Speculative fiction often frames communication with the past as a problem of infrastructure rather than magic. In works such as William Gibson’s The Peripheral, the enabling technology is imagined as an advanced quantum system capable of exchanging information across time, usually by exploiting ideas drawn from quantum mechanics or many-worlds theory. The key move is not literal time travel, but data transfer: messages, control signals, or sensory input passing between eras. This allows the future to talk to the past through networks that resemble an internet stretched across timelines. Crucially, these stories impose rules — no matter crosses the boundary, only information does, and the moment communication begins, a new branch of reality forms. This framing gives the technology a cold, infrastructural plausibility that feels modern and computational rather than fantastical.

However, even within physics-inspired speculation, this idea collapses under closer scrutiny. Quantum mechanics does not permit usable communication backward in time. Quantum entanglement, often invoked in fiction, cannot transmit information at all — let alone into the past — without a classical channel that obeys normal causality. Proposed workarounds, such as closed timelike curves or exotic spacetime geometries, remain mathematical curiosities with no experimental support and, in many cases, imply energy conditions that appear physically impossible. Even if a future civilisation mastered quantum computing far beyond anything imaginable today, it would still be bound by causality as we understand it. At best, speculative models allow correlations across timelines, not conversations with people who already lived, acted, and died in a fixed historical world like 1990.

There is also a more fundamental, and bleaker, barrier: both the finality of causality and the sheer antiquity of the technology that defined 1990. The networks of that era were fragile, local, and transient — dial-up modems hissing over analogue phone lines, CRT monitors driven by decaying phosphors, spinning hard drives and magnetic tape that relied on constant power, maintenance, and human presence. Those systems were never stable endpoints in any enduring sense; their signals vanished the moment they were received, their protocols were crude, and their physical substrates have long since degraded, been erased, or thrown away. Even if physics permitted a message to be sent backward in time, there is nothing left to receive it: no addressable infrastructure, no listening process still running inside that causal frame. The past is not merely unreachable because time forbids it; it is unreachable because its technology was built to disappear. 1990 is not a dormant node awaiting reconnection — it is a powered-down, dismantled world, beyond reach not just in theory, but in every practical, material sense. The past is not offline; it is gone.