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Astronomy texts are filled with unresolved puzzles, but thanks to technological progress, scientists are now able to revisit and solve some of the most perplexing space riddles. From a mysterious “star” that appeared over China 900 years ago to the real story behind the famous Wow Signal, here are ten cosmic mysteries that have now been solved.
10. The Case of Antarctica’s Missing Iron Meteorites
Some space enigmas aren't far from Earth. One such mystery exists in Antarctica. This icy land is the place where the majority of meteorites are found, but the reason for this isn’t the region’s location; it's actually the stark contrast between the dark debris and the bright white surroundings, making it easier to spot than in areas with forests or sand dunes.
Each year, thousands of meteorites enter Earth’s atmosphere, leading one to believe that all types of meteorites would be easily found in Antarctica. However, the continent remains oddly devoid of iron meteorites.
For decades, the mystery remained unsolved until 2016. In that year, researchers in the UK published a study proposing that Antarctica indeed harbors a vast number of iron meteorites—they’re simply hidden. Due to their high iron content, these meteorites heat up more than other space rocks when they enter Earth’s atmosphere. Upon striking the ice or snow, they melt into the surface, disappearing from sight. Antarctica is likely sitting on a hidden cache of iron-rich meteorites, we just can't see them.
9. The Absence of Green Comet Tails
No comet has ever been observed to have a green tail. This was puzzling because many comets exhibit bright green heads as they approach the sun. So, why did the color fail to extend to their tails? This question remained unresolved for a staggering 90 years.
Since the 1930s, scientists had suspected that dicarbon might be the key. Dicarbon is a chemical compound that forms when the organic material on a comet’s head reacts with sunlight, creating the greenish hue. However, sunlight also breaks down dicarbon, which might explain why it never survives long enough to appear in the comet’s tail.
In 2021, this hypothesis was finally proven in an extraordinary experiment. Recreating the process wasn’t easy. Dicarbon exists only in extreme environments (like space), and it is a volatile compound. In an unprecedented achievement, scientists synthesized dicarbon and, in a vacuum chamber, exposed it to gas and lasers to simulate space conditions. The lasers demonstrated how sunlight’s radiation destroyed the dicarbon before it could color a comet’s tail green.
8. The Enigma of Jovian Lightning
For centuries, ancient astronomers speculated that Jupiter, the largest planet in our solar system, might experience lightning. This theory wasn’t proven until 1979 when NASA’s Voyager 1 spacecraft flew past Jupiter. However, Voyager 1's confirmation brought an unexpected revelation: Jovian lightning appeared only near the planet’s poles, whereas lightning on Earth is more common near the equator.
Another flyby was necessary to understand why lightning avoided Jupiter's equator. In recent years, NASA's Juno spacecraft observed the planet and discovered that heat is the key factor preventing lightning from striking the planet's midsection.
On Earth, the equator receives the most direct sunlight, which causes warm air to rise—this is the very condition that fuels lightning formation. On Jupiter, however, the situation is reversed. Sunlight warms the equator, but the planet's upper atmosphere stabilizes, preventing warm air from rising. This lack of atmospheric stability at the poles allows lightning to strike there, with heat from the planet's interior pushing air upward.
7. A Peculiar Light Display
In 2022, the James Webb Space Telescope transmitted a stunning image back to Earth. The photograph depicted a brilliant light at the center of a series of rings, with eight spikes of light extending outward from the center, creating a near-spiderweb effect. As the striking image spread across social media, people were left wondering, “What is this phenomenon?”
Scientists quickly identified the spikes as a “flaw” in the telescope’s imaging. These anomalies appeared when photographing exceptionally bright objects in space. Since the spikes weren’t real, attention turned to the unusual concentric rings surrounding the star.
A more detailed examination revealed that the “light” came from two stars in orbit around each other in an eight-year cycle. Each time the stars drew close and then drifted apart, they produced dust, forming a new ring each time.
6. The Radiant Blobs
In 2000, astronomers discovered an odd phenomenon in space—billions of light-years away, a blob floated. It was as large as a galaxy and shone with the same brilliance, but there was a catch—the enormous space bubble contained no stars, only hydrogen gas. So, what was causing it to emit such a powerful glow?
