Cloud Definition and 241 Threads

  1. K

    Spherical asteroid moving through a dust cloud

    Homework Statement A spherical asteroid of mass m0 and radius, R, initially moving at speed v0, encounters a stationary cloud of dust. As the asteroid moves through the cloud, it collects all the dust that it hits, and slows down as a result. Ignore the increase in radius of the asteroid...
  2. C

    How long does does it take for the probability cloud of an electron to jump?

    Me and a friend at school have been thinking about this question for a while and have come up with a few perspectives, I'm sure there's a 'proper' answer but I haven't managed to find one even after scouring numerous web pages. We are aware that the electron doesn't 'move' in a sense, only the...
  3. A

    Gravitational Conditions: Dust Cloud vs Black Hole

    I am sure to those of you who know GR this will be a simplistic question. I can only hope there will be a simplistic and definitive answer :-) Assume a dust cloud of radius=5 and a mass =mc ANother equivalent mass of condenced matter md=mc with a radius=1 What would be the...
  4. C

    Is Voyager 1 Approaching the Oort Cloud?

    Voyager 1 launched in 1977 is ~10^10 miles out, near heliopause. Continuing at it's current velocity (3x 10^8 mph), for 3300 yrs (100x current 33 yrs), then it will be out ~10^-2 lyrs; that is approaching Oort Cloud outer gravitation limits of our stellar system...
  5. K

    Nagasaki Atomic Mushroom Cloud Ring: What Caused It?

    What caused the ring around the atomic mushroom in Nagasaki?
  6. B

    How to Find the Potential Energy of a Cloud?

    Homework Statement Assuming the maximum electric field sustained by dry air in a cloud is 3x10^6 Vm^-1 And a distanceof 1000 meters between Earth and cloud. The cloud is 4km long and 1 km wide. ausume uniform eletric field. Find the potential difference. Homework Equations V=Ed \mu =...
  7. C

    Charged particle in a cloud chamber?

    Homework Statement when a charged particle enters a magnetic field in a cloud chamber, why does it move in a circular path instead of straight line? I have no idea why. please help Homework Equations The Attempt at a Solution it has something to do with the r changing? as I said...
  8. J

    Newtonian mechanics & Oort Cloud Shell

    Last week there was a documentary program on Nat Geo I believe having to do with the composition and origins of comets. The narrative seemed to imply that comets originate within & are rather randomly dislodged from a spherical shell around the Solar System called the Oort cloud. This...
  9. LarryS

    Uncertainty Principle in Wilson Cloud Chamber Measurements

    An alpha-particle produced by radioactive decay leaves a visible continuous track in a Wilson Cloud Chamber. As it collides with and ionizes the molecules of the vapor, its position is constantly being “measured” by the vapor molecules. If a magnetic field is present, its track will be curved...
  10. T

    Finding the total gravitational potential energy of a gas cloud

    An interstellar gas cloud can be roughly described as spherical with a uniform density. Its radius is R and its total mass M. By considering the gravitational potential energy of a thin spherical shell, show that the total potential energy of the cloud is given by...
  11. S

    Jupiter-sized Planet Lurking in Oort Cloud?

    Lately I've read some articles about the possibility of a Jupiter-sized planet hidden in the Oort cloud. This assertion is based on analysis of cometary deflections and observations of Sedna. What is the likelihood of this? We all know that there must be lots of planet-sized stuff out...
  12. C

    Where Does an Electron Reside in the Cloud Model?

    in the electron cloud model is the electron cloud where you would most likely fin the electron at?
  13. A

    Why Did We Shift from Electron Orbitals to Electron Clouds?

    Atom orbitals, I mean the ones where electrons orbit proton with continuous trajectory like planets orbit around the sun. I do not mean to disagree with modern teachings nor to speculate, I simply do not see how QM actually excludes this possibility. I just want someone walk me through several...
  14. S

    Need help making a cloud chamber

    OK I know many people here are familiar with cloud chambers particularly those of you who are teaching. I have never built one but I want to go all out on my first attempt. I have seen plenty of instructions from researching through google and I was wondering if you guys have any additional tips...
  15. C

    In a typical lightning strike, 2.5 C flows from cloud to ground in 0.20 ms.

