AngelLestat

Yeah, cars should be in KW, this will change with new electric cars. Let me add some things. Litre, Tonne and Hectare use the same system and they are compatible.. but no.. they are not included in the SI. 1 Liter= 1000cm3 = 1dm3 = 0,001 m3 (For Volume in cubic you need to move 3 places the decimal point, BTW.. we use comma) 1 Hectare= 100m x 100m= 10000m2 = 0,01km2 (For area in square you need to move 2 places the decimal point) 1 Tonne= 1000kg = 1mg Heh, so the imperial system is powerful if you are using imperial units? Is like said the Bible is true because the Bible said that is true. For start, you need to give your result using many units instead one. Only works in cases where you can use integers... This guy disagree with on being easier.. Take a look that almost all metric vs imperial videos are made by US citizens. So even the same people who grow up using imperial are agree that imperial is really bad. Why? Because for you is easier? ?? But you need to choose something as base (model).... What you would choose? It is based on a meter scale and the most basic thing that everybody has and need... water. Is based on SI units (metric). What you think that E means in metric? Or C? C= coulomb? All those variables are based on SI. Energy=joules M=kilogram C=speed of light in meters/seconds Take a look to formulas in Imperial, they are full of weirds constants that are impossible to remember.

Ok bad news, maybe I will save you some work.. I read the original paper from Crane on BH propulsion. He said that if the black hole is charged or spinning, then it release its power much faster, (the second until its spinning stop) not sure why.. Also no sure why you said that only QED can explain it, the gravity in this case is enough strong to change things very differently at quantum distances.. In other words, 1000 attometers of difference in a big black hole means nothing, no change on gravity, but on a SBH there is a huge change. So it will need quantum gravity? Here's the original paper, is interesting. http://arxiv.org/pdf/0908.1803.pdf It was only to explain you how a thin and long ship might looks like... Also.. that ship was carefully designed for a scientist. I will not even bother to see where are you wrong.. You need to imagine that the mass of the black hole is antimatter propellent, with few % of neutrinos. 50% of efficiency is achievable just as we discuss with K2, and in theory can be more. In the paper said that a 600000 ton black hole can accelerate at 10% the speed of light in 20 days (160 petawatt), it will be 40 days at 50% efficiency and it will take 1 year to achieve 0.95c, this black hole only last 3,5 years, but due lorenz factor, it can complete the journey to proxima centauri way before drop it, but well that acceleration is too much for humans and the final deceleration will be even higher. A better case for humans will be a spaceship with 500000 tons (which is super super huge if you use light materials), all powered by a proton size BH (the ultimate battery that convert bananas into E=mc2), but this time the black hole will have 900000 tons, its power output at beginning will be 70 PW and its life expectancy 13 years. I will not made the math, but just using the other case as comparison we can estimate it will have a respectable acceleration at the beginning with close to 1 gee deceleration at the end. This ship also can achieve 0.9c if you let it or much more for a long trips. If the interstellar medium would not be a problem, you could travel huge distances (even 150 Ly) in less than 13 years (local time) or something like that. All that just for a crew capacity of 24? XD Units of propellent? How much in metric tons? You wrote a lot.... somethings are very easy to resume not sure why you choice to make 6 lines that can be reduce in few words. I dont have time to answer now, If I try to read all that and confirm some data will take me 1 hour at least. You did not even wrote a conclusion.. which it will be much easier to answer just linking other papers in case I disagree. Solar sails are not affected, all the energy of incoming particles remains in the particle.. you just lost few atoms on the sail.

Celcius is perfect to set temperature for humans, I guess nobody can feel temperature with the skin and predict the real temperature with more accuracy than celcius without decimals. In fact there is other factor that changes everything.. humidity.. Which give you a different thermal sensation, sometimes can be 10 degrees of difference or more. Then wind or a heat surface by radiation also change your thermal sensation, in addiction as someone else said: a room has no constant temperature either. So is completely pointless. And in case someone needs decimals for some unit, what is the problem? Is so hard to understand than 3,5 is the half step between 3 and 4? Now lets go back to the basic.. why someone would not like to change to the metric system? Or one step further.. to adopt the whole SI of units. Just take a look how complicated it is the imperial system just to manage distances (no even mention all the other units) You can see the Meter tens on the right (I know that you use only 6 or 7 of those, but still..) With imperial system you also need to learn all the other units like PSI, pound force, BTU, horsepower, slug and try to find some coherence between them... E=mc2 does not need extra constants because all the units has coherence between them. If someone adopt the metric system (SI), it does not need to renounce to call some products or stuff by its mundane unit.. We use those units all the time even if we dont know it, a cement bag, a bottle of soda (they always add 0.25 liters in promotions until they reach 2,25 liters which become the standard on coke or other soda), 4 limons, etc. But then, the SI makes you life super easy in everything else.

