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Workable Fusion Starship Proposed
Adam Korbitz writes "A former colleague of Edward Teller — father of the hydrogen bomb — has published a new paper proposing a design for what could be the first practical fusion-powered spacecraft (PDF). As described at Centauri Dreams, the design has certain similarities to MagOrion, a 1990s-era proposal for a nuclear-powered spaceship with a magnetic sail and propelled by small-yield fission devices. The proposal's author also has links to the British Interplanetary Society's Project Daedalus, a 1970s proposal for an unmanned fusion-powered interstellar probe designed to reach 12% of the speed of light on its way to Barnard's Star."
See here:
http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
and here:
http://nextbigfuture.com/2008/12/micro-fusion-for-space-propulsion-and.html
If what you are proposing relies on technology already in use, or which could very likely be made usable during the next few years (i.e. technology which's basic scientific implications we understand, but just need a little time to figure some "engineering details"), then it's workable. If not, then most probably it's not.
Actually it's too dense. At high speeds (significant fractions of lightspeed) a magnetic scoop acts like a very effective braking system in interstellar gas. A Bussard type ramscoop rocket could only be expected to reach about 0.12c even with highly efficient engines.
From your post, you don't make it 100% clear, but I suspect your understanding of time dilation might not be 100% accurate.
Say the distance from Earth to another star is 1 light-year, and we manage to accelerate a probe to an average speed of 0.1*c (1/10th the speed of light). For the sake of our thought experiment, let's assume the probe comes back, too, for a total trip distance of 2 light-years.
On earth, 20 years will have passed--it's a simple, easy "distance = rate * time" kind of thing. No time dilation to consider.
If you placed a clock on the spaceship, though, you'd see some time dilation effects on the moving clock. It would have experienced less than 20 years' worth of time passing. So if your Earth-bound clock and your space clock were perfect, and you synced them up before the trip started, they would be out of sync when the ship got back.
Remember, in your own reference frame, you don't experience any time dilation. The fact that the ship is travelling fast doesn't make clocks on Earth run slower.
If this isn't clear, go read the Wikipedia article on time dilation, and read the part where it talks about muons decaying as they travel from the upper atmosphere to the surface of the Earth. That's the easiest example to understand, I think, as long as you get how radioactive decay operates.
Dude...you've got what appears to be about a 50px kinda round thing in a crater, and your first assumption is a man-made biosphere? Well, I've got about a hundred pictures of alien spacecraft for you to look at then....
Seriously though, different planets have vastly different conditions, so it's no surprise you don't see things like this on Earth. I'd say it's essentially a sand dune. There's a _lot_ of similar formations on Mars. In fact, there's a few more on the string of pictures that original is from:
http://ida.wr.usgs.gov/html/m15012/m1501228.html
There's one in the first image, there's some somewhat similar phenomenon in the second and third, there appears to be one in the fourth, two in the fifth, and part of one in the sixth.
I think it is inaccurate to categorize Oppenheimer as a communist sympathizer. My understanding is that Oppenheimer was more in favor of the Utopian ideals of communism and not the reality of Soviet Russia.
But the root of the problem between Teller and Oppenheimer was that Oppenheimer opposed the hydrogen bomb (fission/fusion) and Teller was all for it. That made Oppenheimer an enemy to Teller.
Teller, instead of leaving it as a difference of opinion as to whether such a powerful weapon was needed, went on the attack and set out to discredit Oppenheimer.
In the cold war it was pretty easy to make Oppenheimer seem subversive. The time was paranoid and anyone with a different opinion was suspect. Others set out to paint anyone as communist who they didn't agree with. Teller used it to his advantage to silence and discredit a rival.
Who knows if Teller or Oppenheimer was right. No fission/fusion device has ever been used in war. The only devices that have been used were the ones that Teller and Oppenheimer and many others invented.
However, a good person, a patriot, and someone who in spite of his own misgivings about the kind of weapon he helped develop, did it anyway and in so doing probably saved hundreds of thousands of American lives, had his own life destroyed because Edward Teller was on a personal quest for his own glory, his own stature, and his own place in history.
Edward Teller was an asshole. He took it personal that Oppenheimer opposed developing the hydrogen bomb and set out to destroy Oppenheimer for it.
Gigawatt is incorrectly pronounced jiggawatt.
Fixed that pronunciation fubar for you.
In English, giga is pronounced with a hard-g (as in "giggling girls give gifts"). Check the Oxford English dictionary, or any other English dictionary if you don't believe me. There was an attempt by the US NBS to redefine it to use a soft-g (as in "giant giraffe giblet gin"). http://en.wikipedia.org/wiki/Giga#Pronunciation Thankfully, this hijacking attempt to a new and wrong pronunciation has been quite unsuccessful - I have worked with a great many American scientists and engineers over decades, and every one of them uses the correct hard-g pronunciation (so do the newsreaders on US TV, even). I work in R&D at a fairly large US-centric multinational, and I have yet to hear anyone pronounce giga as "jigga", not even MBA-handicapped marketing types. And it's really hard to imagine an executive saying "jiggabuck" instead of gigabuck - the audience would crack up completely...
If you want to pronounce giga with a soft-g, then please use French...
And it's 10^9 watts, not 2^20.
Indeed it is. Giga means 10^9 numerically, by definition. Alas, we are still fighting against recent attempts to hijack it to a new and wrong numerical definition.
Those who can make you believe absurdities can make you commit atrocities. - Voltaire