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Objective – Describe the characteristics of comets, asteroids, and meteors.

Comet Facts, Myths, and Legends(from NASA - Space Science: Adventure Is Waiting/Hubble – Amazing Space)

The word "comet" comes from the Greek word for "hair." Our ancestors thought comets were stars with what looked like flowing hair trailing behind.

For centuries, scientists thought comets traveled in the Earth's atmosphere. In 1577, observations by Danish astronomer Tycho Brahe showed that they actually traveled far beyond the moon.

Sir Isaac Newton (1642-1727), the great English scientist, discovered that comets move in elliptical (egg-shaped) orbits around the Sun. He also thought that comets were members of the Solar System, just like planets, and that they could return over and over again. He was right!

As early as the 1700's, scientists began developing mathematical formulas that could predict the orbit of a particular comet around the Sun. At that time,

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calculators and computers didn’t exist, so everyone had to do the calculations by hand!

Most astronomers in the 1500's and early 1600's thought that a comet came once and was never seen again. They believed that a comet approached the Sun in a straight line, spun around it, and then disappeared into space in a straight path.

People did not always know what comets were. In ancient times, people thought comets were "power rays" of supernatural beings. They thought comets contained fire because they were so bright in the sky.

Some people in ancient times thought that a comet was a curse. To save himself from the "curse of the comet," Emperor Nero of Rome had all possible successors to his throne executed.

In 1910, people panicked when a comet passed through Earth’s path around the Sun. In Chicago, people sealed their windows to protect themselves from the comet’s poisonous tail. Others committed suicide. Special "Comet Protecting Umbrellas," gas masks, and "anti-comet pills" were sold.

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Not everyone saw comets as bad luck. Some thought they brought good luck. They also believed that comets carried angels through the heavens.

People have known about comets, unlike other small bodies in the Solar System, since ancient times. The Chinese recorded visits by Halley's Comet as far back as 240 B.C.

The famous Bayeux Tapestry, which commemorates the Norman Conquest of England in 1066, depicts an image of Halley's Comet bright in the sky before the Battle of Hastings.

Some people thought this meant that King Harold would lose his throne to William, the Duke of Normandy. He did!

Edmund Halley of England studied comets and developed a theory suggesting that those sighted in 1531, 1607 and 1682 were actually the same object. He was the first to predict successfully the comet’s next appearance in 1758, but he died 16 years before the comet returned.

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Halley’s Comet reappears every 76 years. Its next appearance is in 2061. Maybe you will see it return!

Comets leave a trail of debris behind them. If their path crosses Earth's path, then at that point, every year for a long time, there will be meteor showers as the long-gone comet's debris strikes our atmosphere.

Some of these meteor showers occur every year when the Earth passes the place where the comet

had been long ago.

The Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes through the orbit of the Swift-Tuttle comet. Halley's Comet is the source of the Orionid shower in October.

Comets are brightest when they are near the Sun.

Comet Hale-Bopp 1995

On July 23, 1995, an unusually large and bright comet was seen outside of Jupiter's orbit by Alan Hale of New Mexico and Thomas Bopp of Arizona. Careful analysis of

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Hubble Space Telescope images suggested that its intense brightness was due to its exceptionally large size. While the nuclei of most comets are about 1.6 to 3.2 km (1 to 2 miles) across, Hale-Bopp's was estimated to be 40 km (25 miles) across. It was visible even through bright city skies, and may have been the most viewed comet in recorded history. Comet Hale-Bopp holds the record for the longest period of naked-eye visibility: an astonishing 19 months. It will not appear again for another 2,400 years.

Comet Swift-Tuttle 1982

This comet was first seen in July 1862 by American astronomers Lewis Swift and Horace Tuttle. As Comet Swift-Tuttle moves closer to the Sun every 120 years, it leaves behind a trail of dust debris that provides the ingredients for a spectacular fireworks display seen in July and August. As Earth passes through the remnants of this dust tail, we can see on a clear night the Perseid meteor shower. Comet Swift-Tuttle is noted as the comet some scientists predicted could one day collide with Earth because the two orbits closely intercept each other. The latest calculations show that it will pass a comfortable 24 million km (15 million miles) from Earth on its next trip to the inner Solar System.

Comet Hyakutake 1996

On January 30, 1996, Yuji Hyakutake (pronounced "hyah-koo-tah-kay"), an amateur astronomer from southern Japan, discovered a

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new comet using a pair of binoculars. In the spring of that year, this small bright comet with a nucleus of 1.6 to 3.2 km (1 to 2 miles) made a close flyby of Earth — sporting one of the longest tails ever observed. The Hubble Space Telescope studied the nucleus of this comet in great detail. This is not Comet Hyakutake's first visit to the inner Solar System. Astronomers have calculated its orbit and believe it was here about 8,000 years ago. Its orbit will not bring it near the Sun again for about 14,000 years.

