Parent meaning parent comment, not parent story.
Check the post I was replying to. It basically says "what are you guys doing reading this story when there's a war on".
I was saying it's an article on hydrogen, so keep war comments out of here.
Yeah, it's not like the english invented the language you use or anything;-)
Oh hang on, are you complaining that you're not used to the standard way of spelling 'metre' (ie. you think it should be spelled 'meter' which to everyone else means a little dial that displays some information) or are you not used to the standard metric system itself?
OK, here goes:
NOTE FOR ALL USA CITIZENS:
Replace all instances of the word "nanometre" with "1/25188917" inches. There! Much easier to read!
Note that the operative word here is "Hollow". This ain't your grandfathers optical fibre!
Most optical fibres for communications are solid, that is they work by total internal reflection, where the light bounces off the outer wall of the cylinder (in modern fibres this isn't quite the case, they put different refractive indexes of glass around the outside to 'bend' the light but that's splitting hairs).
The hollow tubes in the article are weird beasts, allowing rather strange things to happen with less than full wavelengths of light -- they're not usually used for communications.
The samples that they made here are only about a centimetre long as well, and I don't think you could make really long tubes because you have to get the baked spider silk out of the tube when you're done! Imagine trying that with a 1 km-long length!
If a Field Judge is unable to continue in the Safety Vehicle, and that inability is of a temporary nature expected to take less than ten minutes to resolve, the Field Judge shall instruct the Safety Vehicle driver to stop, and shall record the time of stopping so that the time stopped may be subtracted from the elapsed time for the team.
Perhaps that should read:
If a Field Judge needs to take a leak, then teams must stop when asked. Team members, on the other hand, are expected to be able to control their bladders.
Is it just me, or is the image of an astronaut trying to dip a metal loop into a container of water extremely funny?
Seeing as how there's no gravity and all...
Do they even have containers of water up there? I thought they only had those squeezy things. Perhaps they had to paint the water on before painting the paint on the water?
If the speed of gravity isn't infinite, then I think you get a paradox when two bodies are orbiting each other.
Let's say we have two bodies, body 1 and body 2, both orbiting a central point.
Both of them are getting pulled in towards the central point by the other one. Right?
But if the speed of gravity isn't infinite, each body will be pulled not exactly towards the center, but towards the point at which the other body used to be, a certain time ago.
Try this experiment: You will need:
1 friend
2 tennis balls
1 roundabout (the circular playground variety)
Stand on a point on the circumference of the roundabout, and get your friend to stand opposite you. Spin the roundabout so you are both orbiting the central point.
Now throw your tennis ball at your friend. Chances are you will miss, because your friend will have moved by the time the ball gets there.
So now change your aim so that the ball actually hits your friend. Get your friend to do the same.
When you've got things sorted, you should get the tennis balls hitting you from slightly 'front-on' compared to the center of the roundabout.
So what this means is that if gravity has a speed, then each orbiting body will be pulled by the phantom ghost of the other one, which will appear to be slightly behind the center of rotation. Therefore, the two bodies will keep on accelerating, pulling themselves up by their shoelaces, until the orbits around the central point become so huge that the effect isn't very big at all.
In other words, orbits won't be stable if gravity has a speed.
If we assume that 2-body orbits are stable, then gravity must be instantaneous, but this introduces a communication paradox (as pointed out by many other posters).
So we have a paradox! If you were God, would you make gravity have a speed, or not? Or do you make it so friggin' hard to measure that people give up and argue over which physicist has the bigger reputation?:-)
All someone has to do is invent a single technology that can reduce mass. Or if you prefer, a technology that converts mass to energy, and then converts that energy back to mass again at the flip of a switch. It needs to be 100% efficiect of course.
Any ideas on how?
Nuclear fission?
I know you don't reduce the mass by much, but you do reduce it by a bit...
Of course the whole convertenergybackintomasstoslowdown issue is overlooked:-)
Here's where the theory falls down though:
Just say there's someone going slightly faster than you, in the same direction. According to them, you would be moving backwards, slowly. When you suddenly got lighter, you should shoot off backwards relative to them (and therefore be slowing down). But according to someone on the ground, you'd shoot off forwards (and therefore speed up).
