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#126 Re: Science, Technology, and Astronomy » Polywell Fusion » 2007-12-16 10:11:41
There's no source reference for this new $2m US Navy contract .. only stories in various blogs that all copy each other
The defensenews.com article mentions it. Are they not a trustworthy source?
#127 Re: Science, Technology, and Astronomy » Fusion » 2007-12-15 22:12:07
Signing of first procurement arrangement marks ITER project progress
http://cordis.europa.eu/fetch?CALLER=EN … &RCN=28773
...
Japan will provide nine out of a total of 18 Toroidal Field (TF) Coils that will confine the plasma within the ITER machine. A further ten - including a spare - will be produced in Europe.
The production of the coils, which require the use of cutting-edge technology, will involve manufacturing about 400 tons of niobium3-tin conductor cable, making it one of the largest superconducting cable procurements in history.
...
Well, it's a start
#128 Re: Science, Technology, and Astronomy » Polywell Fusion » 2007-12-15 21:02:26
Just an update on Polywell Fusion ...
http://www.defensenews.com/story.php?F= … &C=america
Dr. Bussard has died (Oct. 6), but the US Navy decided to refund his project in August (for $2m) and two of his closest assistants are continuing the project.
#129 Re: Meta New Mars » New Message Board Software » 2007-12-08 03:41:39
Maybe choose your favorite topic and get feedback on that first. If there are very many references, then it might be a big value-add to choose the most interesting 10 references or something like that.
If you can't be bothered and just want to dump them, then Free Chat is fine.
If you like the wiki format, then you can also/alternatively put them there for sorting/comment ...
#130 Re: Meta New Mars » Spammer » 2007-12-08 03:35:27
A particularly rude phone spammer ...
#131 Re: Meta New Mars » New Message Board Software » 2007-12-07 23:45:43
I am working on compiling a Bibliography of Mars Articles from peer-reviewed journals. It in Word 2007 format. It's currently at 10 pages - and that's just for November and December of 2007. I also have an introduction explaining the layout of the bib with sections. Is there a way that I can make this available and edit/add to it and receive feedback and ideas?
Hi Phil,
Do you think it would be unreadable if you just copy-pasted it to a new thread?
#132 Re: Not So Free Chat » Sudan, the Barbarian Kingdom » 2007-12-06 11:08:30
The idea of trying to control the world by military force reminds me of the last days of the British empire. By the early 1900s, it was obvious that Germany and the US would eclipsed the UK economically. The response of Britain was unparralled military expenditure, attempting to control the world through force of arms, in order to make up for lost economic influence. This actually hastened Britain's decline by sucking up resources that could have been invested in new technologies and new consumer products.
Nice point.
#133 Re: Terraformation » Terraforming Venus » 2007-12-05 13:16:20
Also, I didn't realize that Venus' lack of magnetism was due to its lack of spin - I guess I figured there was just no solid core or something. Is it established that lack of spin is the problem?
Hi Eyas, maxie wrote about this here ...
http://www.newmars.com/forums/viewtopic.php?t=5675
Basically, the current theory is that you need a metallic core that rotates at a different rate to the rest of the planet. High spin helps, but you also need a liquid layer at some point. Some people say you need a big moon like Earth has to start the system and/or keep it going.
#134 Re: Terraformation » Terraforming techniques to combat global warming » 2007-12-03 23:21:02
How? It is a known scientific fact that the boxing day earthquake shifted the Earth on its axis. At least tell me how I've 'reduced my crediblity to zero'.
You're presumably interested in terraforming. So this should be a fun exercise for you: calculate the rotational energy of the Earth, lookup the energy of the Boxing Day earthquake, guess which is more likely:
- the earthquake induced an axial wobble with a magnitude at the Earth's surface of up to 1 inch that was, as usual, quickly damped by the moon
- the earthquake "shifted the Earth by a whole 2 degrees on its axis, causing hotter summers and colder winters"
?
#135 Re: Terraformation » Terraforming techniques to combat global warming » 2007-12-02 13:32:32
My point was that the temperature increase from thermometers (ed) was, what, a whole 1/2 a degree nearly from the other sources (blue) and that we shouldn't use one source for nearly a millenia and then switch to another source, there is bound to be some *recorded* increase, that may not acurately reflect the actual warming at all.
It is misleading to glue the thermometer record, hockey-stick style, onto the proxy record, but switching to thermometers doesn't necessarily give you a temperature jump - although the urban heat island effect may still be underestimated.
And are these temperature sources from all around the orld or just a few places?
The historical proxies aren't well-distributed, and there are problems with the thermometer record in developing countries, but these days we have these nifty things called satellites, which don't miss much. Actually, until 2005, the satellite record conflicted with the surface record, but they found a subtle error in the way the satellite data was being processed (minor orbit changes meant the processing assumptions were out of synch with the true diurnal cycle). It's possible they'll find more errors with the satellite measurements, but right now they are roughly in synch with the surface measurements.
The Earth is on a cycle. Maybe it isn't greenhouse gasses or the sun. Maybe Earth has some slight variations in orbit that Astronomers havn't been looking for or found yet.
