Vacuum Definition and 1000 Threads

If an object is in a vacuum and it is constantly increasing its velocity, since it would need to use energy to do so it would create a waste. Since it is the largest mass in the vacuum would the waste created be pulled towards the mass causing it never to reach the speed of light?

What would happen under these circumstances: A sealed container of water in a vacuum chamber. Since water doesn't expand like air, I assume that there would be no extra pressure within the sealed container once the air was evacuated around it. Since there would be no, or very little air...

The force in the Casimir effect can be "explained" by two causes, see, http://en.wikipedia.org/wiki/Casimir_effect#Possible_causes In some optics experiments we must account for the fluctuations of the quantum vacuum to get the right experimental results. See, Vacuum noise...

I'v been troubled by something. Einstein's second postulate determines the speed of light in empty space to be a constant c, measured by all observers to be the same. So I was thinking, it is possible to slow light by making it pass through a dense medium like water or glass. If we imagine such...

It is my understanding that on earth, a hotter object surrounded by colder air will decrease in temperature because the faster moving atoms in the hotter object are repelled by the slower moving atoms in the colder air. This isn't worded very well, I hope you know what I mean. By what mechanism...

I put helium in a balloon (with a maximum pressure of 1.5-1.7 atm), but I do not want changes in the volume, so I have to use a rigid material (non-elastic). To make sure that there is only helium in the balloon, I have to create a "strong vacuum." My fear 'that, in the material can break or...

Hello everyone, I am thinking of a thought experiment about a so-called "space tower" but don't have enough information to estimate the numbers. I understand the material strength needed for such high structures is huge, because of the weight of the structure. But what if the "tower" would be...

Hi I have been thinking about this idea and i'we come to the conclusion that i need to discuss this with someone who has a better understanding of physics than i have. First off, let me help you visualize it: You put pieces of hardware that generate heat inside of a container, the container...

I am studying this paper about the strong CP problem and axions by R.D. Peccei: http://arxiv.org/abs/hep-ph/0607268 At the moment I read through the introduction and I have some questions about some points, so please could you help me clear out some things?. [In general I'll try to feed back...

I seek to build a vacuum chamber for shipping radon contamination sensitive samples. The cylinder will have a height of approximately 2 inches, and needs an inner diameter of 10 inches. The plan is to weld stainless steel pipe to a plate on the bottom, and to have a lid bolt on to the pipe with...

Hello everyone, not sure if this is the right forum to post to, but I hope you can help me out. I am not a math person and am completely dumbfounded when it comes to engineering. I believe my request should be pretty straightforward for a person with the right knowledge. Basically, I'm thinking...

Doing some searching about the zero point energy of the vacuum I came up with an excerpt from Google books, Page 62 of...

So, from what I understand, quantum uncertainty means these vacuum fluctuations occur, and out of them come virtual particle and antiparticle pairs. How does this not create a preferred frame of reference? A particular particle pair must have a certain amount of energy, and in one frame where...

Is it possible to use vacuum evaporation, sputtering and ion plating processes to coat the inside walls of holes and other hollow shapes of substrates? I wonder whether the source materials are ejected in the form of atoms or ions? Many books say atom but how can they travel to the substrate if...

Say that there's a large metal box with nothing but a vacuum inside of it, except for a small bag of compressed gas at the center. If the bag were to suddenly pop, is there a specific rate that this gas would accelerate when expanding to meet the space of the container? I think that it might...

Good day, from what I read we can make a vacuum in an enclosed space and we can inject or keep electrons in that vacuum , I hope that far I am right.Vacuum is a good , the book says the best insulator of electrical current, since it has basically no particles or medium for the current to run...

Here is an unsettling question from a practice set that I've been working on today. Unsettling because the answer key contradicts my answer so I need a second thought. A pingpong ball and a golf ball are dropped in a vacuum chamber from the same height and at the same time. When they have...

