Escape Definition and 374 Threads

Atmospheric escape is the loss of planetary atmospheric gases to outer space. A number of different mechanisms can be responsible for atmospheric escape; these processes can be divided into thermal escape, non-thermal (or suprathermal) escape, and impact erosion. The relative importance of each loss process depends on the planet's escape velocity, its atmosphere composition, and its distance from its star. Escape occurs when molecular kinetic energy overcomes gravitational energy; in other words, a molecule can escape when it is moving faster than the escape velocity of its planet. Categorizing the rate of atmospheric escape in exoplanets is necessary to determining whether an atmosphere persists, and so the exoplanet's habitability and likelihood of life.

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  1. V

    Why is horizontal escape velocity less ?

    Homework Statement an asteriod with mass 6.6x10^17kg & radius 46km has escape velocity 44ms, but if the projectile is launched horizontally then the escape velocity is only 31ms, show that this is correct Homework Equations Vesc = SQRT (2GM/R) G = 6.67x10^-11 The Attempt at a...
  2. K

    Escape Speed from Earth for 7500kg Spacecraft

    what is the escape speed from Earth for a 7500kg spacecraft ? radius of Earth is 6.38*10m and mass is 5.98*10kg. Homework Equations square root of 2GM/R [b]3. The Attempt at a Solution . I found escape speed to be 3.4*10ms. Is this right?
  3. K

    Is the Escape Velocity of a 10,500kg Spaceship from Earth Calculated Correctly?

    Homework Statement calculate the escape velocity of a 10,500kg spaceship from earth. mass of Earth is 5.98*10kg and radius of the Earth is 6.38*10kg. elevant equations 2GM/R The Attempt at a Solution Using the formula i found escape velocity to be 3.464*10m/s. Is this correct?
  4. K

    How would I calculate the escape velocity from the earth?

    Assuming a vacuum above the Earth's surface
  5. B

    Calculating Escape Velocity on the Equator: Is It Possible?

    hello... I've got some small problem with Escape velocity. So... is it dependent on geographic coordinate ? I suppose "Yes!"... but is it true? Using conservation of energy, I calculate this velocity on equator this way: \frac{mv^2}{2}= \frac{GMm}{R} - \frac{m(2 \pi R)^2}{T^2*R } Am I right ?
  6. Z

    Escape velocity and Dark Matter

    I was wondering how verifiable is the escape velocity equation. V=SQRT(2GM/r) How accurately has this equation been verified? It does not take into account dark matter. (Related ramblings) The escape velocity from the earth’s surface is about 11.2 km/s But there is also air...
  7. R

    Escape Velocity and Earth's Gravity

    The Saturn V rocket for the Apollo missions had rocket reignition at stage 3 to boost speed from 28,160 km/h to 39,430km/h at a stage 2 altitude of 185km. I got these figures from this site: http://www.aerospaceguide.net/saturn_5.html I calculated Earth's escape velocity at 11.029 km/s...
  8. G

    Can something gradually exerting force escape a black hole's gravitational pull?

    I've heard it said that any object that wants to escape another object's gravitational pull must travel at the object's escape velocity. I assume this is incorrect, and would only apply to something with an initial velocity at the escape velocity (like a bullet from a gun would need to travel at...
  9. R

    Escape Velocity and planet’s gravitational field

    Homework Statement The escape velocity is the velocity of an object at the surface of a planet that would allow it to be removed completely from the planet’s gravitational field. Calculate the escape velocity for an object on the surface of Pluto. mass of Pluto: 1.3 *1022 radius of...
  10. W

    Why can't electromagnetic radiation escape black holes?

