Buzz
Comet Elenin (C/2010 X1) captured widespread attention in 2011, becoming one of the most talked-about viral news stories of the year. Various rumors and theories led people to believe the comet could pose a threat to Earth. Several articles were published exploring the significance of Elenin and its predicted close approach to Earth in October 2011. Some even claimed that the comet was a sign validating the Maya prophecy. As the hype grew, NASA was forced to clarify the situation, stating that the comet posed no danger to our planet. By August 19, 2011, the comet story had quickly gained traction and then faded away. Below are ten intriguing facts about Comet Elenin.
10. What Exactly Is a Comet?
Historically, comets were often seen as ominous signs. These small objects in the Solar System, known as Small Solar System Bodies (SSSBs), develop a visible coma—a thin, temporary, and fuzzy atmosphere—when they approach the Sun. The key distinction between asteroids and comets is that comets display a coma, while asteroids do not. Additionally, asteroids and comets are believed to have different origins. Asteroids are thought to have formed inside Jupiter's orbit, while comets originated in the outer reaches of the Solar System, giving their orbits significant importance.
A comet's coma forms when it passes near the Sun. Composed primarily of ice and dust, the coma can grow to immense sizes. In October 2007, Comet 17P/Holmes temporarily developed a dust atmosphere that was even larger than the Sun itself. On average, around one comet visible to the naked eye is discovered each year. In rare instances, a Great Comet emerges, shining brighter than any star in the sky. Statistically, a Great Comet is expected to appear once every decade.
For a comet to qualify as a Great Comet, it must meet certain criteria: a large, active nucleus, a close pass by the Sun, and a close approach to Earth. In 1996, Comet Hyakutake, which had a nucleus similar in size to Comet Elenin's, made an extremely close flyby of Earth. The Ulysses spacecraft passed through Hyakutake’s tail at a distance exceeding 500 million kilometers (3.3 AU or 3×10^8 miles) from the nucleus, revealing that Hyakutake had the longest tail ever observed on a comet.
9. The Discovery
On December 10, 2010, a Russian amateur astronomer named Leonid Elenin spotted a long-period comet in New Mexico, USA. The near-Earth object was named after its discoverer and was estimated to have a diameter between 3 and 4 kilometers. As soon as the discovery was announced, rumors began circulating on the internet claiming the comet posed a danger to Earth. Many people drew connections between Elenin and potential extinction-level events.
Initially, it was believed that Comet Elenin would pass within 0.24 AU (Astronomical Units) of Earth, a fairly close distance. This would be closer than the Hale-Bopp Comet of 1997, which received more media attention. The story gained further traction when it was revealed that using the JPL Horizons system with an observed orbital arc of 235 days, the comet had an orbital period of roughly 11,800 years. This coincides with a significant period in Earth's history—around 12,000 years ago—marking the transition from the Pleistocene to the Holocene geological epochs.
8. Deep Impact
One reason Comet Elenin attracted so much attention was its resemblance to the 1998 blockbuster movie Deep Impact. In the film, a teenage boy named Leo discovers a comet, which is referred to as Elle (extinction level event). Interestingly, the comet was discovered by a young Russian astronomer, Leonid Elenin, who was born in 1981 and was 17 years old when Deep Impact was released. The similarity between the comet's discoverer and the movie's plot is purely coincidental.
Following the discovery, various articles began to circulate on the internet, with acronyms for ELENIN, such as extinction level event, near impact, or extinction level event nine (indicating a 9 out of 10 on the danger scale or marking the end of the ninth wave of the Mayan Calendar). Some people speculated about November 9, when the comet’s debris tail was predicted to be closest to Earth. In Deep Impact, a U.S. president of African descent orders a mission to destroy the comet with nuclear weapons. The mission succeeds in breaking the comet into fragments, but a piece still strikes Earth. After the impact, martial law is declared, and it’s revealed that the government has been constructing underground shelters. The movie ends with humanity surviving after the larger comet is destroyed.