For example, when we write down the operator definition of quark fragmentation matrix element: ##\Phi_{ij} = \sum_X \int d^4 x e^{ikx}\langle 0|\psi_i(x)|P,X\rangle\langle P,X|\bar{\psi}_j(0)|0\rangle##. Can we rewrite is as: ##\Phi_{ij} = \sum_X \int d^4 x e^{ikx}\langle...

There are many sources which say that a human cannot survive under the abrupt exposure to vacuum. What would happen if the exposure is not abrupt? Can a regularly clothed human survive in a vacuum chamber if we gradually lower the air pressure in the chamber to vacuum values for several hours of...

Taken from another post. The Universe was so hot immediately after the Big Bang, nothing but energy could exist - Current can only flow in one direction through the device between the two electrodes, as electrons emitted by the hot cathode travel through the tube and are collected by the...

A possible breakthrough for space travel, yet lacking an explanation in physics, they say. http://ntrs.nasa.gov/search.jsp?R=20140006052...

If an object is dropped in a hypothetical infinitely long vacuum tube, will it reach a terminal velocity? I assume that it must because according to Einstein, no object that has mass can travel at the speed of light. My guess would be that the terminal velocity of an object in a vacuum would...

Dear Forum, Vacuum is classically interpreted as the absence of everything. But the quantum view of vacuum sees it as a bubbling, dynamic entity from which particles and antiparcles emerge for very short intervals of time. Relativity teaches us that energy and matter can be converted into each...

The best laboratory vacuum has a pressure of about 1.00 x 10-18 atm, or 1.01 x 10-13 Pa. How many gas molecules are there per cubic centimeter in such a vacuum at 293K? PV = nkT P/kT = n/V = N (# of molecules per cm^3) Since V is typically in units of m^3 or liters, should I make my...

Here is my single triode vacuum tube amplifier circuit I understand there needs to be a bias on the grid otherwise the signal will be rectified -not amplified. Is biasing the grid as simple as running a resistor in-between the grid and the cathode on the power supply like this (in red)...

I've been trying calculate the capacity of one of our dust collection systems. It features four vacuum slots lined up (27 inches by 1 inch each) shown as #3 on the diagram attached. Using a manometer, I took pressure measurements at points #1 and #2. Both were around 1.1 inwc, which...

It is well known that when the vapor pressure of a substance is bigger than the external pressure, it boils. In vacuum there are no particles and therefore no pressure, shouldn't therefore, even diamond as for example, boil in complete vacuum?

Hello everyone, I have a question regarding the pattern resulting from droplets of fluid onto a hard surface. Set-up In addition to being a full time student I also work full time in the fuel bay of a local trucking company terminal. Not the most glamorous job, but regardless. This question...

This quantum vacuum thing... I'm thinking about these virtual particles popping in and out of existence. Does that happen everywhere including inside atoms(within electron orbitals), protons, quarks and whatever is smaller? Or just in the space between Atoms... what i would call vacuum? im a...

I have a project that I've been working on for awhile and I've recently decided to try and upgrade parts of it. However, my knowledge on the subject is pretty sparse. What I want to do is have a vacuum pump which will shut off when my chamber reaches a certain level of vacuum. If anyone could...

Why can't the vacuum be magnetized? Another question... Magnetic field induced in a substance, depends on Magnetic intensity (H) and Magnetization (M). If H is too much strong then what happens in a substance.

I was thinking about how a person could create and maintain a vacuum at sea level. I was thinking of any supersonic objects (bullets, etc.), and that a vacuum (or partial) may be directly behind the object as it travels, as the air wouldn't have time to move into replace the void faster than...

Hello all, I was wondering a way to make a simple vacuum chamber with a relatively small volume (probably won't need to be bigger than 300mL at best) from some common materials. I have access to common glassware (beakers, although not sure if they can withstand the pressure), and ideally I...

