Bubble Definition and 236 Threads

Assuming the situation where there is an infinite inflation stream, from which bubble universes are appearing in locally slowed regions. There could be many many such bubble universes and so very rare occurrences in some bubbles can sometimes happen. Also assumed, as is often postulated, that...

Referring to this link : https://qcdloop.fnal.gov/bubg.pdf Using Mathematica Integrate command to solve it does not give the result stated here but I am unclear as to how they got to the result in the 4th line. It is clear that the integrand (1st line) can diverge for certain values of the...

At a single moment of coordinate time ##t##, would a distant observer perceive a warp bubble's interior volume as blown up, or would it seem compressed? Looking in the catalogue of spacetimes at the static local tetrad of the Alcubierre metric, the ##e^x_{(x)}## leads me to think that a static...

(a) I don't know how to identify which one is the anti-proton track. The anti-proton hits proton at point in the figure where all the lines are coming together but how to identify which one is anti-proton? Do I need to know a certain rule regarding the color of each particle? Thanks

https://bgr.com/science/mit-scientists-think-theyve-discovered-how-to-fully-reverse-climate-change/

Hello, couple of questions about bubble universes and the physical constants. I understand in an eternal inflation scenario universes bubble off the original during the inflation phase. Firstly, according to this theory, does the new universe creation only happen at an early inflation phase of a...

The liquid-vapor mass transfer (evaporation and condensation) is governed by the vapor transport equation: $$\frac{\partial}{\partial t} (\alpha_l \rho) + \nabla \cdot (\alpha_l \rho \vec v) = \dot m^{+} + \dot m^{-}$$ In the incompressible flow case (constant density), it reduces to $$...

Consider the decay in a quantum field theory from a metastable vacuum to the "true" vacuum. Here's i my understanding: 1. For a scalar field potential U(\phi), the transition amplitude is finite per unit volume for a finite energy splitting between the 2 classical minima of the potential...

My current project involves constructing an air bubble system to protect stationary docks from ice heave or ice jacking during the winter months. Ice jacking is the vertical lift as ice expands. When this grabs piles supporting stationary docks, it can wreak havoc. I am mainly confused as to...

Hello, Something I’ve wondered about is those amazing air bubbles that are sometimes found in underwater caves. In particular, I was wondering how the depth of the water does or does not affects them. In my Figure 1 example, the water is 50 feet deep and air bubble in the cave has 3 feet of...

So I am a layman in physics, I admit I am trying to grasp big ideas piecemeal via articles, wikipedia and YouTube. I don't pretend to be educated in this regard but I am curious and willing to learn! The idea of the multiverse intrigues me. Sidestepping for a second the fact that the idea has...

I have taken the variables as follows: A[][]=the matrix max=to store the maximum integer value present in the matrix min=to store the minimum integer value present in the matrix sum=to store the sum of boundary elements display()=methos to print matrix sort()=method to sort matrix in descending...

So say I have a bubble embedded in a spacetime with metric: $$ds^2 = -dt^2 + a(t) ( dr^2 + r^2 d\Omega^2_2) $$ how do I compute the normal vector if I assume the wall of the bubble the metric represents follows a time-like trajectory, for any ##a(t)##? Since we are interested in dynamical...

The correct answer is 'C'. I'm having trouble understanding the solution shown on this link (http://www.engineeringadmissionsassessment.com/2019-solutions.html) - scroll down to Section 2, Question 8. From what I've gathered, [final pressure = initial pressure x 'R^3/r^3'], as PV must be...

From Gauss's Law give ##E=\dfrac{\sigma}{2\epsilon_0}## ##\therefore P_e=\dfrac{\sigma^2}{2\epsilon_0}## Consider at equilibrium (before bubble being charged) ##P_i=P_0+\dfrac{4S}{R}## Using Newton's 2nd Law ##\Sigma F=m\ddot{R}## Let ##R+\delta R## be the new radius Give (after binomial...

https://www.google.com/amp/s/www.vice.com/amp/en_uk/article/939g5p/physicists-are-studying-mysterious-bubbles-of-nothing-that-eat-spacetime As far as I know this article summarizes a paper. The paper explores an idea proposed by Written in 1982 about spacetime being unstable and forming a bubble...