7. The Predictions
Following the discovery of Comet Elenin, NASA was firm in stating that the comet would not come close enough to Earth to pose any threat. Despite this, people began to speculate about possible disaster scenarios. One such theory suggested that if the comet were to collide with an asteroid while passing through the Main Asteroid Belt, it could be deflected from its predicted path and cause a catastrophic collision with Earth. This led to growing fears about the comet's massive coma.
By August 2011, the coma of Comet Elenin had expanded to over 200,000 km (124,274 miles). It was predicted that on November 6, 2011, Earth would pass through the comet's debris tail. This prompted many to link the comet's alignment with Earth, the Sun, and the Moon. Some believed that the gravitational pull of Elenin triggered a series of earthquakes and geological events. The comet’s story gained even more traction after the March 11 Tōhoku earthquake and tsunami, especially as several websites had cited March 15, 2011, as a significant alignment date. Elenin was expected to be closest to Earth on October 16, 2011, with the debris field arriving in early November.
6. Hopi Blue Star
In early August 2011, NASA decided to capture an image of Comet Elenin by rotating the STEREO-B spacecraft to photograph it. In the resulting image, the comet appears to have a deep blue hue. This color led some to draw comparisons between the comet and the ancient Hopi Indian prophecy of the blue star. The legend says, “When the Blue Star Kachina makes its appearance in the heavens, the Fifth World will emerge.” The Maya also have their own tales about a perilous blue star. Due to Elenin’s color, Richard C. Hoagland suggested that it could be the Hopi Blue Star, a claim that has inspired many articles.
Carl Johan Calleman, a Swedish toxicologist with a focus on Maya history, also argued that Comet Elenin was the blue star referenced in ancient traditions. Calleman has a unique interpretation of the Maya Calendar, claiming it points to October 28, 2011 (rather than December 21, 2012) as the most significant date. He believes this day marks a time of gradual consciousness transformation and the arrival of a higher unity. Even before Elenin’s discovery, Calleman had identified the comet’s pass by Earth at the end of October 2011 as a crucial moment.
5. 45P/Honda-Mrkos-Pajdušáková
45P/Honda-Mrkos-Pajdušáková is a short-period comet that was discovered in 1948. It follows an elliptical orbit with a period of 5.26 years, and its nucleus is estimated to be between 0.5 and 1.6 kilometers in diameter. On August 15, 2011, the comet made a close pass of just 0.0600 AU (8,980,000 km; 5,580,000 mi) from Earth. On August 19, the same day Comet Elenin was destroyed by a coronal mass ejection, the Goldstone Deep Space Network studied Honda. The network successfully detected echoes from the nucleus of Honda, making it only the fifteenth comet in history to be observed via radar.
Following the public announcement of Comet Elenin's discovery, people began analyzing the potential trajectory of Elenin in relation to Honda. It appeared that the two comets might come dangerously close to one another on September 28 or 29, 2011. As a result, there was growing fear of earthquakes and other disasters around late September. Several articles were written speculating that a shift in Elenin's path could cause a collision with Honda. Another comet, 255P/Levy, was also mentioned in relation to Elenin. Levy passed within 0.2359 AU (35,290,000 km; 21,930,000 mi) of Earth on January 26, 2012.
4. 2005 YU55
Meteors are created when debris enters Earth's atmosphere and burns up. Some astronomers have noted that meteor showers often correspond with the orbits of known comets. These showers don't pose a threat to Earth because the comet's tail typically doesn't contain large objects. On December 28, 2005, a potentially hazardous asteroid was discovered by Robert S. McMillan and named 2005 YU55. The asteroid, measuring about 400 meters (1,312 feet) in diameter, raised concerns at NASA.
On November 8, 2011, the asteroid 2005 YU55 passed Earth at a distance of 324,900 kilometers (201,883 miles), which is roughly the same distance as the Moon. This marked the closest encounter by a large asteroid since 1976, with no other object of similar size predicted to come so near to Earth until 2028. As Comet Elenin gained more attention, many started to link its approach with that of YU55 due to the date November 9, 2011 (11/9/11). On that date, Elenin’s tail was predicted to be closest to Earth, coinciding with YU55’s proximity. This led some to speculate about a potential collision between the two celestial bodies.