This is possible.
And you've also got to take into account natural disasters. The Boxing Day earthquake in the Indian Ocean shifted the Earth by a whole 2 degrees on its axis, causing hotter summers and colder winters in some places that has been blamed on Global Warming.
This is nonsense. Don't make statements like this. They reduce your credibility to zero.
#136 Re: Terraformation » Terraforming techniques to combat global warming » 2007-12-02 00:08:57
The CO2 in the samples only goes up as the types of samples change. Could it ever possibly be that different samples hold different amounts of CO2 anyway?
No, this is silly. They take all this into account.
If you want to argue against AGW, do it properly. The facts of climate change are well established: the global temperature is rising, CO2 concentration is increasing. The scientific points in dispute are: what is causing the warming, and how much warming will we get (in particular, what is the sensitivity of global temperature to CO2 increase). The economic points in dispute are legion (in particular, is it cheaper to deal with any problems now or in the future).
Now CO2 is a greenhouse gas (i.e., having more does in fact warm the Earth), so it is at least a positive feedback. The only other real candidate for warming is solar, so you'd have to present a convincing case as to why the IPCC is wrong went it says the warming isn't caused by solar. Lots of people are trying to do this, so pick your favorite. A tricky problem for skeptics here is that the isotope ratio of carbon in the new CO2 is the same as that in fossil fuels, making it hard to argue that the new CO2 is an effect rather than a cause of the warming.
Predicting how much warming we'll get is much less certain. The IPCC says we'll get something like 1.5-4.5 degrees Celsius for each doubling of CO2, with the most likely being around 2.5 degrees. This is a big issue. If the sensitivity is closer to 1.5 degrees then economic impacts are likely very low. If the sensitivity is closer to 4.5 degrees then we should probably take some action (although timing is a separate question).
Here however, skeptics have a good case for a sensitivity of something like 0.5 a degree, because that is what we actually measure (note that sensitivity is logarithmic, not linear, so we should already have experienced most of the warming from the current CO2 increase). The forecast models ("GCMs") used by the IPCC say that the missing heat is currently stored in the ocean, but will come out any day now and cause a dramatic temperature increase. The problem here is that global temperature hasn't changed at all in the last 5 years (actually, it went down a little), so maybe the models are *gasp* wrong. It is very possible that they are wrong because they (still!) don't include clouds. There is also lots of uncertainty related to various aerosols.
There are people saying that the sensitivity is actually 11.0 degrees and that we'll all have to move to Antarctica, but they are activists not scientists, and should be mocked mercilessly at every possible opportunity.
#138 Re: Science, Technology, and Astronomy » Space Elevators, Ho! - carbon nanotube growth breakthrough! » 2007-11-15 08:13:50
Thanks for posting those details, my browser refused to display that page!
Yeah, I had to open up IE, which I very rarely do.
Why do they quote the tensile strength in terms of another fiber and only give a number approximately?
T1000 is their closest competitor in terms of tensile strength. M70J is closest in terms of stiffness. It's kinda natural to compare. Here is a more detailed table ...
Fiber -- Density (g/cm 3) -- Specific Strength (x 10 cm) -- Specific Modulus (x 10 cm) -- Toughness (J/g) -- Fiber Cost est. $/ft
T1000 -- 1.8 -- 33.3 -- 14.0 -- 38.8 -- 3,332
M70J -- 1.93 -- 16.7 -- 32.7 -- 4.2 -- 1,638
CNT Fiber -- 0.18-0.3 -- 172.7 -- 137.6 -- 316 -- 3,125
... but I'd distrust anything outside of 2 significant figures anyway. With this sort of thing, the exact figures vary by the batch at this stage.
$3000 per foot, for a single thread? That is an astronomic price, maybe because they have only produced tiny quantities so far.
Looks like it is comparable to the T1000 fiber. I'm sure that isn't their cost of production. But hey, they have capital to raise!
Will they be able to get the extra 70% strength from this technology?
It's possible. I'd put it at 1 in 100 chance right now.
If this is all true, it's a BIG step forward!
These guys came out of Los Alamos National Laboratory (lanl.gov), so I don't think it's a scam. Also their presentation materials are so awful - they are definitely scientists 
#139 Re: Science, Technology, and Astronomy » The Evolution of Evolution » 2007-11-14 02:38:27
Thoughts?
Beautiful writing. Usually you're very brief.
I'd go as far with you as envisioning DNA helix forming in a physical vortex. Once the proteins of the right type exist, they naturally curl into that shape. Having a cell with all the machinery that replicates them so perfectly is another matter.
One thing that I find helps is to watch crystals grow (e.g., crystals of different salts). Most people think of crystals as not alive, but they obviously self-replicate - the presence of one crystal determines its neighbor - and the shape of the crystals reflects the underlying atomic structure. it's easy to imagine complex and shifting (self-replication + natural selection = evolution) crystalline structures around ocean thermal vents serving as a catalyst and physical pattern for protein formation and eventually self-replicating proteins (you don't need the full machinery at first, something much more viral will do). After that, well, evolution (but not the details or particular forms of evolution) is inevitable.
