A star that was spotted in 1892 by one of the most gifted astronomical observers of all time but then apparently vanished has been found again – right where he lost it.

Edward Emerson Barnard was an accomplished astronomer, famous for his discovery in 1892 of a fifth moon of Jupiter, Amalthea, almost three centuries after Galileo Galilei saw the first four. But a few weeks earlier, he had made an enigmatic observation that kept bothering him. A short article he published about it in a journal in 1906 was headlined ““.

What he thought he saw was a star, close to Venus on a morning he had pointed his telescope at that planet, hoping to discover satellites.

He estimated its brightness as 7th magnitude, according to the scale astronomers use, where dimmer objects get a higher number. On a dark night, someone with good eyes can see stars of around 6th magnitude at most.

Barnard looked for the star in the only whole-sky catalogue of the day, the Bonner Durchmusterung. It listed all stars of magnitude 9.5 or brighter, so his 7th magnitude star should have been in it, but wasn’t. And observing again later, it seemed gone. The only star he could find near that position was one of 11th magnitude, about a hundred times less luminous.

Could it have been a large asteroid? “Not Ceres, Pallas, Juno and Vesta which were elsewhere,” he later wrote. Some thought the 11th magnitude star he later saw in a similar position, or another nearby star, might have temporarily brightened. Others speculated that Barnard had been fooled by a “ghost”, a stray reflection of Venus in his telescope. But the mystery remained – until, in December 2024, a group of astronomers decided to get to the bottom of it.

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“On a Zoom meeting I have once a week, called the Asteroid Lunch, I just happened to mention it,” says .

Before long, Hunter, an amateur astronomer based in Arizona and co-founder of the International Dark-Sky Association – now – was part of a group of amateur and professional astronomers examining all the explanations that had been proposed. They found good reasons to reject every one of them.

They were about to give up when group member , an optical engineer at the University of Arizona, decided to once more test the ghost theory by looking at Venus at dawn, as Barnard had done. He did so using a telescope fitted with a vintage eyepiece similar to one that Barnard might have used. He was in for a surprise.

Although Venus wasn’t in the position in the sky where Barnard had observed it in 1892, “immediately in the field, I saw a star”, says Ceragioli. He reasoned that it must be pretty bright to be visible at dawn. But the star map on his computer told him it was actually only 8th magnitude – relatively dim.

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Barnard, the group concluded, had experienced something similar. This suggests that the 7th magnitude star he believed he had seen was actually the 11th magnitude star subsequently documented at the location, which had appeared brighter than it really was in the morning light. Barnard was relatively new to the 36-inch telescope of the on Mount Hamilton in California through which he saw the star next to Venus, and he had no other stars of known brightness in view with which to compare it.

Barnard’s error is forgivable, Ceragioli notes, given that determining a star’s brightness by eye was a special skill in Barnard’s time, developed only by astronomers who studied variable stars, which he never did.

Hunter, too, thinks the astronomer’s reputation is still “pretty perfect. We are all very big Barnard fans. It’s a fairly minor error.”

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Close one nostril, stick nozzle up the other, squeeze. The usual way to spray medicine into the nose is the obvious one, but it may not be the most effective, says at South Dakota State University.

That’s according to his computer model of how aerosols enter the nose and reach the nasopharynx, the chamber at the beginning of the throat where the two airways in the nose come together. This is often the target for drugs preventing infections of the airway.

Instead, says Basu, pointing the nozzle towards your face, keeping it almost horizontal as you insert it into the nostril and slightly angled towards your cheek, may be the best approach.

To study what happens to an aerosol on its way to the nasopharynx, Basu obtained three-dimensional scans of noses and incorporated them in a computer model that simulates the airflow inside.

He found that spraying horizontally increases the number of aerosol droplets that land in the nasopharynx by at least a factor of 100. He presented the work at a meeting of the American Physical Society in November.

Basu’s explanation is that by spraying horizontally, the droplets escape the strong airflow of the person inhaling during or after administering the spray, which would otherwise rush the droplets past the nasopharynx into the throat and lungs. “If you’re targeting the upper airway sites, the airflow is not the best medium to transport the drugs,” he says.

He plans to validate his conclusions in physical models of noses and then in people. Such experiments might also lead to improvements in the design of nasal spray pumps, for instance by finding the optimal droplet size.

“Basu’s approach appears to provide a simple, low-cost solution to dramatically increase initial drug targeting to the nasopharyngeal region,” says at Virginia Commonwealth University.

Until experiments on actual noses confirm his numbers, Basu won’t give anyone the advice to disregard the instructions that come with nose sprays. “I don’t have that authority – but in my personal life, I do try to apply the sprays in this direction,” he says.

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