    Homework Statement In a typical lightning strike, 2.5 c flows from cloud to ground in 0.20 ms. What is the current during the strike? Homework Equations I = Q/t The Attempt at a Solution The reason I keep getting this wrong is because it says I am rounding something off wrong. I...
  16. E

    Rain Drops falling down in a uniform cloud

    Homework Statement Consider a uniforms cloud of density ρ1 which consists of many little drops that are approximately still.Consider a special rain drop that is a little more bigger than the others so that it starts to fall down.Water drops stays spherical all the way.But the radius gets...
  17. C

    Gravitational collapse of a cloud of hydrogen

    I often hear that stars form when giant clouds of hydrogen start to collapse under gravitational forces, so I started thinking about this. Gravity depends on the masses and distances of objects. So how many atoms of hydrogen would you need, and at what average distance would the atoms need to...
  18. W

    Cloud of neutral hydrogen is moving towards us at a speed

    1.A cloud of neutral hydrogen is moving towards us at a speed of 70 kilometers per second. At what wavelength would one observe the radio spectral line characteristic of neutral hydrogen? 2. The filament in a regular incandescent light bulb reaches a temperature of 2900 k when it's on. a...
  19. 9

    How to move cloud from one time to another

    Assuming we have 3D clouds at time t1 and t2 in the same area, I'd like to discuss you about the idea moving cloud between two different times. (just in simulation) http://www.freeimagehosting.net/uploads/f7d37951ba.png (there is no any parameter, only cloud volume in the each position)...
  20. N

    Electron cloud from uv pulse aimed at negative plate of a capacitor

    Homework Statement A very short pulse UV laser is used to liberate a number of electrons from the negative plate in the arrangement in (i) above. The electrons drift towards the positive plate under the influence of the electric field over a time scale much longer than the laser pulse...
  21. P

    How Do Field Lines Represent a Hydrogen Atom in a Simplified Model?

    Homework Statement draw the field lines of a simple hydrogen atom model. A case is given where a proton is surrounded by an electron cloud. Without getting into quantum mechanics how would represent the field lines of this mini sphere inside and out. Homework Equations gauss's law The...
  22. X

    Conservation of Momentum for Asteroid in Dust Cloud

    Homework Statement A spherical asteroid of mass m_0 is moving freely in interstellar space (no external forces) with velocity v_0 . It runs into a dust cloud whose uniform density is \rho_d Assume that every particle of dust that hits the asteroid sticks to it and that the asteroid remains...
  23. Q

    Building a Cloud Chamber: Tips and Tricks

    http://www.lns.cornell.edu/~adf4/cloud.html" Has anyone tried this? It looks really cool, and I am thinking about giving it a shot, but I'd like to know how easy it is to get it working, or if there are any other things I should know. One thing I am concerned about is the directions say...
  24. W

    Why Aircraft with Jet Engines Form Cloud Trails

    At higher altitudes in the atmosphere, why do aircrafts (particularly fighter aircrafts) with jet engines leaves some kind of white cloud trailing behind? It doesn't disappear for a reasonable amount of time. What is this? Thanks!
  25. G

    MATLAB Imaging data in Matlab: Point cloud -> interpolated surface?

