I've come up with the following theory, apologies if it had already been posted.
Now, early on, I realized that the increase in the meter, pixel-wise, was not in any way DIRECTLY related to the amounts donated. Instead, it was moving at a steady .05551-ish pixels every 30 seconds. From that, I calculated a table, showing it ending at 3AM. However, as I kept checking, the progress was always faster than my projection, increasing to a rate of .08-ish px/sec. The way I can account for this, and something that makes a lot of sense, is to envision a system where the amount donated increases not the progress in the bar, but the rate of progress in the bar. Therefore, everything you donate makes it move faster, but it doesn't directly affect the position. I could be wrong, but this idea correlates perfectly with what I observed, and with the behavior of the bar.
Explaining how I know it was a linear, time based progression: It was a linear equation. The progress was the SAME every thirty seconds. If you suggest that Gaians donate the same amount every thirty seconds, I'm going to call you a fool.