Star Trek's use of the number 47 started in The Next Generation when writer Joe Menosky began including 47 in his scripts, to be followed by many other writers, so that the number regularly occurs in The Next Generation, Deep Space Nine and now Star Trek Voyager.
So what prompted Joe Menosky? 47 is a mathematical concept that all numbers equal 47, as "proven" by Donald Bentley, professor of mathematics at Pomona College. Joe Menosky, a graduate of that College, liked the notion and incorporated it into Star Trek scripts. His promotion to an executive position in the Star Trek Voyager production staff might mean a proliferation of number 47s!
Here are some examples. It is not intended to be a comprehensive list! 74s and other variations. With the exception of the two episodes without stardates, all [TNG] Season 7 episodes have a substring 47 in the stardate. One of the most notable occurrences of "47" is that Tuvok was born on stardate 38774 [#147 Unimatrix Zero, Part Two], and that the Emergency Medical Holographic channel, mentioned several times in Season 1, is channel number 47.
| Caretaker | The interval of the energy pulses sent by the Caretaker has decreased by .47 seconds |
| Parallax | The Doctor's programme contains the experiences of 47 individual medical officers |
| Parallax | The Doctor tells Janeway to switch to monitor input 47, which is the EMH channel |
| Phage | The Doctor says the blood gas infuser would keep Neelix, whose lungs have been removed, alive for only another 47 minutes |
| Phage | Voyager is 547 metres from the source of the dampening field within the asteroid |
| Emanations | Voyager's crew discover the 247th element known to Federation science |
| Cathexis | Tom Paris has his mind taken over by an alien presence for 1 minute 47 seconds |
| Learning Curve | There are 47 bio-neural gel packs in reserve |
| Projections | The Captain Janeway holographic image is stored in memory block 47 Alpha |
| Elogium | Shields are at 47 percent after the ship has been repeatedly bumped by the giant lifeform |
| Non Sequitur | Harry Kim graduated from the Academy on 47918 |
| Non Sequitur | Harry's office in San Francisco is on level six, subsection 47 |
| Twisted | Twisted Voyager schematics displays: 8-747 and 4786 |
| Twisted | Harry Kim starts counting megapascals of pressure, the camera takes a detour to the Holodeck, and he resumes counting up from 47 megapascals in Engineering when the camera comes back |
| Cold Fire | Tanis says Suspiria will arrive in 47 hours |
| Resistance | A course bearing 219 mark 47 |
| Prototype | B'Elanna Torres repairs Pralor Automated Personnel Unit 3947 |
| Prototype | Aft shields had a 47% loss |
| Threshold | In Sickbay, a computer display of Biomedical Scan 47 shows Tom's two hearts |
| Meld | In Sickbay, a computer display shows a DNA scan with the number 47 top centre |
| Dreadnought | B'Elanna Torres' last access of Dreadnought was Stardate 47582 [and adds that the current stardate is 49447] |
| Dreadnought | B'Elanna Torres observes the readout of Dreadnought's data banks. Travelling up the screen, in the middle column of numbers, is 47 whereas all the other numbers are six or seven digits long |
| Death Wish | In Sickbay, a computer display shows a bio-bed readout of Quinn with the number 47 |
| Lifesigns | The Doctor says that since his activation he has performed 347 medical exams |
| Investigations | Ensign Hogan uses Engineering Authorization Code Omega-47, also used later "illegally" by Neelix to access Tom Paris' LCARS whereupon the code appears on the screen |
| Deadlock | B'Elanna Torres says she has tried re-modulating the comm frequency five times on 47 different frequencies |
| Deadlock | 347 Vidiians had boarded Voyager |
| Innocence | B'Elanna Torres shows Kathryn Janeway Planetary Scan 047 |
| Resolutions | Shields were down to 47% during the fight with the Vidiians |
| Basics | "Vessel Schematic 4747" shows the Doctor where to disrupt the backup phaser banks |
| The Chute | 47 off-duty patrollers were killed in the bombing for which Harry Kim and Tom Paris are convicted |
| Flashback | On the U.S.S. Excelsior, there was a hull breach on deck 12, section 47 |
| The Swarm | Harry Kim reports the Swarm is 40,000 km from Voyager. Tom Paris next report on the Swarm is that they are 7,000 km away (40,000 plus 7,000 is....) |
| False Profits | Arridor is counting profits received and counts aloud the number 147. He stops counting at 148 |
| False Profits | 'The Ferengi Rules of Acquisition' have 47 separate commentaries |
| Future's End | Southern California sank in the Hermosa Quake of 2047 |
| Future's End | The police officer calls his ID number into his radio, which is 247 |
| Future's End | After Rain Robinson's computer hard drive was wiped it read "Fatal System Error: Error 0047" |
| Future's End | A diagram of the timeship on Henry Starling's computer looked at by Chakotay and Kathryn Janeway shows a list of numbers which includes 4747 |
| Future's End | The satellite is SatComm 47 |
| Future's End | The Timeship Aeon is headed to "Penetration point: 96 mark 047" |
