Neptune

Question

Your last stop is Neptune. This planet was discovered in 1846 when astronomers observed that the movement of the planet Uranus appeared to be influenced by the gravity of an unknown planet.

Neptune's average distance from the sun is about 2.8 billion miles (4.5 billion kilometers). It takes nearly 165 Earth years to complete one orbit. Its diameter is 30,800 miles (49,600 kilometers).

Neptune is a gas giant with a thick atmosphere. This atmosphere is mostly hydrogen and helium along with traces of methane gas. It is wrapped around an ocean of water, methane, and ammonia. The temperature at the ocean's surface may be 4500°F (2500°C). The temperature in Neptune's upper atmosphere is about −355°F (−215°C).

At the time of the Voyager 2 exploration in 1989, Neptune's upper atmosphere included the Great Dark Spot, an immense dark blue cloud formation. There were also several smaller dark spots and an unusual white cloud, which moved at a speed different from the speeds of the rest of Neptune's cloud cover. By the time the Hubble Space Telescope was pointed at the planet in the 1990's, the Great Dark Spot had disappeared. It was replaced by similar features that seem to come and go every couple of years.

Neptune's magnetic field rotates once in about 17 hours. The rate of rotation of the features in its atmosphere varies greatly and depends on the latitude of the features.

A system of thin rings encircles Neptune, and the planet has 14 known satellites. Triton is the largest. It has a thin atmosphere, consisting mostly of nitrogen gas. For more information, see the article Neptune.

William A. Gutsch Jr.

The Challenger Center for Space Science Education

President

Answer 1

Neptune: A Fascinating Gas Giant

Discovered in 1846, Neptune is an intriguing planet that draws attention due to its unique characteristics and distant position in our solar system. It was identified when astronomers observed the irregular movements of Uranus, which hinted at the gravitational influence of an unknown planet.

Key Facts about Neptune

• Distance from the Sun: Approximately 2.8 billion miles (4.5 billion kilometers).
• Orbital Period: It takes over 165 Earth years for Neptune to complete one orbit around the Sun.
• Diameter: Neptune measures about 30,800 miles (49,600 kilometers) across.

Atmospheric Composition

As a gas giant, Neptune possesses a thick, dynamic atmosphere predominantly made up of hydrogen and helium. The presence of methane gas gives it a striking blue hue. Beneath the atmosphere lies a vast oceanic layer, which predominantly consists of water, methane, and ammonia. Remarkably, the temperature at the ocean's surface can reach up to 4500°F (2500°C), whereas the upper atmosphere is much colder, averaging around −355°F (−215°C).

Notable Features

During the Voyager 2 flyby in 1989, one of the most prominent features observed was the Great Dark Spot, a massive dark blue storm system. There were additional smaller dark spots and a peculiar white cloud, with unique movement patterns compared to the overall cloud activity on Neptune. However, by the 1990s, when the Hubble Space Telescope observed the planet, the Great Dark Spot had vanished, replaced by temporary similar phenomena.

Magnetic Field and Rings

Neptune's magnetic field is peculiar; it completes one rotation approximately every 17 hours, and the atmospheric features rotate at varying rates that depend on their latitude. Additionally, Neptune is encircled by a system of thin rings and has 14 known moons, the most significant of which is Triton. Triton features a thin atmosphere primarily composed of nitrogen.

Neptune continues to intrigue astronomers and space enthusiasts, offering insights into the complexity of planetary atmospheres and the dynamics of gas giants in our solar system.

For Further Exploration

For those interested in delving deeper into the fascinating world of Neptune and its features, please refer to additional resources that provide comprehensive information about this distant planet.

William A. Gutsch Jr.
The Challenger Center for Space Science Education
President

Answer 2

Mars
Your next stop is Mars, a planet that shines in the sky with a reddish color and is sometimes called the Red Planet. The orbit of Mars is more oval-shaped than that of the Earth. So the distance between Mars and the sun may be as little as 128.4 million miles (206.7 million kilometers) or as much as 154.8 million miles (249.2 million kilometers). The average distance between Mars and the sun is about 142 million miles (228 million kilometers). It takes Mars 687 Earth days to travel once around the sun. It rotates once on its axis in 24 hours and 37 minutes.

