# Questions tagged [escape-velocity]

The velocity an object must travel to successfully exit the gravitational influence of a body.

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### May a star explosion be in that way weak that the expelled material gradually recollapse and form the star again?

May a star explosion be in that way weak that the expelled material gradually recollapse and form the star again? My question is not about would that explosion leave a neutron star as a remnant but ...
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### Black holes are not infinitely dense [closed]

If a black hole is infinitely dense, then therefore its terminal velocity in a determined field of gravity would be greater than the speed of light which is impossible, therefore a blackhole is not ...
2answers
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### What would be the event horizon for charge?

If there was a sufficient charge density, would it be possible for that charge to have an event horizon, a radius at which a charged particle would need to be going faster than the speed of light to ...
1answer
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### Would an anisotropic speed of light possibly allow light to escape a black hole?

It has been proposed that light coming toward the earth is near infinite but that light outgoing is near 1/2 c. I know we cannot directly measure the one-way speed of light, but if anisotropy were ...
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There is the this question: Imagine you are projecting a ball with $3/4$th the escape velocity from the surface of the earth. What is the farthest distance will it reach it from the centre of earth? ($... 2answers 89 views ### Is Acceleration of Earth Constant in its Orbit around the Sun? According to this link , we can say that the Earth's acceleration is constant as the path is circular. But how ? 1answer 67 views ### Could a balloon be thrown from the moon to the earth by a man or woman or machine? Is it physically possible for a three meter radius balloon to be whirled about on a string by a person or if necessary a machine (perhaps held by the person) standing on the surface of the moon and ... 1answer 58 views ### On figuring the eccentricity of an orbit knowing my launch speed [closed] I want to check if I am reasoning a deduction correctly and am not missing some elementary part of the math. I have a rocket that I launch at$10,000\; m/s$. Earth's escape velocity is$11,200\; m/s$, ... 4answers 109 views ### Orbital escape velocity [closed] Given a satellite (black) orbiting a planet (green) in a circular motion with$r_o$being the orbital radius. The orbital the velocity of the satellite is$v_{orbit}=\sqrt{\frac{GM}{r_o}}$, right? ... 0answers 14 views ### How much of the Sun to not evaporate is due to gravity and how much due to magnetism? As protons and electrons on the sun 'surface' have high kinetic energy something obviously should stop them to go away.Its gravity is very high compared to planets but is this enough as magnetism also ... 1answer 40 views ### Finding escape velocity considering two gravitational fields A shuttle has to travel between earth and mars to a point$P$where the gravitational force of each planet is equal. I need to calculate the energy required to reach the point$P$. I was thinking of ... 3answers 2k views ### Does time stop in black holes? [closed] I was going through Hawking's incantations on black holes, where black holes get defined as follows: Black Hole: A region of spacetime from which the escape velocity exceeds the velocity of light. I ... 2answers 23 views ### If I had an initial upwards velocity and thrusted upwards to exactly counter-act gravity at all times, would I eventually escape Earth's gravity? [duplicate] If I understand it correctly, the escape velocity of a body is the velocity I would need to escape that body's gravity if I did not continuously thrust against its gravity. So this question boils ... 2answers 115 views ### Does it take escape velocity to reach orbit? I don't comprehend what is meant by "escape" The internet gives me two meanings thus my following ambiguity: Does escape velocity mean to reach infinitely far from the earth or to just reach ... 3answers 155 views ### Escape velocity from Earth and sphere of influence I know that escape Velocity from the Earth's surface is 11.2 km/s. But is that the minimum velocity to get to orbit (L.E.O I guess) or to escape Earth's sphere of influence? 2answers 86 views ### Would a body have any residual velocity if launched at escape velocity from the Earth's surface? A body is lanuched at escape velocity from the Earth's surface i.e 11.2 km/s ,what would be it's velocity outside the Earth's gravitational field? I guess it would be zero but there's another problem ... 