    I've been trying to massage my data into a usable form for a while now and thought I'd consult the brain trust. I have a triangular mesh that represents the surface of an embryo. I also have a (x,y,z,c) point cloud near that surface where c represents a protein concentration (proportional to...
  26. Astronuc

    Large Gas Cloud near Aquila Rift in Milky Way

    Cosmic Cloud Poised to Birth Massive Star http://www.space.com/scienceastronomy/090609-aas-massive-star-precursor.html Ref: http://news.yahoo.com/s/space/20090609/sc_space/cosmiccloudpoisedtobirthmassivestar A sleeping giant http://www.astronomy.com/asy/default.aspx?c=a&id=8340 The...
  27. T

    HI Cloud & 21cm Line: Calculate, Ratio & Luminosity

    Homework Statement Consider an HI cloud of temperature T ≥ 3 K. a) Calculate the energy level difference between the hydrogen atom states leading to 21cm line emission. Show that the ratio of hydrogen atoms in the upper to the lower state of the 21 cm line is approximately 3:1. b)...
  28. K

    How Long Does an Interstellar Cloud Take to Contract?

    Problem:"An interstellar cloud with a radius of 10parsecs and a mass of 10000 Msun is contracting. How long does this take? (The cloud itself has no pressure)
  29. D

    Calculating Water in a Cumulus Cloud: Volume, Pop Bottles, and Mass

    One cubic centimeter of a cumulus contains 330 water drops, which have a typical radius of 10 μm. (a) How many cubic meters of water are in a cylindrical cumulus cloud of height 2.9 km and radius 1.0 km? (b) How many 1-liter pop bottles would that water fill? (c) Water has a density of 1000...
  30. D

    How Much Water is in a Cumulus Cloud?

    One cubic centimeter of a cumulus contains 330 water drops, which have a typical radius of 10 μm. (a) How many cubic meters of water are in a cylindrical cumulus cloud of height 2.9 km and radius 1.0 km? (b) How many 1-liter pop bottles would that water fill? (c) Water has a density of 1000...
  31. G

    Can Charge and Mass Clouds Explain the Behavior of Particles in an Atom?

    regarding probability clouds: if there is a charge cloud surrounding a particle then could there also be a mass cloud surrounding it? the charge cloud would rotate producing a magnetic moment and the mass cloud would rotate producing angular momentum. both would spin at the same rate but...
  32. D

    How Does an Electron Move in a Magnetic Field Within a Cloud Chamber?

    An electron enters a cloud chamber which has a magnetic field B but the path of the electron is not perpendicular to the magnetic field. I understand that the electron path will describe a spiral. Does the v in the equation F = q(v x B) refer to the component of the electron's velocity which is...
  33. baywax

    What Secrets Do the Lost Cloud People of Peru Hold?

    This article just showed up today about the blonde haired, white skinned nation of people called the Cloud People or Chachapoyas. The site is reported to be about 4.2 hectares in size. What drew the people that found the site to it was the sound of an enormous waterfall they found to be 500...
  34. D

    Why Is There a Hexagon Shaped Cloud on Saturn?

    Here's a picture of it http://www.nasa.gov/mission_pages/cassini/multimedia/pia09188.html I found this very striking and am surprised that there has been so little talk about it. My best guess is that it has something to do with tidal forces being exerted by multiple moons. I'm...
  35. L

    Abundances for Small Magellanic Cloud

    Hi all, Does anyone know if there is a recent table of the abundances of elements in the Small Magellanic Cloud. Thanks all
  36. H

    Could an Orbiting Cloud Chamber Effectively Capture High-Energy Cosmic Rays?

    I've read that cosmic rays are far higher energy than those generated in manmade particle accelerators. Would it be worthwhile to build an orbiting cloud chamber to collect cosmic rays before they impact the Earth's atmosphere? Or would the collision rate be too low to provide statistically...
  37. ZapperZ

    FINAL VOTE Photo Contest - Cloud Nine

    This promises to be a very difficult final round. You have one vote to cast on the picture that best represents our theme - clouds! 1. hypatia 2. Alex:) http://img224.imageshack.us/img224/5396/mousilaukecloudug1.jpg 3. Andre 4. Borek 5. Air 6. larkspur...
  38. ZapperZ

