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March 1, 2009
Lets make Ceres a case for asteroid colonization.
It is a nice big asteroid and it rotates 1/544 times per minute. If we wanted to, we could increase the rotation significantly and achieve artificial gravity with an outward centripetal force. We would naturally dig inside and live inside the outer surface of the asteroid initially. Perhaps later on we would hollow out the asteroid fully, a big spinning cylinder.
Here are some of the calculations involved:
The main equation is:
radius = gravity / 0.011 x RPM^2
Cere’s radius = (930×10^3 m diameter)/2 = 465 x 10^3 m
gravity (what we want) = 9.81 m/s^2
Plug into equation, solve for RPM. RPM = 1/22.8
The increase of rotation from 1/544 to 1/22.8 is a 24X increase.
Problem we need to consider is whether the asteroid would fly apart, how much of it is solid rock or just an almagam of a lot of smaller rocks.
Another alternative would be to perhaps build a train and train tracks that surround the asteroid. If the train went fast enough then it would be just the same as spinning the asteroid.
Also, we’ll need mirrors to magnify the sun intensity, due to the distance of the asteroid from the sun.
Earth: 1 AU, Sun intensity: 1300 watts/m^2 (what hits the ground in the summer).
Ceres 2.767 AU, Sun intensity 330 watts/m^2
A factor increase of 3.5 to 4X for growing plants would likely be needed. Perhaps even less, especially with some plant breeding or genetic engineering.
Filed under: Everything |
Comments (2)
October 31, 2008
Leopard has a really annoying behavior. When you disconnect your macbook from the external monitor, all your windows move over, which is to be expected. But when you reconnect the macbook to your external display, it doesn’t move the windows over.
Apparently the only fix right now is to hit the F7 button on the macbook twice, make it go into mirror and then out of mirror and you’ll find all your windows back on the external (primary) display.
However, here’s a little applescript to move all the Safari windows over:
tell application "Safari"
activate
set the bounds of the first window to {0, 0, 1200, 900}
try
set the bounds of the second window to {0, 0, 1200, 900}
set the bounds of the third window to {0, 0, 1200, 900}
set the bounds of the fourth window to {0, 0, 1200, 900}
set the bounds of the fifth window to {0, 0, 1200, 900}
set the bounds of the sixth window to {0, 0, 1200, 900}
set the bounds of the seventh window to {0, 0, 1200, 900}
set the bounds of the eighth window to {0, 0, 1200, 900}
set the bounds of the ninth window to {0, 0, 1200, 900}
set the bounds of the tenth window to {0, 0, 1200, 900}
end try
end tell
Just paste it into script editor and run.
Filed under: Everything |
Comments (0)
September 25, 2008
I have long wanted to be able to track my usage pattern of applications on the computer. I wanted something that didn’t require dealing with a timer. The problem with a timer is that it requires remembering to start and stop it, also, it is not naturally fine-grained and doesn’t give you feedback on your non-work activities on the computer. Also, it prevents a more natural multi-tasking usage of the computer (yes, I know, multi-tasking is bad when you’re trying to get stuff done).
RescueTime may just finally be the solution I’ve been looking for. Interestingly, it is a Ruby on Rails web-app combined with small downloadable apps that are available for Mac, Windows, and Linux. The downloadable app runs in the background and tracks your time usage of your applications, and even differentiates between the windows/tabs of the application, useful for tracking which sites you are looking at the most, or which terminal window you are in. The time usage information is stored in YAML files (more proof that RescueTime is RoR-based) in ~/Library/RescueTime/Logs/Pending which makes it easy to script something extra.
In fact, someone made a Mac RescueTime Log Script that lets you log your meetings or phone calls to RescueTime by generating a YAML file and putting it in the Pending directory.
BTW, if anyone is having trouble with Terminal.app in OSX not reporting window title (in the YAML files it shows up as window_title: ‘empty’). You need to enable access for assistive devices in Universal Access in System Preferences.
EDIT: Above fixes the window_title: issue, BUT web app dashboard doesn’t actually differentiate between the window_titles with Terminal yet :(
EDIT: I have stopped using this program because I am not entirely comfortable with all the websites I visit being uploaded to their server. An offline version of this program would be nice.
Filed under: GTD |
Comments (0)
September 3, 2008
I had a pdf of a scanned book, unfortunately, each pdf page was two scanned book pages, and each page needed to be rotated too.
First, I used pdfimages to extract the scanned images, but you can probably do it with ghostscript or netpbm or one of the other tools out there.
# had to install poppler for pdfimages
sudo port install poppler
pdfimages input.pdf out # generates a series of pbm files, out-000.pbm etc
#rotate and split each page, return tiff file {i/pbm/tiff} replaces ‘pbm’ from the string with ‘tiff’
for i in out*pbm; do convert $i -rotate 90 -crop 50%x100% ${i/pbm/tiff}; done
#convert all tiffs into pdfs
for i in out*tiff; do tiff2pdf -o ${i/tiff/pdf} $i; done
#merge the pdfs
gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=merged.pdf out*pdf
That’s the command line approach to solving that problem.
Filed under: Everything |
Comments (0)
June 11, 2008
When people think of the inevitable spread of humanity to space and the colonization of it, they tend to think of people living on the Moon and Mars.
The problem with colonizing the various moons and planets is that they are huge gravity holes. We are having far too much trouble climbing out of Earth’s gravity hole in order to go and fall into other holes and set-back our achievement. Not only that, we are limited to the native gravity of the moon or planet. The moon only has a gravity of 0.16 gees. Mars only has a gravity of .38 gee. Our bodies do not fare well in a micro-gravity environment and tend to suffer health problems and bone loss. It is likely they will do poorly on the Moon and Mars.
