Wikimedia Commons // Public Domain
Wikimedia Commons // Public Domain

6EQUJ5: The Wow! Signal

Wikimedia Commons // Public Domain
Wikimedia Commons // Public Domain

It looks like a license plate or a random jumble of letters and numbers put together by a preschooler. But “6EQUJ5” is the most tantalizing lead we have so far towards one day answering one of the most profound questions we can ask: is there intelligent life in the universe beyond Earth?

On August 18, 1977, Ohio State professor and astronomer Jerry Ehman was analyzing a stack of recent computer records from The Big Ear, a radio telescope used to search for alien radio signals as part of Ohio State University’s Search for Extraterrestrial Intelligence (SETI) project (not to be confused with the well-known, California-based SETI Institute). Ehman’s task was to look through printouts of what the Big Ear had recorded, searching for any anomalies or peculiarities. Most of the time, it was probably pretty uneventful. But not on August 18. A signal recorded three days earlier, on August 15, jumped out at him. 

Almost two decades earlier, two physicists from Cornell had theorized that if aliens wanted to contact us, they would use radio signals due to their ability to travel vast distances easily and cheaply. Furthermore, they said, ETs would likely send their message at 1420 megahertz, because hydrogen atoms resonate at that particular rate, and hydrogen is the most common element in the universe.

It took 18 years, but eventually, the Big Ear found evidence that gave some credence to that theory. That’s where Ehman comes in. The numbers and letters he checked daily measured the intensity of electromagnetic signals as they hit the receiver. The series he circled indicated an astonishing convergence of events: Not only did the signal occur on the frequency predicted—1420.4556 MHz—it was about 30 times louder than any other normal noise occurring around it. It lasted about 72 seconds, consistent with the rotation of the Earth. 

Additionally, the signal was a narrowband signal, which requires intelligence to emit: “In order to create a narrowband signal, you have to have some electronics to handle that. It’s not a natural phenomenon,” Ehman explained to NPR. 

SETI scientists were able to trace the signal back to the constellation Sagittarius, northwest of the globular cluster M55, which contains about 100,000 stars. But there was nothing there that could have made the signal. Puzzled, the scientists investigated other possibilities, including that the signal was a satellite transmission, a military signal, an aircraft signal, a broadcast beam, or even a beam that accidentally bounced off of space debris. None of it checked out, leaving “6EQUJ5” a complete mystery.

There’s one problem with the Wow! signal: It has never been seen again. In nearly 40 years, we’ve never detected another signal even close to it. Still, it remains an intriguing blip in the record. Astronomer Robert Gray called it “a tug on the cosmic fishing line. It doesn’t prove that you have a fish on the line, but it does suggest that you keep your line in the water at that spot.” 

Big Questions
What is Mercury in Retrograde, and Why Do We Blame Things On It?

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding for the first time this year on Friday, March 23. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?


Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.


Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This story originally ran in 2017.

science fiction
Why So Many Aliens in Pop Culture Look Familiar

Aliens have been depicted countless times in cinema, from Georges Méliès's A Trip to the Moon (1902) to James Cameron's Avatar (2009). But despite the advancements in special-effects technology over the past century, most aliens we see on screen still share a lot of similarities—mainly, they look, move, and interact with the world like humans do. Vox explains how the classic alien look came to be in their new video below.

When you picture an alien, you may imagine a being with reptilian skin or big, black eyes, but the basic components of a human body—two arms, two legs, and a head with a face—are likely all there. In reality, finding an intelligent creature that evolved all those same features on a planet millions of light-years away would be an extraordinary coincidence. If alien life does exist, it may not look like anything we've ever seen on Earth.

But when it comes to science fiction, accuracy isn't always the goal. Creating an alien character humans can relate to may take priority. Or, the alien's design may need to work as a suit that can be worn by human performers. The result is a version of extraterrestrial life that looks alien— but not too alien—to movie audiences.

So if aliens probably won't have four limbs, two eyes, and a mouth, what would they look like if we ever met them person? These experts have some theories.

[h/t Vox]


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