    Why can't light escape black holes? Isn't light as an electromagnetic radiation massless, thus not affected by gravitational pull? --
  11. S

    Escape Velocity Calculation for an Object on Earth

    How do you Calculating the escape velocity? I googled it but they give bad instructions on how to do it. What is the formula?
  12. E

    Escape from totally closed empty room

    Hi guys! I have one question that bothers me for reeeeally long time (and it's NOT homework! :-) I found one question which goes like this "How can physics help you escape from a totally closed empty room?" Of course it means that room doesn't have any doors or windows, it would be too easy to...
  13. S

    Minimum Length of Emergency Escape Ramp for Truck to Stop

    Homework Statement In Fig. 8-36, a runaway truck with failed brakes is moving downgrade at 130 km/h just before the driver steers the truck up a frictionless emergency escape ramp with an inclination of θ = 15°. The truck's mass is 1.2 x 104 kg. What minimum length L must the ramp have if the...
  14. P

    Finding the formula for escape velocity

    first of all, we need to say that this question is not for homework. Homework Statement our doubt is in the process of finding the formula (not the value) of escape velocity in the earth; we want to use the principle of conservation of energy for that purpose. Homework Equations...
  15. T

    Angular Momentum Conservation Near a Planet: True or False?

    Homework Statement Consider the motion of an object between a point close to the planet and a point very very far from the planet. Indicate whether the following statements are true or false Angular momentum about the center of the planet is conserved. Homework Equations ? The...
  16. rootX

    Daring escape from a Greek prison

    http://news.bbc.co.uk/2/hi/europe/7915137.stm http://www.sofiaecho.com/2009/02/24/680425_greek-government-under-fire-over-helicopter-jailbreak These guys are so smart.
  17. R

    Spring compression and escape speed

    Homework Statement A package of mass 5 kg sits at the equator of an airless asteroid of mass 6.3*10^5 kg and radius 48 m, which is spinning so that a point on the equator is moving with speed 2 m/s. We want to launch the package in such a way that it will never come back, and when it is very...
  18. E

    Final speed of an asteroid using escape speed

    Homework Statement The escape speed from a very small asteroid is only 32 m/s. If you throw a rock away from the asteroid at a speed of 44 m/s, what will be its final speed? Homework Equations Ki + Ui = 1/2mv^2 + (-GMm/R) = 0 (for v<<c) The Attempt at a Solution I am unsure of how to do...
  19. T

    A Narrow Escape: Examining a Near-Miss in San Francisco

    Homework Statement While visiting a friend in San Francisco, you decide to drive around the city. You turn a corner and find yourself going up a steep hill. Suddenly a small boy runs out on the street chasing a ball. You slam on the brakes and skid to a stop, leaving a skid mark 50 ft long...
  20. C

    Help with Escape Velocity Problem

    I know that escape velocity is given by v^2 = 2GM/r My question is what is the approximate escape speed needed to completely escape the moon & Earth's gravity. Is it the sum of their individual Escape velocities? or is it one equation, with the radius' added and masses added? Thanks
  21. J

    Hole where water cannot escape at certain pressure?

    Hi eveyrone! I am completely new to this forum but didnt know where else to turn for a "problem" of mine.. I am trying to design a new kind of waterpump and still in the teory part of the design, i would be interested to know how i can calculate the "thickness" of water at a certain...
  22. S

    Escape Velocity and Earth's gravational pull

    I am a historian[ PhD] who specializes in the History of Science and consequently reads a great deal of physics. Since my childhood I have been fascinated by space travel and have always read that the escape velocity from the Earth's gravational field is 25000 mph. I recently read a book in...
  23. stevebd1

    How Does Curvature Affect Velocity Near a Black Hole's Event Horizon?

    Curved space induces velocity, according to- \gamma\equiv\frac{1}{\sqrt{1-(v/c)^2}}=\frac{1}{\sqrt{1-(r_s/r)}} which results in v_{rel}=-\sqrt{\frac{r_s}{r}}\ c The velocity induced by the curvature at the surface of the Earth is 11.185 km/s, for the Sun 617.746 km/s which, in each case...
  24. H

    Calculate Escape Velocity to Leave Solar System

    Homework Statement when a spacecraft escapes from the earth, it still has to escape from the sun, in order to leave the solar system. at what velocity should a spacecraft be launched if it is 6.4x10^6 meters from Earth's centre and 1.5x10^11 meteres from the sun (M=2x10^30 kg) if it is to...
  25. D

    The Importance of Escape Velocity and Its Role in Space Exploration

    I don't understand why we need an escape velocity, couldn't we escape the planet by accelerating an object above 9.81 m/s^2? Also, say you've got an object one meter off the ground and you apply a constant 9.81 m/s^2 acceleration upwards to it so the object is hovering, where is the energy...
  26. R

    How much force would you need to escape earth's gravity by JUMPING?