I think the way to get your theory to work would be to beam all that energy out the back of your rocket, and use that as the reactive force. After all, 99.99% of 100 tons is an awful lot of energy:-)
Isaac Newton thought the influence of gravity was instantaneous, but Einstein assumed it travelled at the speed of light and built this into his 1915 general theory of relativity.
And then...
Kopeikin found another way. He reworked the equations of general relativity to express the gravitational field of a moving body in terms of its mass, velocity and the speed of gravity. If you could measure the gravitational field of Jupiter, while knowing its mass and velocity, you could work out the speed of gravity.
...using relativity, which has the assumption built in.
I love it! Take a formula with an assumption in it, rework the formula, then get the formula to prove the assumption.
Example:
Let a = 2b + c (1)
a - 2b = c
-2b = -a + c
2b = a - c
Now substituting for 2b in (1):
a = a - c + c
a = a!! Brilliant!! Gravity travels at the speed of light!!!
So we prove relativity using relativity. Erm... what's wrong with this picture?
This seems to me to be another case of the placebo effect. In other words, how to skew your experimental results by using people who "want to believe".
Let's see, how would you do a double blind experiment with these shoes? How can you get shoes that vibrate to not let someone know that they're vibrating?
Miracle cures like this seem to work the following way:
Scientist invents theory to explain something.
Inventor invents application to test theory.
Researcher tests application by a small set of usually questionable experiments.
Experiment is judged a success by the researcher. (Of course it is, what sort of researcher would claim a failure?)
Investor funds building of these devices
People buy "scientifically proven" trinkets.
If any part of this process isn't rigorously tested, then the end result is questionable.
The sad part of all this is that the cure actually might work, simply because the vibration tells the person that the miracle shoes are working and therefore the person will try harder to balance. After all, they bought those miracle shoes at quite a hefty price, so therefore they should be working!
Never underestimate the value of a well-marketed placebo.
That's brilliant!!
You could make a honeypot for the search tools as well, perhaps fake a collection of a couple of terabytes of mp3's.
Depending on how automated the system is, you might just be able to point the trained attack lawyers at some portion of the RIAA itself...
As you alluded to, however, you would need to have one of these programs in captivity before you could really figure out a good exploit for them.
Hmmm.....
This sounds to me of another case of "If you look for something hard enough, then you'll find it". In actual fact there is no parity checking there at all.
Parity checking (in computers) involves adding up the number of 1's in a byte, and putting another bit on the end purely as a form of error control. In even parity there are always an even number of 1's in the (byte + paritybit).
In the article they've figured out that cytosine has 1 donor, and guanine has 2 donors. Then they invent the whole parity thing by letting cytosine equal 1 and guanine equal 0, and when you add all the numbers together you get an even number of 1's. Sounds like circular reasoning to me.
If there was a regular parity bit in the DNA to make sure that an even number of G's or A's occur every 8 or so pairs, then fair enough! But what the article is describing isn't the same parity as you get on your serial port.
It's like saying "Let all starfish with 5 arms equal 1, and all starfish with 6 arms equal 0. Add the numbers up and bingo we've got even parity! Nature is a computer!"
From http://www.info.apple.com/usen/security/security_u pdates.html:
Security Update 2002-08-02
This update addresses the following security vulnerabilities which affect current shipping versions of Mac OS X Server. These services are turned off by default in Mac OS X client, however if these services are enabled then the client becomes vulnerable. It is recommended that users of Mac OS X client also apply this update.
So unless you're a hardcore geek who turns on SSL, and hasn't yet updated to the latest security updates, you should be fine with your version of OS X (client). OS X Server users would probably have updated already.
I've got a 600 MHz iBook, and put simply it's the best system for me that exists now. I get 4 hours battery life, and it's fast, stable, and easy to use.
I also have a toshiba notebook running linux, and with the iBook on my lap sitting on the couch I can hear the toshiba's cooling fan start up from 4 metres away. The iBook is quiet as a mouse.
It's funny, when I got the toshiba/Redhat system I used it all the time, but now there's simply no point anymore. I use it for the parallel port and that's it.
