Comets



All About Comets

For thousands of years comets have fascinated humanity. They appear suddenly and brilliantly, trailing their tails across the sky like a banner of light, and then disappear as quickly as they had arrived. Ancient people considered them ill omens and signs of poor luck, and as recently as 1910 people believed they could be poisoned by gas brought by the comet. There is something admittedly frightening about their somewhat eerie appearance – against the night sky, they look almost like blazing specters. So, then, what exactly are comets? Where do they come from, and where do they return to?

The ‘core' of the comet is, in truth, fairly small. It's thought that cores are at the maximum four miles across, and one mile is considered a more reasonable estimate. The core is most likely a ball of frozen ice and rocks, sort of like a particularly grubby snowball. For the most part it remains in this inert state when left alone. However, when a comet comes near the sun, the ice on the surface of the core melts into gases that form a cloud around the comet known as the coma. This cloud is ionized by the sun, causing the bright colors.

The tails of the comet form when the solar wind pushes the gases that make the coma out behind the comet, forming the long, flaring gas tail. The other fainter tail that some comets form comes from the solid debris that's been freed from the melting core, which turns into a just-visible ‘dust' tail. This curves because the debris is pushed at different rates by the wind, forming a lagging curve.

Thus, when the comets are close enough to appear in our skies they appear as brilliantly glowing points trailed by two tails – one almost as vivid and one ghostly and faint. They can often be quite bright, even to the point of being visible in daylight, and produce a stunning visual effect. It is easy to see why people of the ancient world were fascinated by them.

Comets come in two varieties – periodic and non-periodic. The comets we see in our skies are ones on extremely elongated elliptical orbits that go from the furthest reaches of the solar system to distances close enough to the sun to cause their tails to form. Periodic comets complete this orbit on a scale we can recognize, such as Halley's Comet, which arrives every 75 to 80 years. Non-periodic comets most likely do have a period, but humanity has only been able to witness one orbit due to the extreme length of their orbit. It might well be thousands of years. Most of the periodic comets have most likely become ensnared by the gravity of one planet or another, shortening their orbit as a result.

The passing of a comet is a brilliant, beautiful event, and some comets like Halley's Comet are true once-in-a-lifetime experience. When the next comet comes close enough to be seen in our skies, make sure you go out and look – the sight of that brilliant streak across the night sky will remain with you forever. Far from being an ill omen, comets are instead a miracle of nature.

The Great Comet Scare of 1910

In the vast canvas of the night sky, comets have long captivated human imagination. With their brilliant tails and unpredictable appearances, these celestial visitors have been both awe-inspiring and, at times, sources of fear. Among the most famous of these cometary guests is Halley's Comet, which has made regular appearances in Earth's skies for centuries.

However, perhaps one of the most remarkable and exaggerated episodes in the history of cometary encounters was the Great Comet Scare of 1910 when Halley's Comet caused widespread panic and fascination.

The Enigmatic Halley's Comet: A Brief Introduction

Halley's Comet, named after the British astronomer Sir Edmond Halley, is one of the most well-known comets in human history. Its highly elliptical orbit brings it close to the Sun and then carries it far into the outer reaches of the solar system.

Here's a list of key attributes that define this iconic comet:

  • Orbital Period: Halley's Comet has an orbital period of approximately 76 years. This means that it makes a return visit to our vicinity about once every human lifetime, providing opportunities for observation and study.
  • Highly Elliptical Orbit: The comet's orbit is highly elliptical, taking it from the outer reaches of the solar system, near Neptune, to within the inner solar system, close to the Sun. This journey leads to significant variations in its distance from the Sun and its brightness as seen from Earth.
  • Coma and Tail: As Halley's Comet approaches the Sun, heat causes the release of gases and dust from its icy nucleus. This forms a glowing coma, a hazy cloud around the nucleus, and a tail that points away from the Sun due to the solar wind. These features create the comet's distinctive appearance in the night sky.
  • Variable Brightness: Depending on its proximity to the Sun and Earth, Halley's Comet can vary greatly in brightness during different appearances. Some returns are more spectacular than others, with the brightness ranging from relatively faint to exceptionally brilliant.
  • Nucleus Composition: The nucleus of Halley's Comet is composed primarily of ice, dust, and rocky material. This mixture is often referred to as a "dirty snowball," reflecting its icy and rocky nature.
  • Size and Shape: The nucleus of Halley's Comet is irregular in shape, measuring approximately 15 kilometers (9.3 miles) in its longest dimension. Its size and composition make it a valuable subject of study to understand the origins of comets and the early solar system.
  • Ecliptic Plane: Halley's Comet orbits the Sun in the same plane as the planets, known as the ecliptic plane. This characteristic places it in a position where it can potentially be seen from Earth during its apparitions.

