I've always wanted to travel through space. I don't mean as an astronaut launched into orbit and then back down. All of our spacecraft today are basically projectiles with seats. There is some motion control, but it's mostly for alignment. The shuttle isn't going to explore any planets, much less stars. I want to build a spacecraft that is fully capable of sustaining life. I have quite a few ideas on the subject, but I'll only write about one today since I ended up writing much more than I expected. I should note that these are all ideas and "back of the envelope" calculations. I do not claim to be an expert or that everything will be right. Nonetheless these ideas will be important before a large spacecraft can ever be built.
Acceleration and Inertia are difficult problems for large space ships. Inertia is basically an objects resistance to change it's momentum. Newton's first law states this as "A body at rest remains at rest and a body in linear motion remains in motion with constant velocity until and unless an external force is applied to it." (Wikipedia) So A large ship at rest will stay that way until we apply a force. The force will be equal to the mass multiplied by the acceleration. This acceleration will come from some type of propulsion system.
Well this seems simple enough. The larger the ship the larger the force needed to move it. This is true, but a large ship built out of metals we have today will not act a rigid body. Therefore the part or parts of the ship with the engines will accelerate faster than the other parts due to the inertia. It's like pushing on jello. You are adding a force to one part and it's moving, but the rest of it moves less and less the farther you get from the point of contact. This will lead to bending and eventually failure in metals and cracking and crumbling in concrete and ceramics.
Engine placement is also important to inertial effects. From an engineering point of view it's relatively easy to put a big engine or a few at the back of a ship. There is just one area for propulsion and no one has to worry about emissions. This will affect the ship like a building on the earth. Since the back of the ship will accelerate faster than the front of the ship there will be pressure generated. This pressure is like the pressure the base of a building feels under the weight of the building on top of it. If a building gets too heavy it will collapse because the base will melt. So if we accelerate too fast or have a ship that is too large it will also melt when we turn the engines on. We can get around that by placing many engines all over the ship, but if the ship is large enough the same problem will occur in the center.
The ship can also be accelerated slowly, but this applies to departure and arrival. Gravity on earth acts at 9.8 meters per second squared on the surface, so a sky scraper sized space ship can accelerate about 10 m/s which is actually really fast if it can be sustained. It would take this ship only 87 days to reach a velocity of one fourth the speed of light. That is 75,000,000 meters per second. At this speed relativistic effects begin to be important, so this is probably an unrealistic speed. Also while particle density is extremely low at these speeds there might be some type of friction. I can't find any data on the density of intergalactic space. That's outside my area of space physics. We might not know yet. Qualifiers aside it would take 16 years to reach the nearest star, Proxima Centauri, at one fourth the speed of light. That's not very long at all. Unfortunately it would take 100,000 years to reach the nearest galaxy, Canis Major Dwarf. The closes galaxy would take three times that long and it just gets worse from there.
So we have some compromises to make. The size of the ship determines the maximum acceleration and friction, and possibly other things I haven't thought of will limit the velocity. I'm not an expert on relativity so I'm not sure how important these effects would be on humans in a spacecraft. All I can think of is that it wouldn't effect anyone since they'd all be in the same reference frame. Relativistic speeds could make navigation more challenging though.
Well, I could talk about this forever. Since I'm starting to get off topic and I have to stop somewhere I'll stop here.
Friday, July 24, 2009
Wednesday, July 15, 2009
People change, but do roles?
I first started to think about this subject by observing my father's interaction with my aging grandparents. I see my grandparents entirely different than my father does. This in itself is not all that insightful or interesting, but the reasons why might be.
I see my grandparents as dynamic people who's reality changes on a yearly basis. As they age new challenges crop up that must be dealt with and accepted. Not all problems, such as Parkinson's, can be fixed. Therefore they grow. I'm amazed by my grandparents ability to not become bitter and spiteful.
On the other hand my father is often frustrated with them. I realize that he is sad at their aging and pending death, but he is also missing out on their last years. My question is why?
I started to think about how I think of my father and what bothers me about him. I'm not talking about 80's music and Hawaiian shirts. I'm talking about how he's changed over the years and how that clashes with how I identify him.
