The War Reaching the Stars

Wartime radar crossed 80 light-years. Its detection range ends before the first star.

With supported processing, the recovery horizon is only 0.10 light-years, or 2.45% of the distance to Proxima Centauri. Even the ideal-coherence ceiling stops at 2.42 light-years.

The strongest evaluated historical fixture reaches a peak-EIRP upper bound of 773 MW, and the calculation gives the receiver every advantage. The failure is not caused by choosing a weak transmitter or a pessimistic instrument. Propagation outran detectability.

81 to 91 lydistance travelled by the 1935 to 1945 wavefront by the 2026 release
773 MWpeak-EIRP upper bound of the strongest evaluated historical fixture
9,420 yearsneeded at Proxima with the best modeled receiver, ideal coherence and 1% beam dwell

How far could the signal be recovered?

These are deliberately favorable limits. Both give the receiver ten years and keep the radar beam continuously on the observer. Real scan patterns reduce the horizons. Hover or tap the markers to inspect the assumptions.

Watch the requirement outrun the receiver

At Proxima, the favorable ideal case with 1% beam dwell demands either a 30.7× improvement over the best modeled receiver or about 9,420 years of observation. Drag the distance and change the assumptions to see how quickly the gap opens. Lower jansky values mean greater sensitivity.

4.24 ly
Processing
Beam dwell

Hover, tap or use arrow keys to explore the curve.

"Ideal bound" assumes every pulse can be added coherently, which no source yet documents for wartime transmitters; "supported" assumes no pulse-to-pulse coherence. The curve uses ten years, no sky or solar background penalty and the upper EIRP bound for each fixture. It is a favorable receiver requirement, not a pessimistic forecast.

The favorable result is already severe

The 30.7× endpoint is the floor, not the expected case. It combines the highest SCR-584 EIRP bound, perfect pulse coherence, full operating hours, a known-signal threshold and quiet solar conditions. Removing those advantages raises the requirement as high as 40,182×. These are non-probabilistic bounds over the declared assumption lattice. Pulse coherence creates the largest share of the spread.

Pulse coherenceCould pulses be added in phase?

The surviving records do not establish whether these transmitters maintained phase between pulses. This unknown opens the largest share of the range. Holding the other favorable assumptions fixed, removing ideal coherence raises the receiver requirement by roughly 171×.

Antenna gainHow strong was the strongest fixture?

The SCR-584's gain is derived from its documented 4° beam, not measured. Combined with its documented 250 to 300 kW transmitter-power range, the gain bracket produces a 2.4× span in peak EIRP.

Beam dwell and uptimeHow often did a beam cross one sky direction?

Most scan schedules and all operating-hour fractions are bracketed. AN/APS-6 supplies one source-derived scan. Less time on one sky direction compounds the sensitivity deficit.

About this result

This is the first result from The War Reaching the Stars. It asks a narrow question: could another star system have recovered the radar signals Earth transmitted during the Second World War? It does not try to guess whether anyone was listening.

For the historical fixtures, the answer is no at Proxima Centauri. Even with ideal pulse coherence and a beam crossing the observer 1% of the time, the best receiver reference in the screen would need about 9,420 years. The exaggerated stress fixture in the chart is a boundary test, not a transmitter that actually existed.

Five ranked United States radar fixtures make up the historical public comparison. A sixth, the SCR-540, is retained only to test waveform uncertainty. Where the surviving record is incomplete, the calculation shows a range instead of pretending to know more than it does.

The release makes one formal claim:

Under the stated source-backed and stress assumptions, the selected receiver resource is required to detect the evaluated wartime radar fixtures.