What is Escape: Definition and 372 Discussions

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. A

    I Can a plane escape Earth's gravity with a powerful engine and no air?

    If I drive a plane and the force of engine is bigger than force of gravity of it , if the engine is turn on always ,and assuming no air , will the plane continue moving up and escape from the gravity ?
  2. A

    GPE and Escape Velocity: Understanding the Relationship for Moving Objects

    Is it necessary to be the kinetic energy greater than gpe to move ( I don't talk about in orbits) Example : Is it will be harder to move an object has a bigger gpe ( same mass but bigger hight from ground). And thanks.
  3. Y

    MHB Logo - Help the turtle escape the room

    Hello all, I have a question, would like to have your opinion on the matter. In the Logo programming language, I draw a red blue circle and put a turtle in it. I have specified that the turtle will move forward constantly, but, when approaching a white background (the page's background), it...
  4. S

    Additional Velocity Required for a Satellite Already in Orbit to Escape

    Homework Statement A satellite is orbiting the Earth around an orbit of radius R=2.5R0, where R0 is Earth's radius. What additional velocity is needs to be directed along the radius of the orbit so that satellite escapes Earth's gravity? Homework Equations Total Energy= K + U Conservation of...
  5. G

    KE+PE when a rocket's speed is less than escape velocity?

    Hey people, I just want to ask that what will happen to the total mechanical force of the rocket if its speed is less than escape velocity? a. KE+PE=0 b. KE+PE>0 c. KE+PE<0 d. Depends upon initial speed of the rocket Pick one. And Why??
  6. Alexanddros81

    Pytels Dynamics 12.8: Missile dynamics, acceleration and escape velocity

    Homework Statement A missile is launched from the surface of a planet with the speed v0 at t=0. According to the theory of universal gravitation, the speed v of the missile after launch is given by v2 = 2gr0(r0 / r -1) + v02 where g is the gravitational...
  7. D

    B Escape Velocity from Relativistic Sphere: Derivation & Intuition

    Can you please direct me to ref that shows the derivation of the escape velocity from a spherical object that moves in velocity v~c with respect to rest frame? I suspect the escape velocity is increasing (intuitively since the mass increases). Please comment and suggest alternatives.
  8. Jared

    Need help finding energy for escape velocity

    Homework Statement The gravitational potential energy of a certain rocket at the surface of the Earth is -1.9x10^12 J. The gravitational potential energy of the same rocket 300km above the Earth's surface is -1.8x10^12 J. Assume the mass of the rocket is constant for this problem. A) How much...
  9. R

    Use of forces to escape the Earth

    If gravity is as we know a weak force and magnetism is a strong force, would it be possible to use electromagnetism to propel an object fast enough away from the Earth's surface to escape the pull of gravity and at least put an object in orbit. I assume you would need a long horizontal then...
  10. ckirmser

    Trip to Space -- Can ship with 1g acceleration escape Earth?

    In another forum, the question was raised, "could a ship with 1G acceleration escape the gravity well of a planet with 1G gravity?" A popular response is, if the craft is aerodynamic, it could accelerate laterally until it reached escape velocity and then manage to get to space. I don't...
  11. D

    A What keeps Rhea stable? Simulation shows Titan-assist escape

    Hi everyone, I have created a simulation of the major bodies in the Solar System, using the exact positions, velocities, and masses etc. at midnight on Jan 10 (as provided by the NASA HORIZONS project). Using Newtonian gravity I numerically simulate the forces between all the bodies (with a...
  12. X

    How does water escape the pot?

    I was cleaning up the kitchen, and there was a large pot that had been filled with water to soak in the sink. A rectangular nylon pot scrubber was hanging over the side of the pot, about 2/3 in the pot and 1/3 hanging out. As I ran the tap, the pot filled up and overflowed, but even after the...
  13. Leyzorek

    B Can a photon be made energetic enough to escape a black hole

    why can't a photon escape a black hole? i think it is because the photon is red shifted away to nothing, if this is true, it would be possible to create a photon that would be energetic enough that a black hole would not have enough time to red shift it away to nothing, unless there is some...
  14. D

    Is the usual Escape Velocity eqn an approximation?

    Text books ordinarily give the escape velocity of a mass-M body (in the center of mass frame of the system of the body and the escaping projectile, whose mass I'll label m) as (*) v2 = 2GM/r where r is the distance between the body and the escaping projectile. it doesn’t seem to me that (*)...
  15. Jules Winnfield

    How come escape velocity isn't imaginary?

