Buzz
One of life's greatest joys is witnessing the awe-inspiring sight of a comet as it passes by Earth. If we're fortunate, we may even be able to catch several comets during our lifetime. Some comets are faint and difficult to spot, while others shine brightly in the sky, rivaling Venus or the Moon in their brilliance. It's the latter that we remember most fondly, often naming them the 'Great Comet of (year).' Here are 10 lesser-known comets that, in their own unique way, earn the title of 'great.'
10. Comet Bennett
One of the most memorable comets of the 1970s was the disappointing Kohoutek, which failed to achieve the brightness that had been eagerly anticipated during its appearance in 1973-1974. However, there were two remarkable comets from that decade that captured the imagination of skywatchers—Comet West and the lesser-known Comet Bennett. Though it’s rarely mentioned alongside the dazzling Comet West, Comet Bennett delivered a brilliant spectacle between February and May of 1970.
Comet Bennett was a striking morning comet that could be seen by anyone brave enough to face the cold for a glimpse. The effort was certainly worthwhile, as it reached an impressive magnitude of zero. The astronomical magnitude scale measures an object's brightness in the night sky, with zero being as bright as the summer star Vega. Objects with negative magnitudes appear even brighter and are easier to spot. For context, Venus, the brightest planet in the night sky, has a magnitude of -4. Comet Bennett displayed an extraordinary, long tail that extended behind it, which actually consisted of two tails intertwining. Although it disappeared by mid-May, some astronomers still regard it as one of the most spectacular comets of the 20th century. Comet Bennett is set to return in approximately 17,000 years.
9. The Headless Comet Of 1887
Visible for a brief time in the Southern Hemisphere, the Great Southern Comet of 1887 was unforgettable for one strange feature—it lacked a nucleus, or 'head.' The nucleus is the core of a comet, typically a solid mass of ice and other materials, often called a 'dirty snowball.' This nucleus creates the coma—the cloud of dust surrounding it—and gives rise to the comet's dust tail, which is pushed by the solar wind.
How could the Great Southern Comet of 1887 be so mesmerizing without a visible coma? Scientists have a few theories about why its head may not have been brightly illuminated, but none of them are definitive. Regardless of the reasoning, the absence of a head earned the comet the nickname 'Headless Wonder.' Despite its brief appearance before vanishing, it was a stunning sight, with its tail spanning an impressive 50 degrees across the night sky.
8. Great Comet Of 1861
In 1910, the world eagerly anticipated the return of Comet Halley. By this time, scientists had analyzed the composition of Halley’s comet tail and discovered it contained several chemicals and elements, including cyanide gas. While the amount of cyanide was very low, the press fueled fears that on May 19, 1910, when Earth passed through the comet’s tail, the toxic gas would wipe out all life on the planet. However, when the night passed and Earth traversed the comet’s tail, life continued as usual the next morning.
Forty-nine years before that, in 1861, Earth had another close encounter with a comet—The Great Comet of 1861, also known as Comet Tebbutt, named after its discoverer, the Australian farmer and astronomer John Tebbutt. On May 13, 1861, Tebbutt observed a fuzzy object in the night sky above the town of Windsor, near Sydney, Australia. Unable to identify it, he contacted the Government Astronomer at Sydney University, who confirmed that Tebbutt had made a rare discovery—a comet, which was subsequently named after him. The discovery was published in the Sydney paper, and word of the comet spread throughout the scientific community.
As Comet Tebbutt moved into the Northern Hemisphere, it became visible for much of the summer of 1861. Its brightness steadily increased, eventually reaching magnitude zero, and on June 29, Earth passed through the comet’s tail. The comet brightened to magnitude -4 (as bright as Venus), with a tail that stretched an astounding 120 degrees across the sky. To give you an idea of how extraordinary that was, 90 degrees from the horizon (the horizon) is directly overhead (the zenith). If the comet’s head had been at the horizon, its tail would have arced well past the zenith. Just like in 1910, Earth survived its close pass through the tail of the Great Comet of 1861.
7. Comet Arend-Roland
Comet Arend-Roland, discovered in 1956, was the first great comet visible in the Northern Hemisphere since Halley’s Comet in 1910, and is often considered the first great comet of the modern era. In April 1957, the comet made its closest approach to Earth and became a dazzling sight with a magnitude of zero and a tail that stretched 30 degrees. It also displayed a rare phenomenon: a bright anti-tail, pointing directly toward the sun.