Mars is a small, rocky world that is very dry. Its diameter is 4,200 miles (6,760 kilometers), only a little more than half that of the Earth. Its gravitational pull is weaker than the Earth's.

Mars has two small satellites. Phobos, the larger one, measures about 16 miles (26 kilometers) in its longest dimension. It circles its planet at a distance of 2,462 miles (3,964 kilometers). Phobos completes its orbit in about 71/2 hours, which is less time than it takes Mars to turn once on its axis. Therefore, to a visitor on Mars, Phobos would seem to rise in the west and set in the east. Deimos is smaller than Phobos, measuring about 10 miles (16 kilometers) long. It circles Mars at a distance of 14,700 miles (23,600 kilometers).

Early space probes provided a great deal of information about Mars. They learned that Mars has no magnetic field and that there is very little atmosphere surrounding it. The atmospheric pressure on its surface is 1/600 of the atmospheric pressure on the Earth's surface. Its thin atmosphere is made up almost entirely of carbon dioxide. Temperatures at the planet's equator may occasionally reach 60°F (16°C). But nighttime polar temperatures can plunge to nearly −202°F (−130°C).

The surface of Mars has a variety of features. These include craters, giant extinct volcanoes, and a canyon system almost as long as the width of the United States. In 2004, the robotic rovers Opportunity and Spirit touched down on the surface of Mars. They revealed many details about the planet's geology and topography. They also found signs that liquid water once flowed on the planet, perhaps enough to have supported life. For more information, see the article Mars.

Jupiter
After passing through a belt of asteroids beyond the orbit of Mars, the next stop on your planetary journey is Jupiter. This planet is more than five times farther from the sun than Earth. Jupiter travels around the sun at an average distance of 483 million miles (778 million kilometers). It takes 11.9 Earth years to complete one orbit.

Jupiter is the largest planet. It is one of the four gas giants in our solar system. Its diameter is 89,000 miles (143,000 kilometers). This is more than eleven times greater than that of Earth. Jupiter takes less than ten hours to rotate once on its axis.

What appears to be Jupiter's surface is really the top of a thick, cloudy atmosphere. Nearly 90 percent of it is hydrogen, and most of the remaining 10 percent is helium. There are also very small amounts of methane, ammonia, and some other substances that give Jupiter's clouds their beautiful colors.

The Pioneer and Voyager space probes flew by the planet in the 1970's. They confirmed that at the top of Jupiter's atmosphere it is very cold, about −186°F (−121°C). Deeper down in the clouds, however, temperatures climb to thousands of degrees. The tremendous heat rising through the atmosphere combines with Jupiter's rapid rotation to produce large and violent weather systems. Cloud belts on Jupiter are driven by powerful winds that move at speeds of up to 350 miles (560 kilometers) per hour. The most amazing feature in Jupiter's clouds is an enormous orange-red area known as the Great Red Spot. The Great Red Spot is more than twice the size of our planet.

Deep below the clouds there is no solid surface. Instead, astronomers think there is probably a planet-wide ocean that consists mostly of hydrogen compressed under such great pressure that it forms a liquid with metallic properties. At the center of Jupiter there is probably a core, consisting of iron and silicates, about twenty times the total mass of Earth. The molten metallic materials in the core create a strong magnetic field that extends far out into space. At the top of Jupiter's clouds, this magnetic field is about 14 times stronger than that of the Earth. Jupiter's gravitational pull is about two and one-half times stronger than the Earth's.

Jupiter has 79 known satellites. The largest, Ganymede, is 3,270 miles (5,270 kilometers) in diameter. Callisto is slightly smaller, with a diameter of 3,000 miles (4,800 kilometers). Each of these satellites has an icy surface covered with craters. Another satellite, Europa, which is 1,900 miles (3,100 kilometers) across, is also covered with a layer of ice. Io has a diameter of about 2,200 miles (3,500 kilometers). Its surface is covered with volcanoes and lava flows. The other known satellites range from less than a mile to more than a hundred miles in diameter. Before the Voyager probes, little was known about Jupiter's satellites because they appear only as dots when seen through even the largest telescopes. The later Galileo probe found indications of liquid salt water beneath the ice of Europa, Ganymede, and Callisto. Voyager 1 also discovered a thin, delicate ring of fine particles circling Jupiter. For more information, see the article Jupiter.

