Well, actually, at the latest AAS meeting there was a talk by an expert who said that they now have enough statistics to know that one in ten stars has a gas giant and one in three has a rocky planet similar to Earth or Mars. This is from memory so excuse me if I am slightly off or swapped the numbers. They openly said that they are looking for methods to detect planets capable of having life (i.e. water, CO2, etc).
I guess we are at the point in time where an expert on exoplanet searches knows that finding life in outer space is hard, but achievable, while an expert in another area thinks it is still too difficult.
F*ck MP3 players, how about the fact that the only reason a space colony could function at all is because of high tech. This isn't Earth were you can have some sort of cataclysmic event and practically go back to a primitive agrarian society. You want that space suit to function? That airlock to work? The solar panels to produce heat so you don't freeze to death? If they break down and you can't fix them or replace them you're dead.
Yep. It is interesting to think of what this would imply for education and job market of the colony.
Reminds me; I once read a sci fi - can't remember which - there were a passing reference to other races who had burned the fuel on their planet before reaching spaceflight. They were forever trapped in the gravity well. I assume the same will happen to us.
There are ways to get energy without fossil fuels - if only to reach just outside to get more materials. However, they make it easier when just starting development program - you need less knowledge to get things to work. From this point of view radioactive waste is an investment in the far future, as it will make it easier to start new nuclear programs.
There seems to be a basic human assumption that power plants must reside within the habitable portions of a craft. In reality, the powerplant(s) might be very distantly attached by spars. A mile long spar will introduce some interesting engineering challenges (depending on the materials used to make the spars) but it will most certainly remove most of the radiation hazard.
And, this is where someone asks, "Why in hell would you want mile long spars? How big do you want this craft to be?" Well - thinking in interstellar terms, we don't have the technology to exceed the speed of light. Interstellar colonization will be done with generation ships. They'll have to be BIG, to carry a large DNA pool, plus ship's crew, plus the support personnel that will be needed by the colonists. Unless we get FTL, ships will have to be freaking HUGE! So, putting any hazardous power plants at the far end of a mile long spar just makes sense!
Exactly. There is no better shield than 1/r^2. And, instead of a spar, you can just use a 40km cable and do formation flying. Zero weight radiation shielding!
The actual radiation hazard comes from space itself - it is not empty but full of high energy radioactive stuff. See for example EEv particles - they are fortunately rare, but still have a chance of hitting a sizable interstellar craft. On Earth we are shielded from them by the atmosphere (they trigger less harmfull radiation showers). Lesser energy charged particles are deflected by Earth magnetic field.
Citation needed. Note that none of the astronauts have died due to the lack of gravity. I can't say definitely whether any cosmonauts have died due to lack of gravity, but it seems that we would have heard about it. Sinonauts? (What DOES China call their space explorers? Sinonaut sounds like a nasal problem!) How about European astronauts?
I SUSPECT that you are alluding to health and development problems that are expected to occur in a population without gravity. And, I SUSPECT that said population will adapt. Individuals might die, but the population will adapt. Some recessive traits might become dominant, congenital deformities might become meaningless, while other traits that make us strong in gravity might slowly disappear.
BUT, that's pretty much inconsequential, no matter that I'm right or wrong. Few people seriously propose that we build 0-G environments. We want habitats on the moon, Mars, the moons of the gas giants. You know - places that have gravity, even if it's microgravity. As for space habitats, we can always induce artificial gravity by means of rotating the place.
And to see how evolution proceeds without gravity we just need to look at the sea. Sea lions, dolphins and whales are all descended from mammals that used to live exclusively on land.
Without gravity, we'd die. That's only part of what kills me about the whole manned space settlement concept. I love reading sci-fi where we live on lot's of planets and in space stations, but the fact is we're made of meat grown in a biological soup unique to Earth.
That's where global warming comes in - once the temperature is up by 10 degrees or more we will be prepared for outer space.
Yesterday I was seeing wind speeds of up to 90mph in gusts and 60mph sustained, and today it is flat calm. In January we normally see sustained 120mph winds, but this year they were only about 90mph.
120mph winds ? Your aerospace industry must be top-notch.
