Re: velocity of a sheep in a vacuum in El Reg units
To simply the calculations we set the wool drag to one. We also assume the sheep to be spherical.
347 posts • joined 14 Nov 2007
To simply the calculations we set the wool drag to one. We also assume the sheep to be spherical.
"...walk away from the crash uninjured and refused an offer of medical treatment."
Pro life tip, always refuse medical treatment when uninjured and healthy.
The issue here is that with computers it was fun careless days before we connected them together. In the early days computers were mostly islands and security was really not an issue. Programs were written to work and testing was testing with normal usage and not to check for buffer overflows to break the program. In other words, it was a simpler world. A world that car manufacturers still live in. I do not know if it is a good idea to let these people network a lot of two ton computers with wheels and hurl them down the highway.
Where one human driver can only manage to do so much damage. What happens when the entire line of some self driving cars on feb 12, 13.15 triggers a bug that slams on the breaks on all of them, or more likely they get hacked by some terrorist. We have to assume at least that foreign nations and probably our own will exploit this as a weapon of war.
It is just that the world is a little more complicated than that. "..make these things always recoverable" isn't all that hard, it is just that it requires more fuel and less cargo sent to space. Trying to protect the environment is a good thing indeed, but there has to be a cost-benefit analysis even there. You do not drive a lorry to the other side of the country to pick up piece of plastic bag and then drive back.
Slap some sort tax on them which should be used to collect tenfold the amount of garbage out of the sea from the shore line.
No, good old fashioned racism would be the justification they used for slavery, colonization, ethnic cleansing, apartheid and segregation.
Calling everything that can be regarded as intolerant, any hint of lack of cultural understanding, unthoughtful jokes, and using common neutral words of yesterday that has changed meaning today, for racism is a newfangled idea. And quite frankly it is crude.
That doesn't mean we can't discuss what is okay to say, and what is not. Feel free to think joking with names is lame, but would you stand on the barricade if it was a German name? Did you go to arms when John Oliver did a lengthy segment on the presidents last name?
As far as I know, as of yet, they only land the first stage and that is never left in orbit anyway. Less junk in the ocean though. And I think second stages are often turned around and gets a retro burn to deorbit and those burn up at reentry.
And we do not know how much money they spend getting a Falcon 9 ready for another flight. Personally I believe they have cracked it and will bring costs down. We'll see.
I tried to do the math on how much uranium we would need to heat up the core to get it going again. We are talking back of the envelope calculations here, but around 300 billion tons of uranium 235. If we go for an matter-antimatter reaction we could get away with 5 million tons.
Pitch it to Elon and I bet he'll say that it can be done by 2023 or something.
I am neither a fluid dynamics expert, and I wonder does gravity matter that much? The point of this thing is to slow it down at entry*, right? And it feels like there is basically three things that should affect how a parachute performs, velocity, air density and the force the payload drags it along with. Shouldn't the momentum of the thing at deployment be the main contributor of said force, and not gravity that maintains it when it has slowed down to terminal velocity?
*sounds wrong, but it can't be reentry.
Their updates could break windows machines that ran certain kind of anti virus programs. So they made a key in the registry that had to be set before windows update would allow those updates to be applied. If the anti virus vendor had cleared their own software they should send out an update that should set that key. Of course if you do not run any AV you are screwed.
I don't know if your problem is that, but should be able to check if the key is set manually.
I am not sure I see the reasoning here. Without a limiting time frame I don't see why we shouldn't solve most of the problems:
-radiation. Solvable by bring enough materials with you which currently is limited by launch cost and launch cost only. The energy requirement for getting stuff into orbit isn't really all that much so the problem is purely technological and not a problem of physics. With half a century of space travel so far there has to be limits there still possible to push.
-lack of gravity. Large enough acceleration and it is solved, but there we might bump into what's physical possible to achieve. But, tether two crafts together and send them into a spin and you are set. Just a matter of big enough spacecraft, see above. I suspect a 10 km rope would do wonders.