Saturn
The next stop on your journey is Saturn, another gas giant. It orbits the sun at an average distance of 885.5 million miles (1.4 billion kilometers). It takes nearly 29.5 Earth years to make one trip around the sun.

Saturn is not quite as large as Jupiter. It has a diameter of 74,500 miles (120,000 kilometers). Like Jupiter, Saturn rotates very quickly; it takes 10 hours and 40 minutes for it to turn once on its axis.

Saturn has a very deep atmosphere, which is made up mainly of hydrogen and helium, with some methane and ammonia. At the top of its atmosphere, the temperature is about −300°F (−185°C). This low temperature causes ammonia in the outer atmosphere to freeze, forming high-altitude haze. This gives Saturn a softer appearance than Jupiter. There are also spots similar to Jupiter's Great Red Spot in Saturn's atmosphere, but they are smaller. The largest is about the size of Earth.

The largest of Saturn's 62 known satellites is Titan. The diameter of Titan is 3,200 miles (5,150 kilometers). This is the only satellite in the solar system that has a thick atmosphere. This atmosphere consists mostly of nitrogen. The pressure at Titan's surface is about one and a half times greater than at the surface of the Earth.

Saturn is one of the most beautiful objects in the sky because of the rings that circle the planet at its equator. The entire ring system is more than 170,000 miles (274,000 kilometers) in diameter. But it is less than 1 mile (1.6 kilometers) thick. The rings may have formed at the same time as the solar system, or they may be the remains of a nearby satellite that was broken up by Saturn's gravitational pull, which is almost the same as that of the Earth. For more information, see the article Saturn.

Uranus
Leaving Saturn and traveling even farther from the sun, you come to the planet Uranus. Uranus is 32,000 miles (51,500 kilometers) in diameter. It orbits the sun at an average distance of 1.8 billion miles (2.9 billion kilometers). It takes about 84 Earth years to complete one orbit. Uranus rotates once on its axis in an east-to-west direction in approximately 17 hours. This is also the rate at which its magnetic field, which is anchored in the planet's interior, and its interior rotate. Uranus' magnetic field is only about two-thirds as strong as that of the Earth.

The blue-green color of Uranus is caused by methane in its thick atmosphere. The temperature at the tops of its clouds is −355°F (−215°C). Scientists think that beneath the atmosphere is a vast ocean of water, methane, ammonia, and other elements. This ocean may surround a core consisting mostly of molten rock and metal. At the tops of Uranus' clouds, the gravitational pull is somewhat weaker than that of the Earth. A system of thin, very dark rings encircles the planet.

Most of the planets in our solar system spin in a more or less straight up-and-down position as they orbit the sun, although some are tilted a little more than others. If the solar system could be placed on a gigantic table, the planets would look like spinning tops as they moved around the sun. Uranus, however, tilts at the extreme angle of 97.8 degrees. You could almost say the planet lies on its side as it orbits the sun. This means that the north and south polar regions of Uranus experience alternate periods of day and night (and summer and winter), each of which is up to 42 Earth years long. If Uranus were much closer to the sun, this could result in very extreme seasons. Because of the planet's distance from the sun and the odd wind patterns in its atmosphere, Uranus has rather even global temperatures. The north and south polar regions are actually a little warmer than the regions around its equator.

Uranus has 27 known satellites. The largest is Titania. It has a diameter of about 1,000 miles (1,600 kilometers). The smaller satellites range in size from about 12 to 96 miles (20 to 155 kilometers) in diameter. For more information, see Uranus.

Answer 3

Mars: The Red Planet

Your next stop is Mars, often referred to as the Red Planet due to its distinctive reddish appearance in the night sky. Mars has an elliptical orbit that varies in distance between 128.4 million miles (206.7 million kilometers) and 154.8 million miles (249.2 million kilometers) from the sun, with an average distance of about 142 million miles (228 million kilometers). It takes Mars 687 Earth days to complete one loop around the sun, and it rotates on its axis every 24 hours and 37 minutes.