The Great Comet Scare: A Prelude to Panic

As Halley's Comet's 1910 return approached, excitement and apprehension built up across the globe. By this time, scientific understanding of comets had improved, dispelling some of the ancient myths and superstitions that had surrounded them. However, there was still a degree of uncertainty and fear associated with these celestial phenomena.

Adding to the intrigue, the 1910 return coincided with the Earth's passage through the comet's tail. Although scientists knew that the tail of a comet was composed of gases and dust that posed no real threat, the general public was unaware of this fact. This knowledge gap became the fertile ground on which the seeds of panic were sown.

Media Sensationalism and Public Panic

The media of the time played a pivotal role in exacerbating the comet scare. Newspapers, with their limited understanding of astronomy and penchant for sensationalism, eagerly reported on the comet's upcoming visit. They often gave voice to unfounded claims, including suggestions that the Earth might pass through the tail of the comet, potentially causing widespread disaster. Headlines blared with dire predictions, and the general public was left bewildered and terrified.

In the midst of this frenzy, some charlatans sought to exploit the situation for their gain. Quack remedies, survival guides, and even "comet shelters" were advertised, preying on people's fears and capitalizing on the prevailing hysteria. These opportunistic actions only fueled the widespread panic.

Astronomers Attempt to Calm the Waters

While the media fanned the flames of fear, astronomers and scientists worked diligently to provide accurate information and allay public concerns. Prominent astronomers of the time, including Camille Flammarion and Percival Lowell, used their knowledge to counter the sensationalist claims in the media.

Flammarion, a French astronomer, published a book titled "The Truth About Halley's Comet" in an effort to provide the public with a clear and scientifically grounded perspective. He emphasized the vast emptiness of space and the negligible impact of the comet's tail on Earth. Similarly, Percival Lowell, an American astronomer, used his observatory to carefully observe the comet and educate the public about its true nature.

The Spectacular Anti-Climax

As Halley's Comet approached its closest point to Earth in April 1910, the public held its collective breath, unsure of what to expect. Would the Earth be enveloped in a toxic cloud of comet tail gases? Would catastrophic events unfold? The anticipation reached a fever pitch.

However, as the comet's closest approach came and went, it became evident that the predictions of disaster were unfounded. The comet's tail posed no threat, and the Earth continued its journey through space unscathed. The contrast between the sensationalism of the media and the uneventful reality was stark, leaving many feeling duped and others relieved.

Legacy and Lessons Learned

The Great Comet Scare of 1910 remains a notable example of how misinformation, media sensationalism, and public fears can intersect to create a climate of panic. It serves as a reminder of the importance of accurate and responsible reporting, especially in matters of science and public information. The episode also underscores the significance of scientific literacy, as a lack of understanding about comets and celestial phenomena led to unnecessary fear.

Additionally, the events of 1910 highlighted the crucial role that astronomers and scientists play in educating the public and dispelling myths. Their efforts to provide accurate information and counter misinformation helped to alleviate panic and foster a more informed perspective.

Conclusion

The Great Comet Scare of 1910 serves as a cautionary tale about the power of media influence and the human tendency to succumb to fear in the face of the unknown. Halley's Comet, a celestial wanderer with a long history of captivating humanity, became a vehicle for mass hysteria and sensationalism. The events of 1910 remind us of the need for critical thinking, scientific literacy, and responsible journalism to ensure that future encounters with comets and other celestial wonders are met with curiosity rather than unwarranted panic.

1. What was the primary cause of the panic surrounding Halley's Comet in 1910?

The panic surrounding Halley's Comet in 1910 was primarily fueled by a combination of media sensationalism and public ignorance about comets. Newspapers of the time published sensational headlines and speculative articles that exaggerated the potential dangers of the comet's approach, leading to widespread fear. Additionally, the public's limited understanding of celestial phenomena and the composition of comet tails contributed to the panic.