Instead of letting this culture/nation, Iran, Naturally develop their science to a high level, nuclear weapons, allowing them to flourish much as the USA has..
the US and the big guys on the anti nuke front are actively SQUELCHING the scientific advancement of Iran.. Pushing them further into the past because USA et al wont alllow them to develop naturally (or however iran develops..russian scientists or not)
I personally find it reprehensible that a nation would fight so hard to stifle the scientific understanding and development of a nation/culture/anyone.
The Reverse Prime Directive!! Don't let them get Warp technology! ITS DANGEROUS!
Unfortunately, this is after taking cached data out. This is especially visible if you try installing Kubuntu on a 5 year old laptop with 1 GB RAM - what was plenty for KDE 3.5.x causes swapping when using KDE 4.x. I really do not see what could possibly *need* that much RAM, except for programmer sloppiness.
Kubuntu sucks less than Unity, but it has issues as well. For example, I have 8 GB of RAM and if I leave my laptop running for a few weeks they fill up. And this is without nepomuk running. Whoever thought that writing system daemons in python was a good idea ? KDE 3.5.x was way better
The new krunner (with calculator) is very useful..
Whats so big in this ? Sounds like every now and then someone adds another 10,000 new chips and they have a new world record holding super computer.
Interconnect. Adding more nodes has a linear cost increase, but connecting them all with low-latency links is difficult. It is easy enough to buy a 48-port switch, but a 1000 port switch with low latency is a completely different story, and if you need 10000 ports you are in fully custom territory - it can easily cost a lot more than all the nodes combined.
They need to call it "light" because politicians are stupid enough to ban if they call it "radiation" - although a powerful enough laser won't be visible light, but UV radiation...
No, power of light has nothing to do with its wavelength. In fact, the one common high power laser is the CO2 laser that produces infrared. However, shorter wavelength (like UV) does help to focus the spot tighter providing higher power density.
The speed of light is constant by definition of our units.. Just a way to count. If you think of propagation time of light from point A to point B, then it does change - this is the premise of general relativity.
Gravitational constant is actually fairly poorly known, at least compared to other constants.
If you LIKE the technology, then shouldn't you be trying to get more people involved?
"The technology" is, in this case, radiation detectors. Now, it is true that I like radiation detectors quite a bit. However, I also realize they are expensive, hard to use, and of little to no value to the person asking the question, and thus the only advice I can honestly give is to not bother, as he would be throwing his money away based on a misunderstanding.
Radiation detectors are not that expensive ! You can pick up old ones on the cheap, or get a new one for $300.
A few pointers:
There are radiation detectors that measure alpha, beta and gamma depending on what shield is on top of the geiger counter.
The sensitivity of the detector depends on the volume of the geiger tube. Large ones (pancake, for example) are more expensive.
Most of the radiation is not that harmful, and the real danger comes from what manages to get inside, such as with food.
It is hard to figure out whether the food is dangerous with a regular detector as you need to integrate data from a high-sensitivity detector over a long time to be sure. This is also why a radon check takes tens of hours to do properly.
A sane thing to do with your own detector is to note the level of background radiation usual to where you live and check for any increases. There is usually variation depending on the time of the year (especially with a gas heater), weather, etc.
So, we would need an optical telescope with an aperture/mirror that is 3.7 km in diameter. Needless to say, this is quite a bit bigger than any telescope that exists today (the best is about 12 m [wikipedia.org]). If you want to be able to accurately see the astronaut's eyes, to confirm that he's really not a robot, then the telescope would have to be even bigger (like 40 km in diameter).
This is a large number but not too large - two telescopes spaced apart at 3.7km and connected to form an interferometer would have the same resolution, but, of course, not the collecting area.
This is still quite a project, but doable and interesting for other purposes. Oh, and you since you were interested in features 5cm in size, you could use radio waves instead of light which would greatly simplify interferometer design.
1 nanosecond is a pretty large amount of time. There are commercial TDCs (time to digital converters) with resolution of sub 100ps.
There is one additional possibility that makes the experiment results and conventional speed of light agree - it could be that, for some reason, their pulse shape is distorted and they see the difference between group propagation speed and phase velocity.