Ah ok, I understand what you mean. Is not only in france. is in the whole world.. Yes we could use also volume to measure different types of foods, but that will be conceptually incorrect in many ways. People might grow up not knowing the difference between weight and volume. We solve that issue for the common ingredients with the same type of measuring cups that I show you, you can see the different scales in grams or with a digital balance cup. For small measures we also use spoons. Here a recipe page from my country (choose one): http://www.essen.com.ar/recetas-para-reposteria-y-panaderia/22 fraction of time that she lost in the conversion? If all the world will be using a single measuring system nobody would lose time. We dont need fractions for temperature.. 25c is not much different than 24c, also what is the point, weatherman are not so accurate. And in case you need precision.. you can use 24,1 24,7 (with 6 times more precision than fahrenheit) Not sure what is the problem. 0 degree or less, snow, ice... we have a middle scale between cm and meter, is called dm, but nobody use it. There is no need. Just divide meter in 100. These are the only types of distance units we use: millimeters - centimeters - meter - kilometer - Au - Light year. We have units to fill the gaps always in tens, but there is no need.

In that case why you can not use this on the metric system? He said without scales..

haha that makes me laugh. Why the recipe does not look like this? 500 ml (2,236 cups) all-purpose flour 300 ml (5/4 cups) white sugar 10 ml (1 teaspoons + 3/4 sugar spoon) baking soda 5 ml (half teaspoon) salt You get the point... Also how much is a cup? And a spoon? Also.. how much is 1/2 cup or spoon? If they dont have regular shape.. From what I can see, 4 cups can be 600ml for someone and 1200 ml for someone else. Maybe that is the reason why we have so good food in my country. 100ml is 100ml here or in the china.

All those things looks weird to you because you never use them.. In fact that problem seems harder with ounce and cups than with ml or liters.. That is a piece of cake.

Is your area.. good luck with those estimations, if you pursuit enough details this can be even a paper material. Heh, how much people use it at the same time? I never said that is possible, I just answer you how it could be done with enough technology. Not sure what are you trying to said in your fusion argument.. just answer how much deuterium and lithium you need? I don't see nothing useful in your argument to defend your posture. Again.. few layers of graphene, hits the grain of dust or atom in a rain of ionized particles that can be deflected using a magnetic shield. I can show you several links where good physicists play with these issues and how they solve them. They almost all agree that you can reach 0,8 or 0,9c without a big issue with what we know about the interstellar medium. Take a look to the Venture Star from Avatar movie, is not a perfect example, but it gives you an idea on the area exposed vs your ship. It can have even artificial gravity by propulsion instead rotation, and when you turn around at the middle of your trip to start the slow down, the same propulsion will clean your path.

try the same with imperial... no all cups are the same.. I know perfectly how much is 10cm x 10cm x 10cm = liter. 1 gram of water = 1 milliliter of water = 1 cm3 (I know how much is 1 cm3).

If you have winds higher than 30kmh (something super common at high altitudes) you can not bring it back. Why you don't do the math, how much volume you need with the balloon and how much kg of h2.

Metric for scientific and imperial for mundane things ---> Wrong. Just use Metric for any case and you will save a lot of your time, in addition the world will save billions and billions of dollars. Someone who knows Metric since kid; will do any measure or calculation faster than someone who learn imperial instead. There is no case in where imperial is superior to metric. Now the real question is: how much it will cost for USA to change to the metric system.. I really don't care.. but they should do it.. The excuse time is over. By the way.. enough advantage than the international language is english, so they don't need to waste 4 or 5 years learning another language, but only takes 1 day to learn the metric system.

You need really big balloons with a cuestionable amount of h2, depending the wind you can have a hard landing or a soft landing (and you can not control where you will land). This idea only works in Venus, where you can float your stage at low altitude where is super easy to float, and you dont have a ground to crash and more easy for recovery. PD: you need to reduce your speed before inflate your balloons.