0answers 39 views ### Is the escape velocity of black hole greater than the speed of light ? If not, then why does light can't escape the black hole? [duplicate] I've heard different type pf answers for this qs and not really sure which one to go for. 1answer 84 views ### Really confused about orbital science Okay let’s start straight away, What is Escape Velocity? Is it the speed required to get into orbit, or is it the speed required to escape the SOI (Sphere of Influence) of Earth completely? If it’s ... 3answers 180 views ### Escape Velocity, Misattribution, and Black Holes Escape velocity is the ballistic speed required to escape from a gravitational field to infinity, ignoring any third body dynamics. The operative word here being ballistic, meaning unpowered. ... 2answers 67 views ### Why is the ratio between the escape velocities of different planets not the same as the ratios between their respective surface gravities? Mars has a$g$of about 38% of Earth's, but an escape velocity that is 45% of ours. Not a large difference, but there must be a reason. 1answer 105 views ### Can Binary Stars Escape Each Other? updated 8/27/2020 While the recession of our Moon from the Earth may slow and even stop, (see When will the Moon reach escape velocity?) binary star systems will (1) never stop experiencing mutual ... 2answers 42 views ### Why does a planet with$v_c<v<v_e$approach the sun faster than a planet with$v = v_c$Not sure if I worded the question properly, but my question is about an image shown in Your Daily Equation #17 by Brian Greene He shows the following image: Where red is the case$v = v_c$and green ... 1answer 55 views ### Escape velocity questions This topic really screwed with my head in school and my teacher could never answer my questions so I thought I would ask here. I will break it down with mathematics and then logic. Let's assume we ... 1answer 46 views ### Escape velocity and Conservation of energy If a physical body leaves earth with 11.2 km/s escape velocity with a certain amount of Mechanical energy, then how can it be said that the body will have 0 Mechanical energy at a point at infinity ... 1answer 103 views ### What equation can I use to calculate escape velocity as the radius increases from the Schwarzschild radius? At the Schwarzschild radius, the escape velocity is the speed of light for all objects. However, I'm looking for an equation that will calculate the escape velocity as the radius of the object ... 0answers 44 views ### What is angle of escape velocity? [duplicate] We know if a object has escape velocity (EV) it reaches space (ignore atmosphere friction), but at what angle. if an object travels parallel to earth surface with EV, will it escape curvature and ... 1answer 189 views ### Why can't light travel past the event horizon? Since the event horizon is defined as the boundary within which the escape velocity is greater than the speed of light, and escape velocity is the speed required for that object to reach infinity away ... 1answer 75 views ### where do the gases such as hydrogen and helium end up after leaving the earths atmosphere? I've heard that gases like hydrogen and helium leak out of the earth's gravity a little by little. but where are they going? where do they end up after leaving earth's pull? would the sun pull them ... 3answers 89 views ### Why in the formula to get the escape velocity$v_f$is$0$? The formula to get the escape velocity is: $$K_i + U_i = K + U$$ $$\frac{1}{2}mv^2_i-G\frac{mM}{R^2} = \frac{1}{2}mv^2-G\frac{mM}{r_\infty}$$ $$\frac{1}{2}mv^2_i-G\frac{mM}{R^2} = 0$$ My question is: ... 1answer 222 views ### Escape velocity for electric field As we know gravitational force and electric forces are quite similar I was wondering if there is minimum velocity called escape velocity required to escape gravitational field of earth so is there a ... 4answers 978 views ### Why an object with a velocity of 11.2 km/s only enter space? [duplicate] Can someone explain me what is escape velocity? why cant a bird with enough energy (super bird) fly into space? 1answer 220 views ### Minimum Velocity for a projectile to leave the Earth Let's say we have a cannonball that can shoot at various angles. How would we find the minimum velocity for this projectile to leave the Earth when the cannonball is shot at an angle$\theta$. I think ... 3answers 93 views ### Can the acceleration of the object thrown by man exceed the acceleration of gravity? [closed] Can the acceleration of an object thrown by man exceed the acceleration of gravity? I don't think so. Otherwise, how could the object fall back to the ground? 