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Physics, Astronomy & Cosmology / Can entropy of an isolated system decrease if balanced?

« on: 16/05/2017 00:02:39 »

Is there any way to prepare a system, place a system in a box that isolates it from its environment, wait a while, open the box, and find that the entropy of the contents is less than when it was put in -- if we allow the entropy outside the box to increase by at least the amount lost on the inside of the box?  (The process inside the box would violate the Second Law of Thermodynamics if considered by itself, but if the entropy outside increases by a greater amount than that lost inside, it appears that no violation occurs.) For example, do something to a container of gas that sets in motion the generation of a lot of heat outside the box, then put the gas in the box, close the box, open it a while later and find the gas has liquified (i.e., now is at a lower entropy) but the Second Law is not violated because the heat generated by the initial process more than offsets the cold generated inside. 

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The Environment / Is infrasound used meteorologically?

« on: 01/04/2017 02:10:37 »

It occurred to me that infrasound may provide a way to monitor storms and provide early warning of tornadoes and the like. I wonder if this is currently done.

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Physics, Astronomy & Cosmology / What will scenes look like if time conflicts?

« on: 20/03/2017 08:15:49 »

Suppose there exists a room, called Room A. The room has a window that is glazed in a peculiar manner: the "glass" consists of a plane such that electromagnetic radiation cannot propagate beyond it; it is 100% reflective and constitutes, for purposes of the room, a mirror. The window is actually a light switch that is reflective when "off" but transparent when "on". When "on", light can cross from the room into another room (Room B) then on the other side, and vice versa. Otherwise light is blocked both ways. Observer A in Room A with a camera sits in a chair.  T_A denotes time in Room A. At T_A = -2 seconds, Observer A gets up, walks over toward the window.   At T_A = -0.5 seconds, the window turns "on", optically connecting the rooms. At T_A = -0.003 seconds, Observer A clicks the shutter. At T_A = 0, half of the light from the flash has crossed the window into the other room.  At T_A = 0.003 seconds, the shutter closes.  At T_A = 0.5 seconds, the window switches "off".  Then Observer A goes over to a table and lays down the camera.


Meanwhile, in Room B,  Observer B in  with a camera sits in a chair.   Time in Room B will be denoted by T_B.    At T_B = -2 seconds, Observer B gets up, walks over toward the window.   At T_B = -0.5 seconds, the window turns "on", optically connecting the rooms. At T_B  = -0.003 seconds, Observer B clicks the shutter. At T_B = 0, half of the light from the flash has crossed the window into the other room.  At T_B = 0.003 seconds, the shutter closes.  At T_B = 0.5 seconds, the window switches "off".  Then Observer B goes over to a table and lays down the camera.


The rooms are both completely enclosed, and have no light sources other than the camera flashes.


Now a word about the window. Rooms A and B are in different universes, and therefore use different coordinate systems. Of particular importance here is that they do not use the same clock.  The coordinate systems ordinarily would have nothing to do with each  other; however in this case they become connected during the time when the window is "on" (this connection is how the window is turned on). Working from different universes gives us the option of flexibility in how the connection is made. Specifically, the connection is made in such a way that that T_A = -T_B.  Thus, each observer would see the other's clock running backwards.


Question:  What in general  will each observer see, and what will be the state of the photographic film in each camera at various times throughout the experiment?

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Physics, Astronomy & Cosmology / How extendable is science as we know it to 4 dimensions?

« on: 05/03/2017 03:01:26 »

How compatible are the laws of nature with a hypothetical universe having 4 dimensions of space and 1 of time? Some things extend readily, such as classical geometry. Spheres, cylinders, cones, and other shapes all have readily calculable analogs in four dimensions. As for physics, it is trivial to add to Newton's laws of motion another dimension. In engineering, some rethinking about the way mechanical parts are structured is required, but not impossible. It would seem that the laws of thermodynamics transfer basically unchanged inasmuch as they either grow out of Newton's laws of motion or are based on statistical concepts that are not tied to a specific system. Special relativity seems to be unaffected because the extension of it to an additional spatial dimension seems to require nothing more than the addition of one more dimension at right angles to the direction of motion, in which dimension special relativity has no effect. Things get trickier, however, in electromagnetism. If we are to suppose that the flux of electric force is conserved across "empty" space, that requires that the force falls off inversely as the third power of distance. However, the matter is further complicated by the fact that Maxwell's equations use mathematics that is inherently based on three dimensions of space and one of time, and it is not obvious how this could be rewritten to be compatible with four spatial dimensions, nor that electromagnetic force as we know it would be even possible.  When getting into the atomic realm, things also seem to become difficult, for some of these same reasons. If electric force falls off inversely as the third power of distance, that completely rewrites the book about electron orbits, calling into question their very existence. And who knows what happens at the subatomic level.  Which is maybe why we don't have such a universe.

