Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re: Honestly, pretty neat (Score 2) 141

Did you RTFA?

The hacker news discussions on this post took off. I just want to emphasize that this post is not a complaint. I’m not whining over this. I’m just showing some interesting side-effects of my email in the license text. I actually find these emails interesting, sometimes charming and they help me connect to the reality many people experience out there.

Comment Re:Imagine (Score 1) 477

Actually, Bussard's polywell fusion would work great in space, considering that the enormous vacuum chamber a test reactor would require would be unnecessary, and so long as your radiators can dissipate all the waste heat, you could build some kind of space-cruiser ship without much in the way of launches by launching the magnetic coils in an IKEA-style "flat-pack" configuration, and unpacking them on orbit.

It's still "hot" fusion, but the only technical hurdle to this is scaling it up to critical volume is expensive, if you need to do it where there's air. Small scale test reactors work, and work reliably, and are even used as neutron sources sometimes - but power is proportional to the square of volume or something, and there's a critical volume where any smaller reactor cannot possibly reach break-even.

If the Rossi E-Cat works* - whether it generates energy is important, not the physical process through which it does - you could build a very compact, fast spacecraft with Roger Shawyer's superconducting, second-generation thruster which is supposed to generate (according to IBTimes) "produce thrust many orders of magnitude greater than that observed by Eagleworks" with an implication that it operates at the same power level. In that case, we now have a rather compelling power-to-thrust ratio, and our choice of electric power sources with Russian sodium-cooled satellite fission-reactors as a backstop if none of the lower-mass fusion reactors are ready in time.

*(I'm not going to rule it out - but I'm not going to hold my breath, either.)

Comment Re:My impressions after skimming through the paper (Score 1) 477

"Making sense" is a generic statement which is expected to be understood within the given context.

Except it was not understood within given context. What made sense is, the results did not fit the null hypothesis, and probably didn't fit H1, either. (Null: No thrust detected beyond a threshold of 80 watts of photon pressure. H1: Anomalous thrust generated proportional to input power, exceeding photon pressure.) This is just the scientists saying, "We can't yet rule this out as a crank. Please send more money."

Comment Re:This is BIG news - If you want to know more.. (Score 1) 477

I fear you've misstated the Oberth effect by conflating it with rockets' efficiency at speed. The Oberth effect says you can get more thrust out of a unit of fuel by leaving it with less residual potential energy, by depositing it deeper within a body's gravity well. This coincidentally happens to be at the fastest point of a gravity assist.

Also, you leave out an interesting tangent, which is that rockets' maximum achievable speed is related to exhaust velocity. At this point, the rocket is accelerating the fuel away such that the fuel is at a standstill relative to an observer. To go faster with the same exhaust velocity, the fuel would end up chasing the rocket, which is a physical impossibility according to currently accepted laws of physics.

Comment Re:Any idea how it works? (Score 1) 477

My money, and the money of every other physicist I know, is on the latter.

This could be true and still leave us with a useful space drive. Perhaps the device is generating an enormous plume of WIMPs, like maybe an enormous plume of neutrinos?

Maybe we should point the thruster at a neutrino detector and see if it lights up. If so, we may have a modulated neutrino source useful for communicating with submarines in two directions. ELF transmitters are huge, and receivers fit on a ship. Neutrino receivers are huge, and transmitters fit on a ship.

Comment Re:Remember Romney Care? (Score 2) 304

Charging "what the market will bear" isn't, if immediately after you agree to pay for a product or service you go bankrupt and/or homeless as a result of buying the product or service. 'Course, when the alternative is a quick/slow unpleasant death under hospital/hospice care that ends up costing the same... not much alternative there, either. Really, the only cheap option is euthanasia, and we're not willing, as a society, to go there yet. Another cheap option would be to allow end-of-life pain management at home in a DIY environment. Not like you're going to give yourself the wrong morphine dose, or misplace a vial, right?

Slashdot Top Deals

To get back on your feet, miss two car payments.