As a child he was the epitome of authoritarian rule. Always right, heavy handed with punishment, and doled out rewards sparingly. He had a hard job with a bad marriage, so I don't blame him. In fact I adapted and actually enjoyed the regimented life after a while. I started to excel at school and sports (social life not so much... ). I liked the challenge and it actually made my home life easier to have perfection to focus on.
Now my father is divorced and retired. He is remarried and much happier. He is now getting more education, up on current affairs, and quite a nice guy. I am happy for him and love the changes, but it clashes with my version of him. He is so mellow these days that he is often late which would have been unheard of two decades ago. The military precision of my childhood doesn't leave any room for this. Also his warmth to strangers and their mistakes seems almost impossible. I know these are good qualities, but they have nothing to do with the father I grew up with. I can't stand these things and grow frustrated with him on a daily basis.
So my father changes and I can't adapt to it. This thought brought me back to my grandparents. Maybe my father has the same problem. Maybe he remembers some overpowering facet of their personality from childhood that has softened or changed over time. I have read before that as parents age their children see cracks in the super-hero stereotype from their childhood. That is obviously not the whole story as shown by my father image. Its more general than that. Something about our parents, a trait, becomes central to how we see them. From experience I'd have to say that this identity rarely changes if at all.
Maybe we all see our parents as one dimensional stereotypes. I'm only beginning to think about what this means. I find it an interesting observation that deserves more thought.
I see my grandparents as dynamic people who's reality changes on a yearly basis. As they age new challenges crop up that must be dealt with and accepted. Not all problems, such as Parkinson's, can be fixed. Therefore they grow. I'm amazed by my grandparents ability to not become bitter and spiteful.
On the other hand my father is often frustrated with them. I realize that he is sad at their aging and pending death, but he is also missing out on their last years. My question is why?
I started to think about how I think of my father and what bothers me about him. I'm not talking about 80's music and Hawaiian shirts. I'm talking about how he's changed over the years and how that clashes with how I identify him.
As a child he was the epitome of authoritarian rule. Always right, heavy handed with punishment, and doled out rewards sparingly. He had a hard job with a bad marriage, so I don't blame him. In fact I adapted and actually enjoyed the regimented life after a while. I started to excel at school and sports (social life not so much... ). I liked the challenge and it actually made my home life easier to have perfection to focus on.
Now my father is divorced and retired. He is remarried and much happier. He is now getting more education, up on current affairs, and quite a nice guy. I am happy for him and love the changes, but it clashes with my version of him. He is so mellow these days that he is often late which would have been unheard of two decades ago. The military precision of my childhood doesn't leave any room for this. Also his warmth to strangers and their mistakes seems almost impossible. I know these are good qualities, but they have nothing to do with the father I grew up with. I can't stand these things and grow frustrated with him on a daily basis.
So my father changes and I can't adapt to it. This thought brought me back to my grandparents. Maybe my father has the same problem. Maybe he remembers some overpowering facet of their personality from childhood that has softened or changed over time. I have read before that as parents age their children see cracks in the super-hero stereotype from their childhood. That is obviously not the whole story as shown by my father image. Its more general than that. Something about our parents, a trait, becomes central to how we see them. From experience I'd have to say that this identity rarely changes if at all.
Maybe we all see our parents as one dimensional stereotypes. I'm only beginning to think about what this means. I find it an interesting observation that deserves more thought.
sleep deprivation
I'm about as mentally sharp right now as a hammer, so please forgive gratuitous errors. I recently returned from France (great fun!) and have been running a sleep deficit. The time change, the long travel time, and two weeks of limited sleep have all taken their toll on me.
I've been curious about sleep deprivation for a couple of years. I've noticed that cramming for a test is a sure way to failure, but anxious insomnia has had little effect on physical activity. When I first started cycle racing I came across an article at pezcycling that caught my interest. In it Dr. Stephen Cheung describes military studies on sleep deprivation and performance.
The military is a perfect laboratory for this kind of research. Soldiers are routinely subjected to strenuous mock combat exercises for days at a time. During these exercises doctors and officers can monitor decision making ability and physical performance. Dr Cheung summarizes the results well by noting that while sleep deprivation affects both judgement and physical performance, dedicated training can minimize the losses. This type of training shows similar benefits to ultra endurance athletes. I don't think they need it though. Nothing can stop a century runner!
