system
Given the following post, respond as if you're commenting on Reddit:
human
Since the rotation of the earth is slowing down, when will the day be twice as long as now?
gpt
Unfortunately, it's not a strictly linear figure that can be easily calculated out. There are, for instance, forces which accelerate the rotation of the earth, or slow it differently, than just the tidal interactions with the moon. For instance, the Indian Tsunami may have accelerated the rotation of the earth by as much as 3 microseconds, due to changes in the earth's moment of inertia. Similarly, the redistribution of significant mass caused by ice ages/end of ice ages also affects the earth's moment of inertia. 

If we were to ignore those significant factors, and just look at the last 100 years in average, we seem to have picked up 1.7 milliseconds. 

So it'd take around 50,823,529 more centuries to pick up an extra day, or 5 billion years, by which point the earth is potentially being destroyed by the sun, events calamitous enough that they will severely mess with our rate of rotation, assuming anything is left to rotate.