Characteristics of Mars

• Diameter: 4,200 miles (6,760 kilometers), making it just over half the size of Earth.
• Gravity: Mars has a weaker gravitational pull compared to Earth.
• Atmosphere: Mars has a thin atmosphere, predominantly composed of carbon dioxide, with atmospheric pressure at 1/600 that of Earth. The temperatures can reach up to 60°F (16°C) at the equator, but can plummet to −202°F (−130°C) in the polar regions.

Moons of Mars

Mars has two small moons:

• Phobos: The larger moon, measuring about 16 miles (26 kilometers) across. It orbits Mars at a distance of 2,462 miles (3,964 kilometers) and completes its orbit in approximately 7.5 hours, rising in the west and setting in the east.
• Deimos: Smaller than Phobos, it measures about 10 miles (16 kilometers) long and orbits at a distance of 14,700 miles (23,600 kilometers).

Surface Features and Exploration

Mars features an array of geological characteristics, including craters, giant extinct volcanoes, and an extensive canyon system almost as long as the United States. The robotic rovers Opportunity and Spirit, which landed on Mars in 2004, provided valuable information about the planet's geology and past presence of liquid water—suggesting that Mars may have once supported life.

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Jupiter: The Giant Planet

After passing through the asteroid belt, the next stop on your planetary journey is Jupiter, the largest planet in our solar system. Located at an average distance of 483 million miles (778 million kilometers) from the sun, Jupiter takes about 11.9 Earth years to orbit the sun.

Characteristics of Jupiter

• Diameter: 89,000 miles (143,000 kilometers), which is more than 11 times greater than Earth's.
• Rotation: It has a rapid rotation period of less than 10 hours.

Jupiter’s atmosphere is primarily composed of hydrogen and helium, with traces of methane, ammonia, and other compounds that create its stunning cloud colors. The temperature at the top of its atmosphere can be around −186°F (−121°C). Below the surface, the temperature can reach thousands of degrees due to the immense pressure.

Weather Systems and Features

Jupiter is known for its dynamic weather systems, including the Great Red Spot, a massive storm larger than Earth, and powerful winds that can reach speeds of up to 350 miles (560 kilometers) per hour.

Jupiter has a substantial magnetic field, estimated to be about 14 times stronger than Earth's, with a core believed to contain materials around twenty times the mass of our planet. It boasts 79 known satellites, with major moons including:

• Ganymede: 3,270 miles (5,270 kilometers) in diameter, the largest moon in the solar system.
• Callisto: Slightly smaller than Ganymede at 3,000 miles (4,800 kilometers).
• Europa: 1,900 miles (3,100 kilometers), which may harbor liquid water beneath its icy surface.
• Io: 2,200 miles (3,500 kilometers), known for its volcanoes and lava flow.

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Saturn: The Ringed Beauty

Traveling further, you arrive at Saturn, another colossal gas giant that orbits the sun at an average distance of 885.5 million miles (1.4 billion kilometers). Saturn takes about 29.5 Earth years to complete one orbit.

Characteristics of Saturn

• Diameter: 74,500 miles (120,000 kilometers), making it slightly smaller than Jupiter.
• Rotation: Saturn has a quick rotation period of about 10 hours and 40 minutes.

Saturn's atmosphere is composed mainly of hydrogen and helium, with some ammonia and methane. The icy rings that encircle Saturn are among its most striking features, spanning over 170,000 miles (274,000 kilometers) in diameter but less than 1 mile (1.6 kilometers) thick.

Moons of Saturn

Saturn has 62 known moons, with the largest being Titan, which has a diameter of 3,200 miles (5,150 kilometers) and possesses a thick atmosphere mostly composed of nitrogen.

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Uranus: The Tilted Giant

Continuing your journey, you arrive at Uranus, which is distinguished by its extreme axial tilt of about 97.8 degrees, causing it to roll on its side as it orbits the sun.