I dont know, all that seems very hard to know even for a simple estimation. Not sure how powerful is the software you are using, but at those distances, particles that leave the black hole might not even had time to decay on gamma rays, then not sure the effect on pair production or the outgoing radiation pressure over the orbitals. I think you can figure out with enough time, but no just now. I need to search it, but if I remember right, if you can manage to harvest all that energy and then emit all that power in gamma rays in the same instant on the same tiny tiny point. you create the black hole (in theory). We are talking of 700000 tons of E=Mc2. My garage is not big enough to realize that experiment, but I will see what I can achieve. Or.. be lucky enough to find one black hole of this type and capture it The good news, that once you have a black hole, you can use it to make other black holes. Smaller black holes require less initial energy, but it is harder to feed them to make them big. Ok. take a look to the 3 experiments like biosphere2 that was done, they all fail. And they fail in less than 2 years (no even 2 season cycles). So now you add magic robots that will solve with magic any possible problem that the ship will have.. thanks for the details. So now we can fuse hydrogen atoms? I didn´t knew.. I guess it was deuterium and tritium, good luck searching enough of that in empty space, if you want to carry that on board you will need 150000 tons for the 50000 year trip. But yes, lets said that you can carry that, what about all the other spares you will need in 50000 years? Or even 1000 years if you want to short numbers now. By the way, all nuclear plants last only 40 years before decommission, and this only with full maintenance and spare parts over all its lifetime. You said that traveling at 0.1 you get 2500 times more damage, but I prove you that you get 2000 times more collisions with your 50000 year ship. Now if you add that your ship is much much bigger (you need to sustain a big population a lot of time so this mean a lot of extra area), and you dont know the place and angle in which you will be hitted, is easier to conclude that you receive a lot more damage. One more thing. With a fast ship, you know that all the hits will be in front, so your ship can be long and thin, then you will add as shield several graphene layers (separated by some amount), this will slow down and ionize all the incoming particles or dust, then you can use a magnetic shield to divert all those new particles generated away of the rest of the ship. You can not have a magnetic deflector in your case because you don't know the angle or direction of the incoming particles. Correction: 660000 tons. Even if the black hole falls in the center of earth, nothing will happen. It is too tiny to interact with matter, and the outgoing pressure of its radiation makes that impossible. It will just heat up a bit more the earth core, and that heat will take thousands of year to reach surface, and when it does, nobody will notice the difference. Good try

I lost you there, I can not make a mental picture of the electron shell because I don't understand the physics involved. You mean a super dense cloud of electrons orbiting the SBH as it were a super atom? Or the electrons orbit at higher distance? Even in that case no sure how they can shine in the visual wavelength or stop all the gamma radiation.. That seems a very hard mental exercise. I can imagine from that example that pair production and many other hard physics will happen there. The black hole is super tiny, hard enough is to try to absorb and redirect some % of that energy in opposite direction, no even imagine focus all those elusive gamma rays back to the black hole which is not perfectly still. Even if you convert the energy in the visual or ultraviolet range, I guess this wavelength is bigger than the black hole radius. Also.. not sure what you win with that.. You are wasting a lot of the black hole power. It will be possible to do that placing the black hole in a different point of the focal point. Like a normal engine in neutral gear.

The main point of this, is to reduce the amount of population that you need to keep alive over the whole journey. That reduce by a lot the complexity of the ship. Keep a population alive over more than 10 years without external power source or resources in a closed system is away our reach today. Now if you want 1000 or 50000 years, is easy to said that is "impossible". Why fractional light speed give you problems? Due collisions? The good news of going fast is that you know that all collisions will be in the front of your ship, so you only need a good shield in front. But a ship that makes the travel in 25 year will receive 2000 times less collisions than a ship with a trip of 50000 years. Those collisions you receive produce more damage, but no until the point of increase your risk or damage. What is your power source that will last more than 1000 years? What thing made in earth last more than 1000 years of duty? You did not thought in all possible problem that you need to solve in a long time mission, you should do it. ah I thought you already counted on that, because I did not put much attention on how much 2π represented in the sphere area, this might help for those who had my same doubt. The first I've heard of using plasma as a radiator... I guess it could work, I like the idea. It needs a lot of density or scale to not let pass the gamma rays and to obtain a good heat capacity. The damper will be made by a mirror, maybe it can reflect the whole range of 7000K plasma at certain distance. So it will be like a black hole that creates a sun behind us, and we use a solar sail for propulsion. Then we need a particle accelerator (with a really good accuracy) to feed this black hole once we reach our destiny with at least 2kg of matter by second.

