No, to orbit the earth at an height of let’s say 1000 km you would need a speed of around 7km/s. If you go faster, you don’t follow an circular orbit. Wirh around 11km/s you would be so fast to leave the gravity well of earth. The particles in those colliders are almost moving at the speed of light. To be exact, they move only 3.1m/s slower than the speed of light, so almost 300000km/s. They would fly almost straight and would be barely influenced by the gravity well.
In my opinion this is a bit of a narrow view. It definitely holds true for many Christians. But I think some religions like Buddhism may actually help you find a way without guard rails.
The more self-sufficient you can be, the fewer societal resources you will take up, which could then go to someone else in greater need. That’s my perspective at least.
But the more self-sufficient you are, the more resources of yourself you need to supply yourself. So you can provide less societal resources. If you do not need to provide clothes for yourself, you have more time caring for elderly, etc.
As another view, the total resources need does not directly change by changing who does what. The advantages of helping each other are in the OP. At some point however, I would think, the overhead of organization grows so large that it may not be worth it anymore. Just think of the amount of work put into “useless” administration in many countries. But in a 30 person village, this is probably negligible.
Edit: Thanks for helping other people on the feet!
I think your post is exactly what is criticized by OP. In the first part of the post it is explicitly stated men should not talk over the fear of women. A message like yours seems to blame people just because they criticize the way of discussion in some places. I think it is obvious that men are influenced in a possible negative way, when they are always seen as danger. At least for me it probably contributed to my low self esteem, especially in all sex/gender related topics. I think, we as men do so much harm, I don’t want to take part in this. But i took it to the extreme, so I was ashamed of everything sexual about me. But as OP said, all of this doesn’t invalidate the feeling of any woman. But for example this situation here is not governed by fear, still it seems you can’t discuss the social effects of this sentiment “against” man, without discrediting the other side. Sure, violence done mainly to women is the most important topic. But if men always get portrayed as danger, I can understand some are open to other, more misogynist worldviews.
Acapellascience (Tim Blais)
This wasn’t the point as i read, the question was about confidence. And this has little to do with how “pretty” you are. Your confidence is only in your mind. Sure if others think of you as ugly, it’s harder to gain confidence. But I think especially a lot of girls have confidence issues with their appearance despite looking “good”.
When there is only 50% totality, photovoltaic also makes 50% less. You just do not notice it when looking around, because your eyes adjust to the changed brightness. So a photovoltaic produces less for a longer time. What I found, for the 2017 eclipse, was that around 16GW were impacted with at most a reduction of 5GW in one moment.
Yes. One place in space has different temperatures. I would assume even individual particles are not distributed by a Maxwell distribution, so the concept of temperature is hard to apply. The background radiation has one temperature. If you add the sun, however, you already have a problem as the sun radiation is not in thermal equilibrium. So depending on how you look at it, you get different temperatures. The particles have a high energy, so also a high temperature. But they are so rare, that radiation is the dominant mode of heat transfer and determines the temperature of a thermometer placed in space.
I think it is actually the other way around. You can consider the air inside the balloon to have internal energy from the heat. And additionally you have to make room for the balloon in the atmosphere, so you have removed the atmosphere from the volume the balloon takes, which also needs energy. If you consider both you arrive at the concept of enthalpy (H = U + pV), which is very useful for reactions in the atmosphere as pressure is constant. For this example it is not that useful as outside pressure changes when the balloon rises.
Another way to see it, the pressure has no “real” energy. In a ideal gas, the only energy comes from the kinetic or movement energy of the atoms. Each time a gas molecule is hits the balloon envelope it transfers some momentum. The cumulative effect of the constant collisions is the pressure of the gas. If the balloon is now expanding slowly, each collisions also tranfers some energy, in sum building the work the system has to do to the atmosphere. Leading to a decrease in internal, so “real” energy in the balloon. This corresponds to a decrease in temperature.
The stratosphere is heated not by the ground but directly from solar radiation leading to higher power input at the upper layers. So the top is hotter and now convection never starts and you get no cooling of the air when rising.
While I agree in general, one point is a bit to simplified in my opinion
In other words, there are fewer air molecules per cubic foot (volume of air). The molecules are farther apart and can hold less heat energy. Because “heat” is what we say when we mean molecules are moving around.
