Owner: future of physics URL:http://softcracked.googleapges.com/pb.html Join Date: Thu, 11 Oct 2007 04:25:46 -0500 Rating:0 Site Description: Discipline of Science dealing with the properties of matter and energy. !!!---This blog is particualy for question that will be asked and their answers!!! It is not for journal and research work or an article. Site statistics:Click here
How much power or energy does a black hole have? 2008-02-01 02:00:21 The word "power
" is used in physics to denote the rate that work is done over time. It has the units of (energy per second), and so is appropriate for describing the rate that energy is radiated by an astronomical body. The Sun, for example, emits energy at a rate of about 4 × 1026 Watts (that's a 4 followed by 26 zeros). This is called the Sun's radiant power. Black holes, however, hardly emit any radiation, so their radiant power is nearly zero. Now the word "power" is used in everyday speech to mean anything that is fast or strong. This use of the word may have nothing to do with the rate that energy is emitted. People will use the word "powerful" to mean that the gravity of a black hole is very strong when you are close to it. In other words (in informal speech) a black hole has very
Why doesn't NASA launch rockets from the tops of tall mountains? 2008-02-01 01:59:35 The tallest mountain in the world, Mount Everest, is 29,035 feet (8,850 metres). In comparison, most commercial jet airliners fly at 30,000 to 35,000 feet (9,144 to 10,668 meters). At the summit of Everest most people require oxygen to breathe. The temperature is much colder than at sea level. At the summit of Mount Everest the temperature can be between -100°F and -15°F (-73³C to -26°). High wind are also often a factor at the summit of tall mountains
.Obviously this is not an environment very conducive to building and launching rockets. Lesser peaks will have less extreme conditions, but they also will have a lesser benefit of reduced atmospheric density.The only reason to go to the top of a mountain is to avoid the densest portion of the atmosphere. That is why most astronomical obse Read more:NASA
Difference between Penning Traps and Toroids 2008-02-01 01:56:29 Actually, researchers have come up with many different ways over the years to contain charged particles. Each has advantages and disadvantages, and a scientist tries to choose something best suited for his/her own needs. A Penning trap uses a combination of magnetic and electric fields to confine a group of charged particles in an enclosed space. If you think of the trap as a cylindrical "jar" (an imperfect, but useful analogy), the magnetic field keeps the particles from escaping through the "sides", and an electric field keeps them from leaving through the "top" and "bottom". Because it needs to hold the particles in all three dimensions, the Penning trap is best suited for "cold" particles, that is, with low energies. Many Penning traps have additional facilities to bring trapped ions t Read more:Traps
How does illumination affect the breakdown voltage of a dielectric? 2008-01-31 00:08:04 "Dielectric" is a broad term-it can involve both gases, liquids and solids. I've just read 908725376.Ph, and there the discussion of focused on gases, so I'll restrict this discussion to gases. There are in fact two main mechanisms by which light can influence the breakdown
processes: the first is called photo-ionization, and the second is called tunnel ionization. I'll briefly outline both processes. I'd like to note beforehand that the second process is rather exotic. Furthermore, I'll simplify things a bit, so First, let's define what we mean by breakdown. A normal gas at typical atmospheric conditions consists of uncharged molecules. In order to be able to conduct current, this gas will have to be at least partially split in negative and positive charges. Normally, this involves rippin
Please clarify how electron waves can occur in 1/2 wavelengths 2008-03-13 23:15:07 It would help if in questioning a source, you gave an accurate reference to the source. I have searched Encarta and think I found the quote at exact quote I see in section IV is: "The length of the string, or the distance the wave on the string occupies, is equal to a whole or half number of wavelengths. At these distances, the wave bounces back at either end and constructively interferes with itself, which strengthens the wave. Similarly, an electron wave occupies a distance around the nucleus of an atom, or a circumference, that enables it to travel a whole or half number of wavelengths before looping back on itself." The problem with the quote is the word "similarly". The boundary conditions for a circular loop are different than those for a violin string. The violin string allows h Read more:Please
Why do finger snaps make noise? 2008-03-12 23:37:28 Well, first we have to think about what part of the finger
snapping motion causes the sound. Your students might be interested in doing an experiment to observe that it is in fact the impact of your finger on your palm that causes the "snap". The next question, which you alluded to in your message, is how (and why) we hear this impact. Why do claps make a sound, for that matter? I suspect that this is an oversimplification, but one way of explaining it is that when your palms (or finger and palm) come together quickly, the air between them has to get away in a hurry. This causes a pressure wave –where air molecules get scrunched together– that travels outward from the source. Sound is a pressure wave so when it reaches our ears we hear a "snap".
