The Wow! Signal

On August 15, 1977, astronomer Jerry Ehman was reviewing data from the Big Ear radio telescope at Ohio State University when he noticed an anomalous signal. The 72-second narrowband radio burst bore all the expected hallmarks of extraterrestrial intelligence. He circled it and wrote “Wow!” - giving the signal its famous name.

The Signal

The characteristics:

• 72 seconds long
• Narrowband transmission
• At hydrogen frequency (1420 MHz)
• 30 times stronger than background
• Source: Sagittarius constellation

Why It Was Special

The signal matched predictions for:

• Extraterrestrial intelligence
• Correct frequency (hydrogen line)
• Narrowband (artificial characteristic)
• Strong intensity
• From expected direction

Jerry Ehman

The discoverer:

• Volunteer researcher
• Reviewing computer printout
• Immediately recognized significance
• Wrote “Wow!” on paper
• That name stuck

The Search for Repetition

Following the detection:

• Big Ear searched repeatedly
• Other telescopes joined
• Signal never repeated
• Months and years of searching
• Nothing found

The Location

The signal came from:

• Chi Sagittarii region
• Near constellation Sagittarius
• No known stars at precise location
• Deep space origin
• Empty region of sky

Technical Analysis

The signal:

• Rose and fell as expected for celestial source
• Matched telescope beam pattern
• Wasn’t terrestrial interference
• Wasn’t satellite
• Origin confirmed as space

Possible Explanations

Theories proposed:

• Extraterrestrial intelligence
• Unknown natural phenomenon
• Reflected Earth signal
• Hydrogen cloud interaction
• Remains unexplained

2017 Comet Theory

One proposal:

• Comets passing through area
• Hydrogen cloud could produce signal
• 266P/Christensen suggested
• However, disputed
• Not universally accepted

The Silence Since

Despite searching:

• Signal never repeated
• No similar signals found
• One-time event
• Frustrating for researchers
• Mystery deepens

SETI Significance

The Wow! Signal:

• Best candidate for ET contact
• Demonstrates what to look for
• Remains unexplained
• Inspires continued searching
• Iconic in SETI history

Significance

The Wow! Signal is significant for:

• Best ET candidate signal ever
• Never repeated or explained
• Matched theoretical predictions
• Iconic in astronomy
• Enduring mystery

Legacy

The Wow! Signal remains the strongest candidate for a detected extraterrestrial transmission. Its failure to repeat prevents confirmation, but it demonstrated that whatever we’re looking for might actually be out there - even if only for 72 seconds.