#140 Re: Science, Technology, and Astronomy » Space Elevators, Ho! - carbon nanotube growth breakthrough! » 2007-11-13 19:16:49
The ultrastrong, lightweight carbon-nanotube fiber, branded SuperThread(tm) by the company, can have better properties than steel for many applications and could soon be the primary substance from which airplanes, automobile parts, and sports equipment are made. Initial tests show that SuperThread is pound for pound (for the same weight) one-hundred times stronger than steel and less than one-fortieth the weight.
http://www.lanl.gov/news/index.php?fuse … ry_id=8855
8)
Finally an update ...
Check out their nice powerpoint. Highlights ...
+ Image of a fiber on a spool - these guys are way past 18mm stacks.
+ Achieved 5.3 times the tensile strength of T1000 fiber, which is approx 15 M Pa m^3 / kg, or 30% of the minimum economically viable figure for the space elevator put forward by liftport
+ Quote a price of ~$3000/ft
+ "The Pilot Plant will be operational 15 –18 months following funding and will produce 2 to 5 kilograms per day of CNT fiber."
+ "Once sufficient application and demand is established, CNT Technologies will construct a major production facility in the United States. All CNT “base” fiber will be produced in the USA."
30% of the required strength and it is only 2007. We just may have a shot at this.
By the way, this is _full_ strength required for the Martian space elevator, with generous safety factor.
#141 Re: Science, Technology, and Astronomy » How big can a rocky planet get? » 2007-11-13 14:30:53
My original question was inspired by thinking about how big a rocky plant similar to our own could be.
So I think that is the 14 Earth masses figure. Apparently above that you get runaway gas accumulation during solar system formation and become a gas giant (or at least, that is the current theory).
Also could an increased 'spin' on a heavy planet give enough centrifugal force to significantly mask the planets 'true' gravity?
Yes but very high spin is unstable (bits fly off, which lowers the gravity, so more bits fly off, etc).
When I say true' gravity? I mean hypothetically - if our own Earth stopped spinning everything would become slightly heavier wouldn't it? To what degree I don't know, I wouldn't think its much - But the effect would exist nether the less....right?
Yes, you'd weigh about a third of 1% more. (Obviously, your mass wouldn't change, just the force you experience).
#143 Re: Science, Technology, and Astronomy » How big can a rocky planet get? » 2007-11-13 05:23:07
For some reason 14 Earth masses gets bandied about, but I don't know why. We don't really understand planet formation very well.
At some point gravity will become so high that the planet will be a featureless sphere.
Neptune is about 17 Earth masses, with current theory giving a breakdown of: 1 Earth mass rocky core, 10-15 Earth masses water/ammonia/methane ice "ocean", the rest being the hydrogen/helium/methane atmosphere.
At about 13 Jupiter masses (~ 4100 Earth masses) deuterium starts to fuse and the planet becomes a brown dwarf star.
#144 Re: Human missions » Marsdrive Mission Design » 2007-09-13 09:41:00
Aerocapture is a related but more extreme method in which no initial orbit-injection burn is performed. Instead, the spacecraft plunges deeply into the atmosphere without an initial insertion burn, and emerges from this single pass in the atmosphere with an apoapsis near that of the desired orbit.
How are burns done if there is a heatshield for each atmospheric plunge?
The idea is that there is a single plunge and then you are in orbit ...
http://en.wikipedia.org/wiki/Aerocapture
That's why it is so much harder - you dissipate all that energy in just one pass. Apparently you need perpendicular thrusters for altitude control.
You also need a deorbit burn + heatshield, but that is a very different (and much easier) problem.
Just seems that the farther we would wish to not use references from MS the more we find he has numbers for.
Zubrin is a bona fide genius. There is hostility towards him because he makes even very bright people seem average by comparison. People need to get over themselves and take advantage of the work he's done.
#145 Re: Science, Technology, and Astronomy » Sea Water Greenhouse » 2007-09-11 19:19:26
The process uses seawater to cool and humidify the air that ventilates the greenhouse and sunlight to distil fresh water from seawater. This enables the year round cultivation of high value crops that would otherwise be difficult or impossible to grow in hot, arid regions.
#146 Re: Meta New Mars » Spammer » 2007-09-08 08:13:56
It has been so long since we had spammers on the site so is the software broken or not updating?
I think the spammers are just going through the whole sign-up process.
#147 Re: Meta New Mars » Spammer » 2007-09-08 08:11:19
#148 Re: Unmanned probes » Astrobiology Field Laboratory (AFL) » 2007-09-04 07:04:58
Mars' synodic period is 2 years and 7 weeks. Eventually that "and 7 weeks" will push you from odd years to even years and back again.
#149 Re: Science, Technology, and Astronomy » Fusion » 2007-09-03 10:21:24
European scientists will build on U.S. military research to try to create laser-based nuclear fusion ...
#150 Re: Meta New Mars » Spammer » 2007-08-29 05:25:11
Selling phones ...
http://newmars.com/forums/profile.php?m … ile&u=2814