I have solved it with a force approach, but would like to know how to do it via an energy approach. For starters, here is the force approach. Consider a small, approximately circular, surface element of mass ##m## such that the angle from the centre to the edge of this element is ##\alpha##...

This is an experiment I would have liked to do from the ISS, but an approximation could be done in a vacuum chamber on Earth. How big a soap bubble, polymer bubble, or glass bubble could you blow in the vacuum of space? How to calculate the evaporation rate in vacuum? A liquid exposed to vacuum...

Hi All, I need some help to figure out how to best go about setting-up and analyzing a micro-fluidics design problem I ran across in my research. It's not the typical single-surface contact angle adhesion kind of analysis. Basically, I have a wide micro-fluidic channel that's formed by a...

Homework Statement: A small air bubble at the bottom of an open 4-m depth water tank has a radius of 0.5 mm. Due to some reason the bubble comes off the bottom. Determine the radius of the bubble when it is 0.1 m below the surface. Assume that the pressure inside the bubble is 2/r above the...

Imagine a bubble vibrating in air. Because it vibrates, it's interfacial area increases, thus new molecules are added and removed from the surface as it vibrates. Consider a molecule is initially at position X_0 at the interface, and over a certain amount of time molecules squeeze and disappear...

Hello everybody! Let's begin with the spin. Spin of the ##\Lambda## is ##1/2## and of the pion is ##0##: $$ \frac{1}{2} \otimes 0 = \frac{1}{2}$$ Since I know from the homework statement that ##L=1##: $$ \textbf{J} = \textbf{spin} \otimes \textbf{L} = \frac{1}{2} \otimes 1 = \frac{1}{2} \oplus...

Problem Statement: An explosive liquid at temperature 300 K contains a spherical bubble of radius 5 mm, full of its vapour. When a mechanical shock to the liquid causes adiabatic compression of the bubble, what radius of the bubble is required for combustion of the vapour, given that the vapour...

1. A closed cylindrical vessel filled with water (at room temperature) contains a small air bubble of normal pressure and volume ##V=1~{cm}^3## inside in it.The cylinder is then started to be rotated slowly with a small angular acceleration in a complete weightlessness (at a space station)...

I don't understand how lasers can cut glass since it's permeable to light. Is it because all glass has some imperfections in it? I'm assuming it does *not* work that way but if someone could explain, that would be really helpful. I mean, glass is used to focus lasers so it's odd that lasers...

So, I'm trying to figure out the math for my Dragon Ball GURPS-ification (GURPS is a tabletop system like Dungeons and Dragons). I might have other questions, but first I was thinking about how the personal force field should work. This is made out of ki fused into one flexible sort of bubble...

What I am confused about is why do bubbles of air in water move up. I understand why solids and liquids would move up in water if they are less dense. I get the idea that the deeper you go in water the more pressure there is because of the more water weighing down on the water and so there would...

Hi, I have a question about a rising bubble. I read that the initial acceleration of a bubble (with negligible mass) in water is 2g, where g is the gravitational acceleration. I understand that if a bubble rise then the water move around it, but I can't derive this equation. Could someone help...

Homework Statement Homework EquationsThe Attempt at a Solution Excess pressure inside a spherical soap bubble is 4S/R . How to deal with the cylindrical shape ? Why does the question specify it to be "long" ?

I was watching a conference on YouTube about cosmology and one of the speakers was Anthony Aguirre. He was giving a lecture on different cosmological models that are infinite in time as well as space. Here is a link to one of his papers and one of the models he was presenting. There is not much...

I know this is getting into the highly speculative, but given the mathematics that has been done on versions of these concepts that are not known to be inconsistent: In the inflation concept which leads to a multiverse of the "bubble universes" type, in which the laws governing the space-time...

Is liquid neon popular for bubble chamber detectors?