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Physiology & Medicine / What are the statistics of transgender occurrence?

« on: 08/02/2017 04:42:10 »

Are there any available studies that illuminate the correlation, if any, between the rate of occurrence of transgenderism and various risk factors, such as race, income level, availability of medical care, prevalence of infectious diseases, etc.?  Keep in mind that it is also necessary to inquire into not only the environments of the individuals being studied, but also of their biological parents, inasmuch as we are dealing here with something which by its very nature involves reproduction. And a look at caregivers who are not the biological parents is probably also necessary, to ascertain if there might be any influence that is not simply biological.

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Physics, Astronomy & Cosmology / What would the universe be like with space and time exchanged?

« on: 06/02/2017 06:04:43 »

Einstein's special relativity declares that between any two events, observers disagree as to the separation in space and time, but all agree on the value of the absolute separation, which is
                         [(x₂ - x₁)² + (y₂ - y₁)² +  (z₂ - z₁)² + (ict₂ - ict₁)²]^1/2




What if instead it had been


                          [(x₂ - x₁)² +  (icr₂ - icr₁)²  +  (ics₂ - ics₁)² +  (ict₂ - ict₁)²]^1/2     ,
r  s  and t being dimensions that enter in a temporal rather than spatial manner
?


How would the universe look or behave differently?

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Geek Speak / What media are best for backups?

« on: 26/01/2017 23:39:35 »

I  have a new computer. I am planning to back up certain files on removable media. There is the option of CD-R, CD-RW, DVD-RW and certain others. With the CD-RW I have had past poor experience in that these disks would not uncommonly fail after a while (multiple writings were required on them).  I have not much experience with anything else. Any suggestions?

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Chemistry / Are there four immiscible liquids?

« on: 21/01/2017 05:15:38 »

If I wanted to fill a vessel at room temperature and pressure with four mutually immiscible liquids that would separate themselves out into four layers after having been shaken, are there any chemicals that would do the job?

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Physics, Astronomy & Cosmology / Any way to store antimatter?

« on: 21/01/2017 05:12:03 »

Is there any way to confine antimatter on Earth for long-term use?

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Physics, Astronomy & Cosmology / What do neutrons do when decompressed?

« on: 18/01/2017 07:38:26 »

If a compressed bunch of neutrons, such as in a neutron star, cools to a very low temperature, and is then slowly decompressed, what happens?

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General Science / What would the world look like in ultraviolet?

« on: 14/01/2017 02:28:22 »

Supposing we were to wear goggles that rendered all we saw in wavelengths twice the original. (This would effectively give us ultraviolet vision). What would we see?

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Physics, Astronomy & Cosmology / When will electromagnetic takeoffs and landings be possible?

« on: 08/12/2016 03:07:59 »

On bodies having thin or no atmospheres, and low gravity, it would be highly advantageous for flying craft to be able to hover electromagnetically above a runway while landing at high speed until they had slowed to a point that tires could be used; and also highly efficient to be able to receive their initial thrust for takeoff electromagnetically.  Any chance of seeing this installed on the Moon or Mars within the next 50 years?

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General Science / What is the attenuation of ultraviolet?

« on: 11/11/2016 05:06:59 »

When, to an earthbound observer located at sea level, the sun appears directly overhead on a clear day, what is the ratio of ultraviolet energy reaching the ground to that immediately outside the atmosphere?

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The Environment / Is disinfectant chlorine an atmospheric threat?

« on: 24/10/2016 04:11:29 »

Does the chlorine added to swimming pools and drinking water threaten the ozone layer?

