Planet Earth Part Two: Our Solar System

Section 1: Classifications

Our Solar System is made up of nine* planets and one sun.

Some scientists dispute the number of planets and suggest that Pluto not be classified as a planet, due to its size and lack of control over its orbital path.

Does Pluto qualify to be a planet?

For an object to be a planet, it needs to meet these three requirements defined by the International Astronomical Union (IAU).

It needs to be in orbit around the Sun. Number One

Yes, Pluto does orbit around the Sun, so maybe Pluto is a planet?

It needs to have enough gravity to pull itself into a spherical shape. Number TWO

Yep, that’s a spherical shape! Pluto Basketball

It needs to have "cleared the neighborhood" of its orbit. Number Three

What does "cleared its neighborhood" mean?

As planets form, they become the dominant gravitational body in their orbit in the Solar System.

As they interact with other, smaller objects, they either consume them,

or sling them away with their gravity.

Pluto is only 0. 07 times the mass of the other objects in its orbit Pluto is only 0.07 times the mass of the other objects in its orbit. The Earth, in comparison, has 1.7 million times the mass of the other objects in its orbit.

Any object that doesn't meet this 3rd criteria is considered a dwarf planet. And so, Pluto is a dwarf planet.

There are still many objects with similar size and mass to Pluto jostling around in its orbit. And until Pluto crashes into many of them and gains mass, it will remain a dwarf planet.

So for the sake of this lesson we will consider Pluto a Dwarf planet.

What are the two classifications of planets in our Solar System?

Inner vs. Outer or Rocky vs. Gas Planets correct!

Can anyone name the four Inner or Rocky planets?

That’s correct, the Inner or Rocky planets are Mercury, Venus, Earth, and Mars.

Can anybody name the five Outer or Gas planets?

Correct, the outer planets are Jupiter, Saturn, Uranus, Neptune, and Pluto.

Let’s Review! (Section 1) 1.) How many planets are there in our Solar System? 11 10 9 8

Let’s Review! (Section 1) 2.) What are the two classifications that we can divide the planets in our Solar System into? Rock and Inner Gas and Outer Inner and Outer Innie and Outtie Rock and Gas

Let’s Review! (Section 1) 3.) What are the names of the planets in our Solar System? M___________ f.) S_______________ V___________ g.) U______________ E___________ h.) N______________ M __________ i.) P______________ J____________

Let’s Review! (Section 1) 4.) Which planets are the Rocky planets? Earth f.) Neptune Jupiter g.) Pluto Mars h.) Uranus Mercury i.) Venus Saturn

Let’s Review! (Section 1) 5.) Which planets are the Gas planets? Earth f.) Neptune Jupiter g.) Pluto Mars h.) Uranus Mercury i.) Venus Saturn

Section 2: What’s in a Name?

How do planets and their moons get their names How do planets and their moons get their names? With the exception of Earth, all of the planets in our solar system have names from Greek or Roman mythology.

What’s a Myth? “Myth” is a Greek word meaning the telling of a story in order to explain some phenomenon of nature, customs, the origin of the species…

Here’s an example of a myth Here’s an example of a myth. Some parents tell their children that thunder comes when an angel goes bowling and bowls a strike!

Thunder is the sound that follows a flash of lightening, caused by the sudden heating and expansion of air by electrical discharge.

The Greeks believed that one of their gods named Zeus, would hurl lightening bolts down from the heavens if he was displeased with something or someone.

Myths are just a person’s attempt to explain something that they can’t make any sense of because they don’t have all of the facts and/or technology.

Science, facts, and proof take the place of myths for educated people.

Let’s Review! (Section 2) 1.) How did the planets and their moons get their names? From America’s Got Talent From Persian and African Mythology From Greek and Russian Mythology From Greek and Roman Mythology

Let’s Review! (Section 2) 2.) _________________is a Greek word meaning the telling of a story in order to explain some phenomenon of nature, customs, the origin of the species… proto e.) stellar b) mesa f.) disc c) myth g.) solar d) Ra h.) Zeus

Let’s Review! (Section 2) 3.) Myths are just a person’s attempt to explain something that they can’t make any sense of because they don’t ______. have an education know any better have all of the facts and/or technology they can’t read

Let’s Review! (Section 2) 4.) What three things take the place of myths for Educated people? gossip e) facts National Enquirer f) fairy tales science g) hear say proof h) Oprah

Section 3: The Sun and the Rock Planets

The central and largest member of our Solar System, the Sun.

Our Sun is the closest star to us.

The Sun is the most prominent feature in our solar system The Sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass.

The Sun's interior could hold over 1.3 million Earths.

We think of the Earth as a huge place We think of the Earth as a huge place. The dia-meter of the Sun is about 100 times wider than the Earth as can be seen in the diagram at left.

Some stars are as small as the Earth while others can be 500 times bigger than our Sun.

