The pages of astronomy books are packed with old mysteries. Thanks to the advancement of technology, experts can now look back and solve some of the gnarliest space mysteries on record. From the sudden appearance of a “star” 900 years ago above China to the truth about the famous Wow Signal, here are ten cosmic enigmas that have finally been cracked.
10 Antarctica’s Missing Iron Meteorites
Some space mysteries exist on Earth. One such riddle can be found in Antarctica. This frosty corner of the globe is where most meteorites are recovered. This abundance has nothing to do with location but instead with color differences. It’s easier to spot dark cosmic debris against the white expanse of this region than in places with forests or sand dunes.
Thousands of space rocks enter our atmosphere every year, so one might think that every type of meteorite can be found in Antarctica. Not so. The snow-covered continent is strangely empty of iron meteorites.
The mystery lasted for decades until 2016. That year, UK researchers released a study that suggested Antarctica has plenty of iron meteorites—they are just well hidden. Their iron content ensures that these meteorites become hotter than other space rocks when they enter our atmosphere. Once they impact ice or snow, they’ll burrow under the surface (melt their way down, really) and completely disappear from sight. Antarctica probably has a treasure trove of iron-rich meteorites; we just can’t see them.[1]
9 No Green Comet Tails
Astronomers have never recorded a comet with a green tail. This was odd because many comets develop radiant green heads as they fly closer to the sun. What was stopping the color from spreading to their tails? Interestingly, this question went unsolved for 90 years.
Since the 1930s, researchers suspected dicarbon could explain the whole thing. Dicarbon is a chemical that forms when the organic matter on the comet’s head reacts to sunlight, causing the green color. Unfortunately, sunlight also destroys dicarbon, which could explain why the chemical never survives long enough to reach a comet’s tail.
In 2021, this theory was proved in an amazing way. Scientists had to recreate the process, and that was no easy task. Dicarbon only exists in extreme places (like space), and it’s also a volatile chemical. In a world first, they created dicarbon, and while inside a vacuum chamber, it was brought into contact with gas and lasers to simulate the conditions in space. The lasers, in particular, proved that the sun’s radiation ripped apart the dicarbon before it could turn a comet’s tail green.[2]
8 The Mystery of Jovian Lightning
Ancient astronomers theorized for centuries that the largest planet in the solar system had lightning, but it wasn’t confirmed until 1979 when NASA’s Voyager 1 spacecraft hurtled past Jupiter. However, apart from confirming an old suspicion, Voyager 1 also discovered that Jovian lightning only appeared near the planet’s poles. In comparison, Earth’s lightning is more common among the equator.
It took another flyby to understand why lightning bolts avoided Jupiter’s midriff like the plague. In recent years, the craft Juno buzzed Jupiter and identified heat as the reason why lightning never zings the planet’s equator.
Earth catches the brunt of the sun’s warmth around the equator which fuels rising hot air—the very thing that lightning needs to form. The process is reversed on Jupiter in a peculiar way. Once sunlight makes Jupiter’s equator toasty, the world’s upper atmosphere stabilizes in such a way that it suppresses rising warm air. For this reason, lighting strikes freely at the poles where there is no atmospheric stability, and heat from inside the planet pushes hot air upward.[3]
7 A Strange Light Show
In 2022, the James Webb Telescope beamed back a fantastic photograph to Earth. It showed a bright light at the center of several rings. Cutting through the rings were eight spikes of light that radiated from the center outward, almost creating a spiderweb effect. When the bizarre but beautiful image hit social media, people had one question, “What the heck is this?”
Researchers quickly determined that the spikes were a “fault” on the telescope’s part. It tended to produce such anomalies when photographing bright objects in space. Since the spikes weren’t real, that left the unusual concentric circles around the star.
A closer look revealed that the “light” came from two stars. They orbited each other in an eight-year cycle, and each time the stars came close to each other and moved away again, that’s the moment when they produced dust and threw out another ring.[4]
6 The Glowing Blobs
In 2000, astronomers stumbled upon a bizarre space… thing. Billions of light-years from Earth floated a blob. It was as big as a galaxy and also glowed as brightly as one. But here’s the mystery—the giant space bubble had no stars, only hydrogen gas. So, what caused it to shine so brilliantly?
All told, about 30 blobs were eventually discovered. However, it wasn’t until dozens of astronomers, countless telescopes, and advanced simulations came together that their light source was revealed. Unexpectedly, stars were involved—but in a very unusual way.