Comet Halley 1985

Comet Halley is perhaps the most famous comet in history. It was named after British astronomer Edmund Halley, who calculated its orbit. He determined that the comets seen in 1531 and 1607 were the same objects that followed a 76-year orbit. Unfortunately, Halley died in 1742, never living to see his prediction come true when the comet returned on Christmas Eve in 1758. Each time this comet's orbit approaches the Sun, its 15-km (9-mile) nucleus sheds about 6 m (7 yards) of ice and rock into space. This debris forms an orbiting trail that, when falling to Earth, is called the Orionids meteor shower. Comet Halley will return to the inner Solar System in the year 2061.

Comet Shoemaker-Levy 9 1993

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Between July 16 and July 22, 1994, more than 20 fragments of Comet Shoemaker-Levy 9 collided with the planet Jupiter. Astronomers Carolyn and Eugene Shoemaker and David Levy discovered the comet in 1993. The Hubble Space Telescope took many spectacular pictures of this event as the comet's pieces crashed into Jupiter's southern hemisphere. It was the first collision of two Solar System bodies ever to be recorded. The impacts created atmospheric plumes many thousands of kilometers high that showed hot "bubbles" of gas with large dark "scars" covering the planet's sky.

(source: hubblesite.org)

Myths vs. Reality - Comets(from NASA: Amazing Space)

Myth

Comets come from regions outside the Solar System.

Reality~7~


Comets are part of the Solar System. Scientists believe they come from one of two locations within the Solar System: the Kuiper belt and the Oort cloud. The comets that we see often – every 100 years – come from the Kuiper belt, and comets that we see rarely – every few thousand years – come from the Oort cloud.

Myth

Comets are composed of the same material as asteroids.

Reality

Although comets and asteroids are both tiny bodies that orbit in the Solar System, their composition is different. Asteroids are mostly rock with some ice, while comets are mostly ice with some rock.

Myth

Comets always have tails.

Reality

Comets do not always have tails. They develop a fuzzy, shell-like cloud called a coma, and one, two, or three tails when near the Sun. Comets have no coma or tail when far away from the Sun.

Myth

All comets look the same and don't change their appearance.

Reality

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Comets have a coma and one, two, or three tails when near the Sun, and no coma or tail when far away from the Sun. (A coma is a cloud of gaseous material surrounding the nucleus.)

Myth

Pluto is the most distant and last object in the Solar System.

Reality

Beyond Pluto's orbit is a group of icy objects known as the Kuiper Belt, from which short- period comets emerge. Farther still is a sphere of icy bodies, called the Oort Cloud, from which long-period comets emerge. Short-period comets visit the inner Solar System frequently, while the long-period comets visit infrequently.

Myth

There is empty space between the planets.

Reality

There is gas and dust, also known as the interplanetary medium, between the planets. Comets are responsible for depositing some of the gas and dust found in the inner Solar System.

Name _____________________________________________________________

Comet Facts, Myths, and Legends Worksheet~9~


1. The word comet comes from a Greek word meaning…

a. beard. c. mane.b. hair. d. ponytail.

2. Who was the scientist who proved that comets traveled far beyond the Moon?

a. Tycho Brahe c. Edmund Halleyb. Galileo d. Sir Isaac Newton

3. From ancient times, people knew what comets were.

a. True b. False

4. To save himself from the comet’s curse, Emperor Nero did what?

a. Left Rome for his safety.b. Killed all his possible successors.c. Sent his sons to convents.d. Did nothing because he didn’t believe in comet curses.

5. In 1910, people bought which of the following item(s) to protect themselves from Comet Halley?

a. Comet protecting umbrellas c. Gas maskb. Anti-comet pills. d. All of the above

6. Some people thought comets brought good luck because they carried angels across the heavens.

a. True b. False

7. When did the Chinese first record visits by Comet Halley?

a. 440 B.C. c. 240 A.D.b. 240 B.C. d. 440 A.D.

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8. The Bayeux Tapestry showed Comet Halley in the sky during the Battle of Hastings in 1066 A.D. People thought this meant King ___________ would lose the throne.

a. Charles c. Haroldb. George d. Richard

9. Edmund Halley proposed a hypothesis that the comets seen in 1531, 1607, and 1682 were the same comets. He predicted the comet would return again in 1758. Edmund Halley was…

a. correct. b. incorrect.

Match the Comet with the year it will return.