    Let's for arguments sake say that we have an invincible superpower humanoid with as much strength as is necessary. How much force would this guy have to input into the ground to exceed escape velocity? How much energy is required? The ground would also pretty much explode under his feet...
  27. I

    What is the escape velocity for an object

    Homework Statement What is the escape velocity for an object on the surface of a 1.9x10^27kg planet of radius 7.2x10^7m? Homework Equations Ve = √2GM/r The Attempt at a Solution What I did was take the values for the mass and radius directly from the question then I plugged them...
  28. P

    Harry Houdini's Escape Project

    Anyone know how to do this? I'm in a bit of a pickle trying to solve it :confused: Harry Houdini (1874-1926) was a famous escape artist. In this project we relive a trick of his that challenged his mathematical prowess, as well as his skill and bravery. It will challenge these qualities in...
  29. L

    Can a tachyon escape a black hole?

    Assuming a tachyon exists, can one escape a black hole? Now, at the singularity of a black hole, gravity is infinite, right?* Since gravity is infinite, would it not suck in everything, even superluminal particles? On the flipside, since gravity can't exceed the speed of light, is it able to...
  30. V

    Escape velocity FROM a satellite in orbit?

    The question: At what speed would a small object have to be launched from the satellite in order to escape earth’s gravity, assuming that the satellite is not moving? The satellite is in circular orbit around the Earth and the radius of the orbit is 4.22 x 10^7. The main problem I am having...
  31. OmCheeto

    News Is Bush Trying to Pardon Himself of War Crimes?

    One of my ex-compadres sent me the following: At first I was appalled... Then I was intrigued... Then I smiled...
  32. V

    Escape Speed from Planets with Different Radii

    Homework Statement The escape speed from the surface of the Earth is 11.2 km/s. What would be the escape speed be from another planet of the same density (mass per unit volume) as Earth but with a radius 5 times that of Earth's? Homework Equations I know I have to use v=sqrt2GM/R...
  33. N

    Zoroaster Planet Escape Speed Calculation for Meteor Collision

    Q.) The escape speed from the surface of Planet Zoroaster is 15.0 km/s. The planet has no atmosphere. A meteor far away from the planet moves at speed 5.0 km/s on a collision course with Zoroaster. How fast is the meteor going when it hits the surface of the planet? My answer: 15+5=20km/s...
  34. E

    Kinetic Theory of Gases & Escape Speed

    Homework Statement In the first 2 parts of the problem, I calculated at what temperatures the rms speeds vrms of H2 molecules and O2 molecules would equal the escape speed of Earth (11200 m/s). The answers I calculated for this were 10000 K for H2 and 160000 K for O2. Those answers are...
  35. O

    Escape Death and Prison: Balancing the Antidote Pill

    You are a prisoner in the king's dungeon. You just learned that the food you ate was poisoned. The king has given you a chance to escape death and to be released from prison. You have been given a balance (which you can use no more than three times) and 12 pills with no perceptible...
  36. M

    Potential Energy After Escape Velocity

    I'm not quite sure I'm understanding potential energy correctly. Let's say we have a runaway planet in deep space which is going in a perfectly straight line. The planet is perfectly spherical and doesn't have an atmosphere. If an object on the surface spontaneously (for the sake of simplicity...
  37. H

    Pelican Dive: Calculating Escape Height for Fish

    Pelicans tuck their wings and free-fall straight down when diving for fish. Suppose a pelican starts its dive from a height of 20.0 m and cannot change its path once committed.If it takes a fish 0.15 s to perform evasive action, at what minimum height must it spot the pelican to escape? Assume...
  38. stevebd1

