With a couple of recent exceptions, cosmic phenomena (often hyped up in the media) tend to be underwhelming. Which, to be fair, is probably a good thing. But history has recorded plenty of genuinely spectacular events in the centuries and millennia before modern astronomy.
10. The Julian Star
Caesar’s Comet, aka the Julian Star, appeared after Julius Caesar was stabbed to death in the Senate. It was visible after sunset for seven days during the Ludi Victoriae Caesaris (games held to honor the ruler). Naturally, it became an object of worship. From the Roman writer Pliny the Elder we also learn that Augustus, Caesar’s heir, the first Roman Emperor, saw the comet as a sign that his rule had begun.
In fact, the comet’s appearance was pivotal for Augustus and by extension the world. As Caesar’s grand-nephew, his legitimacy to rule was debated—not least by Caesar’s general Mark Antony, who accused the boy of having sex with his grand-uncle to get his will. For Augustus, the comet was a gift from above. Taking advantage of Roman gullibility, he declared the “new star” the soul of Caesar on its way to join the gods—which, neatly, affirmed his own divine status in the process.
It was so spectacularly timely, in fact, that some wonder if Augustus made it up. They point to unusual discrepancies like the 26-year gap between its alleged appearance and depiction on coins. However, ancient Roman sources are corroborated by Chinese records. Also, comets were seen as bad omens by Romans. Augustus was cunning enough to spin it as auspicious, but it wouldn’t have been his own choice.
9. The Supernova of 1054
In 1054, a supernova bright enough to be visible in daylight was recorded by astronomers worldwide. Ancient Chinese called it a “guest star” and compared it to Venus, the “morning star”, since both were best seen before dawn. Unlike Venus, though, “it had pointed rays on all sides”. Meanwhile, in the Levant, the appearance of this exploding star was linked to an epidemic that killed 14,000 people in Constantinople before spreading southwards to Cairo.
The light hung around for 23 days before it finally fizzled out and dispersed, although it remained visible for 21 months at night. Today, we know it as the Crab Nebula—the brightest remnant of any supernova we can see. However, up until recently, we didn’t know exactly what caused it. We just knew it was unlike any other supernova on record. That is, it wasn’t an iron-core collapse (whereby the mass of a huge star flows into its core causing it to collapse and explode) nor a thermonuclear supernova (whereby a small white dwarf siphons so much mass from another that it explodes). It wasn’t until 2018 that a new type of supernova was discovered: electron capture. Previously only theoretical, it more closely resembled the supernova of 1054. Electron-capture supernovae occur in stars 8-10 times the mass of the Sun when internal pressures force electrons to merge with the nuclei of atoms. This causes the core to collapse and explode.
We didn’t see the supernova of 2018 because it happened 30-40 million lightyears away in the galaxy NGC 2146, whereas the supernova of 1054 happened in our own galaxy, just 6,500 lightyears away.
8. The Total Solar Eclipse of 585 BC
The total solar eclipse of May 28, 585 BC was among the earliest predicted cosmic events. It was foreseen by the Greek philosopher Thales of Miletus, who studied patterns in earlier records.
But it’s remembered for another reason too. On the day of the eclipse, two kingdoms, the Medes and Lydians, were engaged in a brutal battle. But as the moon passed in front of the sun, blocking it out and turning day into night, the fighting suddenly stopped. Both armies interpreted the darkness as an omen—a sign of the gods’ displeasure. They didn’t just stop fighting; they came to a hastily brokered peace agreement that included the marriage of a Median prince to a Lydian princess.
Fittingly, the same eclipse that stopped the savagery on the field (albeit through superstition) ushered in the dawn of rational astronomy. Thales’ prediction showed celestial events follow the laws of nature and not the whim of the gods. It laid the groundwork for future inquiry and marked a shift from superstition to science.
7. Halley’s Comet (1066)
Easily the most culturally significant object of its kind, Halley’s Comet is a part of the human story. One of its most famous appearances was in 1066, shortly before the Battle of Hastings, which imposed on the English a Norman aristocracy that remains in power today—almost 1,000 years later.
The comet was seen as an omen at the time. The Bayeux Tapestry, an 11th-century embroidery, is thought to have been the earliest depiction, showing not only the comet but also men looking up in fear. But not everyone was afraid. Whereas the English saw it as a sign of their doom, the Normans under William the Conqueror took it as a sign of God’s blessing. He wanted them to enslave the English and steal all their land.
Halley’s Comet’s 1066 visit is a classic example of how celestial events have been perceived as harbingers of change. Its appearance not only influenced medieval beliefs and actions but also left a lasting legacy in art and history, symbolizing the intertwining of cosmic phenomena with human destiny.
6. The Great Fireball of 1783
On the night of August 18, 1783, a lone fireball set the skies of Britain ablaze. This bright, slow-moving meteor appeared to be roughly the size of the disk of the moon and was estimated to be half a mile across and traveling at 20 miles per second. It was only visible for a minute before it broke into pieces, leaving only its core continuing on its path.
This so-called Great Fireball, which sailed across the sky just 50 or 60 miles off the ground, inspired awe and curiosity worldwide. Astronomers like Charles Blagden gathered reports, hoping to identify its origin. At the time, however, meteors were seen not as rocks but as electrical phenomena in the upper atmosphere. Hence it didn’t seem to cross anyone’s mind that, given the size and speed of the object, the world had just narrowly avoided a catastrophic impact.