_____ 10. Comet Hale-Bopp

_____ 11. Comet Halley

_____ 12. Comet Hyakutake

_____ 13. Comet Shoemaker-Levy 9

_____ 14. Comet Swift-Tuttle

A. Never

B. 2061

C. 2102

D. 4395

E. 15,669

Match the term with its definition.

_____ 15. Coma

_____ 16. Comet

_____ 17. Dust tail

_____ 18. Nucleus

_____ 19. Solar wind

A. A “dirty snowball” consisting of ices, rocks, and dirt.

B. A stream of charged particles ejected from the surface of the Sun.

C. Forms when the solar wind separates dust from the coma, pushing it outward away from the Sun.

D. The cloud of gas and dust that forms around a comet's nucleus.

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E. The solid icy/rocky part of a comet.

Identify which statement is “reality” or a “myth.”

_____ 20. Comets come from regions outside the Solar System.

_____ 21. Asteroids are mostly rock; comets are mostly ice with some rock.

_____ 22. Comets do not always have a tail.

_____ 23. All comets look the same and don't change their appearance.

_____ 24. Comets are found beyond the orbit of Pluto.

_____ 25. There is empty space between the planets.

A. Myth

B. Reality

Statement True False26.

Only a professional astronomer with a powerful telescope can discover a new comet.

A B

27.

About 100 years ago, some people bought comet-protecting umbrellas and anti-comet pills to protect themselves.

A B

28.

The closer a comet is to the Sun, the brighter it will appear.

A B

2 The ancients thought comets were the A B~12~


9. power rays of supernatural beings.30.

A meteor shower occurs when many comets at once pass over the Earth.

A B

Scoring Guide95-100% - 4 90-94% - 3.585-89% - 3

75-84% - 2.565-74% - 255-64% - 1.5

45-54% - 1 1-44% - .5

Comet Facts, Myths, and Legends – Key I

1. The work comet comes from a Greek word meaning…

b. hair

2. Who was the scientist who proved that comets traveled far beyond the Moon?

a. Tycho Brahe

3. From ancient times, people knew what comets were.

b. False

4. To save himself from the comet’s curse, Emperor Nero did what?

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c. Killed all his possible successors.

5. In 1910, people bought which of the following item(s) to protect themselves from Comet Halley?

d. All of the above

6. Some people thought comets brought good luck because they carried angels across the heavens.

a. True

7. When did the Chinese first record visits by Comet Halley?

b. 240 B.C.

8. The Bayeux Tapestry showed Comet Halley in the sky during the Battle of Hastings in 1066 A.D. People thought this meant King ___________ would lose the throne.

c. Harold

9. Edmund Halley proposed a hypothesis that the comets seen in 1531, 1607, and 1682 were the same comets. He predicted the comet would return again in 1758. Edmund Halley was…

a. correct.

D 10. Comet Hale-Bopp

B 11. Comet Halley

E 12. Comet Hyakutake

A 13. Comet Shoemaker-Levy 9

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C 14. Comet Swift-Tuttle

D 15. Coma

A 16. Comet

C 17. Dust tail

E 18. Nucleus

B 19. Solar wind

A 20. Comets come from regions outside the Solar System.

B 21. Asteroids are mostly rock; comets are mostly ice with some rock.

A 22. Comets do not always have a tail.

A 23. All comets look the same and don't change their appearance.

B 24. Comets are found beyond the orbit of Pluto.

A 25. There is empty space between the planets.

B 26. Only a professional astronomer with a powerful telescope can discover a new comet.

A 27. About 100 years ago, some people bought comet-protecting umbrellas and anti-comet pills to protect themselves.

A 28. The closer a comet is to the Sun, the brighter it will appear.

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A 29. The ancients thought comets were the power rays of supernatural beings.

B 30. A meteor shower occurs when many comets at once pass over the Earth.

Comet Facts, Myths, and Legends – Key II

1. b2. a

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3. b (2 choices)4. c5. d6. a (2 choices)7. b8. c9. a (2 choices)16. A (5 choices)17. C (5 choices)18. E (5 choices)19. B (5 choices)20. A (2 choices)21. B (2 choices)22. A (2 choices)23. A (2 choices)24. B (2 choices)25. A (2 choices)26. B (2 choices)27. A (2 choices)28. A (2 choices)29. S (2 choices)30. B (2 choices)

Comet Facts, Myths, and LegendsScoring Guide

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29-30 – 4 27-28 – 3.526 – 3 23-25 – 2.520-22 – 2 17-19 – 1.514-16 – 1 1-13 – .5

95-100% - 4 90-94% - 3.585-89% - 3 75-84% - 2.565-74% - 255-64% - 1.545-54% - 1 1-44%

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0 – 0 - .5

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