Why does the magnetic field of an electron reverse direction? 2008-03-17 00:25:24 Moving any chargedparticles will produce a magnetic
field around them. If we move theseparticles across an external magnetic field the two fields interact and theparticles feel a force mutually perpendicular to the external field andtheir direction of motion. This is the force that we say induces a currentor voltage and it has nothing to do with whether or not the particles inquestion (electrons in the case of wires) each have an inherent individualmagnetic field of their own or not. Most high school and freshman collegephysics textbooks will have some pretty good pictures of this behavior. Atthe atomic level in a material like copper there is about one electron peratom that is essentially free to move about in the wire. If this wire ismoved across an outside magnetic field then thes
How 'fat' can a spinning black hole get? 2008-03-17 00:24:55 The chances of finding a zero-spin black hole are, as you say, very small; all black holes are likely to have reasonably-large angular momenta. Even if a black hole is born with no angular momentum, it can acquire angular momentum if it "accretes" material from, e.g., a binary companion star.A spinning
black hole is called a "Kerr" black hole. Believe it or not, such a black hole still has a spherical event horizon! The size of this horizon is a little smaller than you'd expect for a non-rotating black hole. Kerr black holes have a second horizon, which delineates something called the "ergosphere". The ergosphere is a region from which it is possible for particles to escape (unlike the event horizon, which is a point of no return), but here the escape is contingent on orbiting the black ho
Why is time relative? 2008-03-19 03:13:11 This is what I've heard. You have 3 objects: A, B, C. Mass A = B and C >>> Aand B. B is closer too C than A. From what I've heard, from A's perspective, Blooks as though is moving slower through time due to the gravity of C, or fromB's perspective, A is moving faster through time.Velocity of B > A, which would mean that from B's perspective, A is movingslower through time or from A's perspective B is moving faster through time.I thought that gravity gave a mass an acceleration. If a mass is acceleratingfaster and faster, the closer it gets to a massive object, wouldn't the effectsof time speeding up due to speed and time slowing down due to the mass cancel out?I've also heard that if a mass moves faster and faster toward the speed of lightit gains mass. Does time slow down when a mas
Why can you see your fingerprints on the side of a glass 2008-03-22 00:16:36 he question: "Why can you see your fingerprints
on the side of a glass? If a glass of water is peered into from above all that can be seen is the inside of the glass. The sides of the glass reflect what's inside. If you touch the outside of the glass, suddenly you can see through, except in the valleys of the finger prints which still display a reflection. This only works if the outside of the glass is wet. What physics are involved? Why doesn't the side of the glass just continue to reflect the inside of the glass?"The phenomenon you are experiencing is total internal reflection (TIR) without the finger on the outside, or the lack of TIR when the wet finger is present on the outside. You can find out details of TIR in many places, one of them being here at hyperphysics.Look at this sketch
why does the recently 'filmed' electron seems to orbit only in 2 dimensions 2008-03-20 23:26:07 The video you linked to was produced at the Lund Institute of Technology in Sweden. It's really good science, and less than a month old, but like many popular science headlines, the description of the video is very misleading and it takes a bit of reading to understand what you are really seeing. What you were seeing is not a direct image of a single electron's orbit, as the title suggests. Instead you are viewing a two-dimensional scattering pattern from many electrons that have been ionized by very short ultraviolet (UV) laser pulses (By short I mean 300 attoseconds, or 300 billionths of a billionth of a second!). The short laser pulses are precisely timed relative to a strong infrared (IR) laser whose electric field holds the ionized electrons in a confined position. The precise timing Read more:recently
is ther ea limit for light brightness? 2008-03-20 23:24:33 There are two ways I could interpret your question. One would be "is there any brightness
beyond which the human visual system saturates, so that increasing the intensity does not increase the response of the eye?" Another would be "is there a brightness beyond which the human eye is damaged?" The first question would be tricky to answer, because human eyes are complicated. The eye can adjust to levels of VERY different brightness by changing the diameter of the pupil, and by modifying the mix of certain chemicals in the retina. If you sit inside a brightly lit room at night, and then walk outside into the dark, you will at first see almost nothing. But over ten or twenty minutes, your eyes will gradually adjust to the lower light
levels. Half an hour later, you'll be able to see stars whi
What is the term for a period of time of extended daylight? 2008-03-23 23:55:43 The length of the day is determined by the rotation of the Earth around its axis. A short explanation can be found here [1]. In principle the rotation of the Earth is what is driving the changing of day and night. Furthermore, the place on the globe has some influence. If you are close to the Equator, day and night are both around 12 hours across the year. When you go away from the Equator, the fact the Earth's axis is tilted has some influence, making days longer in Summer and shorter in Winter. What you are describing sounds like a sudden change in day length. The only thing that could cause this is a slow-down and speed-up of the rotation of the Earth (this would also cause tidal waves). However, the amount of energy required for this is massive. We can compute the amount of energy the
