# Question on the orbit of the Webb telescope

**URL:** <https://boards.straightdope.com/t/question-on-the-orbit-of-the-webb-telescope/958576>\
**Category:** Factual Questions\
**Created:** [January 28, 2022, 4:57pm UTC](https://boards.straightdope.com/t/question-on-the-orbit-of-the-webb-telescope/958576 "2022-01-28T16:57:26Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\
**Post date:** [January 28, 2022, 9:43pm UTC](https://boards.straightdope.com/t/question-on-the-orbit-of-the-webb-telescope/958576/4 "2022-01-28T21:43:47Z")

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IANAP, but this is precisely the question I tried to address in this post:

> [@James Webb Space Telescope general discussion thread](https://boards.straightdope.com/t/james-webb-space-telescope-successfully-launches/956624/380):
>
> I thought about this a bit more. Lagrangian orbits are hellishly complex things that I don’t pretend to fully understand, but I think one can reach a conclusion from first principles. Consider that any object in any orbit must be experiencing a centrifugal force pulling it away from the center of its orbit, and this must be balanced by an equivalent gravitational pull from the center. It cannot be any other way. This is further confirmed by looking at the gravitational potential contours po…

If any of this is wrong, as I said there, I’d be interested in understanding why. I think the “curvature of space” perspective isn’t particularly helpful, but the gravitational potential vs centrifugal force perspective seems to be compelling. This is all in reference to an elliptical halo orbit like the Webb’s which resembles an ordinary Keplerian orbit. Despite the absence of a mass at L2, the JWST is drawn there because it’s orbiting through an area of higher gravitational potential in the earth-sun system. This is similar to a weight on a string that describes an elliptical orbit because it’s drawn to the lower gravitational potential at its natural rest point, even though there’s nothing physically there.

ETA: I should add: the nature of L2 is that it’s the highest point of local gravitational potential along the sun-earth axis. It’s “downhill” on either side. But that’s not where JWST is orbiting. It’s orbit is more perpendicular to that axis. It’s downhill in the direction of its center at L2, just like in a Keplerian orbit around its barycenter.

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