Astronauts can suffer from motion sickness, bone loss, muscle degeneration (atrophy) and blood vessel problems during weightlessness.
Isn't this just the body adapting to the new environment? In low-g you don't need strong bones and muscles to support your weight and the blood vessels need not to be as strong as they don't have to support the hydrostatic pressure. By getting rid of unnecessary structures the body conserves resources - maybe that way one is able to survive with a lower metabolic turnover rate (which, according to research done on animals, could make a longer living-span possible).
because the only thing that differs between particle and antiparticle is it's spin
that's wrong, it's the electric charge that is opposite for particles and their antiparticles. The total spin (magnitude of spin) is the same for both and the actual spin vector is not a fixed property for a particle (except when it's zero).
The argument of cave-ins, earthquakes are however very serious ones. The typical example of a colorado experiment where fluids were injected into deep crustal fissures resulting in earthquakes occuring daily instead of yearly warn us against toying with the earth's structure.
Doesn't that mean that the earthquakes are now far smaller in magnitude ? In fact, the problem with earthquakes is that they release a lot of energy in a short time.
Do you mean the HESS telescope or the nuclear photoelectric effect ?
Both are basic science - there is no immediate practical application (and usually you don't start basic science with practical applications in mind). That is also the reason why these projects are run by the Max-Planck Society, which is the German organization for cost-intensive basic research.
For the HESS, the goal is to understand the creation and origin of the very high energetic particles that are observed in cosmic radiation. You can get more detailed answers at the site linked in my previous post if you proceed to the section "Exploring the nonthermal universe" on the left sidebar. For the nuclear photoelectric effect, I do not know much about that. I assume the goal was initially to verify theory and get some values for the "effectivity" of the process, which would e.g. be important for calculations concerning nuclear reactors, nuclear waste, or nuclear reactions in stars (like our sun). Also, the photoelectric effect is a very simple and basic phenomenon and quite important and useful in its "conventional" (=non nuclear) form (think solar cell, photodiode etc.) and therefore it is important to know more about it in its nuclear analogy, too.
What is the width of an electron ? Hint: it's unknown (for the free electron). We only know that the electron is smaller then 10^-15 meters, compare this to the wavelength of visible light: 10^-6 meters. Visible light has HUGE wavelength (several thousand atom spacings)! Guess why we need UV and XUV etc. light for lithography...to get near atom size with light you actually need X-rays!
These Telescopes measure gamma rays with energies above 40 GeV, far above enegies of nuclear decay (MeV range, a factor of 1000 less). The HESS project page contains more information, about the (cosmic) origin of these gamma rays.
One could measure the change in these isotopes when gamma rays hit them, thus measuring the gamma rays. Has anyone played with this?
You are talking about the nuclear "photoelectric" effect. It is in principle possible, but very inefficient (nuclei do not capture gamma rays very well). Actually this was initially researched by W. Gentner in the 1930ies in Heidelberg, where they now build the HESS telescope (among others).
I just noticed that I misunderstood your question a little bit. The microscope mentioned above is an electron microscope - as such it has no mechanical moving parts. You can see pictures taken with that microscope in this paper (2MB). You were probably thinking of scanning tunneling microscopes that have a tip scanning over the surface of a sample. These microscopes would indeed need mechanical positioning at the mentioned level to measure such small distances.
No, it doesn't imply that. You have to keep in mind that resolution is not the same thing as being able to locate something. Resolution means that you can distinguish two closely spaced objects, rather than seeing just one broad fuzzy spot. Locating refers to a single object: It's easy to determine the location of a fuzzy spot by just determining where the center of that spot is. Now imagine two fuzzy spots 4 Angstroms apart (see here for an example). If one of them moves by 1/100 Angstrom you will see the corresponding fuzzy spot move a little bit to the side. Obviously that doesn't meant that you could distinguish two fuzzy spots just 1/100 Angstrom apart - they would appear as one slightly broadened fuzzy spot.
If you could come up with a final filter for the screen that converted, say, the vertical component of linearly-polarized light into right-circular and the horizontal into left-circular, you could then use circularly polarized glasses and defeat linearly-polarized. But I don't know of any physical mechanism (let alone one that could be turned into a cheap thin film) that would do this, even for monochrome, let alone the near-octave of light used by color displays or the full-octave for black-and-white.
