Why the Earth orbits around the Sun

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Main Question or Discussion Point

As far as I know, the Earth orbits around the Sun because of the centripetal force
, and as far as I know, friction and gravitation from other planets should affect the circular motion of the earth and so the path of the earth should not be necessary that perfect.

In addition, there must be small particles or dust in the space so that there must
be friction which should also affect the circular motion of the Earth

Am I right or wrong??
 

Answers and Replies

  • #2
mathman
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The earth's orbit is an ellipse. The orbit is perturbed by other planets gravity. Dust, etc. has a much smaller effect.
 
  • #3
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The earth's orbit is an ellipse. The orbit is perturbed by other planets gravity. Dust, etc. has a much smaller effect.
But we have some planets e.g. Jupitar that are much bigger than our Earth and not really so far away. Why don't they affect our orbit???????
 
  • #4
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Jupiter is much farther away than the Sun, and just has 1/1000 the mass. It perturbs the orbit in a measurable way, but the effect is very small. More than 99.8% of the mass of the solar system is in the sun.
 
  • #5
phinds
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As far as I know, the Earth orbits around the Sun ...
Just to be sure you understand the full technical detail, it is not quite correct to say that the Earth orbits around the sun but rather that that both orbit around the center of mass of the two bodies (which is deep inside the sun). In day to day terms, we do say that the Earth orbits the sun.
 
  • #6
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Just to be sure you understand the full technical detail, it is not quite correct to say that the Earth orbits around the sun but rather that that both orbit around the center of mass of the two bodies (which is deep inside the sun). In day to day terms, we do say that the Earth orbits the sun.
Just out of interest, how far from the nucleus of the Sun is the Solar System Barycentre right now?
 
  • #7
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Just out of interest, how far from the nucleus of the Sun is the Solar System Barycentre right now?
Close to the surface of sun, it will be outside the sun starting beginning of 2017. https://qph.is.quoracdn.net/main-qimg-118a1175c48f6ff2afd0183dd0040dd4?convert_to_webp=true [Broken] (2016 is at the right side of the sun, the radius of the sun is about 700,000 km).

The difference is mainly driven by the position of Jupiter and Saturn, Earth has a negligible effect (~500 km).
 
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  • #9
tony873004
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Just out of interest, how far from the nucleus of the Sun is the Solar System Barycentre right now?
Any answer assumes there are no other planets orbiting beyond Neptune. If Planet 9 and or other large objects exist beyond Neptune, this will shift the ss barycenter.

Assuming they don't exist, here's a simulation you can run to show you how the solar system barycenter changes with time. You can delete individual planets to see how much influence they had.
http://orbitsimulator.com/gravitySimulatorCloud/simulations/ssbarycenter.html
 
  • #10
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Could play with that simulator for hours, maybe I’ll have some time tomorrow.
 

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