OK, compare the following features:
Instant sleep and wake up, by opening/closing the lid: You might poo-poo this, but it really does make a difference. No 'hibernate', no 'restoring from HD', nothing. Open the lid, and go. Close the lid when you're done. My last uptime was for a month, and it only stopped because I updated the OS!
Emacs key bindings in just about every application. Ctrl-k kills the current line in Mail, Omniweb, BBedit, Emacs, everything.
Global preferences that actually affect the thing they're supposed to affect: Put it this way, I still haven't been able to figure out how to change the time in linux, and get the laptop to remember it. It shouldn't have to be that hard.
There are a bajillion other little things that make the iBook better than anything else on the market (except perhaps the TiBook), and they all add up. Honestly, once you've started using OS X everything else feels like it's stuck in the 80's, including the winNT/98/2k machines I have to work on 8 hours a day.
I don't know why, but just lately (in the past month or so), Google has gone completely nuts and won't show pages that it used to show. For example, my father has a site that's all about little historic stone statues, and you used to be able to do a search for "Venus Figures" on google and get his site. No longer! Even a search for the title of his site doesn't return his site. Even a search for the URL doesn't return his site anymore! It returns some pages with links to his site, but not his site!
For my money, the balance of power of the web search engines is shifting. I now use teoma and www.alltheweb.com when I want to do a search, and then try google.
If we can make a decent operating system, web server, proxy, etc open source, why can't we make a decent open source search engine? Surely the geekier members amongst us can figure something out...
Ben
The standard test I use whenever I learn a new programming language/system is to display the mandelbrot set. Drawing the set isn't that hard, but it doesn't stop there! You can set things up so that when you click on a part of the image it zooms in, you can select different colours, etc. I've done this (including zoom) using C++ in XWindows on a silicon graphics machine, using objective C on MacOS X, and even in perl/apache/internet explorer on a windows NT machine!
The problem is simple enough to be possible, and complex enough to be challenging.
I think nanobots would have other problems besides going too fast though...
A few hundred atoms? That's way smaller than even simple bacteria! A few hundred atoms is tiny, so unimaginably tiny that it would be a bit silly even thinking about trying to make robots that small. I mean just think about the control system a simple robot needs... you need a couple of transistors at the very least, and the last I heard batteries (or capacitors) don't work very well when you've only got a couple of hundred atoms worth of storage to play with.
And just what would a robot that small actually accomplish? No, I think that the robots that we will eventually put into the bloodstream will be in the order of a couple of hundred microns across, not a couple of hundred atoms.
Come on people, why do sites like slashdot exist? Why are there revolutions to overthrow the evil overlords? Because evil overlords exist, that's why!
If M$ software worked first time every time, and their licencing scheme was reasonable, then what incentive would there be for people to work on open source alternatives?
If a trojan program is useful, does that make it any less of a trojan? Where do you draw the line?
To my mind, people have downloaded a program, expecting it to do one thing, and really it has a payload that con do something completely different... Makes me wonder what else the makers of this 'brilliant' scheme aren't telling us about it:-)
One possible solution would be to somehow figure out who the authority was for a particular application... Let's take, for example, the phrase "rubik's cube". A google search reveals www.rubik.com, which would therefore make the owner of www.rubik.com the patent holder for the rubik's cube.
To get the 'patent', you have to buy web space and possibly a domain name, and you have to publish a good enough description that other people want to link to it. So then, when people want to learn about a patented process, they just fire up their patent viewing application (www.google.com), and type in the item they wish to see patent information for, and bingo! there's the list.
So the patent holder for a particular process would be the site at the top of the list.
This makes your work rightfully yours, so long as everyone else agrees that you are the authority on that particular process, for as long as you care to keep people interested...
The nice thing about this system is that it's fair, equitable, rewards those people who publish their process well, rewards the first person to publish, and completely stomps all over big corporations who want to use patent law for their own nefarious purposes. In fact, it's about as democratic as you can get.
If only we were to implement such a system... *sigh*
---
[hosaka:~] ben% traceroute life.liberty.pursuit-of-happiness long delay...
traceroute: not found: life.liberty.pursuit-of-happiness
How long will it be until the port is finished?
