One evening during college, I was stargazing with a young woman I was trying (way too hard) to impress. I was showing her the sky when, near the horizon, I noticed a very bright object, reddish in color.
I pointed to it and started pontificating. “Oh hey, that’s Mars,” I told her. “It’s rising about now, though I thought it would be farther south. Well, anyway, look at the color…” in a monologue that today would rightfully be called mansplaining.
“I think it’s moving,” she told me. I dismissed this possibility, because it was Mars and could rise only so quickly. But after another minute I squinted at it more closely. Was that a green star right next to it? That’s not possible.
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And then it all became clear, as the movement of the “planet” was obvious. It wasn’t the Red Planet. It was an airplane.
Oh, she got a deservedly good laugh out of that, and I’m sure my face turned as red as the iron oxide sands of the fourth planet. I had really blown it; foreshortening of the plane’s trajectory when it was near the horizon minimized its movement, and its initial color came from the navigational lights; through thicker air (and haze) the red light would have appeared much brighter than the green one.
Needless to say there was no second date, and, eventually though painfully, my own arrogance had some of its rough edges worn down. I do still like to explain things, though, which is, after all, why you and I are both here.
It eases my embarrassment somewhat to know that many astronomers have made similar mistakes. My favorite one involves Kat Ross, an astrophysicist at Curtin University in Perth, Australia who studies distant, luminous galaxies.
You can hear her tell this story, but in a nutshell: she uses radio telescopes to study these galaxies, which are very bright in those wavelengths–and because our sky is dark in radio waves astronomers can observe them even during the day. Ross is interested in how the brightness of these galaxies changes over time, so she observes them at several different points during the year.
In one dataset, though, a very bright radio source appeared that wasn’t there before. It showed up in several contemporaneous images in the same spot, so it was clearly real, but it did not appear in an image taken eight years earlier, so something had changed significantly.
Excited that it could be an extremely powerful new radio source—it wasn’t just bright, it was the brightest source in the sky!—she started talking to colleagues to try to figure out what this mysterious object could be. Eventually she checked the observation logs to see what was in that part of the sky at that time, and realized to her shock that she had discovered…the sun.
Yup. Our own local star, literally the brightest object in the sky in most wavelengths, was smack dab where her source was. She had been observing during the day, but hadn’t realized she was pointed at the sun. It wasn’t in the earlier observations of that same patch of sky because they were taken at a different time of the year, and the sun’s position in the sky relative to the background stars had changed. Needless to say, she didn’t publish her “discovery” in a science journal.
Another imposter event occurred in 2018 when astronomer Peter Dunsby of the University of Cape Town found an extremely bright “optical transient”—astronomer-speak for something that either moves or changes brightness—in the very well-studied area of the sky near the galactic center in the constellation Sagittarius. It was so luminous it was easily seen even by eye.
Dutifully, as an astronomer should, he reported it to The Astronomer’s Telegram site, a clearinghouse to rapidly disseminate discoveries worldwide so other scientists can jump in and observe the object themselves. He gave all the information needed, and his excitement comes through clearly in his post.
But then, just 40 minutes later, he issued a follow-up, which I will quote here in its entirety: “The object reported in ATel 11448 has been identified as Mars. Our sincere apologies for the earlier report and the inconvenience caused.”
His encounter with Mars was rather the opposite of my own. I have no information on whether this spoiled a future date for him.
Finally, there’s one that technically wasn’t a mistake, but almost led to one: the mysterious case of perytons.
In 2007, radio astronomers got a big shock: a pair of scientists were looking through archived data from 2001 and noticed a powerful burst of radio energy detected by the Australian Parkes radio dish. Called the Lorimer Burst, after the team leader who discovered it, the flash was far more luminous than anything ever seen like it, and, still more astonishing, the entire event lasted only about 5 milliseconds.
What was it? The signal itself had a signature phenomenon affecting it: dispersion. As radio waves travel across the universe, interstellar gas muddies them, generating a characteristic delay in the signal that depends on frequency.
This event created a lot of attention among radio astronomers, who, over the years, found many other bright, rapidly fluctuating sources. In particular, two radio telescopes (Parkes in Australia and Bleien in Switzerland) reported many such objects, but these were different: they lasted longer (about 250 milliseconds) though they also showed dispersion.
However, it quickly became clear they were not extragalactic, but much more local: they were originating on or above Earth. After many attempts to pin them down, a team of astronomers finally figured it out in 2015: these flashes were not from hungry black holes across the universe gobbling down matter, but instead caused by hungry astronomers inside the observatory who couldn’t wait for the microwave oven to ding before prematurely opening the door and grabbing their food.
When this happens, the oven continues to generate microwaves that rapidly change frequency as the power dies off over a fraction of a second, mimicking dispersion. With the door open these are released into the universe, including into the nearby radio dish. The fact that these were always seen during normal weekday operating hours and peaked at lunchtime was also something of a hint.
Amusingly, these events were nicknamed perytons, after a fictional beast that had the hybrid body of a stag and bird but cast the shadow of a human; a nod to their imposter nature.
Ironically, because astronomers knew perytons weren’t cosmic sources, they started to doubt the reality of the Lorimer Burst as well. However, over time astronomers conclusively showed that this event was indeed real and originated in a distant galaxy. The Lorimer Burst and others like it are now called Fast Radio Bursts, and adding to the irony, astronomers are still trying to nail down their origins today.
If there’s a lesson here, it’s that it’s good to be skeptical of what you see, but don’t let that stop you from recognizing something real. Still, it might just keep you from embarrassing yourself out of a second date.