Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: erickejah on 25/03/2009 00:01:50
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what would be minimum mass of an object that is needed to trike the earth out of its orbit?
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.physics.ucla.edu%2Fdemoweb%2Fdemomanual%2Fmechanics%2Fmomentum_and_collisions%2Fcllsnblls.gif&hash=fb50fe620485c0b7ba870c725123eb69)
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That will depend on the objects velocity relative Earth and the angle of impact it has I think.
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what about at 0°, and 90°
[diagram=439_0]
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Paul Dirac is told to have said "Pick a flower on earth and you move the farthest star." Everything we do have a gravitational effect on our surroundings. So, looking at it this way you only need to pick that flower or shoot that rocket into space, if you like, to change the Earths orbit (even if it is only by the tiniest bit). I saw this example for Mars "you can change the velocity of Mars in one second by about 8.1178 * 10<sup>-59</sup> m / s by picking a flower"
But to make Earth leave the solarsystem at a tangent is another thing :) Then you need to know the Earths mass, kinetic energy and momentum in whatever tangent that might be (its orbit) and probably I'm missing out on other important points here like its rotation etc. Then you will need a object of proper size and velocity to hit it with:)
I think I'll leave that to the guys who can do it properly:)
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Any impact that could change the orbit of the earth by any significant amount would add so much energy to the earth that it would melt it and completely destroy all life. The impact that created the moon did this but it would not have changed the earth's orbit by a lot.
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Paul Dirac was making the assumption that the force of gravity is infinitely divisible, how does this fit with the Graviton theory is the force not quantised?
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The Earth in its orbit around the Sun is moving at a speed of 29.865 Km/s while to escape the Sun it would have to be accelerated to 42.23 Km/s, a body with the same mass as the earth travelling at 29.865 Km/s relative to the Earth hitting it at 29.865 Km/s in an inelastic collision should do the job.
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A direct collision like that would not have the effect you suggest the earth and the impactor would be totally melted and disrupted into small particles by the impact most of the small particle would be travelling away from the centre in a disk shaped splatter at velocities well above the escape velocity of the total mass.
Assuming that the collision was a rear ender the velocity along the line of the earth's orbit would be something like half as fast again as the earth's orbital velocity
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[:o], thanks guys you all are very smart [:)]. It makes happy to know that there is people like you in the world [:D]
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A direct collision like that would not have the effect you suggest the earth and the impactor would be totally melted and disrupted into small particles by the impact most of the small particle would be travelling away from the centre in a disk shaped splatter at velocities well above the escape velocity of the total mass.
Assuming that the collision was a rear ender the velocity along the line of the earth's orbit would be something like half as fast again as the earth's orbital velocity
Yes.. i agree with this concept... both the bodies would melt away forming another big bang!!!
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Off course my calculation was only for a theoretical inelastic collision not what would happen to real bodies.
On further reflection I think what I calculated was for an elastic collision with the colliding body imparting all its energy to the earth.
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I wonder if we could move the Earth out of its orbit by having a Neutron star or blackhole whip past at high speed giving a sling shot effect ?
It is known that when one of two orbiting stars is a Neutron star and its companion a large normal star that collapses into a supernova the neutron star is sometimes ejected at high speed so this is a quite possible scenario.
I believe there are such pairs of orbiting stars quite close to us in astronomical terms!
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Now you are talking more sensibly. A near miss from even an earth sized planet could shift the earths orbit by quite a bit. Although it must not be too close or the differential gravitational forces will cause significant damage to the earth.
On the scale of events like this planets are quite delicate and fragile, while neutron stars because of the re small size and very high density and gravitational field are extremely tough.
You have to remember that planets are spherical because rock is just not strong enough to hold its shape under the effect of gravity and that once a body gets more than a few hundred miles across it has sufficient self gravity to squash itself into a basically spherical blob.