In his book Cosmos, astronomer Carl Sagan recalled one memorable incident involving Comet Arend-Roland. While a graduate student at the University of Chicago, Sagan received a phone call one evening from a drunken man at an outdoor party who wanted to know about the fuzzy ball of light in the sky above. The man was perplexed by how the ball seemed to disappear when he looked directly at it, only to reappear when he turned his gaze away. Sagan explained that it was Comet Arend-Roland. The man then asked, 'What’s a comet?' To which Sagan replied, 'A snowball one mile across.' Refusing to believe such a response, the man asked to speak to 'a real shtrominer.'
6. Comet Encke
Comet Encke earns its place on this list for several noteworthy reasons. First, it holds the title of the periodic comet with the shortest known orbit around the Sun, completing one full cycle every three years. As one of many periodic comets, Encke’s orbit brings it past Earth several times within a typical human lifetime. These periodic comets hail from the Oort Cloud and the Kuiper Belt, distant regions beyond Neptune filled with comets and asteroids. They regularly make visits to Earth as they orbit the Sun. Due to its frequent returns, Comet Encke is often referred to as 'Old Faithful.'
However, Comet Encke hasn’t always been a friendly visitor. Some researchers speculate that this comet may be linked to various historical Earth impacts, such as the infamous Tunguska explosion of 1908. Furthermore, there are theories suggesting that Comet Encke could be the inspiration behind the swastika symbol. A rare Chinese comet atlas from the 4th century B.C. discovered in 1978 includes an illustration of a comet with a shape strikingly similar to the swastika.
Had the ancient Chinese witnessed Comet Encke’s passage in 2007, they would have been astonished to see that it lacked a tail entirely, which had 'fallen off' following a close encounter with the Sun. Additionally, Comet Encke is responsible for the Taurid meteor shower that occurs every November, when Earth passes through the debris left behind by the comet’s tail.
5. Comet Swift-Tuttle
You might not be familiar with Comet Swift-Tuttle, but astronomers and scientists are, and they harbor significant concerns about this particular comet. And their concerns are well-founded—Comet Swift-Tuttle has earned the reputation of being 'the single most dangerous object known to humanity.'
Comet Swift-Tuttle is the largest of the periodic comets, those that make regular, relatively short-term visits to our Sun and Earth. It has been a familiar presence to humans for centuries. Experts believe that records of its 120-year orbital cycle have been made for thousands of years. Its most recent visit was in 1992, not 1982 as originally predicted. We now understand its true orbital period, which brings a new concern: The next time Comet Swift-Tuttle is scheduled to return is in 2126, not 2116, which places it much closer to Earth's orbit. At one point, scientists feared that it could impact the Earth.
The size of the comet’s nucleus is a major point of concern for scientists. Measuring over 26 kilometers (16.2 miles) in diameter, Comet Swift-Tuttle is comparable in size to previous comets that have struck Earth—collisions that led to mass extinctions. Although we now know that the comet will pass safely by in 2126, it will be close enough to Earth to offer a breathtaking spectacle for those fortunate enough to witness it in the night sky. Despite the reassurance, we continue to monitor the comet, just in case it decides to change its course before 2126.
On a brighter note, since Comet Swift-Tuttle returns to Earth on a regular schedule, Earth passes through the debris left behind in its wake. This cosmic dust is responsible for one of the most spectacular and predictable astronomical events of the year—the Perseid meteor shower.
4. The Great Comet of 1811
Known also as Comet Flaugergues, this spectacular comet was first observed in April 1811. It was visible to the naked eye or through a telescope for an astonishing 17 months, stretching well into 1812. At its peak brightness, Comet Flaugergues reached magnitude 1 and boasted a tail that extended 25 degrees across the sky.
Although the Great Comet of 1811 was known as Comet Flaugergues, it is most famously remembered as 'Tecumseh’s Comet' in the United States and 'Napoleon’s Comet' in Europe. In 1811, people were beginning to approach comets and other celestial events with less superstition and fear. However, Comet Flaugergues seemed to challenge this progress by appearing during the onset of the New Madrid earthquakes in the United States, a devastating series of quakes that occurred from December 1811 to March 1812. Two of these earthquakes measured over 8.0 on the Richter scale.
