|This page needs cleanup!|
The reason why Solar Date was switched was because after 12:00 noon Pacific Standard Time, it would be a new Solar Date causing confusion in other time zones. It was move so that each new solar date would come when the Universal Time one did.
Why the Time of the Switch is Not Known
A glitch in the server that hosts the Universe Sandbox Forum cased the page on which the topic was discussed. On the days it was discussed, it was a blank white page. It must have been fixed somewhat as the first six posts appear, then the page terminates. No one knows the exact date but it is pinpointed between October 8, 2009 when NeutronStar said "Sure." and December 28, 2009 when NeutronStar said "Finally everyone goes on it! Now get us to page 5, where we will be able to see this. Edit: YAY! I DID!!!! ".  It is shown to be toward the end because NeutronStar knows it was within a few days of transferring into page 5.
The Time Found?
NeutronStar (atomic7732), has found the date when it occured, since he found a way, by modifying a post, in whichshows the ten posts, before it. 15 posts on a page. 6 are shown, 15-6=9, all which have glithced are there. This technique was found at 4:35 UTC Feb 3, 2010.
It wasn't there.
How it glitched
After the post NeutronStar made, Naru523, the user who made Hiiro and Gliese 1337, had unintentionally glitched it. Naru523 had posted an image, but it somewhat 'countered' back on him and made most of the page blank. It is unknown how it happened or why.