That's easy do to. It's commonly known as quarter wave plate. Put it in front of your h and v polarized screen and rotate it to 45 degrees from h/v. It will turn h polarized in to right (or left) and v polarized into left (or right, depending on the rotation of the qw plate). See here how it works.
So stock polarizing sunglasses read all these screens, no problem.
Or just take the top plate from your old LCD pocket calculator/alarm clock/whatever.
This will provide the capability for people to store the entire printed contents of the Library of Congress on a single disc drive in their notebook computers
Heat is only needed when writing data. In fact, when not heated, it's even harder to remagnetize the new material than the older one (that's why they need to heat it - a magnetic write head alone would not be able to change the magnetization).
Same problem with conventional harddisks. You can't hammer on them as you like. With CDs much of the problem is related to the fact that a) the CDs are removable which means the mounting cannot be optimzed for rigidity only. b) the CDs are supposed to be cheap, which means again they are not as rigid and symmetric as ordinary harddisk platters. (leading to high noise level at moderate rotation compared to harddisks). Btw, CDs skipping means the drives either have not enough read ahead buffer or they cannot sustain the necessary data rate for audio playback. In most computer tasks you don't have the requirement of a minimum data rate, so you won't notice when reading errors occur.
...some things, eg. X-Rays, can, at least practically if not theoretically
no, x-rays are just very high energetic light. a visible light photon has around 2 eV (electron volt) while x-ray photons have hundreds to thousands of electron volts (and gamma rays have millions of electron volts or more).
She'd still need the sine/cosine values to draw the moving tickmarks. So an FPU would speed up compass drawing but not in the circle part. Maybe she just misunderstood her boss.
I can't give you an example for the use of these heavy nuclei, but there is definitely use for non-stable nuclei: for example the technique of beta-NMR uses the decay products of beta-unstable nuclei to find out about electric fields, crystal defects and diffusion in matter. It's a very expensive technique (you need to create the unstable nuclei during the experiment because they are so short-lived), but it gives some information that cannot be gathered by other means.
This fiber device does not look at the data at Gb rate - it's just a switch for different colors of light (at a millisecond rate, way too slow for any ECC logic). Also, the logic of when to switch what is not part of this device - that logic has to be brought to the device as electrical signals from outside.
This microfluidic optic fiber is not a network, it's only a short piece of fiber that is inserted in a conventional fiber. It's more like a switching device than a network. The control signals have to be electric, too (you have to operate the heaters), so the logic is not part of this fiber. The microfluidic fiber is only the device that does the actual filtering. The advantage of this fiber is that you don't have to seperate all the different wavelength modes before you can filter some of them out, but you can do it directly in a fiber.
The fiber has a central channel (core) that transmits the light by total internal reflection. This channel is surrounded by six large channels that contain the fluid/air mixture. The dimensions are such that the light transmission along the core is normally not affected by the presence of the fluid in the outer channels, except for a limited region where they have written a "long period grating" into the core. When the region with the long period grating has the outer channels filled with the fluid the corresponding change in the refractive index leads to a reduced internal reflection in the core and thus light leaves the core and is therefore "filtered out". The filtered wavelength depends on the refractive index of the fluid which can be tuned by the fluid temperature (the authors report 0.10 nm/K shift of the filtered wavelength with temperature).
How is the fluid brought to the grating region? The outer channels are not filled completely with the fluid but only at a certain length - the rest of the channels before and after is filled with air. By heating the air portion of the fiber the pressure of the air increases and the fluid is pushed towards the colder air segment. Of course the channels have to be sealed hermetically - this is achieved by splicing the "active fiber" to a conventional single-mode fiber at both ends.
Note that close to c, things would not simply look contracted paralled to the relative movement but rotated (which results in contraction of the projected length). It's hard to explain with words only, you can get a far better feeling for it by looking at the relativistic ray tracing simulations of a Flight Through Stonehenge. This does not take into account all SR effects (e.g. the Doppler shift) and it does not take into account GR effects (it's also a straight movement, not circular) - but it still might help you to get a feeling for relativistic effects.
And I would add that there are very good reasons Kyoto was rejected. Have you noticed that almost no one else ratified it either? (Yes, the EU did, but this means nothing without the member states signing on, and none of them have done so or even expressed an intention to do so).
You are not up to date. The 15 countries of the EU just ratified the Kyoto Protocol a few days ago.
Slashdot Mirror
it's 20% - you forgot nuclear power, which is non-fossil and therefore does not create CO2.
Astronauts can suffer from motion sickness, bone loss, muscle degeneration (atrophy) and blood vessel problems during weightlessness.