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Chemistry / Can hydrated calcium chloride be reverted to an anhydrous state?

« on: 18/09/2016 06:43:15 »

Can damp calcium chloride be restored to the dehydrated state by heating without it undergoing decomposition, and if so, what is the recommended temperature?

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Physics, Astronomy & Cosmology / Is runway landing on Mars technically feasible?

« on: 27/08/2016 05:02:01 »

In the interest of reducing the costs of space flight, it would seem advantageous if spacecraft to Mars could land in the manner or a space shuttle.  However, Mars has a much thinner atmosphere.  Is there any way to do this?

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Physics, Astronomy & Cosmology / Can Shroedinger's cat produce kittens?

« on: 13/08/2016 06:33:07 »

Most of us have heard of Shrodinger's famous cat, who, using the principle of quantum mechanics, can be both dead and alive at the same time.  This leads to the following interesting question:  Suppose we know that Shroedinger's cat is living, but neglected to measure his/her sex.  So the cat sits in the closed box in the state (|male> + |female>)/√2 .  Both states must be regarded as present, having not been observed.  However, if both are present, there is the possibility that the two states may get to schmoozing, and end up producing a litter of kittens.  So that, if we wait a while, then open the box, we might observe not only the cat, but also kittens too.  Except that a cat upon being observed cannot have any sex other than male or female, which are its eigenstates.  But to observe only a male cat, or only a female cat, along with kittens, would violate the laws of biology, and therefore is not a permissible outcome.  So the conclusion would be that no, Shroedinger's cat cannot produce kittens even if it is in an indefinite sexual state. 

Except that there may be a way around this problem.  If the box has a small hole that is large enough for kittens to escape but not large enough for the cat to escape, the two states of the cat can proceed merrily to produce kittens, and some of them may escape without violating the preceding restriction.  So what we would do, is set up a camera to photograph kittens as they come out, and after a long while, we would expect to see some.  However, its progenitors as a pair are only 50% present. So when any kitten exits the hole, there is only a 50% chance that it would be observed. Therefore, if we wait the length of time required for a normal pair of two cats to produce about 100 kittens, Shrodinger's cat should produce about 50 observable kittens.  Correct?

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Physics, Astronomy & Cosmology / Can a particle collide with itself using the principle of quantum indeterminacy?

« on: 13/08/2016 06:14:48 »

Can a particle collide with itself using the principle of quantum indeterminacy?  The following experiment, based on the Stern-Gerlach experiment, seeks to find out (see diagram).

Silver atoms are ejected from a source toward a magnet M1.  This magnet is designed to create a nonuniform field between its highly dissimilar pole faces (see detail).  The silver atom is characterized by having completely paired electrons except for one, whose spin therefore determines the magnetic behavior of the atom.  The unpaired electron, having a spin number 1/2, admits of two possibilities: If the spin is one way with respect to the field, it will be attracted toward the one magnetic pole; if the other way with respect to the field, it will be attracted toward the other pole.  If the direction of its unambiguous spin is at some other angle, the principle of quantum eigenstates requires that whatever state it is in will split into a combination of the fore/against states just discussed, and that one of them will end up determining which way the atom, if observed, will go -- toward the one pole or the other.  But that unles it is observed, the atom remains in the combination of both states that corresponds to the prior state.

Atoms proceed from the source through M1, which causes each to have the possibility of going in two different directions: Either the axis-up (counterclockwise) spin, or the axis-down (clockwise) spin, as shown. The apparatus is so arranged that the clockwise state will send the atom off toward the trash bin, but the counterclockwise state will send it on to the next magnet M2.  M2 is another magnet of the same type as M1, but arranged at a 90 degree angle from it. It will spit atoms into states axis-left or axis-right.  Because all the atoms that reach M2 have been polarized into a counterclockwise spin by M1, they are in a state that resolves equally into axis-left and axis-right states in M2.  therefore each atom exting M2 has a 50% chance of being found in the axis-left state and a 50% chance of being found in the axis-right state.  From M2, a left-flying atom proceeds to the left ionizer.  The left ionizer strips the unpaired electron off and discards it. This gives the atom an electric charge of +1 and a spin of 0 (because the spin was in the electron).  From there, the atom is propelled by means of its unbalanced charge into a cyclotron ring, where it is accelerated to high speed. 