Progress on the Mac OS X port has been slow. At this time it's not feasible to estimate the amount of time it will take to complete the port.
They're still looking for developers, so if you've got some time to spare then help out!
Slashdot Mirror
Parent meaning parent comment, not parent story. Check the post I was replying to. It basically says "what are you guys doing reading this story when there's a war on". I was saying it's an article on hydrogen, so keep war comments out of here.
Think about it for a second: News about the war has already saturated all the major news outlets. You can't get away from the damn thing.
If you want to comment about the war then for goodness sake do it in the story that's about the war, not in a story about hydrogen. Sheesh!
Yeah, it's not like the english invented the language you use or anything ;-)
Oh hang on, are you complaining that you're not used to the standard way of spelling 'metre' (ie. you think it should be spelled 'meter' which to everyone else means a little dial that displays some information) or are you not used to the standard metric system itself?
OK, here goes:
NOTE FOR ALL USA CITIZENS: Replace all instances of the word "nanometre" with "1/25188917" inches. There! Much easier to read!
Friggin foreigners.
Note that the operative word here is "Hollow". This ain't your grandfathers optical fibre!
Most optical fibres for communications are solid, that is they work by total internal reflection, where the light bounces off the outer wall of the cylinder (in modern fibres this isn't quite the case, they put different refractive indexes of glass around the outside to 'bend' the light but that's splitting hairs).
The hollow tubes in the article are weird beasts, allowing rather strange things to happen with less than full wavelengths of light -- they're not usually used for communications.
The samples that they made here are only about a centimetre long as well, and I don't think you could make really long tubes because you have to get the baked spider silk out of the tube when you're done! Imagine trying that with a 1 km-long length!
If a Field Judge is unable to continue in the Safety Vehicle, and that inability is of a temporary nature expected to take less than ten minutes to resolve, the Field Judge shall instruct the Safety Vehicle driver to stop, and shall record the time of stopping so that the time stopped may be subtracted from the elapsed time for the team.
Perhaps that should read:
If a Field Judge needs to take a leak, then teams must stop when asked. Team members, on the other hand, are expected to be able to control their bladders.
Somebody should write an app that plays one-channel melodies with the RF noise... ;)
http://abaababa.ouvaton.org/tempest/
Is it just me, or is the image of an astronaut trying to dip a metal loop into a container of water extremely funny?
Seeing as how there's no gravity and all...
Do they even have containers of water up there? I thought they only had those squeezy things. Perhaps they had to paint the water on before painting the paint on the water?
I was going to moderate this but there's no +1 Redundant.
If the speed of gravity isn't infinite, then I think you get a paradox when two bodies are orbiting each other.
:-)
Let's say we have two bodies, body 1 and body 2, both orbiting a central point.
Both of them are getting pulled in towards the central point by the other one. Right?
But if the speed of gravity isn't infinite, each body will be pulled not exactly towards the center, but towards the point at which the other body used to be, a certain time ago.
Try this experiment: You will need:
1 friend
2 tennis balls
1 roundabout (the circular playground variety)
Stand on a point on the circumference of the roundabout, and get your friend to stand opposite you. Spin the roundabout so you are both orbiting the central point.
Now throw your tennis ball at your friend. Chances are you will miss, because your friend will have moved by the time the ball gets there. So now change your aim so that the ball actually hits your friend. Get your friend to do the same.
When you've got things sorted, you should get the tennis balls hitting you from slightly 'front-on' compared to the center of the roundabout.
So what this means is that if gravity has a speed, then each orbiting body will be pulled by the phantom ghost of the other one, which will appear to be slightly behind the center of rotation. Therefore, the two bodies will keep on accelerating, pulling themselves up by their shoelaces, until the orbits around the central point become so huge that the effect isn't very big at all.
In other words, orbits won't be stable if gravity has a speed.
If we assume that 2-body orbits are stable, then gravity must be instantaneous, but this introduces a communication paradox (as pointed out by many other posters).
So we have a paradox! If you were God, would you make gravity have a speed, or not? Or do you make it so friggin' hard to measure that people give up and argue over which physicist has the bigger reputation?
