| "Momentum Deferred" | |
|---|---|
| Fringe episode | |
 The formerly detached head of Thomas Jerome Newton (Sebastian Roché) is reattached to a body. | |
| Episode no. | Season 2 Episode 4 |
| Directed by | Joe Chappelle |
| Written by | Zack Stentz Ashley Edward Miller |
| Production code | 3X5104 |
| Original air date | October 8, 2009 |
| Guest appearances | |
| |
"Momentum Deferred" is the fourth episode of the second season of the American science fiction drama television series Fringe. Screenwriters Zack Stentz and Ashley Edward Miller wrote the episode, and co-executive producer Joe Chappelle directed it.
The episode followed the theft of cryogenically-frozen heads by shapeshifters from the parallel universe in their search for a specific head, while the Fringe team attempts to prevent this. Meanwhile, Olivia struggles to remember her conversation with William Bell (guest actor Leonard Nimoy) that took place in the season one finale. "Momentum Deferred" marked the first appearances of guest actors Theresa Russell, Sebastian Roché, and Ryan McDonald.
It first aired on October 8, 2009 in the United States, and was watched by more than 6.02 million viewers. The episode received generally positive reviews, with many critics praising the new revelations about the shapeshifters, the parallel universe, as well as the much-anticipated conversation between Olivia and William Bell. In January 2013, IGN ranked it as the third best episode of the series.