The astronomical symbol for the Sun is a shield with a dot at the middle. This symbol comes the ancient Egyptian sign for "sun" or "Ra" in the hieroglyphic writing system. The source of this symbol is unknown, but some historians think that the dot might represent a huge central sunspot.

Apollo, the Sun god, brings life-giving heat and light to Earth.

In Greek mythology, Apollo was the son of Zeus and Leto.

Leto gave birth to the twins Artemis and Apollo.

Artemis is the goddess of the wilderness, the hunt and wild animals, and fertility (she became a goddess of fertility and childbirth mainly in cities). She was often depicted with the crescent of the moon above her forehead and was sometimes identified with Selene (goddess of the moon).

Apollo was the god of the Sun, logic, and reason, and was also a fine musician and healer.

Mercury is the first planet from the sun.

Mercury is named after the messenger of the gods, who was also the god of commerce, travel and thievery in Roman mythology.

The planet probably received this name because it moves so quickly across the sky. A year on Mercury, one orbit around the sun, equals 88 days on Earth.

poised over divine spirit (circle) and matter (cross) The astronomical symbol for symbol for Mercury represents the head and winged cap of Mercury, god of commerce and communication, surmounting his caduceus (staff). Mind (crescent) poised over divine spirit (circle) and matter (cross)

Mercury Fun Facts Mercury is the closest planet to the Sun. Mercury rotates the Sun in only 88 days. Mercury rotates very slowly on its axis with one day taking 58 Earth days. During the day, the average temperature on Mercury is 800 degrees Fahrenheit. During the night, the average temperature is – 300 degrees. Mercury has the largest known impact crater of any planet, named Beethoven and 643 kilometers in size. Mercury has an eccentric orbit around the Sun, meaning it is closer and farther from the Sun at different points in time. Mercury can be seen with binoculars at sunset.

Venus is the second planet from the Sun.

Venus, goddess of love and beauty, the most brilliant object in the sky

Venus is one of the brightest objects in the night sky.

Venus is so bright because its thick clouds reflect most of the sunlight that reaches it (about 70%) back into space, and because it is the closest planet to Earth.

Venus can often be seen within a few hours after sunset or before sunrise as the brightest object in the sky (other than the moon). It looks like a very bright star. Venus is the brightest planet in the solar system.

Venus is the goddess of beauty, love and fertility in Roman mythology Venus is the goddess of beauty, love and fertility in Roman mythology. She is the equivalent of the Greek goddess Aphrodite and the Babylonian goddess Ishtar . She has the power to create passions whatever the consequences. Venus has several attributes such as the mirror, the belt, the rose and some animals like the ram or the dove, her favorite bird.

The symbol for Venus is designated as the female symbol, thought to be the stylized representation of the hand mirror of this goddess of love.

Below on the left is a picture of an ancient Egyptian mirror from the New Kingdom of Egypt on the right is the astronomical sign for the planet Venus.

This goddess has always inspired artists This goddess has always inspired artists. One of the most famous Venus paintings is The Birth of Venus, by the Italian painter Sandro Botticelli. It dates back to 1484. This painting tells a mythological story, the birth of Venus from the sea.  

Venus, standing on a giant scallop, is about to leave the sea Venus, standing on a giant scallop, is about to leave the sea. She is surrounded by three mythological characters. Zephyrus is the personification of the West wind. His wife is clasping him. She is the Nymph Chloris, the goddess of flowers. The last character is Flora, the season of spring, who is going to cover Venus with a cape to give her modesty.

In the background of the picture, the sea stretches to the horizon  In the background of the picture, the sea stretches to the horizon. On the right of the painting, there is a forest and the coast. In spite of the wind, whose effect is shown in the movement of Venus’s hair, the atmosphere of the painting is very peaceful.

Venus Fun Facts Venus is the brightest natural object in the night sky, with Moon being the only exception. Venus reaches its maximum brightness shortly before sunrise and shortly after sunset. This is the reason why it is usually called the 'Morning Star' or the 'Evening Star'. Venus is sometimes called 'Earth's sister planet', mainly due to the fact that the two are similar in size, gravity, and bulk composition. Venus is the sixth-largest planet in the solar system. The reason why Venus is not visible from Earth in the day is that it is covered with an opaque layer of highly reflective clouds of sulfuric acid. The atmospheric pressure at the surface of Venus is 92 times that of the Earth. One day on Venus is equal to 243 days on Earth, while its one year is equal to 224.7 days on Earth. Just like Earth, the interior of Venus is composed of a central iron core and a molten rocky mantle. Venus is the hottest as well as the brightest of all planets in the solar system. Venus is the only planet in the Solar System that rotates clockwise. All the other planets turn anti-clockwise. The rotation of Venus is opposite than that of Earth and there, Sun rises in the West.

Earth is the third planet from the Sun.

The symbol for Earth shows a globe bisected by meridian lines into four quarters.