Hi. This is something I've been wondering about. If one looks at a phase chart like this: http://en.wikipedia.org/wiki/Phase_diagram#mediaviewer/File:Phase_diagram_of_water.svg you notice something. First off, as the pressure is reduced, the liquid range shrinks and then disappears at...

I found most literatures on Electrical or Magnetic fluxes maddeningly unclear about the MATERIAL in which the equations are applied. In free air only? or not? I would like to know if the following 2 statements are true the electrical flux generated by a single charge will look the same in...

I'm trying to determine the amount of work required to create a vacuum. The vacuum will be within a one cubic meter tube with a pressure of 56,777 Pascals. A pneumatic cylinder will be used to remove the air from the tube to create the vacuum. The standard formula for the work to create a...

Hello all, I was wondering how to create a partial vacuum using common household items. It would be in a small rectangle box which has an opening on top that will be sealed immediately after the vacuum is created. Any ideas would be appreciated. Thanks

What is the result of the charge conjugation acting on the state of vacuum? C|0>=... I have two intuitive problems... If I see the vacuum as something which has no particles, then the charge conjugate would have to lead in the vacuum itself... C|0>=|0> However, if I think of the vacuum as the...

How are the two related mathematically ie QV is SpaceTime devoid of matter and has Zero Point Energy on one hand QF on the other hand at PlanckScales SpaceTime fluctuates at high energies when probed Can you get Quantum Vacuum when probing Quantum Foam?

Suppose I have a field \hat{X}... What kind of operator should it be in order to develop a vev which doesn't break the Poincare invariance? I am sure that a scalar field doesn't break the poincare invariance, because it doesn't transform. However I don't know how to write it down mathematically...

Good day. What happens if a vacuum to put two electrodes, 1 cm apart, and electrical voltage in 1e9? Thank you.

To begin, I'm not sure if this is the right subforum for my question, and whether questions like this, in particular, questions about the details of personal projects, are allowed on this forum. Being new to this forum, if I have made any mistake in this regard, I apologize in advance, and will...

Well this is a doubt that comes from some time ago and I haven't found the answer on the net. Quantum fluctuations in quantum vacuum create particle-antiparticle pairs for very short periods of time satisfying ΔEΔt≥\frac{\hslash}{2} It is very well known that when a pair particle-antiparticle...

I've heard of issues in low pressure chemical reactors where the interior scaling might flake off when a vacuum is pulled. Which principles govern this? I know it has to do with internal shear forces and am wondering if a vessel wall would ever split in half. I saw this related...

Hi, I wondered if it is theoretically possible that the vacuum energy produces an electron/positron pair which then bonds into positronium instead of directly annihilating again. And if it is theoretically possible has this ever been observed ? Thanks and cheers.

From the result of an experiment it seems to be that suction does indeed cause a force that causes a vacuum to move toward what is being sucked. Why this is we do not know. Maybe it is related to the Bernoulli Effect, that because we are restricting the entry area so that the air has to be...

Someone on another forum shared with me that a 6L6 vacuum tube exhibits a blue dot when in operation that is supposed to be Cherenkov radiation. I say nay, as I have worked out the relativistic velocity using $$KE={ m }_{ 0 }{ c }^{ 2 }\left[ \frac { 1 }{ \sqrt { 1-\frac { { v }^{ 2 } }{ { c...

I work for a company which has an interesting problem. We store at cryogenic temperatures in vapour phase, not submerged in liquid. In order to protect the inner bag we place an over wrap over the inner bag then vacuum pack it, in a sterile environment. The bag is then placed into cryogenic...

What may be the boiling point (temperature) of a refrigeration POE oil at, let's say, 500 microns absolute pressure ?

Is it possible to make a liquid evaporate solely with vacuum? If you were to reduce the pressure in a container of liquid to 0, while also insulating it from any outside heat, would it remain a liquid or turn into a gas? If it turns into a gas via lack of pressure alone, does the...