non trivial" to say the least. I suppose you could build a rail-gun and shoot a small mass at high velocity in order nudge a bigger rock into decay, but unless you've got a really huge capacitor, you'll have a tough time "dropping" a rock from orbit that would do much more damage than a standard cruise missile.

It's trivial to track such changes in velocity. So if you can't "drop" your boulder directly on target without taking a couple of orbits to decay, then the weapon loses it's surprise/initiative. The target could simply nuke it in space before it has a chance to de-orbit.

Then you've got the problem of cross-range deflection. Unless you don't mind waiting a few hours (or days, or weeks) until your rock's orbit takes it right over your target, you're going to need some way to widen your zone. The rail-gun can do some of this work, but you're going to need an "aerodynamic" rock in order to hit a precision target.

I'm not saying this is impossible, I just don't think it's very likely, given how many other (much easier) ways we already have to do the same job.

If you're not familiar with potholer54 you should check out his videos on climate change. He cuts through the BS/hype on both sides of the issue, and is reasonably amusing too. Very worth the time.

Mod points can't be changed, only deleted. Could be somebody accidentally down-modded somewhere else in this discussion, and posted with their real uid to undo the mistake. If they had previously up-modded the parent, that mod point would be gone now too.

Thanks again for "translating" the argument into language I can make sense of. IIRC, Lerner does acknowledge the engineering challenges in the "PCST" (nice acronym, btw). But if he can demonstrate the p-B reaction with his method (especially if he can do so for $200k), that could open a floodgate of interest and investment.

Doing that reliably on an over-unity energy budget would be a "BFD" (in the words of VP Biden), and it could dramatically alter the course of R&D. I'm just "spit-balling" here as a non-expert, but the PCST sounds a lot less challenging than the Tokamak.

That is interesting. Thanks for the link. I wish I had the expertise to follow the argument in detail, but I'll just have to take "their" word for it (on both sides) and wait and see how it all turns out.

That said, I confess that I hope Lerner can make his method work. From an engineering POV, it's an elegant solution to the problem of plasma instability... don't fight it, use it to your advantage. The history of science may be littered with "elegant" ideas that didn't pan out, but there are also quite a few examples of ideas that were initially scoffed at by the mainstream, and nowadays are mainstream.

If that is the case, then why haven't they done a single experiment in centrifugal "artificial gravity" yet? Heck, they wouldn't even need ISS for that. The idea has been around since the 60s (at least), but it's never even been tried by anyone that I know of.

Part of the problem is that Mr. Lerner also favors a steady-state model over the Big Bang theory, so he is not taken seriously by the mainstream scientific community. OTOH, he does appear to know a lot about plasma behavior, and has gotten some interesting results with the small-scale "garage" experiments he's done thus far. If $200k is enough to get his work to the next level where he can show some more compelling evidence, maybe that will be enough to get some VC guy like Khosla to give him a few million more.

In any case, he seems harmless enough. And he doesn't appear to be blatantly trying to rip people off, like so many of these "free energy" gurus... I say let him proceed, and see what he can come up with.

If you're curious about the approach, watch his Google Tech-Talk for the details. It's one of the more novel methods I've seen.

If the price to "unlock" the demos is cheap, they might have a winner, but then why would their current customers continue to pay those hefty per-seat fees? OTOH, if they're going for a mass-market shift toward cheap, ubiquitous 3D printing, that would make sense. I just don't see how a big corporation would make a move like that on such a short time scale. Methinks this is more marketing hype than a real strategic shift.

I was thinking the same thing. And this breaks down their analogy to the Google Nexus, since Android was released as "free" and (reasonably) "open" software. OTOH, if you can afford a $5k printer, you can probably afford a "seat" license for AutoCAD too. Seems to me the maker-bot crowd have already sparked the fire, so I'm not sure how this new offering is going to speed up the revolution. I don't see anything wrong with what they're doing either... just have to wait and see what comes of it.

Lady Marmalade

Hey Sister, Go Sister, Sol Sister, Go Sister
Hey Sister, Go Sister, Sol Sister, Go Sister

Today's /. fortune is particularly appropriate: "There has been a little distress selling on the stock exchange. -- Thomas W. Lamont, October 29, 1929 (Black Tuesday)"

Someone has proposed a solution. Actually, more than one solution.

The first video is Amory Lovins giving his presentation Reinventing Fire. This is a detailed plan for eliminating all fossil fuel emissions by 2050 for no greater cost than business as usual.

The second video is Allan Savory showing how to sequester vast amounts of CO2 by reversing desertification with managed grazing of livestock.

Both of these solutions are already happening in many places, it's just not common knowledge yet.

For the most part, yes. But if it travels such a long distance it's more likely to be picked early and "ripened" in transit. Also, supermarket produce is more likely to be treated with pesticides, herbicides, etc.. Your best bet is either to grow your own or get to know your local farmer.

...is also a major culprit in this story, in part due to the "low-fat" orthodoxy that developed in the 1970s. When you take out the fat, you lose a lot of the flavor, so sugar was used to make processed foods more appealing. Even worse, hydrogenated vegetable oil was used as a fat replacement. (Turns out that saturated fats are not as bad as they thought back then.) Another problem with processed foods is that they contain far less fiber, since removing the fiber is an easy way to extend shelf life. But this affects the way they are digested and absorbed, exacerbating the bad side effects.

Dr. Robert Lustig has an excellent lecture about sugar and how it is the single most important change in our diet in the last few decades, and the chief cause of rising obesity and diabetes rates. (The above link is a TED Talk, he also has several long format lectures available on YouTube.)

The author Michael Pollan has a simple set of 3 rules for managing your nutrition: 1. Eat food*; 2. Not too much; 3. Mostly plants.

* What he means by this is "real" food, rather than the "edible food-like substances" that constitute the bulk of the American diet. He has a simple rule for identifying real food: If you've ever seen it advertised on TV, it's probably not real food. Also, for various reasons, there is an inverse relationship between the "realness" of food and the distance it travels from its source to your plate.