I think comets tend to be moving far to fast for a gravitational slingshot to have much effect. Your basic gravitational slingsot involves a near-miss head-on collision with a planet racing towards you. You whip around the planet and fly back roughly the way you came with your initial speed plus the orbital speed of the planet. Obviously you can do a less dramatic maneuver, but you only get a fraction of the speed boost.

Comets meanwhile have typically been falling towards the sun from a good portion of a light year away, and are moving far, *far* faster than the planets, so even an ideal slingshot maneuver wouldn't alter their speed much, relatively speaking. At most their path gets deflected so that they leave the inner system with a very different trajectory than they entered with, rather than heading back out pretty much the way they came, essentially rotating the major axis of their orbit. But their orbital energy, and hence the basic shape of their orbit, remains largely unchanged. Unless of course it hits something, but that's a matter of hitting one of a few dust motes in an Olympic stadium, and is highly unlikely for any given comet.

In the case of periodic comets (those whose highly elliptical orbits will eventually bring them back into the inner system) you can have cumulative effects, especially if it happens to have an orbital resonance with one of the planets. And over the course of several orbits it's possible for gravitational effects to "fine tune" it's path in ways that increase the odds of a collision. But I believe this comet is on a parabolic path rather than an elliptical one (considerably higher orbital energy), so unless it hits something on this pass (or evaporates) it will slingshot around the sun and then depart to interstellar space, never to be seen again.

Sure we do - Solar, wind, nuclear, etc. are all perfectly viable energy sources, they're just currently more expensive than fossil fuels (especially when you factor in battery costs) so market forces have continued to favor those. Prices continue to fall though, and now we have Aquion selling batteries for 1/10th the amortized cost of lead-acid for stationary applications, which will ti the scale even further. And if we stopped publicly funding the various tax-breaks, subsidies, environmental damage immunities, and wars of corporate convenience that are propping up the fossil fuel industry we'd see renewables suddenly take a huge leap forward.

And if you're afraid of the sudden surge in energy prices, take all those public funds saved and distribute them to consumers instead so that they can afford the increased prices. Make oil compete on a level playing field and it really isn't all that attractive anymore as an energy source. Meanwhile as a lubricant we already have far superior synthetics, and we could live without plastic.

Not necessarily - Venus has no geomagnetic shielding either, and gets hit by a far denser solar wind. In fairness it's thick ionosphere interacts with the solar wind to generate an induced magnetosphere, but such a thing could potentially be engineered elsewhere.

Plus, even without a magnetosphere we're talking about a process that takes thousands, maybe even millions of years to strip a planet of it's atmosphere - if we can build it up in the first place we should be able to compensate for the losses easily enough. Hell, Mars *still* has an atmosphere, even if it is pretty thin these days.

Actually IIRC Mars may have been fairly Earthlike (at least geologically) as recently as ten million years ago, which would suggest several billion years of warm, wet history before it became the frozen desert we see today.

Well, if they would stop cutting back funding to fusion research we probably would have it by now - TOKAMAK advances on that front have been keeping pace fairly consistently with initial estimates in terms of progress per dollar, but funding has been decreasing exponentially almost from the day of the initial 20-year estimate.

On the other hand the fringe projects seem to be making some pretty impressive progress on potentially far more efficient fusion strategies. EMC2's polywell fusor seems to have confirmed their theory and it's scaling properties, have worked out most of their engineering problems, and is potentially just one properly-funded full-scale prototype away from generating energy from the holy grail of p-B11 fusion. General Fusion's lead-vortex machine is still proving the components can be built to spec, but I think I heard their theory is pretty well accepted. Then there's Focus Fusion and several others. $100,000 in funding to any one of them, chicken feed compared to TOKAMAK funding, might well get us viable fusion within the decade.

So what? You're not going to alter the planet's trajectory enough to be an issue just by throwing a few pebbles at it. Especially if those pebbles are spread fairly evenly across multiple years so that the perturbations tend to cancel each other out. Even if it was just one ginormous impact that is unlikely to necessitate anything more than altering a few decimal places in the orbital parameters to keep our planetariums accurate.

Remember - both Earth and Mars have been hit by truly *massive* bodies in the distant past - in our case it knocked off enough material to form the Moon, In Mars's case it formed Olmypus Mons on the opposite side of the planet from a basin spanning a good portion of the hemisphere. And yet both planets have almost perfectly circular orbits (yeah, they've no doubt been circularizing ever since, but still).

Plus, if you don't slam the comets into the surface, how are you going to add their water to the planet? Warming the planet substantially with cometary friction heating is a fool's game - the real gains come from increasing the density of CO2 in the atmosphere so you can capture more solar energy. IIRC on Earth the CO2 from burning a single gallon of gasoline will capture something like 1,000,000x as much solar energy as was generated in the initial combustion before it gets recaptured, and without oceans or plant life I'm betting the Martian carbon cycle is *far* slower. Perhaps we could find some asteroids rich in carbon and oxygen and shatter them just before hitting the Martian atmosphere so that the whole thing burns up in the atmosphere, adding a bunch of fresh CO2 and kick-starting a little intentional global warming.

Can we get the politicians to lead the charge?

Only the fat ones.

Conveniently, they're also the easiest to catch.

I've been slacking, hadn't seen that one before.

Sure, given preservation capabilities far in excess of anything the human species has ever accomplished, and a way to exterminate everyone else up front, you could pull it off. Out here in the real world the laws of thermodynamics require that you assume a steadily diminishing breeding pool to pull that off - only the Midgard Serpent can survive indefinitely by eating it's own tail. As is covered just slightly further down that page - assuming everyone is struggling to survive and half the population eats the other half every month to maintain a sufficient caloric intake we'd only last a few years.

Right, because human consumption is the only thing that matters - once we wipe out all other life on the planet we'll be free to eat each other forever!

Care to place a bet on that? Shouldn't be so terribly difficult to write an en/decryption routine in javascript. A bit slow perhaps, but perfectly functional.

1) Rule #1 of UI programming - essential messages will never be read. A "protected" folder might work though. You could also potentially offer an offline key storage service (with heavy validation for retrieval) so that those who are willing to trust you can at least get protection from anyone *else* accessing their data.

2) you may have a point

3) Umm, exactly? You seem to be agreeing with my point. Client-side encryption offers a shot at real security, server-side mostly only offers a minor inconvenience to a competent hacker, and none at all against an NSL, bribery, etc. Same for client-side encryption where they keep a copy of your key on their servers. Sure it'd be nice if they had some server-side encryption to keep at least the script-kiddies at bay, but how big a threat are those, really?

I never said I don't like them - I don't have much use for their services personally, but they seem quite handy for those who do. I was simply correcting the statement:

>One of Dropbox's features is the ability to access your Dropbox files through your web browser. Which can be very convenient for some people.
>Obviously they couldn't do that if your account was encrypted to an extent that even Dropbox couldn't decrypt it.

Because obviously they could do so if they wished to, it would simply involve inputting your encryption key into the web interface. Hell, they could even generate a (crappy) encryption key from your password and keep the current level of convenience - so long as they don't store the password anywhere (which is a crappy security move anyway - that's what salted hashes are for) it would at least make your data a lot more inconvenient for anyone else to access.

That was my takeaway as well.