Fortunately, we can generate full 1 gee gravity with asteroids. The trick is to spin the asteroid and then live inside it, the outward centripetal force can substitute for gravity. As it turns out, larger asteroids don’t have to be spun as fast to generate the an artificial gravity of 1 gee. The rotation rate affects the dizziness and the body’s health, 2.5 RPM is the recommended maximum and 1 RPM or less is considered ideal. This translates into asteroids that are at minimum 140 meters in radius and ideally bigger than 890 meters in radius.
Another advantage of asteroids is there are asteroids that come closer to the earth and have a lower delta-v than getting to the moon or mars. The delta-v determines the energy cost required to get there. In fact, some asteroids come near the earth and then swing back out to the asteroid belt. Wouldn’t that be a great way to colonize the asteroid belt? Jump on a NEA (Near Earth Asteroid), and ride it out to the belt and hop off and colonize all those asteroids?
The microgravity environment and the resources of the asteroid belt are huge pluses for industry. Microgravity would be useful in so many ways, in terms of shuttling resources around, and for science and technology processes. Mining would likely be a very low energy endeavor once established and the various metals will be quite easy to extract.
The ease of getting to asteroids, the ability to generate necessary gravity from spinning, the ability to ride the asteroid out to the asteroid belt, the greater accessibility of resources and access to microgravity environment makes asteroid colonization a clear winner. Lets forget about colonizing anything else. Sure, it is romantic to colonize the moon or mars, but it is a waste of resources when we can achieve much greater freedom and capabilities with asteroids.
Filed under: Everything |
Comments (4)
June 3, 2008
I am making this comparison because the similarities between these two people, one real and one fictional are too good to pass up.
First of all, Eckhart Tolle is the author of a new york bestseller called ‘The Power of NOW’. This book seems to me to be a repackaging of basic buddhistic principles of the mind & consciousness & the unconscious, and on how to achieve joy or enlightenment. His writing on this subject seems a bit superficial and a lot of the concepts are presented in a vague way by using imprecise words. For a better introduction to buddhist concepts, I recommend Mindfulness in Plain English, which is available online for free, but can also be purchased from a bookstore or amazon.com.
Ellsworth Toohey is one of the antagonists in Ayn Rand’s fictional book ‘The Fountainhead’. In the book he is a highly charismatic public speaker and writes a newspaper column and uses his influence to promote a sort of socialism/collectivism. He is well dressed, often wearing suits and his physical description is that of a small frail man with a big head.
Here is a picture of Eckhart Tolle:
Both Eckhart Tolle and Ellsworth Toohey have strange names with the same initials, a common appearance, both are writers, and both promote ‘mysticism’. One via his books on mindfulness/spirituality, the other via socialism/collectivism. Plenty in common!
Those that have read Ayn Rand’s writings will realize that my association of Eckhart Tolle to Ellsworth Toohey happens to be extremely negative. In Ayn Rand’s view, mysticism is tantamount to evil, because it means you are believing something for no reason, you are deliberately refusing to think or reason or be rational about that particular area of your “beliefs”.
Strangely, I’m actually not trying to be negative about Eckhart Tolle, that’s just a side effect of this comparison, because I thought there were so many darn similarities! The commonalities between these two characters is probably just a strong coincidence. I don’t think that Eckhart Tolle is as evil as Ellsworth Toohey.
I strongly think that there are real facts of human nature and the workings of the ‘brain-mind’ behind the various mindfulness & buddhism concepts. And I hope people will explore these fully and develop more precise ways of discussing these concepts.
For that reason, I think that Eckhart Tolle’s writings are probably positive for introducing a wide range of people to the basic concepts of mindfulness. Unfortunately, his writing style is very imprecise and encourages fuzzy-minded, mysticism-based beliefs anyways.
Huh.
Filed under: Everything |
Comments (4)
April 8, 2008
This is going to sound a little weird. But here goes.
I discovered this trick myself. It often works on the first or second try.
The basic mechanics of this trick is to swallow some air, but trap it in the throat, and then swallow on top of that. The second swallow can be done roughly or forcibly to try and shake things up.
Trapping the first swallow of air in the throat, is done in the same manner that you can use to hide something, such as a piece of bubble gum, and then bring it back later. If you are not familiar with this item hiding trick, then you might have trouble getting rid of your hiccups.
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Comments (3)
March 11, 2008
I personally dislike the current naming scheme of partials. Right now they follow the format of _somepartial.html.erb (Rails 2.*). I find it rather distracting and hard to find what I want when I am in a directory full of partial files following that naming format.
My suggestion is to use .perb for partials. I think files like somepartial.html.perb would be much more pleasant to look at, a kind of syntax sugar to encourage more usage of partials perhaps. Also, I think it would be a more consistent naming scheme.
Vote for somepartial.html.perb ;)
Filed under: Everything |
Comments (4)
March 9, 2008
I was trying to figure out how to run a specific version of a gem, in this case, capistrano. I had capistrano 2.2.0 and 1.4.1 installed and I wanted to run the older version.
Trying to run /opt/local/lib/ruby/gems/1.8/gems/capistrano-1.4.1/bin/cap only gave me an error:
undefined method `execute!' for Capistrano::CLI:Class (NoMethodError).
Turns out the trick is to use:
cap _1.4.1_ deploy
I haven’t tried it with other gems, but I am guessing it should be consistent across rubygems and that will be the way to execute older versions of ruby gems.
Filed under: Everything |
Comments (1)
March 9, 2008
28384376 * 1024 = 29065601024
The 1024 is repeated in the answer. I initially thought it was a bug in my program, but double-checked, and I thought it was pretty cool how the 1024 ends up at the end, with a buffer (the zero) between it and the rest of the number.
Perhaps alife could be done entirely using numbers and math operations.
Filed under: Everything |
Comments (0)