I know you don't reduce the mass by much, but you do reduce it by a bit...
Of course the whole convertenergybackintomasstoslowdown issue is overlooked
Here's where the theory falls down though: Just say there's someone going slightly faster than you, in the same direction. According to them, you would be moving backwards, slowly. When you suddenly got lighter, you should shoot off backwards relative to them (and therefore be slowing down). But according to someone on the ground, you'd shoot off forwards (and therefore speed up).
I think the way to get your theory to work would be to beam all that energy out the back of your rocket, and use that as the reactive force. After all, 99.99% of 100 tons is an awful lot of energy
I love it! Take a formula with an assumption in it, rework the formula, then get the formula to prove the assumption.
Example:
Let a = 2b + c (1)
a - 2b = c
-2b = -a + c
2b = a - c
Now substituting for 2b in (1):
a = a - c + c
a = a!! Brilliant!! Gravity travels at the speed of light!!!
So we prove relativity using relativity. Erm... what's wrong with this picture?
Let's see, how would you do a double blind experiment with these shoes? How can you get shoes that vibrate to not let someone know that they're vibrating?
Miracle cures like this seem to work the following way:
- Scientist invents theory to explain something.
- Inventor invents application to test theory.
- Researcher tests application by a small set of usually questionable experiments.
- Experiment is judged a success by the researcher. (Of course it is, what sort of researcher would claim a failure?)
- Investor funds building of these devices
- People buy "scientifically proven" trinkets.
If any part of this process isn't rigorously tested, then the end result is questionable.The sad part of all this is that the cure actually might work, simply because the vibration tells the person that the miracle shoes are working and therefore the person will try harder to balance. After all, they bought those miracle shoes at quite a hefty price, so therefore they should be working!
Never underestimate the value of a well-marketed placebo.
Just when I'd made a ripper of a comment to whore all those +30 karma points, too!
Damn. Hope it goes back up soon, I've got some serious karma grabbing to do...
That's brilliant!! You could make a honeypot for the search tools as well, perhaps fake a collection of a couple of terabytes of mp3's. Depending on how automated the system is, you might just be able to point the trained attack lawyers at some portion of the RIAA itself... As you alluded to, however, you would need to have one of these programs in captivity before you could really figure out a good exploit for them. Hmmm.....
This sounds to me of another case of "If you look for something hard enough, then you'll find it". In actual fact there is no parity checking there at all.
Parity checking (in computers) involves adding up the number of 1's in a byte, and putting another bit on the end purely as a form of error control. In even parity there are always an even number of 1's in the (byte + paritybit).
In the article they've figured out that cytosine has 1 donor, and guanine has 2 donors. Then they invent the whole parity thing by letting cytosine equal 1 and guanine equal 0, and when you add all the numbers together you get an even number of 1's. Sounds like circular reasoning to me.
If there was a regular parity bit in the DNA to make sure that an even number of G's or A's occur every 8 or so pairs, then fair enough! But what the article is describing isn't the same parity as you get on your serial port.
It's like saying "Let all starfish with 5 arms equal 1, and all starfish with 6 arms equal 0. Add the numbers up and bingo we've got even parity! Nature is a computer!"
Stinks of looking for more funding to me.
Security Update 2002-08-02
- This update addresses the following security vulnerabilities which affect current shipping versions of Mac OS X Server. These services are turned off by default in Mac OS X client, however if these services are enabled then the client becomes vulnerable. It is recommended that users of Mac OS X client also apply this update.
- OpenSSL: Fixes security vulnerabilities CAN-2002-0656, CAN-2002-0657, CAN-2002-0655, and CAN-2002-0659. Details are available via:
http://www.cert.org/advisories/CA-2002-23.html
- mod_ssl: Fixes CAN-2002-0653, an off-by-one buffer overflow in mod_ssl Apache module. Details are available via:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN
- 2002-0653
- Sun RPC: Fixes CAN-2002-039, a buffer overflow in the Sun RPC XDR decoder. Details are available via:
http://bvlive01.iss.net/issEn/delivery/xforce/ale
r tdetail.jsp?oid=20823
So unless you're a hardcore geek who turns on SSL, and hasn't yet updated to the latest security updates, you should be fine with your version of OS X (client). OS X Server users would probably have updated already.Aren't all cookbooks by their very design 'open source'?
