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SpaceX's Big Falcon Topic 2

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4 hours ago, maarsen said:

Venus and Uranus both rotate in a direction opposite to all the other planets. A hyperbolic orbit is a sure sign of coming from interstellar space. Any elliptical orbit, not so much. 

But they orbit in the same direction as other bodies.  Don’t the strange rotations of Venus and Uranus indicate massive impact at some point?

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4 hours ago, maarsen said:

You are right. The assumption is that conserving angular momentum requires all bodies in our solar system to have the same angular momentum as the original cloud from whence all came. Having a few large bodies not following the rules  means smaller bodies not following the rules are not a sign of much. Consider also that the axial tilt of Uranus is 90 degrees, and as such is also at odds with the other planets in terms of angular momentum. 

I think you are confusing two different angular quantities, one centered on the axis of a given planet and one centered on the Sun (well, the center-of-mass of the Solar System, but it's pretty much the Sun). The spin of the individual planets can be affected by a variety of factors (collisions, tidal forces, etc.), but the orbital motion around the Sun needs something from outside the Solar system to mess it up.

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3 minutes ago, Ser Scot A Ellison said:

But they orbit in the same direction as other bodies.  Don’t the strange rotations of Venus and Uranus indicate massive impact at some point?

Don't play coy, Scott. Tell us more about the Deep Impact on Uranus.

:rofl:

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7 hours ago, Altherion said:

I think you are confusing two different angular quantities, one centered on the axis of a given planet and one centered on the Sun (well, the center-of-mass of the Solar System, but it's pretty much the Sun). The spin of the individual planets can be affected by a variety of factors (collisions, tidal forces, etc.), but the orbital motion around the Sun needs something from outside the Solar system to mess it up.

The total angular momentum should be the same as that of the primordial gas cloud in theory. Passing objects with a different source of angular momentum can add angular momentum into what is assumed to be a closed system. As the primordial cloud that birthed our sun probably birthed hundreds of other suns, assuming our solar system has always been a closed system is not helpful. 

Look at the creation of our moon. Some Mars sized planet slammed into the Earth to create the moon but where it now? It could be orbiting another sun perturbing net angular momentum calculations for astronomers in that system. 

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RIP Alan Bean.

Another one gone. I hope we land on the Moon again before all of the Apollo Program moon-walkers pass away, but I'm not optimistic.

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