1977, the WOW! Signal received from space.

The Wow! Signal's transmission at 1420 MHz in a narrowband is significant for a few key reasons, rooted in both physics and the logic of the Search for Extraterrestrial Intelligence (SETI). Let’s break it down: The Hydrogen Line (1420 MHz) as a Universal Beacon: The 1420 MHz frequency corresponds to the 21-centimeter hydrogen line, which is a natural emission frequency of neutral hydrogen, the most abundant element in the universe. Hydrogen atoms emit radio waves at this frequency due to a hyperfine transition (a spin-flip of the electron relative to the proton). In 1959, physicists Philip Morrison and Giuseppe Cocconi, in a seminal paper, proposed that if an extraterrestrial civilization wanted to communicate with others, they might choose this frequency. Why? Because it’s a universal constant—any technologically advanced civilization would likely know about the hydrogen line, as it’s fundamental to radio astronomy and observable across the cosmos. It’s like a cosmic "meeting point" for intelligent life to signal each other, a frequency that would stand out as a logical choice for intentional communication. Protected Spectrum for Minimal Interference: The 1420 MHz frequency falls within a protected spectrum reserved for astronomical research, where terrestrial transmissions are generally forbidden. This reduces the likelihood of interference from human-made sources, making it an ideal channel for detecting potential extraterrestrial signals. A signal at this frequency is less likely to be confused with earthly noise, which is why the Wow! Signal’s detection at 1420 MHz raised eyebrows. However, as noted in the web results, a 2010 study did find instances of terrestrial interference in this spectrum, either from adjacent bands or illegal transmissions, but the choice of 1420 MHz still minimizes such risks compared to other frequencies. Narrowband as a Hallmark of Intelligence: The Wow! Signal was a narrowband emission, with a bandwidth of less than 10 kHz, meaning its fractional bandwidth was small (~1% of the total frequency). In nature, most radio emissions—like those from stars, pulsars, or other astrophysical phenomena—are broadband, spanning a wide range of frequencies. A narrowband signal, on the other hand, is a strong indicator of an artificial source because it suggests intentional focusing of energy into a specific frequency, something that typically requires technology. For example, human radio communications, like FM radio or satellite signals, are also narrowband. The Wow! Signal’s narrow bandwidth (less than 10 kHz) stood out against the broadband background noise of the universe, making it look like a deliberate transmission rather than a natural phenomenon. Practical Considerations for Detection: From a SETI perspective, a narrowband signal at 1420 MHz is easier to detect with the technology available in 1977, like the Big Ear telescope. Narrowband signals concentrate their energy into a smaller frequency range, making them stand out more clearly against background noise. The Big Ear’s receiver was designed to scan for such signals, and the Wow! Signal’s intensity—peaking at 30 times the background noise (with the famous “6EQUJ5” code)—was exactly the kind of anomaly SETI researchers were looking for. The narrow bandwidth also aligns with the idea that an intelligent civilization might optimize a signal for detection over vast distances, where a narrowband signal would lose less energy to dispersion compared to a broadband one.

space meets sound

@BrianRoemmele The 72-second burst detected by Ohio State's Big Ear telescope remains our strongest candidate for extraterrestrial intelligence. Astronomer Jerry Ehman's famous 'Wow!

Decoded message: We hear you taste like chicken?

Sounds like a modem.

If it "lasted exactly 72 seconds" meaning 72.0000000000000000000000000000 seconds (or to what precision?), then that would be a message in itself from stars away, since the time length of "1 second" is arbitrary (tho in recent years heard of naming it by particular time-crystals)

Anyone try running that through a fax machine?

that's so cool ! the WOW signal is still one of the most fascinating unsolved mysteries in space exploration , can you believe it's been that long since it was detected? 🕰️

Fu#*k that tiny dot is a galaxy 🌌. That’s like haystack in a haystack with a probability that there's no needle 🪡

@politicalwilli

We certainly are not alone.