    Going through several definitions, it appears that escape velocity is equal to the potential energy. That is:$$\frac{1}{2}m v^2=-\frac{G M m}{r}$$but if I solve for velocity, $v$, I get:$$v=\sqrt{-2\frac{G M}{r}}$$So how do I get an escape velocity that isn't imaginary?
  16. TheSodesa

    Escape Velocity of a Neutron Star: Relativistic Calculation

    Homework Statement Calculate the escape velocity on the surface of the neutron star in the previous problem (##m = \frac{2}{3} \cdot 2,1 \cdot M_{\odot}##; ##R = 15km##). Hint: Basic physics. Note, however, that the escape velocity is not going to be small when compared to the speed of light...
  17. I

    Temperature inside a box as particles escape a small hole

    Homework Statement Edit: Thanks to gneill for showing me the LaTeX ropes. Equations should work now. A perfect gas enclosed within a container escapes into vacuum through a small circular hole. The particle flux through the hole is ##\frac{nc}{4}## and the energy per particle escaping can be...
  18. S

    Rocket Launch: Achieving Escape Velocity w/ Fuel-Mass Ratio of 300

    Homework Statement Rockets are propelled by the momentum of the exhaust gases expelled from the tail. Since these gases arise from the reaction of the fuels carried in the rocket, the mass of the rocket is not constant, but decreases as the fuel is expended. Show that for a Rocket starting...
  19. R

    Escape Velocity: Unraveling the Mysteries of Kinetic & Potential Energy

    Why does a planet's kinetic energy become 0 when it reaches infinity? And why does a planet's kinetic energy get converted to gravitational potential energy when subjected under another planet's gravitational field? Escape velocity seems very abstract to me!
  20. L

    B Escape Velocity & Black Holes: Can Something Escape?

    It is my understanding of black holes that nothing can escape them because their escape velocity is higher than the speed of light. The place at which the escape velocity becomes higher than the speed of light is known as the event horizon. My question is what happens if there is a normal force...
  21. kiwaho

    I How can the e- escape by overcome the suck force in β- decay

    Not like decay of β+ or EC(electron capture), in β- decay, the nucleus positive charges definitely exerts strong suck force to negative charged electron, and the heavier the nuclide, the stronger the force! So, no coulomb barrier for β+/EC, but does for β- decay. How can the electron in a β-...
  22. Geofleur

    D.E. Littlewood's comments about escape velocity

    I have been reading D.E. Littlewood's book "The Skeleton Key of Mathematics", and near the beginning he says that if a projectile weighing one (long) ton were given a velocity of 44 miles a second, this would be "sufficient to raise it to a height of 1000 miles above the Earth's surface."...
  23. N

    Escape velocity and kinetic energy

    is it right to say, "when all the potential energy is converted in kinetic energy the object is moving at the escapevelocity. and "when the change in potential energy and kinetic energy is constant at the same time it is laying still on the ground or in a perfect circulair orbit. and the last...
  24. marcus

    A Info escape from BH (videos up from Nordita conference)

    20 videos from last summer's conference have been posted: http://www.nordita.org/video/index.php?ev=hrad2015 For example here is Rovelli's 39 minute talk on a solution of GR which allows tunneling of BH to WH and calculating time and amplitudes for transition of collapse to explosion...
  25. B

    Can a Thief Escape a Building Using a Rope?

    Homework Statement A 75 kg thief wants to escape a building. He has a rope that supports 58kg how can he escape? Homework Equations f=ma The Attempt at a Solution 75kg*g = W 58kg*g = T T - W = 75kg*a a = (t-w)/m If he applies a acceleration upwards at 2.2 m/s^2 he would survive. When i do...
  26. K

    B Can gravitational wave escape a black hole

    light waves created inside a black hole cannot. Can gravitational waves escape from inside of black holes? in classical GR. does the answer change in string theory?
  27. K

    Basic particle accelerator - escape speed (grade 12)

    Homework Statement The device has two parallel plates, one positively charged and one negatively. The positive plate has a hole to allow electrons to fire out of it. b) How can the device be modified to accelerate protons? c) How does the escape velocity of a proton compare to that of an...
  28. F

    Escape Velocity = Freefall from Height of One Radius?

    I was doing some calculations using the escape velocities from Earth, Moon and Mars. Then by chance I calculated the velocities attained when an object was "dropped" from a height of the radius on each of these bodies, assuming the acceleration due to gravity remained constant during the fall...
  29. G

    How can EM interaction escape a black hole?

    Hi. Charge is one of the few properties a black hole can have. EM interaction is mediated by photons. How can they escape the BH?
  30. P

    Finding Escape Speed for an Electron that's Initially at Res

    Homework Statement What is the escape speed for an electron initially at rest on the surface of a sphere with a radius of 1.0 cm and a uniformly distributed charge of ##1.6\times 10^{-15}##? That is, what initial speed must the electron have in order to reach an infinite distance from the...
  31. Y

    Will Radial Escape Velocity Launch a Satellite Into Orbit?

    If we provide a satellite with escape velocity perpendicular to the earth(radially), would it start orbiting it?
  32. Z

    Gravitational pull of Earth and escape velocity

    I know once the escape velocity is reached, the object will continuous to move away from the Earth. But the Earth's gravity can still act on the object no matter how far it goes, so what keeps the object from stopping or even returning back to Earth? Thanks in advance!
  33. Neon

    Discovering Earth's Escape Velocity: The Ultimate Measure of Gravity's Power

    The Earth's escape velocity is in km per s. But i can jump off the ground! i know but the estimate for the Earth's escape velocity in for an object of what mass? Defintely more than a ton.
  34. G

    Exploring Earth's Escape Velocity: A Non-Physics Perspective

    Hi, First FYI, I have no education in physics. Anyway - I know Earth's escape velocity is about 41,000 kph. Anything less, and you'll eventually fall down back to earth. Two points that seem to contradict each other - 1. Escape velocity gets decreased the farther away you are from the...
  35. Ryan Reed

    How Can Gravitons Escape A Black Hole?