ok, so you mean absorb all the heat and release it in a collimated way? The problem with that approach that your radiator mass increase because you can only radiate using one size of the surface. But I guess it can be manageable if we reach to the point that we can create such SBH, besides the mass of the black hole will be >> than the damper + radiators I guess. About electrical power, yeah that is the less of your concern, you can also use the rotation of the black hole with its magnetic field to be used as an electric generator. Not sure why PB666 wants a 50000 years ship. But we have a new generation every 20 years, so a 50 year ship is a generational ship, those had more sense, although there are still many problems to solve, you can not harvest extra resources or power over the whole trip, sustain that close system over 50 years sounds a nightmare. It will be easier to transport people in some kind of cryo frost or just embryos.

You read what I said? Or you read the book in the (travel time) section? NASA is not planning a manned mission to other stars! that is the big difference. But if they will start to think about those.. you will find NASA scientist talking about ships that can make the trip in less than 50 years or at least 100 years, that is what you call a generation ship. If you have problems with future technologies.. then tell me how you plan to make a ship to survive over 50000 years with a finite number of spares for damage props on use or by being hitted by interstellar rocks? We need to constantly fix the ISS sending spares, take a look to the external foil layers.. Now multiply that by 50000 years. It will be easier to find the solution for warp drive in 10 years than find the solution of how to make a ship survive 50000 years.

So is an assumption to think that technology advance?? According to your numbers we should be going back in technology.. that is how logic works? If you think that forget about the technological evolution is an intelligent thing to do when you are planning a 50 years project or even a 50000 years project.. wake up.. is not. Is the worst choice that someone can make. An educated guess would be said: "we dont have the technology yet, so we need to wait or these might be possible future solutions". About me, if I need to find solutions, I always use near future technologies. On interstellar travel my opinion always was: manned missions we are far away, but we can send solar sail probes at 5 or 7% the speed of light using just the solar light as propulsión on a close approach (less than 0.05 AU) . These probes would be super cheap and you can sent many. This book said that if your mission travel time overseed the 50 years then it should not be started at all due tech evolution.

In the earth poles! ah no.. wait...

where?

How you focus the black hole radiation to achieve the thrust? Those things are not impossible but they need higher tech advance than an antimatter drive. The radiation emitted by a black hole is harder to block and redirect compared to the radiation from some kind of antimatter annihilation. Feed these stand-up guys with matter is also very tricky and make one in the first place also hard. What is the point of that? Even if you take into account that our tech increase linearly (instead exponential as it does), let's imagine you make this ship, now in the time it takes to build it, you will be find a much better way of propulsion that can reduce your trip time by a lot, by the time this ship start its travel, just 100 years or 1000 years later, you can have a big part of the human population already living in your planet destination. Maybe even teleporting between places, but this ship still has 49000 years of trip to go.

the problem with subatomic black holes is how do you feed them... Or how you made them in the first place. Not sure what of those 2 is harder. For the feed to be practical we should use matter, to not waste more energy that the one you will get back. Then to make the black hole; you need to concentrate a ""huge"" power of gamma rays in a same instant over a super tiny point. The last problem but maybe no so big as the first two.. is how you focus that power to get thrust. Is harder to focus those emissions than a antimatter annihilation.

Kip thorne, the physicist behind the movie "interstellar", must be jumping in one leg, he is the father of Ligo. He was the first to come out with the idea and one of the scientist who most work on this since 1970 formulating the physics and predicting the type of signals that would be seen in the detector.

The video OP does not work. Here is another note on the article: http://www.sciencealert.com/live-update-big-gravitational-wave-announcement-is-happening-right-now And a video explanation made by PBS Space Time folks: https://www.youtube.com/watch?v=gw-i_VKd6Wo This is a good news.

But I was answering the question from the movie perspective, of course is a plot. In any case why they didn't sent the astronauts with the tools to make their own food, an inflatable module with 25 m3 will be enough to keep an astronaut feed all the time they wanted planting its own food. That plus its food reserves will give it a more long survival expectancy.