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.” 

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NASA, Getty Images
Watch Apollo 11 Launch
Vice President Spiro Agnew and former President Lyndon Johnson view the liftoff of Apollo 11
Vice President Spiro Agnew and former President Lyndon Johnson view the liftoff of Apollo 11
NASA, Getty Images

Apollo 11 launched on July 16, 1969, on its way to the moon. In the video below, Mark Gray shows slow-motion footage of the launch (a Saturn V rocket) and explains in glorious detail what's going on from a technical perspective—the launch is very complex, and lots of stuff has to happen just right in order to get a safe launch. The video is mesmerizing, the narration is informative. Prepare to geek out about rockets! (Did you know the hold-down arms actually catch on fire after the rocket lifts off?)

Apollo 11 Saturn V Launch (HD) Camera E-8 from Spacecraft Films on Vimeo.

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iStock
Astronomers Discover 12 New Moons Around Jupiter
iStock
iStock

As the largest planet with the largest moon in our solar system, Jupiter is a body of record-setting proportions. The fifth planet from the Sun also boasts the most moons—and scientists just raised the count to 79.

A team of astronomers led by Scott S. Sheppard of the Carnegie Institute for Science confirmed the existence of 12 additional moons of Jupiter, 11 of which are “normal” outer moons, according to a statement from the institute. The outlier is being called an “oddball” for its bizarre orbit and diminutive size, which is about six-tenths of a mile in diameter.

The moons were first observed in the spring of 2017 while scientists looked for theoretical planet beyond Pluto, but several additional observations were needed to confirm that the celestial bodies were in fact orbiting around Jupiter. That process took a year.

“Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant solar system objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our solar system,” Sheppard said in a statement.

Nine of the "normal" moons take about two years to orbit Jupiter in retrograde, or counter to the direction in which Jupiter spins. Scientists believe these moons are what’s left of three larger parent bodies that splintered in collisions with asteroids, comets, or other objects. The two other "normal" moons orbit in the prograde (same direction as Jupiter) and take less than a year to travel around the planet. They’re also thought to be chunks of a once-larger moon.

The oddball, on the other hand, is “more distant and more inclined” than the prograde moons. Although it orbits in prograde, it crosses the orbits of the retrograde moons, which could lead to some head-on collisions. The mass is believed to be Jupiter’s smallest moon, and scientists have suggested naming it Valetudo after the Roman goddess of health and hygiene, who happens to be the great-granddaughter of the god Jupiter.

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