Celestia Forums

Hello folks.
Does anyone have a formula or something for working out the correct rotation for a world to be tidally locked based on its distance from a star?

And please, be gentle. The mathmatical part of my brain was lost after a heavy night of excess four years ago!


Cheers

When a body is tidally locked to its primary, then one side is always facing its primary, the object that it's orbiting around. In other words, its rotation period equals its orbital period. It turns around once on its axis while it goes around once in its orbit.

To put it another way, a tidally locked planet's siderial day is equal in length to its year.

In Celestia, a planet's RotationPeriod is measured in Earth days, while a planet's Period is measured in Earth years, so you have to multiply the number of years in a tidally locked planet's Period by 365.25 to get the number of days in its RotationPeriod.

*However* if you omit RotationPeriod and Orientation, then Celestia automatically tidally locks a planet or moon to its primary. You don't have to tell it to do so.

Does this answer your question?

selden wrote:*However* if you omit RotationPeriod and Orientation, then Celestia automatically tidally locks a planet or moon to its primary. You don't have to tell it to do so.

Aw hell, I didn't know that! That makes things simple....

...John...

Dollan wrote:

selden wrote:*However* if you omit RotationPeriod and Orientation, then Celestia automatically tidally locks a planet or moon to its primary. You don't have to tell it to do so.

Aw hell, I didn't know that! That makes things simple....

...John...

Is that true for stars orbiting a barycenter as well? (too lazy to try right now)

I believe so, but don't know for sure.
I'd have to test it.
I'll leave it to you to do that.

selden wrote:
Does this answer your question?

Admirably, cheers!