Characteristics of Uranus

• Diameter: 32,000 miles (51,500 kilometers).
• Distance from Sun: It orbits the sun approximately 1.8 billion miles (2.9 billion kilometers) away and takes about 84 Earth years to complete an orbit.
• Rotation: Uranus rotates every 17 hours.

The planet has a blue-green hue due to methane in its atmosphere. Its upper cloud temperatures can drop to −355°F (−215°C), while its gravitational pull is slightly weaker than that of Earth.

Moons and Rings

Uranus has 27 known moons, with Titania being the largest at approximately 1,000 miles (1,600 kilometers) in diameter. It also possesses a faint ring system composed of dark, narrow rings.

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This journey through Mars, Jupiter, Saturn, and Uranus showcases the diverse characteristics and phenomena of these fascinating planets in our solar system! For more detailed exploration, consider consulting specific articles on each planet for in-depth information.

Answer 4

In ancient times, sky watchers observed that there were five special points of light in the night sky. All the other points of light always kept their same positions relative to one another. These were the stars. The constellations they formed remained the same year after year, lifetime after lifetime. The five points of light were different. They slowly moved among the stars. The ancient Greeks called these points of light the planetai, a word that means "wandering stars." And the Greeks named them after their gods: Hermes, Aphrodite, Ares, Zeus, and Chronos.

Today we know that these points of light, which we call planets, wander slowly in the sky because they are other "worlds" traveling around our sun. Instead of using the names of the Greek gods, we call these planets by the names of the equivalent Roman gods: Mercury, Venus, Mars, Jupiter, and Saturn.

Our own Earth is also a planet. If you could observe Earth from outer space, you would see that it, too, seems always to be moving among the stars. Planets give off no light of their own. They shine brightly in the night sky because they reflect the sun's light.

What Is a Planet?
Until recently, defining a planet was simple. A planet was any large, rounded object that revolved around a star, such as our sun, in a path called an orbit. However, as astronomers have learned more about our solar system and all the different kinds of objects it contains, this simple definition has proved insufficient.

Today a celestial object must have three characteristics to be considered a planet: It must orbit the sun; it must have enough mass for its own gravity to shape it into a sphere; and it must be massive enough to clear other large objects from its orbit.

Our solar system contains eight planets. These include the Earth, the five known since ancient times, plus Uranus and Neptune. Pluto, discovered in 1930, had been called a planet until 2006. Astronomers then decided it was a dwarf planet, not a true planet. In 2008 Pluto became the first dwarf planet to be called a plutoid. For more information, see the articles Planets, Dwarf and Pluto.

Some of the planets in our solar system have satellites, or moons, that revolve around them. Much of what we now know about the planets and their moons has come from space probes. These probes have orbited, flown by, or even landed on many of these planets and transmitted valuable information back to astronomers on Earth.

In this article, you will travel outward from the sun and visit the planets one at a time. Your first stop is Mercury.

Mercury
Mercury is the closest planet to the sun. Its average distance from the sun is about 35.9 million miles (57.8 million kilometers). The orbits of all the planets are ellipses, or flattened circles. But Mercury's orbit is particularly flattened. As a result, at various points in its orbit Mercury can be as close as 29 million miles (46.7 million kilometers) from the sun or as far away as about 44 million miles (70.8 million kilometers). It takes 88 Earth days for Mercury to complete one trip around the sun. In other words, one Earth year of 365 days is longer than four Mercury years. Mercury rotates on its axis once every 59 Earth days. Its diameter is 3,032 miles (4,880 kilometers).

Mercury appears tiny and almost without features, even when observed with powerful telescopes. Little was known about this planet until Mariner 10 flew past it in 1973 and sent back hundreds of images. These showed thousands of craters, long cliffs called scarps, and a giant impact basin about 800 miles (1,288 kilometers) across.

An extremely thin veil of helium gas has been detected around Mercury. These atoms, which are actually given off by the sun, flow around the planet as it orbits the sun. A very thin atmosphere of oxygen, sodium, and hydrogen gases, which probably escape from Mercury's surface, has also been detected. The magnetic field that surrounds Mercury is much weaker than the Earth's magnetic field. Its gravitational pull is also much weaker than that of the Earth.