At the time, the great Shawnee leader Tecumseh—whose name, coincidentally, meant 'Shooting Star'—was uniting various Native American tribes to fight against the United States for taking their land. As Tecumseh met with other tribal leaders, only 80 kilometers (50 miles) from the epicenter of the quakes, the first tremor (magnitude 8.1) struck the New Madrid region in Missouri.
Meanwhile, Napoleon reportedly saw the comet as a divine sign affirming the righteousness of his reign. Yet, this period coincided with his disastrous decision to invade Russia. In fact, during the time between Napoleon's invasion and eventual retreat, three comets were observed in the sky.
3. Comet Donati
Comet Donati holds two significant historical distinctions. First, it is often referred to as 'Lincoln’s Comet' because it was observed by the future president of the United States. In 1858, when Lincoln was still a young Senate candidate from Illinois, he spent considerable time admiring the comet in the night sky. Second, and perhaps more notably, Comet Donati is recognized as the first comet ever to be photographed.
Photography, invented by Louis-Jacques-Mande Daguerre in 1839, quickly found its way into the field of astronomy. Astronomers soon realized the potential of photography for their work. The first successful photograph of the Moon was captured in 1840. By 1858, when Comet Donati was visible, the wet collodion method was improving upon earlier techniques. George Bond, an astronomer at Harvard, used this method along with a telescope to create the first-ever photograph of a comet. Though the image was modest, it marked a pivotal moment in history.
In addition to its historical importance, Comet Donati was an awe-inspiring sight in the sky. The 1800s, free from the blight of light pollution, offered perfect conditions for comet viewing. People across the Northern Hemisphere marveled at the many incredible comets that graced the sky during this period. Observing these celestial wonders must have been an unforgettable experience, with dark skies providing an unobstructed view of the cosmos.
2. Great Comet Of 1618
Nearly 150 years after the Great Comet of 1472 appeared, Europe found itself captivated by the wonders of observation, study, and analysis. However, not everyone embraced the era's intellectual awakening. In Prague, Protestants were throwing Catholic noblemen from windows, sparking the Thirty Years’ War. Meanwhile, Johannes Kepler was busy formulating the third law of planetary motion, though few took note of his work, including the Catholic Church (which proved to be fortunate for Kepler). What everyone did notice, however, was the comet that appeared in the sky in 1618.
Referred to as 'the Angry Star' due to its fiery red hue and long, threatening tail, the Great Comet of 1618 remained visible for seven weeks, offering plenty of time for 17th-century Europeans to marvel at this celestial visitor. One individual who was particularly intrigued was Galileo, who saw it as an opportunity to challenge Aristotle’s claim that comets were simply 'fiery objects.' He argued that comets were unlike planets with fixed circular orbits (which was incorrect) and insisted that comets were not true objects, but only 'appearances' (both claims were wrong). Even Galileo wasn't always right.
What truly captured widespread attention, though, was King James I of England, who had noticed the comet and even wrote a poem about it. In his royal style, King James reassured his people not to make too much of the comet, advising that it was simply a comet. Even if it were sent by God, he argued, typical Englishmen should not overreact and should 'keep his rash imaginations till he sleep.'
1. The Comet Of 1472
In 1472, Leonardo da Vinci was at the peak of his career, while Columbus was still two decades away from his historic discovery of the New World. This year also witnessed the appearance of one of the most remarkable comets to mark the closing chapter of the Middle Ages.
When the comet appeared in 1472, scientific observations were still in their early stages. The scholars of the time attempted to measure the comet's distance from Earth, the length and direction of its tail, and the size of its nucleus. While their calculations left much to be desired, they were pushing the boundaries of science at the time. Remember, the telescope was still over a century away from being invented.
Among the first astronomers to study the 1472 comet was the German mathematician Johannes Regiomontanus. Not only did he study the comet, but he also meticulously recorded his observations. The comet appeared at a crucial moment in history for Regiomontanus, as the printing revolution was spreading across Europe. His notes would later be published as 'De Cometis,' one of the earliest astronomy books ever printed.
Regiomontanus was not alone in his observations. Angelo Cato de Supino, an Italian philosopher and physician, also studied the comet and described it as being as bright as a full moon with a tail extending over 30 degrees. The comet was observed by astronomers in Korea and China, where the Chinese called it a 'broom star' and noted that it 'even appeared at midday.' Visible for 59 days, the comet would ultimately reach a brightness of -3 magnitude.
