The first season of the re-imagined series of Battlestar Galactica kept track of the episode timeline meticulously, announcing the number of days since the Fall of the Twelve Colonies during the first scene on Cylon-occupied Caprica in each episode.
While this convention was abandoned during the second season, the timeline can still be established based on various date references scattered throughout episode dialogue. However, when the available information is compiled, it becomes clear that there is an discontinuity of approximately 75 days in the middle of season two.
Summary
There is a roughly 75 day discontinuity between Roslin's date of death as projected during the first half of the season (firmly dateable to a span between days 114-117, with 114 being likeliest) and the actual moment of her would-be-death (a few days after day 189).
Consequences
This discontinuity cannot be plausibly explained or "fanwanked". It is not simply a matter of Cottle's medical opinion being incorrect by a span of three months, since there are numerous other contradictions which arise from the error:
- Sharon Valerii (Caprica copy) goes from doing sit-ups in a tight tank-top in "Pegasus" (consistant with a pregnancy in its third trimester) to very visibly pregnant in "Epiphanies".
- Presidential elections, predicted at 7 months after "Bastille Day" (Day 222) and then 6 months after the end of "Colonial Day (Day 229) have yet to take place as of "Lay Down Your Burdens, Part I", explicitly stated to be in the vicinity of Day 270.
In short, it appears that the missing 85 days have not merely been glossed over, but were elided entirely. Valerii's pregnancy progresses by 85 days, but Roslin's cancer does not; elections are delayed by two months without explanation; and while all other references to the timeline have advanced by approximately three months, no actual events during that span have been alluded to.
Full Evidence
Season 2.0
Events of the first half of Season 2 can be dated with a good deal of certainty from the last episode of Season 1 as follows:
Scattered, Valley of Darkness, and Fragged
These three episodes clearly take place during the same day as the first season cliffhanger, "Kobol's Last Gleaming, Part II", which is explicitly stated to take place 51 days after the Cylon attack.
The Farm
This episode begins with William Adama resuming command of Galactica. In the episode "Final Cut", D'anna Biers states that Saul Tigh was in command of Galactica for "over a week". The pragmatics of the phrase "over a week" imply at most a 10 day span, since 11 days is "almost two weeks", and absolutely rule out any time span longer than 13 days.
Thus, "The Farm" probably begins no later than day 61, and absolutely no later than day 64.
Resistance
The majority of "Resistance" appears to cover a two-day period. At the beginning of the episode, Lee Adama asks Anastasia Dualla, "How's my father today?". The tone of their conversation implies that this is not the first time he's asked, as does Ronald D. Moore in his podcast:
- "...they've established this routine each day of her happening to fall in with him as he's on his way back to the brig."
Lee's first opportunity to have this conversation would have been the morning of day 52. If this conversation has happened at least once already, that puts the earliest possible date for this episode at day 53.
A comparatively early date for this episode is also suggested by Tigh's interrogation, which cannot have taken place very long after his rescue from Kobol in the previous episode, at the end of day 51.
Another limit can be placed on this episode based on a scene cut from beginning of "The Farm" in which Roslin states that it's been an "entire week" since her escape, which takes place at the end of this episode. Since, as established above, "The Farm" cannot begin any later than day 64, "Resistance" cannot end any later than day 57.
Thus, the earliest (and most likely) dates for "Resistance" are days 53-54, with the latest possible dates being days 56-57.
Flight of the Phoenix
Cally is detained for "discharging a firearm without permission" and sentenced to thirty days in the brig on the evening of day 54. Cally is released at the beginning of "Flight of the Phoenix", dating the beginning of this episode to day 84.
Shortly before Cally's release, Dr. Cottle updates Laura Roslin's prognosis, stating that she has one month to live, "at the outside". This puts her projected death at day 114.
Season 2.5
Following the mid-season break, it became apparent that a fairly large period of time could not be accounted for.
Resurrection Ship, Part I
In this episode, Helena Cain offhandedly asks "Is this what the two of you have been doing for the past six months? Debating the finer points of colonial law?"
Epiphanies
President Roslin is transferred to the Galactica at the beginning of this episode, which is explicitly stated to begin some 189 days after the Cylon attack. As her death draws nigh, Adama notes that she "has been aboard Galactica for the last few days".
The Captain's Hand
When asked to make a projection on the fleet's population trend, Baltar states that he "made an initial calculation on these figures over seven months ago". We might speculate that this was done concurrently with the calculations he presented in "Water", putting this episode at roughly day 235, but in any case no later than day 225.
Lay Down Your Burdens, Part I
Tom Zarek comments that people of the fleet have been "cooped up in metal boxes for nine months", putting this episode at roughly Day 270.