In total, around 30 of these enigmatic blobs were found. However, it wasn’t until a team of astronomers, numerous telescopes, and sophisticated simulations came together that the source of their light was uncovered. Surprisingly, stars were involved—but in an entirely unexpected manner.
These gigantic orbs turned out to be stellar nurseries. Within the depths of the blobs, new stars were forming at a pace 100 times faster than the rate of star formation in our own Milky Way galaxy. Strangely, nearby galaxies also contributed star-forming materials to the mix. The light emitted by the blobs originated from the birth of new stars. At the moment of their creation, the stars release a burst of intense ultraviolet light, which scatters within the hydrogen gas, causing the blob to shine.
5. The 900-Year-Old Enigma
In 1181, astronomers from Japan and China noticed something unusual in the night sky. A new light appeared, as bright as Saturn, and remained visible for six months. Based on their descriptions, modern researchers concluded that they were likely witnessing a supernova. This stellar explosion became famous in scientific circles, mostly because no trace of it could be found.
In 2021, nearly 900 years after the enigma of the missing supernova began, the origins of the so-called “Chinese Guest Star” were finally traced. Ancient records indicated that the light appeared between the Chinese constellations Huagai and Chuanshe. In that region, a star and nebula were discovered, believed to have formed when two White Dwarf stars merged. Such an event is known to trigger supernovas, and the location, light description, and age of the nebula all align with the events of 1181.
4. The Time Betelgeuse Flickered
Stargazers are well-acquainted with Orion, also known as “the hunter,” and Betelgeuse, the red supergiant that marks its eastern shoulder. Betelgeuse is one of the brightest stars in the night sky, so when it began to fade in September 2019, astronomers immediately took notice. Over time, the dimming persisted, and by February 2020, the star had lost an unprecedented 35 percent of its brightness.
Though Betelgeuse eventually regained its former brilliance, scientists were baffled. No one could explain why this red giant had seemingly “blinking.” After much deliberation, researchers proposed that the dimming could be due to a dust cloud or a drop in temperature. As multiple teams analyzed observatory data and satellite images, they discovered that both hypotheses were correct.
Betelgeuse had ejected a massive cloud of gas from its core, and it wasn’t until the star’s photosphere cooled that the gas turned into dust. This dust temporarily obscured the star’s light.
3. The Mystery 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.
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 explanation seemed plausible until 2015, when a suggestion emerged that gravitational lensing could be the cause. This extraordinary phenomenon occurs when massive celestial bodies align in a straight line, warping light and space-time in such a way that distant objects appear much closer than they truly are. Often, this alignment also creates optical illusions, resulting in the appearance of duplicate objects sitting side by side.
Upon closer examination of the cosmic setup that might be behind Hamilton’s Object, researchers discovered that a vast galaxy cluster lay between Earth and the 'twins.' This cluster was responsible for the duplication effect, but in reality, Hamilton’s Object is a solitary spiral galaxy.
1. The Photograph of the Lunar Fireball
In 1953, Dr. Leon Stuart from Oklahoma captured a remarkable photograph of an event on the Moon. He believed that the massive fireball he photographed was the result of vaporized rock. If this was true, he would have been the first to witness and document a lunar impact. The event was dubbed “Stuart’s Event,” but despite investigations, including by astronauts and space probes, no crater could be found.
Nonetheless, the photograph confirmed that something extraordinary took place on the Moon in 1953. In 2003, NASA researchers examined the image and calculated that the impact would have created a fresh crater up to 1.24 miles (2 kilometers) wide. Using photographs from the 1994 lunar-orbiting Clementine spacecraft, they searched a 22-mile (35-kilometer) grid, hoping to find the elusive crater.
Remarkably, the NASA team discovered Stuart’s crater. Though it was smaller, measuring just 0.93 miles (1.5 kilometers) across, it was pristine, bore the right characteristics, and was situated exactly in the center of the iconic photograph. The size of the crater corresponded with the estimated energy release of the impact, which would have been 35 times more powerful than the atomic bomb that destroyed Hiroshima.