2. Were there any actual dangers associated with Halley's Comet's passage in 1910?

No, there were no actual dangers. While the public was led to believe that the Earth might pass through the tail of the comet, scientific knowledge of the time confirmed that comet tails are composed of gases and dust that are so diffuse that they pose no real threat to our planet. Astronomers and scientists tried to convey this information, but the media's sensational reporting overshadowed their efforts.

3. Did the Great Comet Scare of 1910 lead to any lasting changes in public perception of comets?

While the immediate panic subsided after Halley's Comet's uneventful passage in 1910, the episode had a lasting impact on public perception of comets. It highlighted the potential for misinformation and sensationalism to drive widespread fear, even in the face of scientific knowledge. However, over time, improved scientific education and more responsible journalism have helped to temper public reactions to such celestial events.

4. Has Halley's Comet caused similar panics during its other returns?

Halley's Comet has a long history of appearances, and while the Great Comet Scare of 1910 stands out as one of the most dramatic instances of panic, there have been other episodes of public concern during its previous returns. However, with each passing appearance, scientific understanding has improved, and efforts to educate the public about comets have become more effective in preventing widespread panic. The last appearance of Halley's Comet in 1986, for example, was met with fascination and curiosity rather than fear.

Comets That Can Be Seen

Not too long ago, people used to think that comets were a bad omen. They took it as a symbol for something bad that was going to happen, such as a plague, wars, or other undesirable events. People were very ignorant about how and why objects were presented in the sky. Therefore, comets were a sign of great disturbance to them. Nowadays, we have the knowledge that comets are a small Solar System body, made up of nothing but clumps of ice and dust that travel to the center of the Solar System sporadically, in a predicted manner. Some comets come back more than once. When close to the Sun, its heat makes comets begin to evaporate. What we can see from Earth are the long tails that are formed from jets of gas and dust. At times, these tails can be millions of miles long.

If you are interested in catching a glimpse of a new comet, you may do so using a wide-field telescope (good for capturing pictures) or with binoculars. It is quite rare to find comets that are visible to the naked eye. However, several times a year you can see comets with an amateur-type telescope. There are some returning and new comets that can possibly be seen from Earth and in the near future. Not all comets are visible from anywhere on Earth. It depends highly on your location. If you are looking to observe some comets soon, here is a list of upcoming comets that will be visible in August 2011. (To see full list and other comets visit http://cometchasing.skyhound.com)

1. 45P/Honda-Mrkos-Pajdusakov: - a morning comet that can be seen with binoculars.

  • Visibility 8/13: Low in southern sky during morning around 4:50 am (latitude: equator).
  • High in moonlight around 4:10 (latitude: 30°S)
  • 8/20: Low in eastern sky 5:20 am (latitude: 30°S)

2. C/2009 P1 (Gerradd): – evening comet, visible with binoculars.

  • 8/13: High in moonlight 11:00, 11:10, 11:10, 11:20 pm at latitudes of 55°N, 40°N, Equator, 30°S respectively.
  • For visibility of 8/20 and 8/27 see website.

3. C/2010 X1 (Elenin): – evening comet, visible with small telescopes

  • 8/13: High in western sky during evening twilight 7 pm (latitude: equator)
  • High in western sky during evening twilight 6:40 pm (latitude 30°S)
  • For visibility of 8/20 and 8/27 see website.

4. C/2011 M1 (Linear): A far-northern morning comet visible in an 8-inch telescope

  • 8/13: High during morning twilight 2:20 am (lat: 55° N)
  • High in northern sky, morning twilight 3:50 am (lat: 40°N)
  • For visibility of 8/20 and 8/27 see website.

5. C/2010 G2 (Hill): A northern hemisphere morning comet visible in a 14-inch telescopev

  • 8/13: High during morning twilight 2:20 am (lat: 55° N)
  • High in northern sky, morning twilight 3:50 am (lat: 40°N)
  • For visibility of 8/20 and 8/27 see website.

6. 213P/Van Ness: A morning comet visible in very large telescopes

  • 8/13: High during morning twilight 2 am (lat: 55°N)
  • High in moonlight at 2 am (lat: 40°N)
  • High in moonlight 1:50 (lat: equator)
  • High in moonlight 1:50 (lat: 30°S)
  • For visibility of 8/20 and 8/27 see website.

Seeing Halley's Comet Up Close

In 1986, Halley's Comet made one of its rare returns to the sun and Earth, opening up an opportunity that had never been present before – namely, the chance to send a spacecraft to examine the comet up close and learn more about its nature and structure. Five craft, manned by the USSR, the European Space Agency, and Japan, went to the comet to study it, snapping pictures and obtaining data that had never been available before. These five craft, known collectively as the Halley Armada, helped formulate much of our modern knowledge of comets in general and Halley's Comet in particular.