Isn't this just the body adapting to the new environment? In low-g you don't need strong bones and muscles to support your weight and the blood vessels need not to be as strong as they don't have to support the hydrostatic pressure. By getting rid of unnecessary structures the body conserves resources - maybe that way one is able to survive with a lower metabolic turnover rate (which, according to research done on animals, could make a longer living-span possible).
because the only thing that differs between particle and antiparticle is it's spin
that's wrong, it's the electric charge that is opposite for particles and their antiparticles. The total spin (magnitude of spin) is the same for both and the actual spin vector is not a fixed property for a particle (except when it's zero).
try LinNeighborhood
The argument of cave-ins, earthquakes are however very serious ones. The typical example of a colorado experiment where fluids were injected into deep crustal fissures resulting in earthquakes occuring daily instead of yearly warn us against toying with the earth's structure.
Doesn't that mean that the earthquakes are now far smaller in magnitude ? In fact, the problem with earthquakes is that they release a lot of energy in a short time.
Do you mean the HESS telescope or the nuclear photoelectric effect ?
Both are basic science - there is no immediate practical application (and usually you don't start basic science with practical applications in mind). That is also the reason why these projects are run by the Max-Planck Society, which is the German organization for cost-intensive basic research.
For the HESS, the goal is to understand the creation and origin of the very high energetic particles that are observed in cosmic radiation. You can get more detailed answers at the site linked in my previous post if you proceed to the section "Exploring the nonthermal universe" on the left sidebar.
For the nuclear photoelectric effect, I do not know much about that. I assume the goal was initially to verify theory and get some values for the "effectivity" of the process, which would e.g. be important for calculations concerning nuclear reactors, nuclear waste, or nuclear reactions in stars (like our sun). Also, the photoelectric effect is a very simple and basic phenomenon and quite important and useful in its "conventional" (=non nuclear) form (think solar cell, photodiode etc.) and therefore it is important to know more about it in its nuclear analogy, too.
What is the width of an electron ?
Hint: it's unknown (for the free electron). We only know that the electron is smaller then 10^-15 meters, compare this to the wavelength of visible light: 10^-6 meters. Visible light has HUGE wavelength (several thousand atom spacings)! Guess why we need UV and XUV etc. light for lithography...to get near atom size with light you actually need X-rays!
These Telescopes measure gamma rays with energies above 40 GeV, far above enegies of nuclear decay (MeV range, a factor of 1000 less). The HESS project page contains more information, about the (cosmic) origin of these gamma rays.
One could measure the change in these isotopes when gamma rays hit them, thus measuring the gamma rays. Has anyone played with this?
You are talking about the nuclear "photoelectric" effect. It is in principle possible, but very inefficient (nuclei do not capture gamma rays very well). Actually this was initially researched by W. Gentner in the 1930ies in Heidelberg, where they now build the HESS telescope (among others).
I just noticed that I misunderstood your question a little bit. The microscope mentioned above is an electron microscope - as such it has no mechanical moving parts. You can see pictures taken with that microscope in this paper (2MB). You were probably thinking of scanning tunneling microscopes that have a tip scanning over the surface of a sample. These microscopes would indeed need mechanical positioning at the mentioned level to measure such small distances.
No, it doesn't imply that. You have to keep in mind that resolution is not the same thing as being able to locate something. Resolution means that you can distinguish two closely spaced objects, rather than seeing just one broad fuzzy spot. Locating refers to a single object: It's easy to determine the location of a fuzzy spot by just determining where the center of that spot is. Now imagine two fuzzy spots 4 Angstroms apart (see here for an example). If one of them moves by 1/100 Angstrom you will see the corresponding fuzzy spot move a little bit to the side. Obviously that doesn't meant that you could distinguish two fuzzy spots just 1/100 Angstrom apart - they would appear as one slightly broadened fuzzy spot.
If you could come up with a final filter for the screen that converted, say, the vertical component of linearly-polarized light into right-circular and the horizontal into left-circular, you could then use circularly polarized glasses and defeat linearly-polarized. But I don't know of any physical mechanism (let alone one that could be turned into a cheap thin film) that would do this, even for monochrome, let alone the near-octave of light used by color displays or the full-octave for black-and-white.
That's easy do to. It's commonly known as quarter wave plate. Put it in front of your h and v polarized screen and rotate it to 45 degrees from h/v. It will turn h polarized in to right (or left) and v polarized into left (or right, depending on the rotation of the qw plate). See here how it works.