    Escape Velocity in GR - PhysicsForums

    (This was originally posted in https://www.physicsforums.com/showthread.php?t=248625&page=2" but I started a new thread as it was going slightly off topic) Einsteins equation for gravity is g=ρc2+3P (basically energy density plus 3 times the pressure)- The equation for Newtonian gravity...
  39. M

    Derivation of Escape Velocity Inconsistency

    Hey, I'm a first year Astrophysics student, and in revising the Schwarzschild radius, I wanted to derive it and so I started by deriving the escape velocity from first principles, then rearrange to get the Schwarzschild Radius. Child's play, really. However, depending from where you come from...
  40. W

    Helium & Hydrogen Escape Rates: Table & Physical Mechanism

    Where could one find a table of Helium and/or Hydrogen escape rates through various materials? What is the Physical mechanism: is it tunneling only or other things contribute as well? Thanks!
  41. W

    Earth Radius Shrunk to 4.13 x 10^12 for 50 km.h-1 Escape Speed

    To what radius would the Earth have to be shrunk, with no loss of mass, so that the escape speed from the surface of the Earth is 50 km.h-1 50kmh-1 = 13.9 m/s v=sqrt(2GM/r) G=6.67 x 10^-11 M=5.98 x 10^24 r=? 13.9=sqrt(7.98 x 10^14/r) 193.21=7.98 x 10^14/r 193.21r=7.98 x 10^14...
  42. W

    What Are the Escape Velocities for Callisto and a Neutron Star?

    Determine the escape speed from (a) Jupiter’s moon Callisto with a mass of 1.07 × 10^23 kg and radius 2.4 Mm and (b) a neutron star twice the mass of the sun and a radius of 6 km. I want to make sure I'm doing this and have the correct equations.. For part a) Okay, so escape speed is...
  43. J

    Escape velocity for rocket launches

    escape velocity is defined in resnick,halliday,walker as 'the certain minimum initial speed that will cause it to move upward forever, theoretically coming to rest only at infinity. This initial speed is called the escape speed.' the way escape speed is defined here gives me the impression...
  44. H

    Physicists Demonstrate How Information Can Escape From Black Holes based in LQG

    Here is the news: http://www.sciencedaily.com/releases/2008/05/080515092615.htm"
  45. Holocene

    Using mathematics to escape the disconsolation of reality?

    Has anyone found that doing mathematics actually results in a sort of soothing "disconnect" from the drudgery of everyday life? I'm being serious. Something about the numbers, variables, mathematical symbols and theorems...they seem to represent a very unambiguous "reality", entirely free...
  46. B

    Moon earth system escape velocity

    Homework Statement A projectile is fired straight away from the moon from a base on the far side of the moon, away from the earth. What is the projectile's escape speed from the earth-moon system? Homework Equations Escape velocity = sqrt[2GM/R] The Attempt at a Solution What...
  47. S

    Estimating Photon Escape Time from Center of Sun

    I have a question that I can't figure out. In the Sun, it takes several hundred thousand years for a photon released in the core to reach the surface. Use the speed of light and the radius of the sun to estimate the escape time for a photon from the center of the sun if there were no...
  48. T

    Density of Asteroids, Escape Velcoity and Jumping

    [SOLVED] Density of Asteroids, Escape Velcoity and Jumping Homework Statement The question wants to know the maximum radius of an asteroid that you can escape from by simply jumpibng off. The Variables given: densities = 2500 kg/m cubed radii = 470km downwards height of jump = 1m...
  49. Y

    Explaining Escape Velocity: Zero KE and PE at r=infinite

    Escape Velocity: "An object given the escape speed will have zero kinetic energy at r=infinite, and the potential energy is defined to be zero at that point, so the total energy is 0" I understand having zero potential energy at infinite distance but I do not correlate with having zero...
  50. F

    Man severs & cooks hand to escape god's wrath

    religious nuttiness reaches a new low (well I guess it isn't just religious...): http://www.upi.com/NewsTrack/Top_News/2008/01/09/man_severs_hand_to_escape_gods_wrath/1800/
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