"There are various theories about how the solar system formed, but scientists haven't been able to agree on a single model that explains all the quirks of our corner of space as it exists today. Now, scientists at the University of Chicago have...

Hi pf, I was wondering about a bubble moving with constant velocity in a liquid, and how the motion affects the mass transfer. Since the viscosity of the gas is significantly smaller than the viscosity of the liquid, the condition ## \tau_{gas} = \tau_{liquid} ## tells me that $$ \mu_{gas} (...

Homework Statement as title Homework Equations force exerted by atmosphere on bubble = 2(on account of dual layer) * 2pi*r*L(surface tension) work is the integral of force *dx The Attempt at a Solution so we're looking at int ( 4pi*r*L *dr) but since not it 1 particle is traveling against...

1. 2. The force due to gas pressure = p(V0/V) dA The force due to atmospheric pressure = p dA The force due to electrostatic repulsion = undetermined 3. Though I don't surely know what the expression for electric force should be, I took an educated guess and solved using the relation...

We know interference of waves play a role in causing "colors" on soap bubbles. But does light refraction play a role in bubble iridescence? When the light wave travels into the soap bubble surface, won't it refract since the wave is into a different matter (what matter the soap bubble surface...

Question about bubble chambers. How can particles with small mass, such as electrons, create ionized path without having their trajectory disturbed by the ions they are creating? Seems like we should see them scattered around somewhat rather than following that nice circular pattern. Is this...

Consider that the criterion for bubble nucleation (in a field theory) is the following: $$\exp(-S_{3}/T) \gtrsim \frac{3}{4\pi} \left(\frac{H}{T}\right)^{4} \left(\frac{2\pi T}{S_{3}}\right)^{3/2},$$ where ##S_3## is the three-dimensional action of the theory and ##H## is the Hubble scale. 1...

Homework Statement There is a total of ##Q## charge on soap bubble of radius ##R##. What force is acting on one hemisphere by the other ? Homework Equations Electrostatic pressure is ##P_e = 2\pi \sigma^2## for a spherical shell. The Attempt at a Solution ##P_e = F/A## therefore ##F =...

Not really sure what's happening here, did a short search online to see if anyone else has documented this before. (If it's not clear from the photo, there seems to be a air bubble trapped right under the stream) It sustained itself for a couple minutes, took a short video of it too before it...

I've been reading about this interesting topic today. So the first radio signals emitted from the Earth are about 110 light years away from Earth now. Most authors point out that an advanced alien civilization only 125 light years away would have no idea of our existence. Fair enough, but the...

Hi, I am trying to create a device that would "simply" make a bubble under the water. What I am aiming for is production of small bubble but continuously and under the water. When I say continuously, it doeant have to be for extended periods of time, could be just for ~2 hours but the longer...

Homework Statement [/B] The question is from chapter 9 of "Exercises in Introductory Physics" by Leighton and Vogt. The answer given in the book is ##R = 4.9 \times 10^{-5} \rm{cm}##. Homework Equations $$\sigma = \frac{\Delta P \cdot R}{4}$$ Where, ##\sigma## is the surface tension...

I observed that if you pour soda into a glass cup and leave the straw inside, bubbles seem to form on the plastic cup at a much much quicker rate. Why is this? Why do bubbles form on the straw at all? Not sure if this should be in general physics or chemistry

Hello, The particle Reynolds number makes me confused and I hope someone can help me on this please! Normally (as I read in every books and papers) that when a bubble or drop rises in a fluid, the bubble/drop Reynolds number is calculated by: Re = ρUD/μ where U is particle velocity, D can...

I want to calculate the force-displacement curve for a damper that would have hydraulic oil with an air bubble in it, so very similar to an air spring with a limited amount of volume. I came up with the following solution: F(x)=Po*A((Vo/Vo-A*x)-1) where F would be the external force applied...

Hi, I love the movie "The Marsian". I did not start reading the book (I'll do soon). What do you think about discussing the physics? I am wondering why the NASA in the end suggested to cut a hole in the rover and to build that plastic foil bubble on top. There must be a really good reason to try...