As any historian of medieval East Asia or player of Civilization V: Brave New World will tell you, 15th century Koreans were really, really, really good at science.
Under the judicious rule of Sejong the Great, the kingdom's top researchers spent a lot of time looking at space and making maps of it.
In 1437, during one of these looking sessions, a bunch of scientists thought they discovered a bright new star, one that easily outshone everything else in the sky (eat it, Luyten 726-8A).
14 days later, it disappeared.
Unbeknownst to the ancient sky-watchers, the "new star" was not new at all. It was, instead, what's known as a "classical nova" — an ultra-dense, white dwarf star that sucks so much matter off a neighboring star it causes a giant, nuclear explosion. The star gets super bright for a short period of time before once again fading into the cosmic background — like a stellar version of Pokémon GO.
The problem is, 15th century Korean scientists didn't exactly keep the best records. For starters, it was the 15th century, and pretty much everyone had rickets. Also, the modern Korean alphabet wouldn't be invented for another seven years.
You'll be shocked to learn the location of the star that went nova was lost to time.
Until now.
After 580 years of searching, a team of researchers from four continents has finally located the star, making it the oldest such nova to have its location accurately documented.
Lead researcher Michael Shara had spent nearly 30 years looking for remnants of the stellar explosion, known as Nova Scorpii. (A great name for any Dutch speed metal band that might be looking, btw. Don't sleep on it!)
Shara told The Atlantic's Marina Kornen that attempting to locate the site had been like "searching for a needle in a billion haystacks." Initially, the American Museum of Natural History curator and his team believed they'd find the nova between two stars in the constellation Scorpio. With the aid of online astronomical catalogs, which weren't a thing the first time Shara looked back in the 1980s, the astronomers combed through records of hundreds of millions of stars until, eventually, they focused in on a planetary nebula near the original search area.
In a classic "That's no moon, it's a space station" moment, the team rapidly realized that the nebula was the nova — or at least the remnants of it. They had been looking between the wrong two stars the entire time.
The team published its findings in the August edition of Nature.
"When we relaxed our criteria as to where to look in the constellation, we found the nova in 90 minutes," Shara told Space.com.
This 2016 image, taken by a telescope in Chile, shows the star — indicated by two long, red hashmarks — surrounded by the cloud of hydrogen it ejected in 1437. The smaller red "plus sign" in the center shows the star's location at the time it went nova almost six centuries ago.
Thanks to research by Shara and others, we know a lot more about novas than we did in 1437 — and even more now that Nova Scorpii has been tracked down.
In addition to classical novas, astronomers have observed frequent "dwarf novas" — much smaller explosions — across the visible universe. Shara has long suspected that both types of novae arise from the same star systems at different points in time rather than from different systems altogether.
Images from the 1930s and '40s, published in the paper, show the star pair that produced the 1437 nova undergoing a series of dwarf novae — lending Shara's theory some weighty backup.
Whether you specifically care about the dynamics of matter exchange in binary star systems of not, it's hard to deny that — holy crap — this is amazing.
When those 15th century Korean astronomers looked at the sky, they knew they were witnessing something important about their universe.
With the right tools, some tenacity, and a bit of luck, human beings have made it possible to find out what that is. Even after a 600-year search.
Science, then, as now, totally rules.