2answers 140 views ### Doubt regarding derivation of escape velocity [closed] In my text book the derivation goes like this: The minimum speed required to project a body from the surface of the Earth so that it never returns to the surface of the Earth is called escape speed. ... 2answers 119 views ### Making a black hole using charge instead of mass? You can just skip the background portion if you are interested in the real question. A bit of Background I was reading about gravity in my textbook and it mentioned about how in the recent years there'... 1answer 76 views ### Could a planet have terminal velocity greater than its escape velocity? I've had 2 semesters of college-level physics (1 of Mechanics and 1 of E&M) and was wondering after exploring a bit about terminal velocity: Is it physically possible for a planet to have a ... 2answers 149 views ### Calculate escape velocity without using energy? [closed] Is it practically doable to calculate the escape velocity on the earth not by using the principle of energy conservation, but by calculating the velocity of the particle as a function of time using ... 12answers 5k views ### Escape velocity - Won't the orbital path just become larger with higher initial velocity? Escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a massive body. However, gravity has infinite range. Object$A$is always getting pulled by the ... 0answers 72 views ### Escape Velocity and its effect on the atmosphere I’ve been doing some world building and wound up with a bit of a physics puzzle that’s stumped me. So rather than a long winded explanation I’ll simply state the primary parameters. Under otherwise “... 3answers 111 views ### Answering simple questions about black holes to someone not knowing GR In the Newtonian description of a black hole, it is a gravitating astrophysical object for which the escape velocity exceeds the speed of light in vacuum ($c$). But what does this actually mean for a ... 2answers 81 views ### What if we set the exact equality$u^2=\frac{2GM}{R}$? Escape or not? Let an object of mass$m$is thrown up with an initial velocity$u$from a spherical gravitating body$A$of mass$M$and radius$R$. Let us assume that when it reaches a height$h$its velocity ... 2answers 413 views ### How does General Relativity explain escape velocities? In general relativity, objects follow the shortest possible path through curved space-time called a geodesic and that there exists no such force of gravity which pulls objects, it is just because ... 2answers 580 views ### What is the escape velocity of a neutron particle (not neutron star) I'm not sure if this question makes sense (if not maybe you can explain why) But if the neutron has mass and have a size, then it should have a escape velocity in the "surface" right? I know the ... 1answer 110 views ### Gravitation and escape speed [closed] I applied conservation of energy at the surface and at the centre of earth which brought me to equation $$- \frac{GMm}{R} =\frac{1}{2} m v^2$$ Having asked my sir, he said that gravitational potential ... 1answer 99 views ### Escape velocity of Kerr black Hole [duplicate] Do the event horizon of Kerr black Hole have escape velocity is equal to the speed of light same Schwarzschild black hole? 2answers 51 views ### Could a rover drive to orbital velocity? Could a rover, assuming it is on a perfectly smooth sphere in space, eventually reach orbital velocity? Would there be a limit on the possibile speed? 1answer 80 views ### At what velocity will the moon be able to escape the earth's orbit? I haven't found an answer to this question online so correct me if I am wrong. This is the escape velocity equation:$v_{esc} = \sqrt{\frac{2GM}{r}}$and by plugging the known values, this is the ... 2answers 110 views ### What would happen if a planet's escape velocity exceeded the speed of light? What would happen if a planet's escape velocity exceeded the speed of light? Would it also collapse into a black hole (by Heisenberg's uncertainty principle and Pauli's exclusion principle) or would ... 5answers 4k views ### I don't understand why escape velocity is necessary [duplicate] I have read multiple explanations of escape velocity, including that on Wikipedia, and I don't understand it. If I launch a rocket from the surface of the Earth towards the sun with just enough force ... 1answer 91 views ### Does space expansion mean the escape velocity at a black hole event horizon is strictly less than$c\$?

The title pretty much sums it up. I could ask this question slightly differently; does the expansion of space cause the effective event horizon to shrink below what it would be for flat space? If so,...