The way that this works, is that you start with nice strong pulse with some distribution and someplace in flight the trailing 75% part of the pulse is cut off. Then if you measure where the peak of the new pulse is it would be ahead by 25% of initial pulse width.
This is fairly well-known, so I would be surprised if they did not consider this already - chances are there is no obvious mechanism to truncate the pulse.
Slashdot Mirror
Fox-It is based in the Netherlands. This makes it likely that the author's native language is not English.
Would you be able to form a coherent thought in Dutch that a native speaker wouldn't find awkward?
Onze visie op de eigen slagkracht van de overheid.
I guess we are at the point in time where an expert on exoplanet searches knows that finding life in outer space is hard, but achievable, while an expert in another area thinks it is still too difficult.
F*ck MP3 players, how about the fact that the only reason a space colony could function at all is because of high tech. This isn't Earth were you can have some sort of cataclysmic event and practically go back to a primitive agrarian society. You want that space suit to function? That airlock to work? The solar panels to produce heat so you don't freeze to death? If they break down and you can't fix them or replace them you're dead.
Yep. It is interesting to think of what this would imply for education and job market of the colony.
Reminds me; I once read a sci fi - can't remember which - there were a passing reference to other races who had burned the fuel on their planet before reaching spaceflight. They were forever trapped in the gravity well. I assume the same will happen to us.
There are ways to get energy without fossil fuels - if only to reach just outside to get more materials. However, they make it easier when just starting development program - you need less knowledge to get things to work. From this point of view radioactive waste is an investment in the far future, as it will make it easier to start new nuclear programs.
There seems to be a basic human assumption that power plants must reside within the habitable portions of a craft. In reality, the powerplant(s) might be very distantly attached by spars. A mile long spar will introduce some interesting engineering challenges (depending on the materials used to make the spars) but it will most certainly remove most of the radiation hazard.
And, this is where someone asks, "Why in hell would you want mile long spars? How big do you want this craft to be?" Well - thinking in interstellar terms, we don't have the technology to exceed the speed of light. Interstellar colonization will be done with generation ships. They'll have to be BIG, to carry a large DNA pool, plus ship's crew, plus the support personnel that will be needed by the colonists. Unless we get FTL, ships will have to be freaking HUGE! So, putting any hazardous power plants at the far end of a mile long spar just makes sense!
Exactly. There is no better shield than 1/r^2. And, instead of a spar, you can just use a 40km cable and do formation flying. Zero weight radiation shielding!
The actual radiation hazard comes from space itself - it is not empty but full of high energy radioactive stuff. See for example EEv particles - they are fortunately rare, but still have a chance of hitting a sizable interstellar craft. On Earth we are shielded from them by the atmosphere (they trigger less harmfull radiation showers). Lesser energy charged particles are deflected by Earth magnetic field.
"Without gravity, we'd die."
Citation needed. Note that none of the astronauts have died due to the lack of gravity. I can't say definitely whether any cosmonauts have died due to lack of gravity, but it seems that we would have heard about it. Sinonauts? (What DOES China call their space explorers? Sinonaut sounds like a nasal problem!) How about European astronauts?
I SUSPECT that you are alluding to health and development problems that are expected to occur in a population without gravity. And, I SUSPECT that said population will adapt. Individuals might die, but the population will adapt. Some recessive traits might become dominant, congenital deformities might become meaningless, while other traits that make us strong in gravity might slowly disappear.
BUT, that's pretty much inconsequential, no matter that I'm right or wrong. Few people seriously propose that we build 0-G environments. We want habitats on the moon, Mars, the moons of the gas giants. You know - places that have gravity, even if it's microgravity. As for space habitats, we can always induce artificial gravity by means of rotating the place.
And to see how evolution proceeds without gravity we just need to look at the sea. Sea lions, dolphins and whales are all descended from mammals that used to live exclusively on land.
Carbon based life will probably just be a catalyst to bootstrap silicon based life.
Let's not get selective too early. All of GaAs, SiN and plain C (diamond) can be fun too.
Without gravity, we'd die. That's only part of what kills me about the whole manned space settlement concept. I love reading sci-fi where we live on lot's of planets and in space stations, but the fact is we're made of meat grown in a biological soup unique to Earth.
