Halley's Comet: An Occasional Visitor

Have you ever been awestruck by the night sky with its twinkling stars and mysterious planets? One of the most fascinating cosmic phenomena that have been mesmerizing people for millennia is the Halley's Comet. This article will explore the mystery of Halley's Comet and delve into some of the facts and figures associated with it.

Introduction - What is Halley's Comet?

Halley’s Comet is a short-period comet that appears in the night sky approximately every 75-76 years. It is one of the most easily recognizable comets in the solar system and is one of the few that can be seen with the naked eye. The comet is named after Edmond Halley, an 18th-century British astronomer who was the first to recognize that it was a periodic celestial object. Halley's Comet is composed of a nucleus, coma, and tail. The nucleus is the solid core of the comet, and the coma and tail are the gas and dust that surround the nucleus.

The comet has been observed since ancient times and has been linked to some of the most notable events in history, including the birth of King Henry I of England in 1101, the Norman Conquest of England in 1066, and the Great Fire of London in 1666. While its appearance has been a source of both fascination and fear throughout the centuries, modern astronomers have been able to study the comet in much more detail and predict when it will appear in the night sky.

History of Halley's Comet

The first recorded observation of Halley's Comet dates back to 240 BCE by Chinese astronomers. The comet was also seen by the ancient Greeks and was recorded by Ptolemy in 87 CE. In 837 CE, the comet was observed by the Japanese and was linked to the fall of the Tang Dynasty. The comet was also seen in 912 CE, 1066 CE, and 1301 CE.

Halley's Comet Seen by Europe's Giotto Probe from 600K away. (image Credit: ESA, Lindau)

In the 17th century, Edmond Halley studied historical records of the comet and realized that it had appeared in the night sky at regular intervals. He was the first to hypothesize that the comet was periodic and that it would return in 1758. He was right and the comet was promptly named after him.

In the 19th century, Halley's Comet was observed by astronomers in Europe, the United States, and around the world. In 1835, the comet passed by Earth and its tail was visible for months. In 1910, the comet made a close approach to Earth and was even visible during the day.

Facts about Halley's Comet

Halley's Comet is one of the most studied and well-known comets in the solar system. Here are some interesting facts about the comet:

• Halley's Comet is the only short-period comet that can be seen with the naked eye.

• The comet is made up of a nucleus, coma, and a tail.

• The nucleus of the comet is composed of ice, dust, and rocky material.

• The nucleus of the comet is estimated to be between 6 and 15 km in diameter.

• The coma is made up of dust and gas, and is estimated to be between 20 and 80 km in diameter.

• The tail of the comet is made up of dust, gas, and ionized particles and can stretch for millions of kilometers.

• The comet is estimated to be around 4 billion years old.

• The comet is believed to have originated in the Kuiper Belt, a region beyond the orbit of Neptune.

Halley's Comet's Orbit

Halley's Comet orbits the Sun in a highly elliptical orbit, with a period of approximately 75-76 years. It is believed that the comet was formed in the Kuiper Belt and was thrown into its current orbit by the gravitational pull of the outer planets. The comet's orbit is highly inclined to the plane of the solar system, with an inclination of 162 degrees.

Halley's Comet as Captured in 1986 during a close-to-Earth fly-by. (Image Credit: NASA)

When the comet is closest to the Sun, it is traveling at a speed of around 135,000 km/h. As it moves away from the Sun, its speed slows down to around 35,000 km/h.

Halley's Comet's Last Appearance in 1986

Halley's Comet was last observed in the night sky in 1986. This was the comet's closest approach to Earth since 1910, and it was visible for weeks. The comet was studied by astronomers from all over the world and numerous photographs were taken.

The comet reached its perihelion, or closest approach to the Sun, on February 9, 1986. During this time, the comet was traveling at a speed of around 135,000 km/h. The comet was estimated to be around 20 km in diameter, and its tail stretched for millions of kilometers.

During its approach and the comet was easily visible in the night sky with the naked eye. It was also visible during the day, and its tail was estimated to be around 8 million kilometers long.

When Will Halley's Comet Return?

Halley's Comet will next appear in the night sky in the year 2061. This will be the comet's closest approach to Earth since 1986, and it will be visible for weeks. The comet is expected to reach its perihelion, or closest approach to the Sun, on July 28, 2061.

How Big is Halley's Comet?

Halley's Comet is estimated to be between 6 and 15 km in diameter. Its coma is estimated to be between 20 and 80 km in diameter, and its tail can stretch for millions of kilometers.

The nucleus of the comet is composed of ice, dust, and rocky material. The coma is made up of dust and gas, and the tail is made up of dust, gas, and ionized particles.

Halley's Comet 1986 Photo

The 1986 pass of Halley's Comet was a once-in-a-lifetime event, and numerous photographs were taken of the comet during this time. This photograph shows the comet's nucleus and its coma, along with its tail stretching for millions of kilometers across the night sky.

Conclusion

Halley's Comet is one of the most well-known and studied comets in the solar system. It is a short-period comet that appears in the night sky once a human-lifetime and has been observed since ancient times.

The mystery of Halley's Comet is sure to captivate people for centuries to come. From ancient times to the present day, it has been a source of awe and fascination and is sure to continue to be so in the future.