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This answer is currently accepted. I believe the physics is wrong, since conservation of angular momentum prevents a satellite from raising its orbit around a spherically symmetric body by using only gravity.

The problem in the answer is the conflation of center-of-mass and center-of-gravity, which are of course are usually not the same position in a gravity gradient, and certainly not blindly interchangeable.

The explanation and equations given there express the central body's contribution only through μ which is G time the mass of the Earth. Without torque, you can't use Earth's gravity to boost the orbit.

I think this site generally regards physical principles like conservation of angular momentum in few-body mechanics problems as given, and within that context, the answer is therefore wrong.

I know this is stack exchange and wrong answers happen and get accepted, but this one is demonstrably wrong based on basic conservation of angular momentum arguments.

I've left several comments there within the long comment chain that exists there, though a key few relating specifically to torque are now missing.

Options I can think of include

  1. add more comments.
  2. write an answer that just explains why the other answer is incorrect.
  3. write a correct answer to the question, and in doing so help make it clear why the other answer is incorrect. (This is hard, but doable)
  4. with coming up on 10,000 questions here, don't worry about it.

Any thoughts?

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  • $\begingroup$ I reaccepted this answer not to mess up your question. Definitely #2 and not 4. $\endgroup$ – Muze Nov 16 '18 at 23:01
  • $\begingroup$ @Muze FYI - that's a bad reason to reaccept an answer. If you believe it accurately addresses your question, accept it. If you don't believe it accurately addresses your question, don't accept it (or if necessary, unaccept it if you had previously accepted it). If anyone doubts that the answer was accepted, it's your word against theirs, and you are the OP. $\endgroup$ – called2voyage Nov 19 '18 at 16:03
  • $\begingroup$ @called2voyage I unchecked it at uhoh comments saying bad math. Then when I saw this message not to invalidate his question. I haven't seen any real math by anyone else detesting this. He is the only answer so far that says yes it han be done and shows math, but any new answer could be accepted. $\endgroup$ – Muze Nov 19 '18 at 19:35
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Ideally, the way it ought to work is to write a better answer.

In practice, it will be difficult to displace the wrong answer. It already has upvotes, and was awarded a bounty. You might be able to get the question asker to accept your answer, if that user is still active.

The hard part is to attract users to your new answer to an old question, so it gets upvotes. One trick that could work is to ask a new question, with a link to your new answer. The new question shouldn't be a duplicate of the old question, yet has to be close enough to justify the link. I'm not enthusiastic about doing this, but if you feel that strongly, it's an option for you.

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  • $\begingroup$ I've done that once so it certainly is an option. To this answer I then asked this and this and in the process discovered this and this so there was a great collateral benefit to the exercise. $\endgroup$ – uhoh Feb 19 at 5:08
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Downvote, comment, upvote good answers, make a better answer if you can, move on.

You could also add a bounty to try to encourage better answers, if you want.

Wrong vs. "demonstrably wrong" is not a distinction we make here. Technically incorrect answers should be voted down--that (and optionally commenting) is all the action that needs to be taken. Unless the post does not provide a justification* for the answer (in which case you can flag as low quality), it does not merit further action for simply being wrong.


* I do realize that errors in justifying an answer can look like failing to justify the answer. That is a fuzzy line. Generally, we should be relying on the community to resolve these issues. Moderators will usually step in only if there is a flagrant disregard for justifying information. I would not consider this one of those cases.

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  • $\begingroup$ I've started a bounty, perhaps that's another option. It worked here, after some cosmic bounty inflation at least. $\endgroup$ – uhoh Nov 19 '18 at 15:20
  • $\begingroup$ @uhoh Good point, added. $\endgroup$ – called2voyage Nov 19 '18 at 15:22
  • $\begingroup$ I've added a second one now, looking forward to a fun ride. Let's see how high this flies. $\endgroup$ – uhoh Nov 28 '18 at 15:10
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Sometimes I will accept an answer that is completely wrong will have a positive effect as a driver for a better answer. The accepted answer usually will rest on the best answer by vote sometimes to the lower Rep. user if it is there 1st answer for retention.

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  • $\begingroup$ I'm down voting to indicate that I disagree with this thinking. Down votes in meta don't really count like they do in the main site, they're just away for readers to express their level of agreement or disagreement. $\endgroup$ – uhoh Nov 20 '18 at 0:11

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