File this under "Things I'd Really Like a Freakin' Answer To:"
Mars is rotating more quickly than it used to, according to data that NASA's InSight lander collected on the red planet. ...
Astronomers determined that the planet's spin is increasing by about 4 milliarcseconds per year², or shortening the length of a Martian day by a fraction of a millisecond per year. A Martian day lasts about 40 minutes longer than a day on Earth.
The increased acceleration seems incredibly small, and researchers aren't quite sure what is causing it.
Everyone on Earth to NASA right now:
To be sure, Mars is kinda far away. It's not like they can just bop on down there and set up some observational systems whenever they want. It takes planning.
Researchers do think it might have something to do with "ice accumulation at the Martian poles or the rise of landmasses after being covered in ice." Which sounds as good an explanation as any. I'm not going to challenge that one.
As an aside, astronomers found out about the increased rotation by a particularly ingenious use of the Earth-based Deep Space Network system:
Scientists used the Deep Space Network to beam signals to RISE on InSight, which then reflected the signal back to Earth. These relayed signals helped researchers track small frequency changes caused by the Doppler shift, which is what causes sirens to change in pitch depending on their distance. The frequency changes correlated with the planet's rotation.
Presumably they'll get it figured out, either soon or when we colonize the planet. Hopefully the Martian day won't have gotten too short by that point!
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