Less molecules mean less heat, it has nothing to do with the temperature, if you just decrease the density by removing half the molecules, you have the same temperature.
It cools down because it expands adiabatically. Consider a very thin balloon filled with air which is warmer than the surrounding. This now rises up, but as it does, the pressure decreases, causing the balloon to expand. During this expansion, the balloon transfers energy away from itself, because it has to push away air, to make room for expanding in the surrounding. This work cools the air inside the balloon. Assuming the air inside is dry, it would cool around 10 °C per km it rises. Now if you think about it, the balloon just stopped the inside from mixing with the outside. If you look at a large “piece” of air, it does not mix very fast, so you can remove the balloon and just consider what happens with warm air heated from the ground.
Now this does not mean, it has to be cooler when higher up. The same points hold, inside a house, but there it is often warmer when higher.
The best explaination is when looking where the heat comes from and goes too from the air. The atmosphere is mostly heated from the surface of earth, so the bottom and cooled from the upper layers. So naturally it gets hotter where it is heated. The question is now by how much? There are three modes of heat transfer in the atmosphere: radiation, conduction and convection. The first two are very slow. Connection is fast but has limits. Consider the piece of air, if it rises, it cools. So at some place it may be the same temperature as the surrounding air, so it stops rising. This means the convection works only when the air gets cooler by 10 °C/km going up (~6.5°C when the air is moist and precipation happens). So this temperature gradient is observable very often.
Yes, the file itself (so the data and inode) is not gone as long as the handles live on. Only the reference is gone. You canstill recover the file. https://superuser.com/questions/283102/how-to-recover-deleted-file-if-it-is-still-opened-by-some-process#600743
Ja das stimmt, da hab ich aus der Physik kommend zu anwendendunsorient gedacht.
Aber für die Frage ob komplexe zahlen gebraucht werden, reicht es, eine isomorphe alternative zu haben. Die komplexen Zahlen haben auch nicht mehr mit Quantenmechanik zu tun wie die Matrizen, nur sind sie leichter handzuhaben.
Die gesamten 2x2 R Matrizen nicht, aber es gibt eine Untermenge die ein Körper ist und isomorph zu C. Nämlich alle die sich durch Linearkombination der Einheitsmatrix und der Rotationsmatrix um 90° ergeben.
Also a+ib ~ [[a, -b],[b,a]]
https://math.stackexchange.com/questions/1028371/complex-number-isomorphic-to-certain-2-times-2-matrices#2644514
I just want to say, i loved Dragon’s Egg for this level of detail to the physics. I even did some quick calculations why you want 6 compensator masses not less to reduce the effect of tidal forces. Or the black holes inside the sun, at first i thougt, this is impossible. Then i read some more on it an noticed its well researched.
The links are actually only random images from an image search with the terms “solar eclipse through tree leaves” and “iss in front of sun”.
I think you have in mind, that the rays are not parallel because they have to arrive at different positions. As you say, this is negligible, and it can even be avoided by the tilting of the mirrors. However, the rays start from different parts of the sun, and as the sun is huge, this angle is not so small.
I’ll try to explain it in more detail, sorry for the wall of text, it got longer than expected. In this case, we can use simplified ray optics and ignore the wave nature of light. This means, the light of the different mirrors or even pieces of mirrors just adds to one another. An important point, even if obvious, is that each point on the mirror surface can only have one orientation. Now we “select” the orientation of this point, we orient it in a way, that it reflects the rays from the center of the sun1 directly on the sun.2 But until now, we have ignored the rays which come from the rim of the sun. These rays start at a different position, namely the sun radius (695700 km). Due to different starting position, the rays have a different angle to arrive at the power plant, arcsin(sun radius / sun-earth-distance), which is 0.27°. Now we already oriented the mirrors parts in a way, that the rays from the center of the sun are reflected onto the satellite, but the rays from the rim of the sun come at an 0.27° differing angle. If the incidence of the ray on a mirror is changed by an angle, the outbound ray is also changed by the same angle. This leads reflected rays leaving in a direction 0.27° offset from the direction to the satellite. Assuming the satellite is at a height of 300 km and directly above, it is 300 km away, the smallest realistic distance. With this angle, it leads to a miss of plant-satellite-distance * sin(angle) leading to 1.4 km. This thought is valid for all points on the rim. Similarly, the rays between the rim and the center land between the satellite and 1.4 km off target. Hence the plant projects an image of the sun onto the satellite with a radius of 1.4 km.
