Time Leap Machine#
| Designation | Time Leap Machine (unofficial FG number) |
| Function | Sends a person's memory of the present into their own past body |
| Predecessor | Phone Microwave |
| Requires | A living recipient at both ends of the leap |
| Maximum confirmed range | 48 hours |
| Payload | Memory only — no matter, no message text |
| Primary risk | Donor collapses; recipient gains unexplained memories |
| Built by | Okabe, Kurisu, Daru |
| Housed at | Future Gadget Laboratory |
| Status | Operational, use restricted |
The Time Leap Machine is the lab's second confirmed time-manipulation device and, unlike the Phone Microwave, it sends no matter and no data across time at all — only a memory, and only within a single person's own timeline. Where a D-Mail changes the past for everyone, a time leap changes what one specific person remembers, snapping their consciousness back into their own body at an earlier point along the same worldline.
Lab members consider it both more precise and more dangerous than a D-Mail: precise, because it never spawns the wide, unpredictable divergence a message can; dangerous, because the "sender" experiences something very close to dying in the process. #lore
The device grew out of an accident, not a design. During an attempt to D-Mail a memo to a lab member's own past self, the transmission failed to leave the building's internal phone network — instead of reaching a phone in the past, it reached the sender's own mind at an earlier hour. The recipient blacked out for several seconds and woke up with a memory of an event that, from their perspective, hadn't happened yet.
Kurisu recognized the failure mode immediately: the payload had substituted a person's own neural state for a text message. Reproducing it on purpose — and reproducing it safely — took considerably more work than anyone expected, mostly because early attempts left the "sender" apparently unconscious for minutes at a time while their mind was, functionally, somewhere else.
Development notes
- Accident discovered during routine D-Mail test
- Confirmed reproducible after 6 attempts
- Range capped deliberately at 48 hours
- Never tested beyond a single worldline
A time leap routes a compressed neural snapshot through the same discharge circuit the PhoneWave uses, but targets it at the sender's own electromagnetic signature rather than an external handset. The energy profile is comparable — on the order of tens of joules per attempt — but the receiving "device" is a living brain, which the lab's equipment was never rated to interface with directly.
$$E_{\text{leap}} \approx \tfrac{1}{2}CV^2 + \Delta E_{\text{neural}}$$
The additional term $\Delta E_{\text{neural}}$ was never rigorously measured; Daru's working estimate is "however much a human brain costs to move," which is not a unit anyone has managed to standardize.
Under six hours. Recipients report mild disorientation and a brief headache. The lab's informal safety threshold.
Twelve hours or more. Recipients black out for an extended period at the sending end and report the returning memory as "loud," overwriting recent short-term memory of the hours immediately before the leap.
No transfer occurs; the sender simply loses consciousness briefly with no memory gained on the other end. More common than either successful mode.
Every confirmed long leap has been followed by measurable donor fatigue lasting days. The lab suspended non-essential testing after the third such case. See divergence-meter for how a leap is distinguished from an ordinary D-Mail on the instruments.
| Attempt | Leap length | Outcome | Divergence change |
|---|---|---|---|
| 1 | Unintentional | Discovered phenomenon | 0.000000 |
| 2 | 2 hours | Success, mild fatigue | 0.000012 |
| 3 | 6 hours | Success | 0.000031 |
| 4 | 11 hours | Success, extended blackout | 0.000058 |
| 5 | 24 hours | Failed | 0.000000 |
| 6 | 48 hours | Success, severe fatigue | 0.000149 |
A leap beyond 48 hours was attempted once. The sender did not regain consciousness for several minutes and reported, afterward, "reaching for something and not finding it." No further long-range attempts have been authorized. #wip
Compare with the Phone Microwave's message-based approach and the theoretical framing in attractor field theory, which the lab uses to argue why leaps within a single worldline avoid the large-scale divergence a D-Mail can cause. For background on memory and consciousness generally, see Memory.
The device shares its physical footprint with the PhoneWave — both draw from the same capacitor bank — which is why only one can be used per day without risking a brownout across the whole building.1 The lab has, separately, speculated about a hypothetical Reading Steiner amplifier that would let a leap recipient retain memories across a full worldline shift, not just within one; no such device exists yet.
Footnotes#
-
This happened once, during a thunderstorm, and knocked out the building's CRT repair shop downstairs for an afternoon. ↩