Why does the shape of the balloon affect the distance the balloon will travel? 2008-03-27 01:49:46 Why does the shape of the balloon affect the distance
the balloon will travel? I am trying an experiment with balloons, but I don't know how to explain the results. Two different-shaped balloons, one oblong and the other round: when the air is released from them one travels further than the other. What is the reason for one balloon to travel further?"There are two major reasons for the difference:a) differences in the force and energy of the propulsion, andb) differences in the aerodynamic resistance of the balloon.Point "a)" has to do with the amount of air that is in the balloon, the strength of the balloon's material, and the shape and size of the balloon's opening. A larger balloon would contain more air, so, all other things being equal, we would expect the larger balloon to be able t
How does the heat from a light bulb reach my hand through the air? 2008-03-27 01:49:24 The question: "How does the heat from a light
bulb reach my hand through the air? I would like to know if heat from a light bulb
reaches my hand through the air using radiation, conduction, convection or a combiantion of those mechanisms. I can think of a few answers: * A. Conduction from the filament to other parts of the bulb followed by convection through the air. * B. Radiation from the filament through the vacuum, followed by conduction through the glass followed by convection through the air. * C. Radiation from the filament through the vacuum, glass and air. * D. Combinaton of the above or somthing else (in this case which effect is the strongest?)"The answer is "D": a combination of the first three, with "C" usually being the predominant way in which heat reaches your h
how do we measure the radius of an electrons' orbit by an experiment 2008-03-26 00:05:17 References;1.Atomic orbitals w.chemguide.co.uk/atoms/properties/atomorbs.html2. Scanning Tunneling Microscope (STM) n.wikipedia.org/wiki/scanning_tunneling_microscope3. Scanning Tunneling Microscope (STM) pictures Atoms of Highly Oriented Pyrolytic Graphite (HOPG). purdue.edu/nanophys/stm.html4. Wikipedia article Atomic Force Microscope pedia.org/wiki/Atomic_force_microscopeTo plot a path for something you need to know exactly where the object is and be able to work outexactly where it's going to be an instant later. You can't do this for electrons. While most booksshow electrons in orbits like planets around the sun, in reality electron orbits are much morecomplex. Reference 1. discusses atomic orbitals and has drawings of the probability of where theelectrons will travel around the atom
How fast does water need to move not to freeze??? 2008-03-28 21:15:18 It's almost impossible to give a precise answer to this kind of question, as it will depend on specific material of construction (more than one plastic can be used to make pipe, and with varying wall thicknesses), how the system is laid out (is the pipe buried or in the air?), etc.That said, maybe we can get an idea of what to do.You will need to establish an effective measure of how readily the system transfers heat. Probably the best way to do this is to measure the temperature of the water
at the well head, Tw, and at the return point (or some other point far away from the well head) Tr.Heat transfer can usually be modelled as a constant times the temperature difference (between the outside ambient and the water inside), or something likedQ = U (Twater-Tair) dLwhere L is a length elemen
Parts of Space Observable from Earth 2008-04-01 00:30:47 Before the advent of the satellite telescope, were there parts of our galaxythat could not be observed by using a land-based telescope? I ask this becauseof the tilt of the Earth
and the once inaccessible nature of the Arctic andAntarctica.In fact it is not as hard as you might think to see the sky above the northpole: that's exactly what you are doing when you look at the north star. Of course, if you were in the arctic, that part of the sky would be rightoverhead, and you'd get a good view, but nonetheless, from Europe, Asia andNorth America it can be seen, and astronomers are able to study all the skyof the northern hemisphere. In order to study the parts of the southern sky not visible from America orEurope, at the end of the 19th century and in the early part of the 20th,astronomers Read more:Parts
, Space
the challenge of large numbers Richard E Crandall Richard E Crandall 2008-03-30 21:58:19 As computer capabilities increase, mathematicians can better characterize and manipulate gargantuan figures. Even so, some numbers can only be imagined Richard
E. Crandall Large numbers have a distinct appeal,a majesty if you will. In a sense that they lie at the limits of the human imagination which is why they have long proved elusive,difficult to define,and harder still to manipulate. In recent decades though computer capabilities have dramatically improved. Modern machines now possess enough memory and speed to handle quite impressive figures.For instance it is possible to multiply together million-digit numbers in a mere fraction of a second. As a result we can now characterize numbers about which earlier mathematicians could only dream.Interest in large
numbers dates back to ancient