-supplies. As of now, humans still need an ecosystem to function. We are less and less dependent, but we are not there yet. However, there is no reason we can not achieve an artificial ecosystem where food is either grown on the waste or synthesised directly. Carbon dioxide capture and oxygen production will regardless be a side effect.
-energy. Some sort of nuclear reactor (be it fission or fusion) has to be brought along and fuel to feed it. But we should be able to do that today, if we really wanted to, so no problem there either.
The problems that might be unsolvable is time or speed. Even at light speed, you are correct, we will not reach very far in a life time, just a second, some guy is calling about relativity. Where was I. Yes, if we achieve on the outside, half the speed of light, we will not get very far in a life time. So either we have to extend the life time or we have to send our children even further and so on.
Becoming intergalactic might also be out of limits. The distances can become so large that without physics yet to be known can come to our aid, we can for all practical solutions be stuck in the Milky Way.
The increase is in harmful radiation and not radiated power. Also a good part of it comes from space due to the sun not shielding us due to lower output.
So the radiation bit here does not directly affect the power budget of Earth. However there is a theory that cosmic rays that reach as far in as Earth and hits the atmosphere can on impact start a cascade of reactions ending up with nuclei for water vapour to turn into clouds. This will in turn isolate the Earth during the night and trap heat. This is of course disputed as all that relates to climate is. And since there are two debates over climates, one scientific and one political, I really can't be bothered to figure out which is which. (I just read a debunking of the theory, but it was a straw man where they refuted the claim that cosmic rays are the cause of climate change where the claim is that it can affect it.)
You still get all the fertilizer here. During the digestive process the body breaks up the food and extracts nutrients. A lot of energy rich molecules can't be broken down in the digestive process and is sent down to the large intestines. There bacteria that are able to break down and feed of the left overs thrive. In return they break out vitamins etc that is extracted by the body. Crucial when it leaves the cow, in this instance, there is still a lot of fibres left that are continued to be broken down in a process that produces a mixture of carbon dioxide and methane. If you collect the manure in tanks, collect the gas produced and then use it as fertilizer makes no difference than if use it as fertilizer straight away and gas will be released straight into the air instead.
I don't know if I quite see the big breakthrough here though. Basically what they are doing is collecting the carbon dioxide in the biogas, enriching it with hydrogen and producing methane. A well known process I would think. And it requires an energy input so where is the benefit?
Low earth orbit is not a particular height, but a height and speed. The height is not really where all the energy go, most go into obtaining the speed.
A conveyor belt can't be built up to LEO without anything supporting it, so basically you have to build a couple of hundred kilometres tall structure. Our current record is about one. Then there is the space elevator which is a theoretical possible idea. The basic principle is that if you go further out the orbital velocity decreases and the length of the orbit increases. Both of these contribute to the length of the orbital period increases also. At some point it goes up to 24 hours instead of one and a half which is about what it is in LEO. At equator the ground also "orbits" the centre of earth in 24 hours. Thus an object that far out over the equator will seem to stay put or as we say synchronous. Call it geosynchronous if you will. Since you then have an object seemingly floating out there you could tie a rope to it and lower it down to the ground. This will of course shift the centre of mass of the object downwards which you compensate by having a more massive object and also place it a little outside GEO so that the rope and the object combine has a centre of mass in GEO. Pull yourself up along that rope and you have an space elevator.
First problem, it doesn't go to LEO, but GEO. You could get something to height of LEO using it, but you still need the velocity afterwards.
Second building it. At the moment we are not sure if there even exists a material strong enough to hold it's own weight while stretched out so far. The distance to GEO is about 36 thousand kilometres.
"Cant think of any lawful ones though yet."
Imagine a world where every text ever written can be read aloud by Morgan Freeman.
First of all, I would argue that carbon monoxide isn't a highly toxic gas, but the Wikipedia does indeed say that. I guess it comes down to what qualifies as "highly".
