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Chapter 4: Psychology

Interpreting the "Wow!" Signal

Dear Dr. SETI:
About a year ago, I watched a show on the Discovery channel which showed a printout of the famous "Wow!" signal. As an electrical engineer, I began to question the format. I waited for almost six months until that particular show came on again and taped it, attempting to get a better look at the printout. Until yesterday when I received this month's copy of the IEEE Institute, I could not find an answer to my questions about the received 'transmission.' I have played out my own scenarios as to what 6EQUJ5 actually stands for: i.e., a sequence in need of completion, a matrix in need of expanding, a computer malfunction, etc. Can I assume that 6EQUJ5 is the ASCII equivalent to the following binary codes? Namely:
6 = 00110110
E = 01000101
Q = 01010001
U = 01010101
J = 01001010
5 = 00110101
Thank you for your help. This has been an unanswered question for over a year and a half.
RZ, Bensalem, PA

The Doctor Responds:
Your curiosity and creativity are to be commended, RZ. Unfortunately (or maybe fortunately), it's nothing quite so complicated.

The best known and most tantalizing SETI "hit" to date, the "Wow!" was received on the neutral Hydrogen frequency, at the Ohio State University Radio Observatory, on 15 August 1977. The name derives from one word written in the margin of the computer printout by investigator Dr. Jerry Ehman, when he saw (and understood the significance of) the sequence you cited above. After 19 years and over a hundred follow-on studies, the signal has never repeated.

Let me emphasize that the "Wow!" sequence itself is not a message. What was received appeared to be a CW (unmodulated) signal. The numbers and letters in the much-reproduced computer printout are merely a time-series representation of the signal amplitude, as received at the Big Ear radio telescope.

Specifically, the symbols represent the number of standard deviations by which the received signal exceeded average background noise, on a scale of 0 to 35. So a 0 means no stronger than background noise, 1 is one sigma above noise, 9 means nine sigma above noise, an A would be ten units, and U (the strongest peak of the actual signal) is 30 standard deviations above the mean background noise in the receiver. If you graph the sequence as amplitude values over time (each time increment is about twelve seconds), you get roughly a Gaussian distribution, consistent with the antenna pattern of the Big Ear in drift-scan mode.

For a look at the "Wow!" signal both in raw computer-output form, and plotted, as well as info on the real significance of the "Wow!" signal (as a benchmark for calibrating the sensitivity of our systems), see the newest research article on The SETI League's World Wide Web site, found on the Internet at

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