1 Well they actually do not come directly from the sun, they still come from very close to the surface, but they seem to come from the center of the sun and for rays it is not important how far they have already traveled. We can just assume the sun is a disc.
2 If we assume the mirror is optimally shaped, we can reflect every ray, which seems to come from the center of the sun, perfectly on the satellite. Such a mirror would be part of an ellipsoid, with focal points at the center of the sun and the center of the satellite. In practice, it would be practically indistinguishable from a paraboloid with the satellite (deviance of 1.5 µm with a guessed plant size of 1 km). This is possible as the rays through the center of the sun falling onto the plant are, as you say, almost parallel.
Yes, you are right, considering the rays emerge from a point. And yes, each panel or all panels in unison can act like a magnifying glass. However, if they focus the light on a point at the height of the satellite, they work like a magnifying glass, or telescope with a focal length of the satellite – power plant distance, so at least 300 km. Considering the angular size of the sun, this telescope would lead to an image of the sun, the size of 3 km.
No sun rays are not parallel. If you looked at the sun (don’t, it will burn your eyes), would you see it as a point or a disc? As a disc. Why? Because even looking in slightly different directions, you see the sun. So the rays from the sun are not almost parallel, the rays from other stars are, they look point like.
Two interesting images for you: A solar eclipse viewed trough tree leaves: You can see the partial sun disc by using the small free points in the tree cover as pinhole cameras. Sure, the tree cover does not have lenses, but they only make the image sharper, not smaller. In this image the focal length is only the height of the trees and the image is already a few cm across. It also shows that the rays from the sun are not parallel. If they were, all rays going through the small free spots in the tree cover would end up at the same spot on the ground.
International Space Station, ISS, flying in front of the Sun: As the sun and the satellite are far away, we can assume that the angular size of the original sun and the virtual sun image are approximately the same when viewed from the power plant. Hence, this image shows how the mirrors would form an image of the sun, where only a small part of it hits the sun.
As the sun is much larger than the ISS, the angle of rays which come from the sun is much larger than the angle of rays which hit the ISS.
Yes i am, because it is unimportant if the light comes from the sun or the moon or a 3km large satellite (assuming they would have the same radiance). It would be important if the power plant were ten times larger, the satellite would be closer or larger. However in this case the limit to the power is is the etendue of the light at the satellite. The maximum power is the etendue at the satellite times radiant flux of the sun.
If you want a fun and interesting read which does explain a related “problem”, there is a relevant xkcd
I could explain it to you in at least five different ways in detail, three of them i have already done in short here in the comments. However, you never argued directly against my point. You don’t talk to me seriosly but laugh about it.
This is not what a serious disussion looks like
like. If you want an explaination, i would be motiviated to take the time and explain it in detail.
Note that i listened to your point, considered it and argued why it plays no role. You have not considered my explainations.
No i am talking about all the mirrors as one surface, no matter they are really one or consist of small pieces
For the 65 W/m^2 i already used the size of the whole system, so all 10000 mirrors.
The sun has a angular diameter of 32 arcmin. (see here) Hence, the rays hitting one point of the one mirror, have come from different angles, namly filling a circle with this angular diameter. By reflection, the directions of the rays changes. But rays hitting the same spot on the mirror which were misaligned before by 32 arcmin are also misaglined by 32 arcmin after the mirror, independent of its shape. Therefore, the rays emerging from the power plant diverege by at least 32 arcmin. This is not a problem for operation, as this leads to a size of 4.6 m at an estimated maximum distance of 500 m between tower and mirrors. When the mirrors point at a satellite however, a distance of 300 km leads to a beam diameter of 2.8 km calculation
Even an ideal mirror can only project a point source onto a point. It is impossible to focus the rays of an extended source onto one point. See https://en.wikipedia.org/wiki/Etendue if you want to know details. With conservation of etendue you can also calculate this in a similar way.
This post and thread gives me (back) so much hope. I always hoped for something like described here. But I never came anywhere close and so I have lost the hope over time. I was thinking in the direction of “I just want someone to share my life with. It will work out to be ok somehow.” But some recent events and post like this give me back the hope to find a the person I really want to share time with. It also brings me the motivation to work on myself, so to be more like I would like to be. Thanks you all.