Second, carbon monoxide isn't the byproduct, but the product and it is used as an example. In their report it says that the use are for endothermic gas reactions that requires heat and a catalyst. As an example where you want to produce carbon monoxide and hydrogen gas from water and methane. That require heat and you end up burning some of the methane to keep the process going. However, if you use the sun as the heat source you can save some of the methane. In addition due to it being an endothermic reaction there is more energy in the end product than the gas you feed into it.
What you most certainly will not do is to dump it into the atmosphere. You have after all gone through great lengths to produce it. You either use it as a energy carrier i.e. fuel, or as a component in further chemical reactions.
In addition I see some commentards claiming the use it as heat during the night, but no. Their proposal is to use air as a thermal storage to tap into at night.
Thanks for informing me of punitive damages. A term I have heard lots of times, but never have really taken the time to read up on. Now I have, and looking back on my original statement I have to say I have to let it stay. Maybe refine it a little and just say that punitive damages is mindblowingly ridiculous.
Civil lawsuits should be that somebody asks the state to settle a dispute and possibly decide a compensation for a loss due to said dispute. If it follows that crime might have been committed then the state should bring up criminal charges in addition. Financial gain (as in gain and not compensation) for any party should never be the outcome.
"..could have been.." Can you sue for things that could have happened in USA?
It is hard to assess the value of quite a lot of things and thus also hard how to compensate the loss of such thing. But these lawsuits you have over there are just ridiculous. It is not even she that sues. How on earth does the damage caused by ONE other person seen your girlfriends vagina amount to four million dollars?
I have no idea on what they actually did, but if you can determine the orbital speed you can also determine the escape velocity. This is since both only rely on the mass of what you orbit and the distance to the centre of it. You have to assume the orbit to be circular, or establish the entire orbit and with galactic years tending to be long years I don't think they have waited for that.
You also have the assumption that you orbit something where the mass is in the centre. Witch is of course not true for galaxies. The neat thing about calculating gravitational pull from within an object is that you can disregard all the mass situated further out from the centre than yourself, assuming the mass is symmetrically placed i.e. in rings or shells around the centre.* Thus when you start to escape you start to pass more and more of the mass further out to you that adds to the gravitational pull.
But I assume that if you manage to map the average orbital velocity on objects far enough out then you should be able to determine the entire mass. And if you map for enough orbits then you should be able to map the mass profile distribution. So easily I thought that I wonder why they either have gotten it wrong with that method or why they havn't done it before.
*Among other things enabling the fun fact that inside a hollow planet if it is a sphere you are weightless, regardless of where you are in it.
Seems to have pasted a link from another commentard instead of my own link...
Better off Ted did this already, watch it, it is brilliant.
Feel free to correct me if I am wrong about this. I think that the conditions, basically the climate, on a planet is not solely dependent on the sun it orbits, but also on radiation from nearby and faraway sources in space. I thus imagine that being thrown through centre of a galaxy on a regular basis will tend to make the planet inhabitable. Not to mention what the gravitational forces nearby stars can do the orbit. So any life on these rocks will be long gone before they get eaten by a black hole. So unless they are truly advanced and can vacate the premises, and move to a mostly harmless planet orbiting a star situated far out in the uncharted backwaters of the unfashionable end of the Western Spiral Arm of the Galaxy, they are goners.
As for the odds, I'll recommend starting with Drake's equation and narrow it down to the set of stars involved.
Let us assume that cheap equals crap, and this if for the most part true. Then it doesn't follow that expensive equals quality. Actually on scale from one to five where one is the cheapest the highest average quality often can be around two. Where a large part of the fives are the same junk as ones, but with better branding. The caveat here is of course that this is only true for the average within each price range. The highest quality products you will still find hidden among the fives. My problem is that I am happy to pay 200£ for a pair of boots, but actually getting a good pair that last at a minimum ten years of regular use is unlikely.
I blame the stupidity of consumers. We accept buying products without specifications.