Because Mercury is so close to the sun, temperatures can reach about 800°F (427°C) during the day. However, Mercury's thin atmosphere retains little of this heat, so during its long nights the temperature can plunge to −280°F (−171°C). Mercury has no known satellites. For more information, see the article Mercury.

Venus
Your next stop is Venus. This planet travels around the sun in a nearly circular orbit, at an average distance of about 67.2 million miles (108.2 million kilometers). Venus takes 224.7 Earth days to make one trip around the sun. It is nearly the same size as the Earth, and its diameter is about 7,519 miles (12,100 kilometers). Its gravitational pull is almost the same as that of the Earth.

Venus comes closer to the Earth than any other planet. It is only about 26 million miles (41.9 million kilometers) away. Even so, we can see virtually no details in a telescope because Venus is completely covered by thick clouds. These clouds reflect the sun's light. At times Venus is the brightest object in the sky except for the sun and the moon.

Venus' atmosphere is composed mostly of carbon dioxide. It creates a surface pressure that is about 90 times greater than the pressure at the Earth's surface. The carbon dioxide traps the sun's heat and creates a very strong greenhouse effect. This raises the surface temperature of Venus to more than 800°F (427°C). Venus has no magnetic field and, like Mercury, has no known satellites.

By using radar to penetrate the clouds of Venus, scientists have learned that its surface spins very slowly, completing one rotation in 243 Earth days. However, Venus' clouds can circle the planet in as little time as four Earth days. Another discovery was that Venus rotates from east to west, as Uranus does. All the other planets rotate from west to east.

Radar waves bounced off Venus, from Earth as well as from spacecraft, have allowed scientists to map the surface of this planet in great detail. Such maps show that about 60 percent of its surface is covered by flat, gently rolling plains and a few craters. Two large areas, the size of small continents on Earth, consist of mountainous terrain. Radar maps suggest that, unlike Earth, Venus is made of only one continental plate. There is nothing that resembles the Earth's mid-ocean ridges or similar features. For more information, see the article Venus.

Earth
Beyond the orbit of Venus is Earth. The Earth's orbit is almost as circular as that of Venus. The Earth travels around the sun at an average distance of 93 million miles (150 million kilometers). It completes one orbit around the sun in 365.25 days. It takes 23 hours and 56 minutes for the Earth to rotate on its axis.

The Earth is a ball of rock and metal. Its diameter is 7,923 miles (12,751 kilometers) at the equator. Surrounding the Earth, like a great blanket of gases, is an atmosphere made up mainly of nitrogen and oxygen. As seen from space, however, the Earth's atmosphere appears very thin. If the Earth were the size of an apple, its atmosphere would be thinner than the apple's skin.

Unlike Mercury and Venus, the Earth has a satellite—the moon. It orbits the Earth at an average distance of 240,000 miles (386,400 kilometers). Because the moon rotates on its axis in the same period of time as it revolves around the Earth, it always keeps the same face toward the Earth. The moon is 2,160 miles (3,478 kilometers) in diameter. This is more than one-fourth the diameter of the Earth. For more information, see Earth and Moon.

Answer 5

The Journey Through the Planets: Mercury, Venus, and Earth

In ancient times, sky watchers noticed five special points of light in the night sky, which appeared to move differently compared to the fixed positions of stars. The ancient Greeks named these celestial bodies the planetai, meaning "wandering stars." Today, we refer to them as planets: Mercury, Venus, Mars, Jupiter, and Saturn. Our own Earth is also a planet, reflecting the sun's light just like the others do.

What Is a Planet?

Defining a planet has evolved over time. Initially, any large, rounded object orbiting a star was considered a planet. However, the modern criteria specify that a celestial object must meet three conditions:

1. It must orbit the sun.
2. It must have enough mass for its own gravity to shape it into a sphere.
3. It must be massive enough to clear other large objects from its orbit.

Our solar system has eight recognized planets, including Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was once considered the ninth planet until it was reclassified as a dwarf planet in 2006.

