Ripples in the Dirac Sea
- Eloi Gold Medal
- 1989 Nebula
- by Geoffrey A. Landis
- Short Story
- Science Fiction
- Adults
- Definite Time Travel
- English
- “Ripples in the Dirac Sea” by Geoffrey A. Landis, in Asimov’s Science Fiction, October 1988.
A physics guy invents a time machine that can go only backward and must always return the traveler to the exact same present from which he left.
—Michael Main
- Travel is possible only into the past.
- The object transported will return to exactly the time and place of departure.
- It is not possible to bring objects from the past to the present.
- Actions in the past cannot change the present.
Tags
(19)
- Time Periods
- Age of Reptiles (252 Ma to 66 Ma: Mesozoic/Triassic/Jurassic/Cretaceous): In a flashback: One time I tried jumping back a hundred million years, to the Cretaceous, to see dinosaurs.
- Ancient History (3000 BC to AD 476: Bronze/Iron Ages): to the crucifixion
- Circa AD 1800 to 1899: the Sierra Nevadas in September 1853
- Circa AD 1900 to 1929: San Francisco earthquake
- Circa AD 1930 to 1939: The trip to kill his father was possibly in the 1930s.
- Circa AD 1960 to 1969: The trips to see Dan all start in 1965.
- Circa AD 1970 to 1999: presumed starting period in the lab
- Timeline Models
- Branch-and-Return Timeline: Dirac-sea branches exist only as long as the traveler’s trip.
- Branching Timelines
- Time Travel Methods
- Themes
- Grandfather Paradox: Yes, he does kill an ancestor (his father) twenty-three years before he was born. [. . .] [Y]ou have to try these things. How else could I know for sure?a paradox in this variant of branching timelines.
- Self-Visitation: at least once, when he tries to talk himself out of going to Santa Cruz
- Real-World Tags
- Dinosaurs: Quite a disappointment.
- Jesus: Christ is mentioned, although it sounds like the narrator didn’t actually see the crucifixtion because he got ambushed.
- Paul Dirac: Oddly enough, he never mentions visiting Dirac, but he tells us about Dirac’s sea of negative energy.
- Groupings
Variants
(1)
- “Ripples in the Dirac Sea” by Geoffrey A. Landis, in Asimov’s Science Fiction, October 1988.
Translations
(6)
- Dutch.
“Golfjes op de Diraczee” by Geoffrey A. Landis, in De beste science fiction verhalen van het jaar, edited by Donald A. Wollheim (Loeb, 1989). - German.
“Untiefen im Meer der Zeit” by Geoffrey A. Landis, in Die besten Stories der amerikanischen Science Fiction: Worlds Best SF 8, edited by Arthur W. Saha and Donald A. Wollheim (Bastei Lübbe, July 1989). - German.
“Wellen im Diracschen Meer” by Geoffrey A. Landis, in Isaac Asimov’s Science Fiction Magazine 35, June 1990. - Italian.
“Increspature nel mare di Dirac” by Geoffrey A. Landis, Urania #1142, 16 December 1990. - Italian.
“Increspature nel mare di Dirac” by Geoffrey A. Landis, in I tempi che corrono, edited by Bill Adler, Jr. (Mondadori, October 1998). - Modern Greek.
“Ρυτίδες στη θάλασσα του Νταιρακ” by Geoffrey A. Landis, in :Ψηφίδες από το μέλλον :: Psifídes apó to méllon:], edited by Θανάσης Μαντζάρας :: Thanásis Mantzáras, Απειρον :: APEIRON [/d]1991[/d].