Nevertheless, the fireball’s appearance and subsequent studies marked a shift from this old view to one of meteors as extraterrestrial objects.
5. The Great Comet of 1744
Also known as de Chéseaux’s Comet, the Great Comet of 1744 dazzled observers on November 29, 1743. Although initially quite dim it brightened as it got near the sun. By mid-January the following year, the comet had a tail seven degrees long (roughly four finger widths at arm’s length). By February 1, it rivaled Sirius in brightness, with a curved tail extending 15 degrees (which is roughly the distance between the tip of your index finger and pinky spread apart at arm’s length). Still, though, the comet continued to intensify. By February 18, it was as bright as Venus and had two tails. It peaked on February 27 at a brightness of -7 apparent magnitude. The full moon is -11 and Sirius is 1.5. It was visible even in daylight, despite being just 12 degrees from the sun.
The Great Comet reached its perihelion on March 1. But the show wasn’t over just yet. When it reappeared in the morning sky on March 6, it appeared to have six brilliant tails fanned out like a Japanese hand fan across 60 degrees of the sky (four times the distance between the tip of your index finger and pinky spread apart at arm’s length!). Interestingly, these six tails were really just the most visible parts of a single, enormous curved dust tail.
4. The Great September Comet of 1882
Often said to be the brightest comet on record, the Great September Comet of 1882 was first seen by Italian sailors. By the middle of the month, near the Sun, it was bright enough to see in broad daylight. It was only 264,000 miles from the Sun’s surface, which, although it sounds a lot, is actually just a tiny fraction of Mercury’s distance of 28.5 million miles. It’s also not far off the distance between the Earth and the Moon. Hence the Great September Comet’s classification as a Kreutz Sungrazer—a comet that passes close to the Sun.
Spectacularly, this incredibly close approach illuminated the comet 1,000 times brighter than the full moon. Observers called it a “blazing star” or “super comet” and watched in awe as its nucleus broke up into fragments. It was visible in the sky for weeks and was witnessed around the world.
3. The Great Meteor Procession of 1913
The Great Meteor Procession of February 9, 1913, remains both rare and unexplained to this day. Unlike normal meteor showers, where meteors zip across the sky at blink-and-you’ll-miss-it speeds, this procession moved slowly with the meteors crawling across the sky in formation. Also, because of their nearly horizontal trajectory, they were visible for much longer than usual: up to a minute for individual meteors and several minutes for the whole procession. There was no radiant point from which they emerged, as with meteor showers.
Witnesses across North America, the North Atlantic, and even down to Brazil reported seeing the phenomenon. Some even reported rumbling sounds suggesting the meteors might have been close to Earth when they finally broke up and disappeared. Canadian astronomer Clarence Chant, who gathered more than 100 eyewitness reports, described the meteors as two bars of flaming material trailing sparks, followed by a bright, star-like ball of fire.
Theories about the procession’s cause vary. Some think the meteors may have been fragments of a temporary second moon—a small, short-lived, natural satellite of Earth. Despite extensive study, though, the Great Meteor Procession remains a mystery to science.
2. The 1833 Leonid Meteor Storm
Ever stayed up late for a meteor shower, only to be disappointed? The term—a favorite of the media—is misleading. Even “meteor drip” would overstate it. In most cases, you’ll be lucky to see 50 in an hour, which isn’t even one every minute. It’s nothing like what people imagine. That would be a meteor storm, which is worth staying up for.
On November 13, 1833, the skies of America were utterly transformed by as many as 20 meteors per second, or 72,000 meteors per hour. It was so intense that the region of the sky around Leo looked like an umbrella of falling lights. Of course, in those days, very few knew what it was and the phenomenon caused widespread panic. People described the lights as falling “thick as snow in a snowstorm”. Fearing the end of the world, many fell to their knees and prayed. Others ran into churches to manically ring the bells. The spectacle didn’t end until dawn, fading with the first light of day.
Today, it’s remembered as the most stunning meteor storm on record. It was also the beginning of meteor astronomy. Before this, “shooting stars” were not considered worthy of study. Hence astronomers later identified the phenomenon as caused by the comet Tempel-Tuttle and predicted its return 33 years later. Right on cue, 1866 brought another spectacular Leonid meteor storm—this time over Europe.
1. The Carrington Event
The Carrington Event of September 1-2, 1859, remains the most powerful geomagnetic storm on record. It was caused by a coronal mass ejection, a cloud of superheated plasma flying out of the Sun toward Earth. Basically, the Sun shot a magnet at our planet. And when it collided with the Earth’s magnetic field, auroras usually only visible in the far north (like Iceland and Greenland) were seen as far south as the Caribbean.
This geomagnetic storm also caused telegraph systems right around the world to malfunction, giving electric shocks to operators, sending sparks flying, setting paper alight, and even sending telegrams without a power source. The distortion of the Earth’s magnetic field by the charged solar particles was so great that it electrified the air around us. If an event of this magnitude happened today, in our hyperconnected world, the fallout would be catastrophic. And there’s no reason not to expect one. In fact, there was a near miss in 2012 that, had it hit, would have caused trillions of dollars in damage.