I also have a toshiba notebook running linux, and with the iBook on my lap sitting on the couch I can hear the toshiba's cooling fan start up from 4 metres away. The iBook is quiet as a mouse.
It's funny, when I got the toshiba/Redhat system I used it all the time, but now there's simply no point anymore. I use it for the parallel port and that's it.
OK, compare the following features:
There are a bajillion other little things that make the iBook better than anything else on the market (except perhaps the TiBook), and they all add up. Honestly, once you've started using OS X everything else feels like it's stuck in the 80's, including the winNT/98/2k machines I have to work on 8 hours a day.
Hope this helps!
I don't know why, but just lately (in the past month or so), Google has gone completely nuts and won't show pages that it used to show. For example, my father has a site that's all about little historic stone statues, and you used to be able to do a search for "Venus Figures" on google and get his site. No longer! Even a search for the title of his site doesn't return his site. Even a search for the URL doesn't return his site anymore! It returns some pages with links to his site, but not his site! For my money, the balance of power of the web search engines is shifting. I now use teoma and www.alltheweb.com when I want to do a search, and then try google. If we can make a decent operating system, web server, proxy, etc open source, why can't we make a decent open source search engine? Surely the geekier members amongst us can figure something out... Ben
The standard test I use whenever I learn a new programming language/system is to display the mandelbrot set. Drawing the set isn't that hard, but it doesn't stop there! You can set things up so that when you click on a part of the image it zooms in, you can select different colours, etc. I've done this (including zoom) using C++ in XWindows on a silicon graphics machine, using objective C on MacOS X, and even in perl/apache/internet explorer on a windows NT machine! The problem is simple enough to be possible, and complex enough to be challenging.
I think nanobots would have other problems besides going too fast though... A few hundred atoms? That's way smaller than even simple bacteria! A few hundred atoms is tiny, so unimaginably tiny that it would be a bit silly even thinking about trying to make robots that small. I mean just think about the control system a simple robot needs... you need a couple of transistors at the very least, and the last I heard batteries (or capacitors) don't work very well when you've only got a couple of hundred atoms worth of storage to play with. And just what would a robot that small actually accomplish? No, I think that the robots that we will eventually put into the bloodstream will be in the order of a couple of hundred microns across, not a couple of hundred atoms.
:-)
Besides, what about brownian motion?
Come on people, why do sites like slashdot exist? Why are there revolutions to overthrow the evil overlords?
Because evil overlords exist, that's why!
If M$ software worked first time every time, and their licencing scheme was reasonable, then what incentive would there be for people to work on open source alternatives?
If a trojan program is useful, does that make it any less of a trojan? Where do you draw the line? To my mind, people have downloaded a program, expecting it to do one thing, and really it has a payload that con do something completely different... Makes me wonder what else the makers of this 'brilliant' scheme aren't telling us about it :-)
One possible solution would be to somehow figure out who the authority was for a particular application... Let's take, for example, the phrase "rubik's cube". A google search reveals www.rubik.com, which would therefore make the owner of www.rubik.com the patent holder for the rubik's cube.
To get the 'patent', you have to buy web space and possibly a domain name, and you have to publish a good enough description that other people want to link to it. So then, when people want to learn about a patented process, they just fire up their patent viewing application (www.google.com), and type in the item they wish to see patent information for, and bingo! there's the list.
So the patent holder for a particular process would be the site at the top of the list.
This makes your work rightfully yours, so long as everyone else agrees that you are the authority on that particular process, for as long as you care to keep people interested...
The nice thing about this system is that it's fair, equitable, rewards those people who publish their process well, rewards the first person to publish, and completely stomps all over big corporations who want to use patent law for their own nefarious purposes. In fact, it's about as democratic as you can get.
If only we were to implement such a system... *sigh*
---
[hosaka:~] ben% traceroute life.liberty.pursuit-of-happiness
long delay...
traceroute: not found: life.liberty.pursuit-of-happiness