Gaea the Earth goddess, in Greek mythology, she created the Universe and gave birth to both the first race of gods (the Titans) and the first humans. The ancient Greeks thought of her as Terra Mater or Earth Mother.

The word Earth originates from the Middle English word, erthe, which came from Old English.

It is akin to Old High German erda.

This, then traces back to the Greek,

Which comes from the Hebrew erez, meaning ground.

Earth is the only planet whose English name does not derive from Greek/Roman mythology.

Earth Fun Facts The earth is rotating at approximately 1000miles per hour.  The actual speed depends on the latitude of the observer.  The Earth orbits the Sun at a speed of 29.79 km (18.51 miles) per second, or 107,870 km (67,000 miles) per hour. Earth is referred to as the BLUE PLANET. WHY? Because from space, the oceans combined with our atmosphere make our planet look blue. Three quarters of the Earth is water. Earth is estimated to be 3-5 Billion Years old. Earth is estimated to weigh 6,585,600,000,000,000,000,000 tons. The area of the earth is almost 200 million square miles. Earth travels through space at 66,700 miles per hour. Earth's oceans are an average of 2 miles deep. Earth's rotation on its axis makes a day at 24 hours... Earth's orbit around the sun makes a year at nearly 365 and 1/2 days Earth is tipped at 23 and 1/2 degrees in orbit. That axis is what causes our seasons. Antarctica is the coldest place on earth. The continent is almost entirely covered in ICE ! Only 11 percent of the earth's surface is used to grow food. Breeze carries about 100 Million tons of sand particles around the earth yearly. That means if you live in America-you could have Sand that came from the Gobi desert in China.

Mars is the fourth planet from the Sun

The symbol for Mars represents the shield and spear of the god of war, Mars.

Mars is the Roman god of war

and agriculture.

Sometimes Mars was related to agriculture and has his own spring month named after him, March.

Spring was also the time the Roman legions began their conquests and you guessed it, got their march-ing orders.

Mars probably got its name from its red color, the color of blood.

Mars was very important to the Romans because he was the father of Romulus and Remus, the mythical founders of Rome.

Mars gets it red color from the iron oxide in its soil.

Iron Oxide is another way of saying Rust.

Rust occurs when iron comes into contact with water and oxygen.

The surface of Mars has many channels, valleys, and gullies.

These Martian features when first viewed by people back on Earth were presumed to be canals dug by living creatures.

They looked like some surface features on Earth.

These Martian canyons are thought to be caused by EROSION.

Erosion can be caused by both wind which can blow off layers of the top soil.

Which in turn will blast objects in their way and sometimes turn them into works of real beauty.

Or cause the destruction of existing structures.

and Water

Or both at the same time.

Mars Fun Facts Mars is the seventh largest planet in the Solar System. There has been strong evidence, mainly in the form of channels, valleys, and gullies, that Mars once had water flowing on its surface. Mars is home to 'Valles Marineris', a canyon system that is much deeper and much longer than the Grand Canyon in the United States. Mars boasts of having mountains that are higher than Mount Everest, the highest peak on Earth. It also houses Olympus Mons, the highest known mountain in the Solar System. One year on Mars is equal to 687 days on Earth. One day on Mars is 24 hours, 39 minutes and 35 seconds long. Mars has the distinction of the being the planet with the largest volcanoes in the solar system. The surface of Mars resembles the impact craters of the Moon as well the volcanoes, valleys, deserts and polar ice caps of Earth. Mars was first visited by the Mariner 4, in 1965.

Let’s Review! (Section 3) 1.) What celestial body is the central and largest member of our Solar System? Sun e) Earth Mercury f) Venus Mars g) Mirror Zephyrus h) Flora Chloris i) Gaea phrodite j) Ishtar

Let’s Review! (Section 3) 2.) What was the ancient Egyptian name for "sun" or "Ra" in the hieroglyphic writing system. Sun e) Earth Mercury f) Venus Mars g) Mirror Zephyrus h) Ra Chloris i) Gaea Aphrodite j) Ishtar

Let’s Review! (Section 3) 3.) What is the name of the Greek Sun god? brings life-giving heat and light to Earth. Sun e) Earth Mercury f) Venus Mars g) Mirror Zephyrus h) Ra Chloris i) Apollo Aphrodite j) Ishtar

Let’s Review! (Section 3) 4.) The Greeks said that Apollo brought what two things to the Earth? Sugar d) Spice Heat e) Children Everything Nice f) Light

Let’s Review! (Section 3) 5.) In Greek mythology, Apollo was the son of Zeus and _________. Leto e) Earth Mercury f) Venus Mars g) Mirror Zephyrus h) Ra Chloris i) Apollo Aphrodite j) Ishtar

Let’s Review! (Section 3) 6.) Leto gave birth to the twins _____ and _________. Apollo e) Artemis Mercury f) Venus Mars g) Mirror Zephyrus h) Ra Chloris i) Apollo Aphrodite j) Ishtar

Let’s Review! (Section 3) 7.)