Follow Slashdot stories on Twitter


Forgot your password?

Comment Re:Here's a thought... (Score 2) 309 309

When I was a teen in the late 90's and early 2000's I was a member on a number of forums and I had a pretty thorough presence on the 'social media' sites of the time. Yet I don't think I ever wrote something of significant embarrassing consequence to me now. I don't think it was because I was particularly mature (I wasn't, actually it was the opposite) but instead I think the nature of social media changed. Back then you would mostly be talking with a small group of like-minded friends. Anything dumb that you wrote would never have been known by a large number of people. Nowadays twitter and facebook and youtube make it possible for 14 year olds to have thousands of followers. A premature brain should not have that kind of exposure. Of course bad stuff is going to happen.

I don't know how to change this. Maybe restrict the access of teenagers to mass social media, or put educational programs in schools that inform kids of the dangers.

Comment Re:Blimey (Score 1) 502 502

Ignorant. The law of conservation of momentum is a law that can be precisely formulated in mathematical terms and ever since it was, no violation of it has ever been observed. Not even a little. Further, it has deep theoretical underpinnings that would mean a universe that violates it would look very very strange indeed and probably nothing like our Universe. By comparing it with the theory of epicycles you're simply showcasing your scientific ignorance and stupidity.

Comment Re: Blimey (Score 1) 502 502

It's not impossible that the theory is wrong. It's just so remotely improbable that even considering it as a possibility is almost certainly a waste of time. Why are some people so eager to throw out established science, when it's far, far, FAR more likely that it's an experimental error or miscalculation?

We saw this with the bogus and unnecessary 'explanations' for the pioneer anomaly, the FTL neutrinos, and the e-cat device. There is no shortage of contempt for science, it seems.

Comment Re: Looking more and more likely all the time... (Score 2, Informative) 502 502

> The science behind it is openly shared without any secret sauce claims.

There is no 'science behind it'. At best there's some experimental data which is probably measurement error or a mundane effect that isn't being considered.

> the science is genuinely sound.

Actually, the claim of "thrust without reaction mass" is not only unsound, it's so far off the scientific deep end that it boggles the mind. You may not need to carry any propellant for this engine to work, but you sure as heck need to carry tons of LSD to keep it working.

> It's not even the only known way to get thrust without fuel - solar sails do that too.

Solar sails use reaction mass. They just don't store it on board.

> Engineering scams are nothing new but this breaks every pattern

It doesn't fit the pattern of 'scam', true. It does, though, fit the pattern of 'hopeless optimism getting in the way of actual science.'

Comment Re:Blimey (Score 2) 502 502

ANY non-zero amount of thrust requires reaction mass, even if the amount of thrust is 'negligible'. Sometimes the reaction mass is stored externally (e.g. light sails), sometimes it's a planet (orbital magnetic thrusters) but it's always there.

Either no thrust is being produced or there is reaction mass. You just have to find out what it is. If the reaction mass is not sufficient to explain the thrust, then it's bunk. Plain and simple.

Comment Re:Uhmmmm (Score 1) 617 617

The ballpoint pen is actually a fairly recent invention. Ballpoint pens of similar quality and reliability of what we use today weren't really available before WWII. It's slightly tricky to come up with balls of good fit and ink that won't clog up the ball's rolling.

Fountain pens date back a few centuries, and various types of quill and bamboo pen are older still.

Comment Re:Richard Feynman said something I can't forget (Score 1) 60 60

I don't fault Feynman and the others for working on the bomb during the war. There was good reason to think Hitler might have been after a bomb, and the true nature of the weapon being constructed wasn't known to anyone except a small group of people. Most of the scientists were just given a few anonymous equations to solve and they did it.

I do, however, fault those that chose to stay after the war and continue working on nukes.

Comment Re:It only works without humans (Score 1) 503 503

> A military target should make a point of either being hardened enough that it could take such a hit without serious damage

Well, with a foil weighing just a few micrograms you could get a yield equivalent to several kilograms of TNT, assuming an impact velocity of several thousand km/s (and thus significant fusion yield). Increase the impact velocity by a couple of orders of magnitude and you're looking at about a ton of TNT.

> or unpredictable enough that you simply couldn't be that sure.

How? In space it's not like you can just change direction at will. Doing so requires a lot of fuel and a lot of mass. You yourself are saying that your missiles would have to be light and they'd fire their thrusters once to head towards their target.

> Beyond that... the laser would be detectable. It would both make the "foil" detectable which would mean it could be intercepted by something else.

Not necessarily. Unless you're directly in the beam path, it's hard to detect lasers. And if you're in the beam path it's already probably too late.

Comment Re:It only works without humans (Score 1) 503 503

One possible option for a kinetic weapon would be, for instance, a high-power laser shooting thin metal foil at a target. The foil is accelerated by the laser power from the moment of launch up until it hits the target. i.e. the projectile is in constant acceleration during flight. We've already been able to accelerate thin films to 1000 km/s velocity; this would cause considerable damage if it were to hit a target as the atoms in the foil would fuse with the atoms in the target, multiplying energy output by 100x or more.

Your good nature will bring you unbounded happiness.