Will humidity affect a balloon that's on a white or black bottle? 2008-04-04 05:13:19 I'm not exactly sure what you are asking here, but I'll try to give it my best.I think that any humidity effects are going to be too small to observe. Humidity may affect the elasticity (stretchiness) of the balloon, but Ithink that won't be affected on a short time scale (in other words, if youstore it for a long time in dry conditions, in might become more brittlethan if you left it around humidity - but nothing you'd see different overa few hours or even a few days).Humidity can affect pressure - humidity is a measure of how much waterexists in the air as a gas. According to the Law of Partial Pressures,this could change how hard the air in the bottle
is pushing on the balloonas it is heated, but that would be a fairly complicated case (and isprobably not something you'll learn about u
If a plastic jug was dragged under a car at high speed, would it spark? 2008-04-06 09:50:53 You are correct in that spark
s occurring on friction or impact are usually caused by metallic objects: the abrasion creates tiny particles. At the same time a high temperature is reached due to the energy converted into heat. This causes the metal particles to glow and burn. This was the principle of cigarette lighters before the piezoelectric models came about. Plastic (i.e. thermoplasts like polyethylene), on the other hand, softens on heating, so that no abrasion (grinding) takes place: the material is deformed or smeared out. I could just about imagine that on an extremely cold day, the plastic would be so brittle that some grinding could occur, but this is unlikely to result in sparks. By the way, some metals, like e.g. aluminum, don't cause sparks either. Sparking should not be confu
What are 'grow toys' made of? Why do they expand in water? 2008-04-06 09:50:08 His toys are made of Aqua-Keep, PVAC, and EVA, which are all various types of polymers, or very long chain molecules.PVAC is an abbreviation for polyvinyl acetate which is a polymer mainly used as a binder or glue. White household glue is probably mostly polyvinyl acetate. EVA is an abbreviation for ethylene vinyl acetate, a soft and flexible polymer that is used in a variety of applications including mouth guards. As a thermoplastic polymer, it is the reason that mixtures of these three materials can be molded into a specific shape. The PVAC and EVA holds everything together, just like a cell membrane holds everything together in biology. Aqua-Keep, as described here: -AqK001.pdf is comprised mainly of sodium polyacrylate. Sodium polyacrylate was invented by Robert Niles Bashaw, Bobby Ler Read more:water
influence of light in directing plasma 2008-04-08 10:30:05 ive searched and found it is possible for light
to influence
plasma like lightning, where a pulsed laser was directed at a storm cloud to instigate lightning that travelled along the pulsed laser path. i am interested to understand if such action could be used in a fluid, like water, to be conducive to the flow of electrons between points in electrolysis.my interest and contribution source can be found here: The interaction of plasma and light is a pretty complex field that is a little bit too broad to cover here, but I can describe a few common mechanisms in which light can influence plasma. Some of those would work on liquids or solids, too. Your example of a storm cloud is a good one. In a storm cloud, positive and negative charges are separated. This situation is not very stable: if a
what role does heat emissions by engines play in global warming? 2008-04-16 00:19:18 There is no doubt that human consumption of energy adds to the Earth's heat budget. However, the amount of solar energy available to the Earth has been estimated (1) as 3850 zettajoules per year (ZJ/yr)[zetta = 10^21]. Total human energy consumption is something around 0.5 ZJ/yr (2). Human's direct energy contribution is insignificantly small. The reason that greenhouse gases can have a measureable effect is that they are essentially cumulative, that is, once they are added to the atmosphere, they persist for relatively long times and so continue to build up to higher and higher concentrations (3). Good links are: Read more:emissions
, engines
f entire universe is accelerating how can Sp. Relativity apply? 2008-05-16 23:26:07 This is a great question and it really emphasizes the need to understand two different kinds of acceleration, and the addition of one more relativity postulate called the Equivalence Principle.It is true that the first postulate of Special Relativity states basically that all the laws of physics are the same in all inertial reference frames, and an inertial reference frame is a coordinate system t Read more:entire
Are there any foods that exhibit phosphorescence with regard to microwaves? 2008-05-29 23:09:07 In order for this to happen: 1) The food would have to have an electronicstate that was pumpable with energy from vibrational states, as microwavesexcite only rotations and vibrations (by transfer); 2) The electronic statewould have to be stable enough to have a half-life in seconds at least.Possible, I suppose, but it would be surprising if true. There are bacteriathat are luminescent (e.g., Pseu
Why do cans of diet soda turn horizontally when they float? 2008-05-29 23:08:40 In fact, I'm not so sure that the horizontal position is as stable as the vertical position, because in the horizontal position any deviation from perfectly horizontal may provide enough torque ("turning force") to cause the can to flip to the vertical position as the contents of the can move around inside. It is a matter of how far below the physical center of the can the center of gravity is in Read more:float
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