# Escape velocity is needed to escape the earth **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [March 10, 2005, 11:43pm UTC](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924 "2005-03-10T23:43:56Z")\ **Posts on this page:** 4\ **Page:** 4
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 19, 2005, 12:16am UTC](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924/61 "2005-03-19T00:16:18Z")
> [@](#): > > Why does the electrostatic force disqualify an object from being “escaped”, while the gravitational force does not? I must say that this has been a very good argument and I did have some second thoughts to it. The main reason I can’t say such an object has escaped, is that it’s ‘escape’ is forever dependant on pushing off the earth. But I must admit that this has made me understand that it is a matter of definition. > [@](#): > > . In such a universe both objects have the same property of traveling away from the earth forever, never to return. Both can therefore be said to have escaped the earth. **Exapno Mapcase** I think I accepted that is it possible for an object to approach infinity at sub escape speed, and basically get to any point in the universe. Now ignoring the fact that this object is impossible and allowing things such as ghosts who can move w/o the constrains of gravity, we can say that such an object was never captured in the 1st place. IF you are talking about a starship with a TDDD, that would be effected by gravity, but can actually thrust using the slaves of the 45th dimension who physically move the ship, I would have to say, yes there should be enough slaves, given current and expected breading rates, to move that starship from earth to infinity at less the escape speed. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 19, 2005, 1:12pm UTC](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924/62 "2005-03-19T13:12:56Z")
I had some more thoughts on the charged cannonball (CC). If you increases the charge you should be able to totally negate the force of g, and the CC would continue along w/o any speed change (and eventually go past ES as some point). You are basically making something with effectively ‘more’ mass for it’s weight. Increasing it further you make the CC act like an antigravity ball. I don’t know **Chronos** I may have to give in on the CC. I still don’t like the idea of it having to support itself against the earth as a condition of escape, and it depends on the earth keeping it’s charge, so nobody can experiment with shooting other differently charged objects from that planet. ---
**Author:** ![Worzo](https://avatars.discourse-cdn.com/v4/letter/w/c5a1d2/32.png) [@Worzo](https://boards.straightdope.com/u/Worzo)\ **Post date:** [March 19, 2005, 8:39pm UTC](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924/63 "2005-03-19T20:39:17Z")
Since electromagnetic and gravitational forces are both inverse square forces, can we combine their potentials to create a potential map of the universe based on every discrete body’s charge and mass? You could possibly use the idea of specific charge - bodies with large specific charge would be affected more by electromagnetic forces than gravitational, for example. I think maybe then any questions about charged cannonballs and the like could be easier to answer. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 19, 2005, 9:24pm UTC](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924/64 "2005-03-19T21:24:17Z")
If you’re talking about the actual Universe, then such a map would be horrendously complicated (though possible in principle). We’re not even sure how the gravitational map alone works out. But if we’re working in a simplified universe, say, one consisting solely of a charged planet and a charged cannonball, then sure. For an object of any given specific charge, the potential map will look just like that of a pure gravitational field (though with a different effective mass). [Previous page](https://boards.straightdope.com/t/escape-velocity-is-needed-to-escape-the-earth/293924.md?page=3)