    VOTE Photo Contest Group 2 - Cloud Nine

    This is the second polling group for this contest. You have one vote to cast here. 1. Andre 2. Borek 3. rewebster 4. Integral 5. Air 6. ~christina~ http://img105.imageshack.us/img105/6097/sunslandscaperaysbywhitfo4.jpg 7. larkspur...
  39. ZapperZ

    VOTE Photo Contest Group 1 - Cloud Nine

    This promises to be another difficult contest to vote on. There are 15 entries spread out over 2 different polling threads. You have one vote to cast in each poll. Please vote for the picture that best represents our theme, which is focused on clouds. 1. edward...
  40. ZapperZ

    PF PHOTO CONTEST - Cloud Nine (7/26-8/1)

    [FONT="Comic Sans MS"][SIZE="5"]Cloud Nine This week's theme is simple - it is on clouds in the sky. Zz. [SIZE="4"]Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're...
  41. L

    Is Cloud Movement Dependent On Wind?

    It seems to make intuitive sense for cloud movement to be dependent on wind, but is it actually true? Isn't the Coriolis Force a bigger factor in cloud movement?
  42. P

    Can dark matter be just a cloud of protons?

    I have been thinking about this for a while, and I am not sure about how I can visualize this. Lets imagine that there can exist clouds of primordial matter, far away in space. 1. Can it be possible for a cloud to exist and be made out of strictly protons at 0 kelvins? I don't...
  43. A

    How High Are Mesospheric Clouds That Appear 38 Minutes After Sunset?

    Homework Statement Homework Equations theta = length / radius The Attempt at a Solution I came across this question in Fundamentals of Physics (Resnick / Halliday / Walker), in the chapter Measurement. Now I understand that this is a simple geometry-based question. Basically, the '38...
  44. Loren Booda

    Gravitationally bound, ionized cloud of hydrogen

    An isolated, spherical cloud of ionized hydrogen at temperature T initially nears gravitational-electromagnetic equilibrium. How will the cloud's structure evolve?
  45. B

    Can Methylated Spirits and Liquid Nitrogen Work for a Cloud Chamber?

    Hi, I'm attempting to make a condensation cloud chamber to display alpha and beta particle tracks to a class of school kids as part of my placement. I get how it all works but I'm having real trouble with two things... 1) Finding a source of high purity alcohol. 2) Getting hold of...
  46. C

    Force on Particle in Dust Cloud

    [SOLVED] Force on Particle in Dust Cloud The following problem is from Thorton & Marion's Classical Dynamics, Ch. 5 Problem 5-13 (p. 205 in the 5th edition of the text) Homework Statement A planet of density \rho_{1} (spherical core, radius R_{1}) with a thick spherical cloud of dust (density...
  47. J

    Calculating Water Volume in a Cumulus Cloud

    Homework Statement A cubic centimeter in a typical cumulus cloud contains 50 to 500 water drops, which have a typical radius of 10 µm. For that range, give the lower value and the higher value, respectively, for the following. How many cubic meters of water are in a cylindrical cumulus cloud...
  48. A

    How much water is contained in a cumulus cloud and what is its mass?

    [SOLVED] Mass of water in a cloud Homework Statement One cubic centimeter of a cumulus contains 220 water drops, which have a typical radius of 10 μm. (a) How many cubic meters of water are in a cylindrical cumulus cloud of height 3.0 km and radius 1.0 km? (b) How many 1-liter pop bottles...
  49. M

    What is the Electron Cloud and Why is it So Mysterious?

    Simple question here, I know where the protons, neutrons etc. are, but what I can't seem to find anywhere is what I have labeled "X" in my poorly drawn diagram. Everywhere I look it calls it an "electron cloud" is that all it can be described as because we don't actually know exactly what is in...
  50. deccard

    Bucket launched into cloud of star dust.

    Homework Statement An empty bucket (mass M, area A) is launched with velocity v0 from a space station into a cloud of dust (density ρ). As the bucket moves through the dust it will collect dust in it until the bucket comes to a stop. Solve the place of the bucket x=x(t). 2. The attempt at a...
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