3. NASA's Response
NASA has issued several statements regarding Comet Elenin, consistently downplaying its significance and any potential threat to Earth. After Elenin was destroyed in space, Don Yeomans of NASA remarked: “I cannot begin to guess why this little comet became such a big Internet sensation. The scientific reality is this modest-sized icy dirtball’s influence upon our planet is so incredibly minuscule that my subcompact automobile exerts a greater gravitational influence on earth than the comet ever would.”
Yeomans further explained that the destruction of the comet was not unexpected, saying: “Comets are fragile and loosely held together like dust balls, so it doesn’t take much to get a comet to disintegrate, and with comets, once they break up, there is no hope of reconciliation.” NASA’s position on Comet Elenin is clear: they avoid discussing it because it doesn’t compare to other pressing issues. Yeomans added: “Comet Elenin has rung down the curtain and joined the choir invisible. This is an ex-comet.”
2. The Demise of Comet Elenin
By August 2011, Comet Elenin's visibility had reached a magnitude of 8.3. The comet was on track with NASA’s predictions until August 19, 2011, when it was destroyed by a coronal mass ejection (CME)—a massive burst of solar wind. During this event, Elenin disintegrated and broke apart. NASA officials stated that such occurrences were extremely rare, with only 2% of new comets approaching the sun being destroyed in this way. By mid-October 2011, Elenin made its closest pass to Earth, but by then, it was just a pile of debris. Even large ground-based telescopes failed to detect any remnants of the comet.
After its disintegration, Comet Elenin’s remains were likened to the debris field of Shoemaker-Levy 9, which was filled with fragments. The remnants of Elenin will follow a similar path as other broken-up comets, trailing behind in a debris cloud. This debris will continue its journey out of the inner solar system, and it’s unlikely that the scattered remains of Elenin will return for nearly 12,000 years.
Amid the controversy surrounding Elenin, its unusual destruction left a lasting impression. In the week leading up to the CME, online articles speculated that the European Space Agency had a plan to destroy an asteroid headed toward Earth. For instance, the Daily Mail posted an article titled 'Fact following fiction? Scientists plan mission to blow up an asteroid hurtling towards Earth.' This article, last updated on August 18, 2011, just one day before Elenin’s destruction, discussed the Don Quijote space probe, which was designed to study the impact of crashing a spacecraft into an asteroid.
1. The Broad Implications
When Comet Elenin was first discovered, many expected the mainstream U.S. media to cover the story, but that didn’t happen. This sparked suspicions that NASA was withholding information. The significance of Comet Elenin was considerable, especially since NASA has a congressional mandate to track all near-Earth objects (NEOs) at least 1 kilometer in diameter. Such objects could have catastrophic consequences if they were to impact Earth. Studies indicate that the U.S. and China are the most vulnerable countries in the event of a meteor strike.
The general rule for NEOs is that they have an aphelion distance of less than 1.3 AU. As of May 2012, a total of 8,971 NEOs had been discovered, with 91 of those being near-Earth comets and 8,880 being near-Earth asteroids. This makes Comet Elenin a rare find. What makes it even rarer is how closely the comet’s remnants passed Earth on October 16, 2011—just 0.2338 AU away, which is quite close compared to other famous comets of similar size.
Several smaller asteroids have passed by Earth at closer distances. One of note is asteroid 2010 AL30, which flew by on January 13, 2010, at a mere 122,000 km (76,000 miles) away. Though only 10-15 meters (33-49 feet) wide, if AL30 had entered Earth’s atmosphere, it could have created an air burst equivalent to between 50 and 100 kilotons of TNT. For context, the Hiroshima “Little Boy” atom bomb had a yield of 13-18 kT. This underscores the importance of monitoring comets and asteroids of all sizes to keep them from entering Earth's atmosphere.
