Universe Sandbox
Universe Sandbox Legacy => Universe Sandbox 2008 | Discussion => Topic started by: theronrr on January 04, 2009, 09:53:52 PM
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In the sixes there was a movie called "Journey to the Far Side of the Sun"
Where there was another earth opposite of the sun. It was a bad movie
but an interesting thought.
It has been fun playing around with the xml files.
I made a copy of the Solar System XML and added
<Body>
<Object>Earth2</Object>
<Name>Earth2</Name>
<PositionX>1700.0</PositionX>
<PositionY>-1.00au </PositionY>
<PositionZ>0.17</PositionZ>
<VelocityX>29.8418002280664</VelocityX>
<VelocityY>-5.18082741020703</VelocityY>
<VelocityZ>0.000886779706252172</VelocityZ>
<Diameter>12742.02</Diameter>
<Mass>59736</Mass>
<Density>5.515</Density>
<Obliquity>23.45</Obliquity>
<RotationPeriod>23.9345</RotationPeriod>
<Notes>5.9736E+24 kg</Notes>
<Texture>earth.dds</Texture>
<ColorReal>556583</ColorReal>
<ColorVivid>Blue</ColorVivid>
</Body>
The two Earths are not always opposite, but interesting to watch
thought I share it
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The two Earths are not always opposite, but ...
they would be always opposite only if the orbits were circular (in this case the velocity would be costant) ;)
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Very awesome...
And here's an easier way to accomplish the same goal:
<Body>
<Object>Earth</Object>
<Name>Earth 2</Name>
<Action>L3=Sun,Earth</Action>
</Body>
The <Object> tag looks up all of the properties of the Earth. All other two tags modify the default Earth settings. L3, of the Earth & Sun, is an unstable point that's directly opposite the Sun from the Earth. You can also use the commands: L1, L2, L4, L5.
What is the L3 point?
http://en.wikipedia.org/wiki/Lagrangian_point
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The L3 point isn't at the same distance of Earth from the Sun; it's a little less.. But they are details ;)
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That's true... My suggestion is a little different than what theronrr was suggesting.
Something else worth noting is that the 2nd Earth (since it's as large as the 1st) will have a detectable pull on the 1st and change its orbit. The L1, L2, L3 points are all inherently unstable too and won't last too long even under perfect conditions. L4 & L5 are stable and will last indefinitely.