I get that to enter a stable nice circular orbit by burning fuel instead of using the atmosphere amounts to more fuel spent. However I don't understand why entering a large elliptic parking orbit should cost that much fuel. As I understand it they first have to leave the Earth's gravity well, then climb a bit out of the sun's and then fall into the gravity well of Mars. If you just barely have the velocity to pass the hill between the sun and Mars then you only need a small burn to not fall out on the other side. Okay, the velocity is probably a little larger to get there in a reasonable time, but it can't be that much.
So, they have to plan for this, and figure out a whole lot of orbital mechanics, but from what I hear they are quite good at that. Or am I missing something?
I am not sure about this, but I think that we are not actually all that sure where the planets and other objects are. The problem is that with a probe around them we can calculate the distance quite easily down to probably centimetres, but the rest is a bit more tricky. When the probe stick around for a while we can probably triangulate quite well when the earth shifts its position due to its orbit around the sun. But most of the planets we do not have permanent probes around.
Again, not sure about this, but I think the error of margin on placing objects in the outer solar system can hundreds of kilometres. The adjust the approach visually with navigation cameras. Both due to uncertainty of where the probe is, but also about where the object really is.
Anybody know if there is any benefit to this, whatsoever?* That is, a benefit to anything we currently do and not interstellar travel that is decades if not centuries away. Would this compete with or supplement navigation within the solar system? Maybe map position of objects to a greater degree?
*I need to clarify here that I do mean this as a question, not as a science without an immediate pay-off is stupid kind of statement.
They could have at least given the end user information about this through windows update. I was wondering why there wasn't any update yesterday and whether I happen to read an article in The Register or not isn't something I should have to rely on to keep my system updated.
"If you've specifically decided to go naked as it were, it's kinda your own fault and you should be paying attention to things like this."
Come on! How is it my fault that line of products that I do not use are faulty? And how exactly show I be paying attention to things like this.
I am a fairly simple man running a fairly simple system. I do simple things and manage to keep it tidy. I run no AV because they do more harm than good and I have got infect two times. Once around 1993 from 1.44 floppy disks with pirated games, and once in 2004 when I foolishly tried to patch a fresh win2k install on an open network. I manually apply all updates because I want to know my system and I need it to behave in a predictable way. There is no superfetch running and all activity on the hard drive, i.e. the blinking light, I can account for. I do however keep software updated and even though I have come to distrust windows update since it is used for advertisement and spyware, I have yet to experience it holding back on updates.
So I am supposed to seek out the local Microsoft office or what to get the news? Displayed in the basement perhaps? The basement without stairs or lights. Where there might be a notice on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying "Beware of the Leopard".
"Is that right?"
No, not really. The moon eclipse the sun because it is about 400 times closer and the sun is 400 times bigger. Given that the closest star is over 270 000 AU away then 80 won't do much difference, some, but not much. So we have to look at dimming, and assuming at least our capabilities at the receiving end it would have to the size of a planet. Our planet is something we would have trouble spotting, depending on the size of the star it orbits. So even with greatly superior techniques we are talking a rather large device. After all at these distances there is only that many photons left.
If you build further out the orbital speed would be lower and thus you should be able to keep it longer between the target star and our sun, but the further out the more narrow the shadow also becomes. Also at 80 AU the speed is still 3.35 km/s so keeping it still will not be an option.
Then there is the time aspect. We are talking many years for light to reach the systems in the neighbourhood and we don't even know if there are anybody around the see it.
I do like the idea though. Made me think.
It is not a premium product... Well, if you define premium as something expensive that people want, yes, then it is. But neither of those two qualities are determined on how well made or useful a product is. Humans are exceptionally bad at assessing the value of something, we are however social and thus cheat by assessing what value other humans put on things. Why money works, marketing is more vital than engineering and capitalism doesn't really work (not saying that anything else works either).
So, premium in the sense that they are good at marketing, but not premium as in they are good at engineering.