As it turns out, these mammoth orbs are star factories. Deep inside the blobs, fresh stars are being produced at a rate 100 times faster than those born in our Milky Way galaxy. For some reason, nearby galaxies also pour star-forming materials into the chaos. But the actual light comes from the moment when new stars are born. In that instant, the stars exude a burst of bright ultraviolet light, which scatters in the hydrogen gas, causing the blob to glow.[5]
5 A 900-Year-Old Mystery
In 1181, Japanese and Chinese astronomers noticed a difference in the night sky. A new light had appeared, shone as brightly as Saturn, and stayed for six months. The description given by these early star gazers provided modern researchers with enough reason to believe that they were describing a supernova. This celestial explosion became quite famous in scientific circles, mostly because nobody could find any trace of it.
In 2021, roughly 900 years after the mystery of the missing supernova began, the origins of the so-called “Chinese Guest Star” were finally discovered. The ancient reports stated that the light had appeared between the Chinese constellations of Huagai and Chuanshe. In this region were a star and nebula thought to have been created when two White Dwarf stars merged. Such an event is known to trigger supernovas and the location, description of the light, and the age of the nebula all fit the events of 1181.[6]
4 That Time When Betelgeuse Blinked
Stargazers are very familiar with Orion. This star constellation is also known as “the hunter,” and Betelgeuse is the red supergiant that marks Orion’s eastern shoulder. The star is among the most luminous in the night sky, so when it suddenly dimmed in September 2019, astronomers quickly noticed. For a while, the fading continued, and by February 2020, Betelgeuse had dimmed by an unprecedented 35 percent.
Although the star regained its former brilliance, experts were at a loss. Nobody could explain why the red giant had “blinked.” Putting their best guesses on the table, researchers theorized that the dimming was the result of a dust cloud or a drop in temperature. During a multinational attempt, researchers combed through observatory data and satellite images and realized that both theories were correct.
Betelgeuse had ejected a massive cloud of gas from its innards, but it wasn’t until the star’s photosphere started to cool that the gas condensed into dust. This dusty atmosphere temporarily cloaked the star’s light. [7]
3 The Lunar Fireball Photograph
In 1953, Dr. Leon Stuart from Oklahoma photographed an event on the Moon. He believed that the gigantic fireball he captured was a plume of vaporized rock. If true, that would make him the first person to witness and document a lunar impact. It became known as “Stuart’s Event,” but nobody, not even astronauts or space probes, could find the crater.
Yet, the photograph proved that something had happened on the Moon in 1953. In 2003, NASA researchers analyzed the image and calculated that the object would’ve left a fresh-looking crater up to 1.24 miles (2 kilometers) across. Taking cues from the lunar landscape, they searched a grid of roughly 22 miles (35 kilometers) using photographs taken in 1994 by the lunar-orbiting Clementine spacecraft.
Incredibly, the NASA team found Stuart’s crater. It was smaller, measuring 0.93 miles (1.5 kilometers) across, but it was fresh, had the right appearance, and was also located in the middle of the famous photograph. The size of the crater also matched the estimated energy output of the impact, which would’ve been 35 times stronger than the atomic bomb that had devastated Hiroshima.[8]
2 The Impossible Twin Galaxies
No two galaxies are alike. Keeping this rule in mind, scientists were blown away when they discovered identical twin galaxies in 2013. The pair even sat next to each other, making it immediately obvious that they were freakishly similar. The odd phenomenon became known as Hamilton’s Object.
No theory made sense until someone suggested, in 2015, that gravitational lensing might be responsible. This rare phenomenon is bonkers. When large celestial bodies line up in a row, they can actually curve light and space-time in such a way that when astronomers view the objects through telescopes, they appear closer than they really are. Very often, they also produce mirages of themselves. The result? The illusion that two identical objects are sitting side by side.
When researchers looked closer at the setup that might be causing Hamilton’s Object, they discovered that between Earth and the “twins” sat a massive cluster of galaxies. The latter is causing the duplicate effect, but in reality, Hamilton’s Object is a single spiral galaxy.[9]
1 Origins of the Wow Signal
In 1977, a legendary mystery was born. Astronomer Jerry Ehman captured radio waves from space that were unlike anything he’d ever seen before (or anyone else, for that matter). He wrote “Wow!” next to the printed signal, and the name stuck. Even today, the Wow Signal is touted as proof of alien contact or, at the very least, an unsolved mystery. In truth, the origins had already been discovered in 2017.
Researchers from St Petersburg College suspected that comets might be the culprits. More specifically, a pair called 266P/Christensen and 335P/Gibbs. Both were enveloped in clouds of hydrogen gas. This detail is important because hydrogen naturally emits 1420MHz. This was the same radio frequency the “alien” signal emitted.
The telescope that picked up the Wow Signal was pointing at a specific group of stars in the Sagittarius constellation, and both comets were confirmed to have been in the area at the time. A closer look also revealed that 266/P Christensen was probably the comet that sparked the 40-year-old mystery. When its radio signals were compared to those from the Wow Signal, they were a match.[10]