One of the craft, the European Giotto, was the first to obtain color pictures of the nucleus of the comet. While many of the observations made were what was expected, others came as a surprise. The theories of Fred Whipple, who had speculated that comets were “dirty snowballs”, were proven mostly right – the cause of the brilliant coma and streaming tail of the comet was indeed the evaporation of ice and the freeing of dust particles. However, observation showed that most of the surface of the nucleus was covered in non-volatile dust, with only small parts of the surface (around 10%) responding in an ‘active' way. This showed that the “dirty snowball” was in fact mostly dirt with only a small amount of snow, surprising scientists.

The center of the comet was in fact only very loosely collected, being mostly a loose collection of rubble held together by gravity. In addition, the core was surprisingly small and jet black, despite the huge and bright appearance of the comet overall – all the extra size and brightness resulted from the emissions of the comet.

The emissions themselves proved to be mostly water, with some carbon monoxide, methane, and ammonia, and slight traces of hydrocarbons. Early speculation held that the composition of the ice was close enough to our ocean's water that comet impacts could have helped build Earth's water supplies, but further study showed that the composition was in fact much different. It is clear Halley's Comet has very different ice than our own.

Halley's Comet has turned out to be one of the most active comets of its type despite its seeming dimness and lack of activity, beating comets much like it (such as Encke and Holmes) by multiple magnitudes of order. This is why it is so vivid and startling in the skies when it arrives.

The Halley Armada is a brilliant example of international cooperation in science, showcasing the ability of humanity to explore the world around itself in new ways through cooperation and technology. The Armada helped us to better understand the universe, confirming old theories and introducing new questions and surprises. Hopefully in 2061 the nations of the world will repeat the effort, allowing us to discover even more new and startling things about Halley's Comet, that spectral visitor who still holds many questions for us to answer.

Halley's Comet: 1910, 1986 and Beyond

Halley's Comet, one of the most famous celestial objects, has a rich history that spans millennia. Its periodic appearances have been documented since ancient times, and its 76-year orbital cycle brings it back into Earth's vicinity with clockwork regularity. One of the most storied returns of Halley's Comet occurred in 1910, a year that witnessed both scientific triumphs and public hysteria. Let's explore this significant event in detail.

Historical Context

To understand the significance of Halley's Comet's 1910 return, it's essential to look at the historical context. The late 19th and early 20th centuries were periods of rapid scientific advancement. From the discovery of X-rays in 1895 to the widespread adoption of the telephone, the world was becoming a smaller, more interconnected place.

Yet, with this rapid progression came a general sense of uncertainty. Many people were both fascinated and fearful of the unknown, making the return of Halley's Comet an event of particular importance.

Scientific Predictions and Discoveries

Edwin B. Frost's Observation: Using the Yerkes Observatory's 40-inch refractor, astronomer Edwin B. Frost observed the comet as early as 1908, providing crucial data on its trajectory.

The Tail of the Comet: One of the most groundbreaking discoveries was that Earth would pass through the tail of Halley's Comet. This realization intensified the scientific and public interest in the event.

Cyanogen Gas Discovery: Spectroscopic analysis revealed the presence of the toxic gas cyanogen in the comet's tail, which led to widespread panic among the general public, fearing the gas would infiltrate Earth's atmosphere.

Public Reaction and Comet Fever

The 1910 return of Halley's Comet is as much a tale of human psychology as it is about the comet itself.

End-of-the-World Predictions: Predictably, with the discovery of cyanogen in the comet's tail, many doomsayers prophesied the end of the world. Newspaper headlines and pulpits alike spread rumors about the impending apocalypse.

Entrepreneurial Ventures: Opportunistic entrepreneurs capitalized on the widespread fear. They sold "comet pills," claiming these would counteract the effects of the toxic gas, as well as comet-themed merchandise like postcards and souvenirs.

Nightly Skywatching: Many people spent their evenings staring at the sky, waiting to catch a glimpse of the comet. Telescope sales boomed, and impromptu viewing parties became common.

Cultural Impact: The comet influenced many areas of culture, from literature to music. Many artists, writers, and musicians incorporated Halley's Comet themes into their work.