MrK's law: The quality of a product is inversely proportional to the number of colours on the box.
You don't get people that find Git hard, I don't get people that somehow don't value work that doesn't require higher education or is particular difficult to do. Feel free to have an opinion about the intelligence of people finding Git tricky, not the most constructive way of commenting, but meh. On the other hand I really don't see what employees at McDonalds have to do with it and why you need to talk them down. Muppet.
But isn't this how technology companies have always formed? Well, to be more accurate a sizeable portion of them. I kind of remember reading several articles throughout the years about how businesses came to be and several followed the path of: 1. Come up with an idea that you think might be possible. 2. Seek out venture capital where you tell that you have cracked it. 3. Head back to the garage after you have secured the funds and learn the skills needed to solve the problems. 4. If it pans out, sell and go to one. If it doesn't, sell and go to one. (To be fair, a few keep it if it succeed.)
This will go on as long as there is enough stupid venture capital out there, venture capital is high risk anyway and you keep reading about these kids that made it big on a simple idea. After all technology is complicated so just go with your gut about what you think has a chance. Spread your billion on a hundred companies and hope that one of the return your investment a thousandfold.
Oh, that's just life. Good news is that it will pass.
Isn't this technology that has been around for a great while already? I really do not see the technical challenge here. Making a small and cheap enough drone that runs on batteries, sure we had to make good enough batteries first. Making large stuff fly we have figured out ages ago, and autonomous we have done for decades.
Sure, there are many more hurdles to overcome like reliability and degrees of autonomy, but actually just getting something to take of, go in a straight line and then land can't be that hard. There are probably a lot of choppers out there that could fly on their own to some degree if you tweak the software and allow them.
Or am I missing something fundamentally here?
About 0.00001 nanoWales
It feels like technobabble, looks like technobabble and sounds like technobabble...
I hope they are just exaggerating, and it really isn't my field of expertise, but it triggers a lot of alarms in my head which usually would result in a dismissal. However considering the source only scepticism.
I do hope it is as they claim though, and lets hope they next can create a chip that creates water into beer (I don't drink wine).
"It's because there is no facility to extend a sentence unless another crime has been committed or new evidence received and it is returned to court."
Fair enough, but we are talking about changing the system here so why not change that bit as well. This is a democratic problem and seems to be fairly common in different countries. How we as a society hand out punishment is important for people and thus it is a part of who we vote for and why. To have any hope of an honest democratic public debate we should work to remove anything that muddies the water. And I do think that if all sentences where the minimum you had to serve (at least within ordinary circumstances excluding pardons, reforms etc) and they could all be extended to the double of that minimum, it would be a lot easier for people to understand. The end result is the same, just the wording that is different. "Three years in prison with a maximum of six years." instead of "Six years in prison with a minimum of three years." (That kind of wording might be in a different country, but the principle stands).
Expansion wins, and it is not even a contest.
Short version is that the universe will expand to the point where we will not even be able to detect anything beyond our own cluster of galaxies. And with time even the galaxies themselves will scatter. And then there will black holes roaming the place and slowly evaporating.