So stock polarizing sunglasses read all these screens, no problem.
Or just take the top plate from your old LCD pocket calculator/alarm clock/whatever.
No, It has been redefined min 1983 to make the speed of light the value mentioned by ColaMan, see here.
Warsitting (hack all the other War-drivers/flyers/riders/walkers etc.)
Heat is only needed when writing data. In fact, when not heated, it's even harder to remagnetize the new material than the older one (that's why they need to heat it - a magnetic write head alone would not be able to change the magnetization).
Same problem with conventional harddisks. You can't hammer on them as you like. With CDs much of the problem is related to the fact that a) the CDs are removable which means the mounting cannot be optimzed for rigidity only. b) the CDs are supposed to be cheap, which means again they are not as rigid and symmetric as ordinary harddisk platters. (leading to high noise level at moderate rotation compared to harddisks).
Btw, CDs skipping means the drives either have not enough read ahead buffer or they cannot sustain the necessary data rate for audio playback. In most computer tasks you don't have the requirement of a minimum data rate, so you won't notice when reading errors occur.
...some things, eg. X-Rays, can, at least practically if not theoretically
no, x-rays are just very high energetic light. a visible light photon has around 2 eV (electron volt) while x-ray photons have hundreds to thousands of electron volts (and gamma rays have millions of electron volts or more).
Why that? You'd be an independent country and all MS tax would stay in the city.
She'd still need the sine/cosine values to draw the moving tickmarks. So an FPU would speed up compass drawing but not in the circle part. Maybe she just misunderstood her boss.
I can't give you an example for the use of these heavy nuclei, but there is definitely use for non-stable nuclei: for example the technique of beta-NMR uses the decay products of beta-unstable nuclei to find out about electric fields, crystal defects and diffusion in matter. It's a very expensive technique (you need to create the unstable nuclei during the experiment because they are so short-lived), but it gives some information that cannot be gathered by other means.
This fiber device does not look at the data at Gb rate - it's just a switch for different colors of light (at a millisecond rate, way too slow for any ECC logic). Also, the logic of when to switch what is not part of this device - that logic has to be brought to the device as electrical signals from outside.
This microfluidic optic fiber is not a network, it's only a short piece of fiber that is inserted in a conventional fiber. It's more like a switching device than a network. The control signals have to be electric, too (you have to operate the heaters), so the logic is not part of this fiber. The microfluidic fiber is only the device that does the actual filtering. The advantage of this fiber is that you don't have to seperate all the different wavelength modes before you can filter some of them out, but you can do it directly in a fiber.
The fiber has a central channel (core) that transmits the light by total internal reflection. This channel is surrounded by six large channels that contain the fluid/air mixture. The dimensions are such that the light transmission along the core is normally not affected by the presence of the fluid in the outer channels, except for a limited region where they have written a "long period grating" into the core. When the region with the long period grating has the outer channels filled with the fluid the corresponding change in the refractive index leads to a reduced internal reflection in the core and thus light leaves the core and is therefore "filtered out". The filtered wavelength depends on the refractive index of the fluid which can be tuned by the fluid temperature (the authors report 0.10 nm/K shift of the filtered wavelength with temperature).
How is the fluid brought to the grating region?
The outer channels are not filled completely with the fluid but only at a certain length - the rest of the channels before and after is filled with air. By heating the air portion of the fiber the pressure of the air increases and the fluid is pushed towards the colder air segment. Of course the channels have to be sealed hermetically - this is achieved by splicing the "active fiber" to a conventional single-mode fiber at both ends.
Note that close to c, things would not simply look contracted paralled to the relative movement but rotated (which results in contraction of the projected length). It's hard to explain with words only, you can get a far better feeling for it by looking at the relativistic ray tracing simulations of a Flight Through Stonehenge.
This does not take into account all SR effects (e.g. the Doppler shift) and it does not take into account GR effects (it's also a straight movement, not circular) - but it still might help you to get a feeling for relativistic effects.
An overview of simulations of special relativistic flights can be found Andrew Hamiltons Homepage.
And I would add that there are very good reasons Kyoto was rejected. Have you noticed that almost no one else ratified it either? (Yes, the EU did, but this means nothing without the member states signing on, and none of them have done so or even expressed an intention to do so).
You are not up to date. The 15 countries of the EU just ratified the Kyoto Protocol a few days ago.