That's where global warming comes in - once the temperature is up by 10 degrees or more we will be prepared for outer space.
Yesterday I was seeing wind speeds of up to 90mph in gusts and 60mph sustained, and today it is flat calm. In January we normally see sustained 120mph winds, but this year they were only about 90mph.
120mph winds ? Your aerospace industry must be top-notch.
Gotta love how the real world is a lot different from TV..
http://en.wikipedia.org/wiki/Prime_Directive
Instead of letting this culture/nation, Iran, Naturally develop their science to a high level, nuclear weapons, allowing them to flourish much as the USA has..
the US and the big guys on the anti nuke front are actively SQUELCHING the scientific advancement of Iran .. Pushing them further into the past because USA et al wont alllow them to develop naturally (or however iran develops..russian scientists or not)
I personally find it reprehensible that a nation would fight so hard to stifle the scientific understanding and development of a nation/culture/anyone.
The Reverse Prime Directive!! Don't let them get Warp technology! ITS DANGEROUS!
No, the TV show is spot on. You just need to read the page which corresponds more closely to our society.
That's normal. http://www.linuxatemyram.com/
Unfortunately, this is after taking cached data out. This is especially visible if you try installing Kubuntu on a 5 year old laptop with 1 GB RAM - what was plenty for KDE 3.5.x causes swapping when using KDE 4.x. I really do not see what could possibly *need* that much RAM, except for programmer sloppiness.
The new krunner (with calculator) is very useful..
Here is a cheer for Slackware !
$2 is really cheap for MIL-SPEC part, it was probably just a surface mount resistor or capacitor that got replaced with a $0.05 non-MIL-SPEC version.
With so much power one would think that it could have already discovered fusion [...]
No, the number of cores needs to increase by another two orders of magnitude before we achieve ignition.
A car analogy? Or how may libraries of congress / football fields?
Seriously I doubt 10.51 petaflops means anything to anyone except a small coterie of supercomputer nerds.
That's why I read Slashdot.
Whats so big in this ? Sounds like every now and then someone adds another 10,000 new chips and they have a new world record holding super computer.
Interconnect. Adding more nodes has a linear cost increase, but connecting them all with low-latency links is difficult. It is easy enough to buy a 48-port switch, but a 1000 port switch with low latency is a completely different story, and if you need 10000 ports you are in fully custom territory - it can easily cost a lot more than all the nodes combined.
They need to call it "light" because politicians are stupid enough to ban if they call it "radiation" - although a powerful enough laser won't be visible light, but UV radiation...
No, power of light has nothing to do with its wavelength. In fact, the one common high power laser is the CO2 laser that produces infrared. However, shorter wavelength (like UV) does help to focus the spot tighter providing higher power density.
If you LIKE the technology, then shouldn't you be trying to get more people involved?
"The technology" is, in this case, radiation detectors. Now, it is true that I like radiation detectors quite a bit. However, I also realize they are expensive, hard to use, and of little to no value to the person asking the question, and thus the only advice I can honestly give is to not bother, as he would be throwing his money away based on a misunderstanding.
Radiation detectors are not that expensive ! You can pick up old ones on the cheap, or get a new one for $300.
A few pointers:
Are you posting from the Hilbert Hotel?
No, but we'll use this principle once quantum computers get better ;)
And cloud servers don't use hard drives?
No, they just send data back and forth, using the Internet as a giant delay line.
This is a large number but not too large - two telescopes spaced apart at 3.7km and connected to form an interferometer would have the same resolution, but, of course, not the collecting area.
This is still quite a project, but doable and interesting for other purposes. Oh, and you since you were interested in features 5cm in size, you could use radio waves instead of light which would greatly simplify interferometer design.
And valgrind
There is one additional possibility that makes the experiment results and conventional speed of light agree - it could be that, for some reason, their pulse shape is distorted and they see the difference between group propagation speed and phase velocity.
The way that this works, is that you start with nice strong pulse with some distribution and someplace in flight the trailing 75% part of the pulse is cut off. Then if you measure where the peak of the new pulse is it would be ahead by 25% of initial pulse width.
This is fairly well-known, so I would be surprised if they did not consider this already - chances are there is no obvious mechanism to truncate the pulse.