mezarashi

Apparently this may seem to be in the wrong forum. Anyway.... The matter of the fact is that humans now rule the planet. We take what we can from the planet in order to "survive". Apparently our rule for the game is that we try to make as many of our kind survive as possible (social welfare and medicine), but it doesn't matter to us what else we destroy. Without our "sympathetic behavior" for other species on the planet, they certainly wouldn't survive (less the types I had listed). The dying off of endangered species is natural. They are not the fittest to survive in the world of humans. From a species perspective, humans are fit to survive. Species that do not live off of humans or live for humans will not. However, my original question was within the human species itself. Yes, everybody has the right to live. So do all animals, but they don't have the social welfare structure that we have. We have built this, and now things are different. I'm not sure if it's for the better or for the worse.

My questions here today are: Have we effectively stopped human evolution? If not, then are we evolving in a different way than we have? My opinion would be that we have ourselves stopped evolution, and are even trying to impose the same thing on animals and plants. This is because we have built for ourselves medicine, and most importantly social welfare. Why does this matter? As Darwin's survival of the fittest model goes. If you are born dumb, if you are born physically weak, if you are born with anything disadvantageous to your survival, you will not live long enough to reproduce, and thus soon your genes will become extinct. This is not the case as it is today however. Schools school kids who are smart, dumb, and with learning disabilities. We have welfare for the jobless, we have medicine for the sick (obviously not all diseases, but still). And the sad truth is, the more "unsuccessful" people have more children. Take for example Africa. Well educated, wealthy individuals however have very few children to carry on whatever genes they possessed to make them "successful". In effect, unless you have a reproductive deficiency, everybody survives long enough to reproduce. Now we try to play God and protect endangered species, try to preserve species, and try to protect the weak that would otherwise not survive. I'm sorry to say, but animals that don't live off humans or for humans (pests, cockaroaches, rats, dogs, cats, cows, chickens) will have no place in our world. That's the way the survival of the fittest game works. Does this worry you? And how will our world be different as a consequence?

/me applauds. Now THAT is the trademark of a genius problem-solver

Firstly, as far as I know, there are no real worldly objects that do not "respond" to the visible spectrum. An object is visible when it absorbs and then re-emits photons incident on its surface. Another point, taking for example the perfect black-body, a body that absorbs everything and emits nothing as a response. The term black body is a bit misleading, as we know, anything that has a temperature will radiate electromagnetic waves. So even if it did absorb all radiation, it would be forced to radiate some light as predicted by the Stephan-Boltzmann law. Because of this, whether it will appear black in the visible spectrum will also depend on its temperature. Yes indeed. My digital camera responds to infrared light. It appears on the LCD as a blue color. This happens when I flash the remote towards the lens.

Right you are. That's the way it is, but sometimes, sometimes, just for the sake of clarity to a struggling learner, it is helpful to use analogies we can visualize or are familiar with. When I was learning kinematics in 10th grade, my physics teacher never told me to keep in mind that time wasn't universal. He never told me that we couldn't travel faster than the speed of light. He never told me that there's no way we could make perfectly precise measurements. But yet I was able to do classical mechanics and predict (to his satisfaction), where a ball falling off a ramp would land.

I feel for you The thing is, the doppler effect for sound and light are actually very similar. Actually you can use the same equations if you are not considering sources that are moving at relativistic speeds or close to the speed of sound (in the sound case). For relativistic calculations, you add in a correcting factor. Don't get confused. The fact that you can change the speed of sound in air because you can change the properties of air, has nothing to do with the Doppler effect. I think this is the point you want to make clear to yourself. The ability to move faster than the speed of sound means that you will create sonic booms, which obviously is not related to the doppler effect... only that now you know that there won't be an "electromagnetic booms".

An elementary school text book would quote something similar to: As clouds rise higher and higher, the air gets colder and colder. When the water vapor in the cloud becomes too heavy, it falls back to the ground as rain or snow. As you grow older, you may learn about the mechanisms and conditions in which water evaporates, and in which it condenses. Despite all that, I still can't answer the question, why does it rain. Let me explain more about my confusion. I am not discussing about the precipitation that occurs at the boundary between a warm and cold front. That mechanism is fairly clear as you have an abrupt change in atmospheric temperature, and suddenly the once warm air is no longer able to accomodate the excess moisture. But as we know, even without fronts, it rains. The evaporation and condensation process seems to be one that is fairly slow, but the "rain process" is rather abrupt. If we for example, leave a tub of water in an air-sealed room, it will not rain in the room. Even if we pump moisture into this room, the "raining phenomena" will not occur. I find it interesting that on Earth, the clouds can reach a "critical point" in which it just pours down everything all at once, and then nothing in between. Naturally, I would think that a kind of equilibrium would exist instead. Any insight would be much appreciated, and thanks

Wow, to apply to a Masters program without knowing what it's about. I commend you for your dauntlessness. Good lucks >.<

As swansont has corrected, centrifugal force is virtual. It exists only to fulfill Newton's third law of force pairs. The force that keep's an object in circular motion is called the "centripetal force", and this force may be gravity in planetary orbits or a string if you spin in circles a rock. The rock is subjected to a centripetal force and thus centripetal acceleration. Your hand feels the centrifugal force tugging on the string (the force that appears to cause the rock to pull on the string), which is in fact only an equal and opposite force since you are using the string to pull the rock into circular motion. On the original question. A better question would be, what portion of the Earth's gravity contributes to the centripetal force that keeps us in circular motion about the Earth's surface. Obviously, if all the gravity contributed to keeping us in rotation around Earth, then we would feel weightless as astronauts do in space. The numbers will vary depending on where you live on earth, but let's take for example the equator. We know that the Earth has a circumference of about 40,000km, which we transverse in 24 hours, leading to speeds of 462 meters/second. According to a = v^2 / r, the centripetal acceleration required to keep us on the surface of the Earth is 0.03557 m/s^2 while the gravitation acceleration created by the earth's gravity is 9.79m/s^2.

