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==== Maybe those orbit lines on space diagrams are real and very heavy ====
 
==== Maybe those orbit lines on space diagrams are real and very heavy ====
βˆ’
Diagrams of our solar system (or any planetary system) often show lines representing the elliptical paths the planet takes around its sun. These lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2Ο€ AU) and Neptune's would be 28 ''billion'' kilometers long). [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the planets, including the Earth, which would probably be a problem.{{Citation needed}} Their mass would also affect planetary motions in ways which we would detect.  A related worry about space travel was expressed in previous centuries; it was thought that the planets were embedded within {{w|Celestial spheres|crystal shells}} (spheres or Platonic solids), and a rocket into space could smash the shells and send planets plummeting to Earth. Another joke candidate.
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Diagrams of our solar system (or any planetary system) often show lines representing the elliptical paths the planet takes around its sun. These lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2Ο€ AU) and Neptune's would be 28 ''billion'' kilometers long). [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the planets, including the Earth, which would probably be a problem. Their mass would also affect planetary motions in ways which we would detect.  A related worry about space travel was expressed in previous centuries; it was thought that the planets were embedded within {{w|Celestial spheres|crystal shells}} (spheres or Platonic solids), and a rocket into space could smash the shells and send planets plummeting to Earth. Another joke candidate.
  
 
==== Title text ====
 
==== Title text ====

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