- #36
Drakkith
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Edi said:If object A is accelerated to orbital speeds it will not fall at all. It will fall around the planet, but not directly down.
...but that isn't what you said...
Edi said:If object A is accelerated to orbital speeds it will not fall at all. It will fall around the planet, but not directly down.
Drakkith said:...but that isn't what you said...
Edi said:Well, context is important..
More precisely, object A would not as much push object B up while accelerated/ moving at orbital speeds, but it will hold object B from falling down for the time being or, at least, slow down B's decent? (assumed both started with no orbital speed at all.)
Drakkith said:No, it takes time to accelerate object A, during which both A and B are falling at the same rate. A is not slowing B down at all.
Edi said:OK.
Then what about this:
Object A is already orbiting the planet and object B is orbiting the same planet in a orbit just slightly above A's orbit. Object B hits another object, object B1, that is the just like object B, orbiting the same path, but in the opposite direction, so when they hit each other, they both come to a full stop. At that exact point in time, object A just happens to be in the spot of collision, just a bit, bit lower so it is sliding beneath object B and B1 - will this delay their [object B and B1] descent ?
Take two identical balls, each doing just half of the orbit, bouncing elastically at two opposite points. An orbital Newton's cradle.Edi said:As I figure [and have consulted with some physicists], there no reason why this would not work: object orbiting a planet in one direction, then, half way trough, hits something that propels it in the other direction [at orbital speed, of course], orbits the planet the other way around and hits something that propels it in the other direction again and then the cycle continues back and forward, keeping the object in orbit, but not in a full orbit, but, in this case, just orbiting, essentially, one side of the planet.
Sure, you can have a ball bouncing back and forth between the walls of an evacuated spaceship, that is in orbit. But you loose energy on each bounce.Edi said:Now, that (if) this works, there should be no reason why it has to be the whole half of a planet - it can be any distance at the orbits circumference. Even 100 meters. Right?
Adeste said:I think it will fall while in the process of bouncing back as it cannot do this instantaneously without an infinite force.
During bouncing back it will have a velocity less than required to maintain orbit
Edi said:As I figure [and have consulted with some physicists], there no reason why this would not work: object orbiting a planet in one direction, then, half way trough, hits something that propels it in the other direction [at orbital speed, of course], orbits the planet the other way around and hits something that propels it in the other direction again and then the cycle continues back and forward, keeping the object in orbit, but not in a full orbit, but, in this case, just orbiting, essentially, one side of the planet.
yep... still good...Now, that (if) this works, there should be no reason why it has to be the whole half of a planet - it can be any distance at the orbits circumference. Even 100 meters. Right?
Now the most interesting part.
If we put this object a, say, evacuated tube with magnetic system to propel the object back and forward...
Edi said:And what about the ball in a string scenario?
If it object can stay in orbit by bouncing, can it stay in orbit while rotating parallel to the ground?
TurtleMeister said:No. An object remains in orbit not only because of it's velocity but also because of it's trajectory. Are you familiar with Newton's cannonball? If the object has orbital velocity then it will orbit because the Earth curves away faster than gravity can pull it down. If the object were to travel in a circle parallel to the surface then it could not achieve orbit no matter how fast it travels. That's because it will always be parallel to the Earth's surface and thus the same distance from the source of the gravitational force - regardless of how fast it is traveling. In other words, in order to maintain orbit the object must have orbital velocity tangent to the great circle around the earth.
Edi said:What about an ellipse instead of the circle?
Edi said:What about an ellipse instead of the circle?