I agree. Assembly language is ridiculously tedious. Figuring out what's going on in that language is an eyesore. The best two languages in my opinion, and I think I'm being objective here, are: C++ and Java They are languages which can serve as foundations for other languages you may be interested to learn in the future. Plenty of documentation and books are available for them, so they are fairly accessible in that sense. With C++, I've been able to program myself real practical programs that someone who likes to fiddle with computers would want on their desktop. My point is, it is a general-use sort of language, while other languages are more specialized for a particular application.

Yes indeed, and floppy's are still required if you want to build robots like this: http://www.generation5.org/content/2001/floppy.asp

In anycase, there was nothing wrong with the experimental setup. The optical interferometer did what we would want it to do. However, people still refused to believe that the ether was non-existent. In fact, decades after the experiment various schemes were devised in an effort to explain why the light travelled at the same speed and to defend the ether theory. Here are some: 1. "ether drag" - the Earth takes along with it a local supply of its own ether. Like a shield against the universal ether wind. 2. "emmision theories" - where the speed light would be governed also by the motion of the source. This one goes as far as saying: 3. Ether wind physically compressed all matter (including the MM apparatus) in just the right amount to conceal the variation in speed. All of these have been proven wrong from experiment or observation. The main death blow to the ether theory was probably Einstein's postulate in which he derived his theory of relativity. That the laws of physics are the same regardless of the inertial reference system chosen.

If I remember correctly, I believe this question was asked before >_> but I could be wrong. Anyway, yeah, there will be less and less acceleration as you "fall" towards to the center of the Earth. The gravitational force acting on you is proportional to the mass within the volume of your current radial position from the center. Meaning, once you reach the center of the Earth, there will be no gravity, and in fact you will kind of be floating. However, in the situation where you are to jump into a hole that runs through the Earth, when you reach the center of the Earth, you're velocity would be at a max. Neglecting any possible air resistance or friction, you will continue moving until you reappear at the other side of the Earth and start falling back again repeating the same cycle forever. Where damping is present. You will just oscillate back and forth until finally you settle at the center of the Earth.

Physicists and engineers engage in alot of experimental verification of well-known or not so well-known theories. This usually leads to a better understanding of certain phenomena and may lead to a technological application. There are also scientists who work on the analytical aspect of physical theories, such as proving relationships or deriving some of their own. Although it is not common to see absolutely new theories like back in the day of Einstein, there are certainly some. To make you understand what is in the field of graduate studies and beyond, why not try reading the American Journal of Physics. The abstracts should not require much knowledge of mathematics to understand. http://scitation.aip.org/dbt/dbt.jsp?KEY=AJPIAS&Volume=CURVOL&Issue=CURISS#MAJOR1

LED stands for Light Emitting Diode after all You generally need resistors in any circuit, especially one with LEDs. LEDs are non-linear devices. Once the bias voltage exceeds their rated voltage, say for example 2.1 volts, the current rises exponentially and quickly reaches some insanely high value which will in effect destroy the poor diode. If there is no resistance in the circuit, you are relying only on internal resistances which is very low and your LED will forcefully take the entire voltage drop. A voltage discrepency of 0.1 volts can create an excess current of say 50mA or more.

Actually I would have expected them to already have landed according to schedule, but apparently bad weather in Florida has delayed it. There was suppose to be a backup landing site at Edward's Airforce Base in California, but I don't know what happened to that. According to NASA, the next possible re-entry opportunity should be Tuesday at 5:07 a.m. Eastern Time.

From what I know, dissolving solutions in water changes it's density. Strictly speaking, the word dissolve in chemistry means (I believe), the breaking down of the solute in question into its ions within the solvent thus making the solute and solvent inseperable. However, even with sugar, where the sugar molecules are simply sandwiched between water molecules rather than "dissolved" we see a change in density, as shown in experiments in chemistry labs for those of you lucky enough to have had tried. With that in mind, I would think that gases would not make any exception and that dissolved gas would to a certain extent change its density, although only so little gas can dissolve in water naturally (unless you fiddle around with Henry's Law).

In semiconductors as in blackbodies, I guess there is an obvious limit in the electromagnetic frequencies that can be emitted depending on the materials electron configuration. However, in other systems like radio wave production, is there really a quantum limit? I've only analyzed such systems using Maxwell's plane wave equations, and thus the notion of a non-continuous spectrum is a bit odd to me in this field. Should someone care to explain why we cannot create any arbitrary wavelength with this respect. *blink*