The Actual Event

When the day finally arrived for Earth to pass through Halley's Comet's tail, the event was anti-climactic for most. Contrary to the panic-fueled rumors, the world did not end. The cyanogen gas in the comet's tail was far too diffuse to have any effect on Earth's atmosphere, much less be harmful to humans.

However, the comet's appearance was a marvel to behold. Its bright nucleus and vast, glowing tail adorned the night sky, providing a once-in-a-lifetime spectacle for many. Amateur and professional astronomers alike observed and documented the event, leaving behind a rich repository of data for future generations.

Aftermath and Legacy

The 1910 return of Halley's Comet reinforced a few essential lessons:

  • Scientific Literacy: The event underscored the importance of scientific literacy. A more informed public might have reacted with less panic to the discovery of cyanogen in the comet's tail.
  • Media Responsibility: The media's role in exacerbating public fears highlighted the importance of responsible journalism. Misinformation can lead to unnecessary panic.
  • Celestial Marvel: Above all, the comet's return was a testament to the wonders of the universe. For many, it was a humbling experience, reminding humanity of its small place in the vast cosmos.

The 1910 return of Halley's Comet offers a compelling glimpse into the human psyche and our relationship with the cosmos. While it reminds us of the wonders that lie beyond our planet, it also cautions us about the dangers of misinformation and the need for informed public discourse.

The 1986 Return

After its memorable appearance in 1910, the world eagerly awaited Halley's Comet's next visit. By the time 1986 rolled around, both society and technology had undergone dramatic transformations.

  • Space Exploration: The most significant difference between the two visits was our capability to explore space directly. In 1986, a fleet of spacecraft, including the European Space Agency's Giotto and the Soviet Union's Vega 1 and 2, were dispatched to encounter Halley's Comet. These missions provided unprecedented close-up images of the comet's nucleus and valuable scientific data.
  • Public Engagement: The world was much more interconnected in 1986, with televisions in most households. This meant that even those who couldn't see the comet due to their geographic location or cloudy skies could still witness its beauty through broadcasts.
  • A Dimmer Display: Unlike its brilliant display in 1910, the 1986 appearance was relatively dimmer. This was due to the comet's position relative to Earth and the Sun, making it less visible from our vantage point.

Anticipating 2061

With the advancements in technology and our growing understanding of the cosmos, the 2061 return of Halley's Comet is eagerly anticipated.

Space Tourism: By 2061, space tourism might be a reality for many. Companies could potentially offer trips for people to witness the comet from space, providing an unparalleled viewing experience.

Advanced Monitoring: With the rapid advancements in telescope technology and satellite capabilities, by 2061, we will have the means to observe, study, and document Halley's Comet like never before.

Cultural Celebrations: Given the historical and cultural significance of Halley's Comet, its return in 2061 will likely be accompanied by global celebrations, festivals, and educational events, making it a unifying event for humanity.

Incorporating the past, present, and future appearances of Halley's Comet gives us a broader perspective of its significance. From being a mysterious harbinger in ancient times to becoming a subject of scientific study and global celebration, the comet's journey through human history is a testament to our ever-evolving relationship with the cosmos.

Why was the 1910 return of Halley's Comet significant?

It was significant due to the scientific discoveries associated with it and the widespread public reaction, ranging from fear to fascination.

Did the cyanogen gas in Halley's Comet's tail pose any threat to Earth?

No, the cyanogen gas was too diffuse to affect Earth's atmosphere or its inhabitants.

When did Halley's Comet last appear, and when will it return?

After its 1910 appearance, Halley's Comet last graced our skies in 1986. It's expected to return in 2061.

How did the comet impact culture in 1910?

The comet influenced various cultural domains, from literature and music to visual arts, with many creatives integrating comet themes into their work.

Why was the 1986 appearance of Halley's Comet dimmer than its 1910 appearance?

The brightness of the comet's appearance from Earth is influenced by its position relative to both the Earth and the Sun. In 1986, the positions were such that the comet appeared dimmer to observers on Earth compared to its 1910 pass.

What advancements in technology or space exploration can we expect to utilize for the 2061 appearance of Halley's Comet?

While it's hard to predict with certainty, by 2061, we might have more advanced space telescopes, better satellite imaging capabilities, and potentially even space tourism options that could allow people to witness the comet up close from space. Additionally, there might be international collaborative missions to study the comet in greater detail, leveraging sophisticated sensors and instruments.


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