First, let us just state the fact that the gravity from black holes is a function of their mass as everything else. The fact that they are black holes does not change how gravity behaves. The only special thing about them are that they are so dense that you can get extremely close to their centre. And since gravity is a function radius squared it will eventually be so great that light can't escape. However, if you collapse the moon to a black hole and manage to keep it stable, the effect on Earth will mostly not be noticeable except that there will be no moonlight. https://what-if.xkcd.com/129/
With that in mind we can look at the size of the universe and current theories to see that it is ever expanding. If a black hole gobbles up a nearby star this will have no effect on the pull of far away objects. Their combined mass and centre of gravity is more or less the same before and after the event. While it is true that galaxies collide from time to time that is on "local" scale and the general rule is still that the further away you go the faster everything moves away from us. Making everything in the "local" area one object will not change that. More about the structure of the universe as it is now: https://www.universetoday.com/37360/structure-of-the-universe/
Thus the best thing a black hole can hope for is to gobble up everything nearby, meaning it's own galaxy and maybe the one next over. However even that will not happen. Grab some empty space without anything affecting it, even from the outside. Throw three objects into and unless you throw them to hard they will start to orbit each other. But the orbits will be chaotic. And they might collide, but that is actually quite unlikely. Since volume and thus mass is a function of radius cubed and gravity is a function radius squared, gravity tends to become a rather strong force when you grow the size to astronomical bodies. Just look out how far the pull of the sun goes compared to the radius of the sun itself. So since they won't hit each other they will create an infinite number of different orbits, until two of the objects manage to work together in such a way that they will eject the third (usually the smaller) out of the system all together. Now then, do this on a galactic scale with a huge number of objects and you will eventually scatter all, but two objects (usually the bigger ones). So what makes black holes eat matter at all then? The answer is friction, either tidal friction within the stars or friction in gas and dust particles which allows them to slow down their orbital speed enough to fall into the hole. https://en.wikipedia.org/wiki/Future_of_an_expanding_universe#Stellar_remnants_escape_galaxies_or_fall_into_black_holes
My understanding of this is rather limited, but when talking about Earth's magnetic field we are talking about magnetic flux density at the surface. Which is nice when you want to compare magnetic strength from one place to another, but when you are to compare magnets or create an equivalent one you have to integrate over the whole field (or something like that). So we can either look at this like standing on a large body comprised of matter with weak magnetic properties, but which in sum creates a huge field and due to it's large radius will extend far out before it diminishes. Or we can say that is an extremely powerful magnet far away in the core where the field out here on the surface is rather weak, it is will extend far out since the density of the field will weaken relative to current distance to the source which is already big. Kind of like if you double the distance to voyager the signal will only weaken to a quarter, and by now double is long long way.
Well, if I am right. I tried to read up on this, but I seem to recall that I really understand this at uni, and I have not improved since. Enlightenment please.
The latest version is 184.108.40.206, so the check update thingie seems to be lagging or something. It seems that it is the point one that does the trick.
"Any country name with the words 'People' and 'Democratic' means exactly the opposite."
Does this also apply to countries with "great" in them?
I might be wrong about these things, but I thought that if you modulate a given signal with a given bandwidth onto a carrier frequency you will occupy the spectrum around the carrier frequency equal to the bandwidth of the original signal. If I am correct about that, will it not be so that there is a lot more room around the higher frequency bands? So while it is true that higher frequency does not dictate higher data rates, it does indeed allow for it.
Take for example a signal of 1 MHz bandwidth. Transmitted on 2MHz it will occupy the area from 1.5MHz to 2.5MHz, a rather large part of the spectrum, effectively blocking out anything else from being transmitted at the same time. Shift it up to 1GHz on the other hand and you will occupy the spectrum from 0.9995GHz to 1.0005GHz, allowing for other signals to be transmitted nearby, or expanding the bandwidth of the signal in the first place.
Disclaimer, I am unsure if I remember these things correctly so please correct me if I am wrong.
Do you mean something like the Great Collapsing Hrung Disaster?
"And you may wish to review my middle finger, this is an English language website."
Would that be one significant digit?
Come on guys, it is bleedin' obvious that Trump winning the election and is now president is fake news.
I think the simple version is like this:
Temperature is internal motion and at absolute zero the atoms are motionless. Then you run into a problem with the uncertainty principle which states that there is a limit to the how well you can know the position and speed of a particle. And increased precision in one decreases it in the other. At absolute zero you then know the speed and thus you no longer know where the particle is.
Or something like that.
In science velocity is a vector and thus including a direction. However according to the dictionary it can simply mean speed. So I think it is one of these instances where a field of study has taken two words that mean the same and added a distinction that wasn't there, before they go out and pester people that actually use it correctly. (I don't actually know the historical development of this word though)
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