Meanwhile, the exact same action happens in the other side of the system, the atom going through the right ionizer, becoming likewise propelled into the cyclotron in the opposite direction. 

If a swarm of atoms enter this process, they can be expected to collide, when the beams are switched together, at the collision point, sending a shower of particles into the detectors.

However, let the experiment be conducted in the following unusual way: Let the rate of emission of atoms from the source be reduced to a very low rate so that there is virtually no chance that more than one atom will be in the system at a time.  Under this condition, the atom goes through the magnets as already discussed, and in M2 is placed in a mixed quantum state corresponding to axis-left and axis-right.  The direction it takes after M2 depends on which of these states apply. However, the path of the atom remains unobserved, so it must still be in the mixed state.  That being so, each state is still "live" and able to take a path, much as a particle going through the double slit experiment appears to go through both slits if it is not detected while doing so.  So we have the axis-left state going left into the left leg, and the axis-right state going right into the right leg. Because both states remain equally viable, they both are eligible to participate in the subsequent acceleration in the cyclotron ring.  Once they have reached a very high energy, the two states are allowed to collide.  And the critical question is, what will be observed?  I opine that the two states of the atom will collide and produce a shower of particles, but because each state is only 50% present, only 50% of the particles that would ordinarily be detected actually will be. If that happens, it will demonstrate that the atom existed in two different places and velocities at the same time.

Thoughts?

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Physics, Astronomy & Cosmology / What happens when flying current loop hits electrostatic field?

« on: 02/08/2016 05:01:47 »

Consider two dielectric plates, each given a static charge, one negative and one positive, and mounted a fixed distance apart to create a field between them.  Now consider a ring made of superconductor and carrying a current that travels tangentially around the ring the way a normal current loop travels, thereby becoming a magnet.  Under ideal conditions (0 g,  vacuum),   the ring is propelled rapidly but without rotating into the space between the plates, moving, at the time of entry,  parallel to them and half way between them.    What  happens to the ring as it continues on its journey?

Consider the same plates and ring, only this time the ring is caused to spin rapidly as it drifts slowly from the outside into the space between the plates on, like before, a parallel trajectory.  The tangential speed of the ring is much greater than the drift speed of its center. What happens to the ring once it gets between the plates (assuming that it does)?
 

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Technology / Will these magnets generate electricity?

« on: 30/07/2016 07:18:47 »

Consider a magnetic toroid composed of four permanent magnets as follows:  There is an upper and lower bowl section (figures 1 and 2), and an upper and lower funnel section (figures 3 and 4). Each section is magnetized in such a way that the field always lies in a plane that includes the central axis, and otherwise follows the lay of the material (see blue arrows).  These four magnets are then assembled by bringing the bowls together and placing the funnels inside them as shown in Figure 5, so that the entire assembly constitutes a toroid in which the magnetic field circulates in planes that include the central axis, except that there is left small gaps between the various pieces (See Figure 5, and for a cross section, see Figure 6). These gaps are small, so that the flux straying due to them is presumably negligible.  The four magnets are held in this relative position, keeping the gaps small but greater than zero, by an external mechanical apparatus (not shown).    A conducting circuit is added to the assembly, consisting of a rectangular loop that lies in a plane containing the central axis (the orange rectangle in Figures 5 and 6).  It passes through the magnetic assembly in the upper and lower gaps that exist between the upper bowl and funnel, and between the lower bowl and funnel, as shown.  There are four switches placed in the circuit, A, B, C, and D, located just outside and inside the toroid near the upper and lower gaps. 

Now, the external mechanical apparatus is activated in such a way that the upper bowl and the upper funnel spin about the central axis with the same angular speed ω that is different than 0,  but the lower bowl and funnel are held stopped.

With all the switches open:

What is the potential difference between the ends of the conductor from Switch A to Switch B, passing through the upper gap?

What is the potential difference between the ends of the conductor from Switch C to Switch D, passing through the lower gap? 

What is the potential difference between the ends of the conductor inside the toroid from Switch B to Switch C? 

What is the potential difference from Switch A to Switch D measured along the external circuit?

If all switches are closed, will a current flow?