Tell me more ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.
up vote 2 down vote favorite

With Geostationary orbit your limited to the equator and ~36000km.

Would it be possible to orbit the sun at the same speed as Earth, and then in basically the same place so that the distance to the Sun is slightly less or more than Earth, and the inclination is slightly less or more, in order to achieve a geostationary effect over any point at any height.

Wouldn't the Earth's gravity interfere.

(The reason I ask is, would this be a way of creating a space elevator?)

share|improve this question

2 Answers

up vote 8 down vote

It took me several tries to properly understand the question.

You may be thinking about the Lagrange points. There are a set of equilibrium points associated with every pair of bodies in simple orbits around each other where third (light) bodies may be placed. The ones you are looking for are L1 and L2.

They are however,

  1. Not stable, which means you would need active station-keeping. (L4 and L5 are stable, but they make point (3) below much much worse.)
  2. Not usable for building a space elevator in the Earth--Sun system, because the moon will crash into the cable from time to time.
  3. Much further away than a geo-stationary orbit.

If you do not mean the Lagrange points, then the short answer is no.

Every thing in orbit around the Earth is also in orbit round the sun. (Indeed, the gravitational force exerted by the Earth on the Moon is considerably less than that exerted by the sun.)

But the fact that an object orbits the sun does not prevent it from being acted upon gravitationally by the Earth, so it must also be in orbit around the Earth if the situation is to be stable.

share|improve this answer
No I mean having a satelitte which orbits the sun at 1 AU so that relative to warthog appears not to move. The simplest would've a satelitte orbiting the sun directly above the north pole. So that ifyou were to stand on the north pole and look up you'd see the satelitte 24/7. I think you are talking about the midpoint between the earth and sun (gravitationally) – Jonathan. May 1 '11 at 0:25
2  
@Jonathan No, that is not possible. The satellite above the north pole would fall due to Earth's gravity. – Mark Eichenlaub May 1 '11 at 0:33
@Jonathan: dmckee answered correctly. A position above the North Pole is not a Lagrange point and will accelerate away from its original position. – Vortico May 1 '11 at 3:05
@Vortico: You might want to look at the detailed time hashes. Mark came in when the OP first made the question clear, at that time I had only the text above the second h-span. – dmckee♦ May 1 '11 at 3:32
@dmckee, the reason I asked was also because I'd seen a wikipedia article, which I couldn't remember. Here is the article. It says this is theoritcal (and it's from wikipedia which isn't great), and than sunlight could be reflected down to Earth to counteract gravity? IS that realistic, or would you need the sail to be much to big? – Jonathan. May 1 '11 at 10:38
show 1 more comment
up vote 1 down vote

Satellites orbiting the Earth, including geostationary satellites, already are orbiting the sun.

To build a geostationary satellite, you need to be about six Earth radii from the Earth. A space elevator built there would feel some tidal effects from the sun. Other than those tidal effects, the sun's gravity is already accounted for when we talk about satellites orbiting Earth.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.