    Past the event horizon of a black hole, gravity is so immense that even light can't escape. Wouldn't this cause the the gravitons, which travel the speed of light, to be trapped, making a singularity?
  36. Ajit Kumar

    Thrown Object & Earth's Escape Velocity

    If an object is thrown upwards with escape velocity, will it orbit the earth?
  37. a1call

    What's Wrong with Vacuum-Filled Vertical Tube Escape Velocity?

    Ignoring drag, terminal velocity and friction, input 1143 seconds here: http://keisan.casio.com/exec/system/1224835316 It yields a velocity of 11.2 km/s (Earth's Escape Velocity) at freefall from a height of 6.4 km (a fraction of the height/depth of Everest, Antarctic ice cap and deepest oceanic...
  38. Salvador

    Calculating an Escape from Earth's Gravity: Can It Be Done?

    this is an interesting thought i had but i don't have the mathskills to calculate the answer so I thought I could ask for your help. So I want to drive my car up to space for example , imagine I have built a ramp on which the acceleration goes in the opposite direction of the rotation of earth...
  39. Stephanus

    What is the escape velocity of Earth?

    What is escape velocity? According to Wikipedia http://en.wikipedia.org/wiki/Earth Earth: Escape velocity: 11.186km/s? What does that mean? Does the projectile should be fired perpendicular with respect to the ground angle? According to this: According to this, can the projectile be fired in...
  40. 1

    How Does Planet X's Gravity Affect Rocket Escape Velocity?

    1. Problem A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is a) 2 v b) (√2)v c) v d) v/2 e)...
  41. RandyD123

    Escape the Horizon: Can I Pull My Friend Back?

    Suppose I extend a tether into a BH horizon. My spaceship is on the outside and my friend is on the end of a very long tether and crosses the event horizon...can I pull him back?
  42. AakashPandita

    Escape velocity earth confusion

    Namaste If escape velocity on Earth is 11 km/s and velocity of Earth is 30 km/s how is that the atmosphere doesn't escape the pull of earth. Is the escape velocity with reference to Earth ? I don't think so because when finding the formula we add kinetic and potential energy and then equate to...
  43. Chris T.

    Escape Velocity, with varying acceleration as a(y)

    Homework Statement Find: The minimum initial velocity at which a projectile should be shot vertically from the surface of the Earth so that it does not fall back to Earth. Note: This requires that v=0 as y approaches infinity. Homework Equations a = -g[(R^2)/((R+y)^2)] g = 9.81 m/s^2 R =...
  44. N

    Escape velocity for Saturn (Introductory Mechanics)

    Homework Statement The radius of Saturn (from the center to just above the atmosphere) is 60,300 km (60300✕10^3 m), and its mass is 570✕10^24 kg. An object is launched straight up from just above the atmosphere of Saturn. (a) What initial speed is needed so that when the object is far from...
  45. B

    Differential equations and escape velocities

    Homework Statement Good day all! I'm stumped on a question: If I fire a bullet straight up what will be the initial velocity such that the bullet doesn't come back down? I need to model a differential equation (it will be first order) some how! Also, Gravity is not constant, but rather, the...
  46. D

    Will a body ever escape in a 3 body problem?

    I am asking this question because I found it in a lecture by Stephen Wolfram which you can see at this link at about 54:10: Apparently the question cannot be answered with current methods of physics- Wolfram describes it as "undecidable". But what is the question? When he says "escape" does...
  47. C

    Escape velocity (from the earth) of the Earth-Sun system

    Escape velocity is an estimate of the launch velocity of a spacecraft (without any propulsion) to overcome a planet system's gravitational pull in order to escape to ``infinity''. In this problem we consider both the gravitational attraction of the Earth and Sun (but ignoring the effects of...
  48. J

    How Can we Find the Escape velocity of a black hole

    How Can we Find the Escape velocity of a black hole.
  49. M

    Determine its escape velocity in miles/s?

    Homework Statement A space probe is to be launched from a space station 200 miles above Earth. Determine its escape velocity in miles/s. Take Earth's radius to be 3960 miles. Homework Equations None. The Attempt at a Solution m(dv/dt)=-(mgR^2)/(x+R)^2 dv/dt=-(gR^2)/(x+R)^2 Now what? The...
  50. Suraj M

    Escape velocity and kinetic theory

    Homework Statement imagine a planet with half the mass and half the radius of Earth ..with temperature reaching 800K k=1.38×10-23 mass of O₂ = 5.3×10-26 does the planet have O₂ or not? Homework Equations ½mv² = ½kT or ½mv² = kT or ½mv²= 3/2 kT either only vertical or anything other than...
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