| Q and the Grey | Supernova at 217 mark 47 |
| Macrocosm | The Doctor beams down to the infected mine colony and tells Chakotay he will proceed on vector 147 |
| Fair Trade | Biomimetic gel needs the Starfleet standard issue container L647-X7 |
| Fair Trade | Neelix found a container number L647-Y6 |
| Alter Ego | Chakotay says that shields "are down to 47 percent". |
| Alter Ego | Stardate 50471.3 |
| Unity | Chakotay is told via the former Borgs' mind-meld to go to module 47-Omega of the Borg cube |
| Rise | Neelix stabilised the tether's velocity at 47 kilometres per hour |
| Before and After | Stardate 56947 is mentioned |
| Before and After / Year of Hell | The temporal variance of the chronoton torpedo is 1.47 microseconds |
| Before and After | While having her picture taken with her new grandson, Kes is told by Harry Kim it is stardate 56947 |
| Real Life | Tuvok reports a shock wave on bearing 047 mark 19 |
| Distant Origin | The Voth species and humans share 47 genetic markers |
| Worst Case Scenario | The "Insurrection Alpha" holoprogram had been accessed 47 times Tuvok's security clearance is 4774 |
| Scorpion | Doctor's blood cell close-up was entitled "Image Enhancement 047" |
| Scorpion, and various episodes | Borg designation "Species 8472" |
| Scorpion | The Doctor examines the Borg nanoprobes technique on monitors labelled "Image Enhancement 047 (twice) |
| The Gift | Seven of Nine was born on Stardate 25479 The Starfleet ID of the communications node that Seven of Nine sees is 595478 (the last figure could be B). |
| Day of Honor | Structural Integrity had fallen 47% in the shuttlecraft |
| Nemesis | Chakotay is captured by the Vori Fourth Regiment and they late find the remains of the Seventh Regiment |
| Scientific Method | Tom Paris looks at Vessel Schematic 4747 before a site-to-site transport to see B'Elanna Torres, flowers in hand |
| Scientific Method | Seven reports hull breaches on decks 4, 7, 8 and 12 |
| Year of Hell | Day number 47 of the Year of Hell is featured and labelled by sub-title |
| Year of Hell / Before and After | The temporal variance of the chronoton torpedo is 1.47 microseconds |
| Concerning Flight | Voyager's main computer processor says it has simultaneous access to 47 million data channels |
| Concerning Flight | At one point, Leonardo da Vinci's holo-emitter is reported as being "4.7 kilometres outside the city" |
| Waking Moments | Stardate 51471.3 |
| Message in a Bottle | Voyager is at co-ordinates 18, mark 205, mark 47 |
| Message in a Bottle | Romulans used attack pattern Beta 47 |
| The Killing Game | In the World War II simulation Katrine's club made in the evening shown 1247 francs and 81 Reich marks |
| The Killing Game | The Sickbay console shows Kathryn Janeway the Auxiliary Systems 0470 display |
| The Killing Game | Janeway and Harry both access the Auxiliary Systems 0472 display |
| Demon | Seven orders the annular confinement beam to be narrowed to .47 terahertz |
| One | Seven adjusts the ship's course .347 degrees starboard |
| One | Seven orders from the replicator nutritional supplement 14beta7 |
| Hope and Fear | The computer says the launch date of the USS Dauntless was 51472 The "video message" from the Admiral says they performed 47 trial runs on the slipstream technology Seven looks at a screen with "energy simulation 2473" Sickbay monitor shows cellular degration of 12.47 |
| Night | Tom reports the vortex will intercept Voyager in 47 seconds. The "vital sign" monitor display of the Night-alien shows 13.47. Janeway asks how long to the vortex and is told 47 seconds. |
| Drone | The drone is stated to have assimilated 47 billion teraquads of information |
| Extreme Risk | B'Elanna Torres ran holoprogram 'Torres 216' for only 47 seconds. |
| In the Flesh | More mention of Species 8472. Chakotay's service number is 4-7-Alpha-6-1-2 |
| Once Upon a Time | Naomi Wildman cites Starfleet regulation 476-9 |
| Infinite Regress | Naomi Wildman knows all 47 suborders of the prime directive |
| Timeless | The Delta Flyer computer reports a vessel approaching on bearing 184 mark 7 |
| Thirty Days | The Monean's ocean world has 47 regional sovereigns |
| Gravity | Temporal differential between the planet and Voyager is .4744 seconds per minute, and Tuvok says that by that formula, the thirty minutes Kathryn Janeway specifies translates to 2 days, 11 hours, and 47 seconds. |
| Relativity | USS Relativity's registry number is NCV-474439-G. |
| Warhead | A sickbay monitor displays "INTERFACE 047" giving the Druoda's orders to the tactical warhead. |
| Tsunkatse | The captain's log which opens the story after the 'teaser' and opening titles, is dated stardate 53447.2. |
| Author, Author | The Doctor makes a chief medical officer's personal log entry on stardate 54740.8.At the Federation Dilithium Processing Facility an EMH Mark 1 tells another EMH Mark 1 to see holoprogram 47beta, which is the Doctor's holonovel 'Photons Be Free'. |
| Endgame | Seven informs a staff meeting: "My analysis of the tritanium signatures suggests there were at least 47Borg vessels inside the nebula." |