I found that medical papers on the subject are somewhat fascinating, but less practical. It seems intuitive that prolonged wakefulness leads to death in lab animals. Also medical tests on humans usually involve stationary people with acoustic stimulation. This is hardly a real life test. Records held in sleep deprivation are also staged for limited activity to increase wakefulness. Although I find it amazing that the record is for 11 days of constant consciousness. Most of the knowledge about sleep deprivation is over significant amounts of time and the concept of a "sleep debt" is highly debated. I guess you can't or don't have to make up for lost sleep.
I also have some friends that experiment with their sleep cycles. I don't know much about it, but its something I want to investigate further.
All of this leads to the fundamental question, why do we sleep? In the papers and articles I've read sleep seems to do quite a lot of good things for us. Sleep does things like refresh our ability to think and help our cells stay healthy. I know from my own work that coupled systems often have no single solution.
I'm only recovering from two days of almost total wakefulness. I did sleep for about an hour on the first plane. Also the 4 hour mark seems to be the critical amount in medical tests. So my two weeks of 5 hours a night should be just fine although I don't plan on making a habit of it. I value my sleep. Also the time change of 10 hours probably has something to do with my sleep habits and recovery time. So I guess my jet lag is just that. We'll see if I feel any smarter tomorrow!
I've been curious about sleep deprivation for a couple of years. I've noticed that cramming for a test is a sure way to failure, but anxious insomnia has had little effect on physical activity. When I first started cycle racing I came across an article at pezcycling that caught my interest. In it Dr. Stephen Cheung describes military studies on sleep deprivation and performance.
The military is a perfect laboratory for this kind of research. Soldiers are routinely subjected to strenuous mock combat exercises for days at a time. During these exercises doctors and officers can monitor decision making ability and physical performance. Dr Cheung summarizes the results well by noting that while sleep deprivation affects both judgement and physical performance, dedicated training can minimize the losses. This type of training shows similar benefits to ultra endurance athletes. I don't think they need it though. Nothing can stop a century runner!
I found that medical papers on the subject are somewhat fascinating, but less practical. It seems intuitive that prolonged wakefulness leads to death in lab animals. Also medical tests on humans usually involve stationary people with acoustic stimulation. This is hardly a real life test. Records held in sleep deprivation are also staged for limited activity to increase wakefulness. Although I find it amazing that the record is for 11 days of constant consciousness. Most of the knowledge about sleep deprivation is over significant amounts of time and the concept of a "sleep debt" is highly debated. I guess you can't or don't have to make up for lost sleep.
I also have some friends that experiment with their sleep cycles. I don't know much about it, but its something I want to investigate further.
All of this leads to the fundamental question, why do we sleep? In the papers and articles I've read sleep seems to do quite a lot of good things for us. Sleep does things like refresh our ability to think and help our cells stay healthy. I know from my own work that coupled systems often have no single solution.
I'm only recovering from two days of almost total wakefulness. I did sleep for about an hour on the first plane. Also the 4 hour mark seems to be the critical amount in medical tests. So my two weeks of 5 hours a night should be just fine although I don't plan on making a habit of it. I value my sleep. Also the time change of 10 hours probably has something to do with my sleep habits and recovery time. So I guess my jet lag is just that. We'll see if I feel any smarter tomorrow!
Tuesday, July 14, 2009
The beginning
I'm just starting this blog even though I've been writing some of these ideas for a while. A blog was suggested to me a few months ago by a friend after a good discussion. I can't remember what we were talking about, but a potential band name came out of it. Most important discussions can be reduced to a rule for life or a great band name!
I continued to drag my feet until a new friend (and excellent blogger) asked if had one. So here I am.
I used to have a personal blog, but the repetitive nature of day to day life and an overzealous fan made me take it down. Instead of another personal blog I'm going to make this one an idea board. Someplace to put random thoughts and subjects for in depth research. We're all caught by flights of fancy and I'm tired of letting them escape as I drift off to sleep.
Enjoy,
reverseclipse
I continued to drag my feet until a new friend (and excellent blogger) asked if had one. So here I am.
I used to have a personal blog, but the repetitive nature of day to day life and an overzealous fan made me take it down. Instead of another personal blog I'm going to make this one an idea board. Someplace to put random thoughts and subjects for in depth research. We're all caught by flights of fancy and I'm tired of letting them escape as I drift off to sleep.
Enjoy,
reverseclipse
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