Mercury: The Closest Planet to the Sun

Mercury is the innermost planet, with an average distance of about 35.9 million miles (57.8 million kilometers) from the sun.

• Orbit: Mercury's elliptical orbit allows it to be as close as 29 million miles (46.7 million kilometers) and as far as 44 million miles (70.8 million kilometers) from the sun.
• Year and Day: It completes one orbit around the sun in 88 Earth days and rotates on its axis every 59 Earth days.
• Diameter: Mercury has a diameter of 3,032 miles (4,880 kilometers).

Observations from the Mariner 10 spacecraft in the 1970s revealed a surface riddled with thousands of craters, long cliffs (scarps), and a significant impact basin. Mercury has a very thin atmosphere composed mainly of helium, oxygen, sodium, and hydrogen. Due to its proximity to the sun, daytime temperatures can soar up to 800°F (427°C), while nighttime temperatures can plunge to −280°F (−171°C).

Mercury has no known satellites.

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Venus: Earth's Twin

Next is Venus, which orbits the sun at an average distance of about 67.2 million miles (108.2 million kilometers).

• Orbit and Rotation: Venus takes 224.7 Earth days to complete one orbit and rotates slowly on its axis once every 243 Earth days.
• Diameter: Its diameter is about 7,519 miles (12,100 kilometers), making it nearly the same size as Earth.

Venus is often referred to as Earth's twin due to its similar size and gravitational pull. However, it is totally obscured by thick clouds that create a powerful greenhouse effect, leading to surface temperatures exceeding 800°F (427°C). Despite being closer to Earth than any other planet—only about 26 million miles (41.9 million kilometers) away—Venus has no magnetic field and no known satellites.

Radar technology has allowed scientists to map Venus’s surface, revealing vast plains and mountainous terrain, with about 60% of its surface being covered by flat areas.

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Earth: Our Home Planet

Beyond Venus lies Earth, our blue planet.

• Orbit: The Earth travels around the sun at an average distance of 93 million miles (150 million kilometers) and completes its orbit in 365.25 days while rotating on its axis every 23 hours and 56 minutes.
• Diameter: Earth’s diameter is 7,923 miles (12,751 kilometers).

Earth is enveloped in a thin atmosphere, primarily made up of nitrogen and oxygen. From space, this atmosphere appears incredibly thin, as if were a mere blanket around the planet. Earth is unique among the three discussed planets in that it has one satellite—the Moon.

• The Moon: The Moon orbits Earth at an average distance of 240,000 miles (386,400 kilometers) and has a diameter of 2,160 miles (3,478 kilometers). Because the Moon rotates on its axis in the same period as it revolves around Earth, it always shows the same face to us.

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As you continue your journey through the solar system, you'll witness more remarkable worlds and their unique characteristics, deepening your understanding of our cosmic neighborhood. For further exploration of these planets, consider diving into dedicated articles on each celestial body.

Answer 6

3. Read the article "Planet." You will use information from this article to answer the
following questions.
a. Make a list of the distances from each planet to the sun, written in scientific notation.
If there is a shortest and longest distance, use the average distance from the sun.
b. Choose two of the distances of planets from the sun and add them. Show your work.
c. Choose two of the distances of planets from the sun and subtract them. Show your work.
d. Choose two of the distances of planets from the sun and multiply them. Show your work.
e. Choose two of the distances of planets from the sun and divide them. Show your work.
use the information to solve these problems

Answer 7

Sure! Let's gather the distance information from the article you provided and perform the required operations.

Distances from Each Planet to the Sun (in Scientific Notation)

1. Mercury: Average distance = 35.9 million miles

   • In scientific notation: 3.59 × 10^7 miles

2. Venus: Average distance = 67.2 million miles

   • In scientific notation: 6.72 × 10^7 miles

3. Earth: Average distance = 93 million miles

   • In scientific notation: 9.3 × 10^7 miles

4. Mars: Average distance = 142 million miles

   • In scientific notation: 1.42 × 10^8 miles

5. Jupiter: Average distance = 483 million miles

   • In scientific notation: 4.83 × 10^8 miles

6. Saturn: Average distance = 885.5 million miles

   • In scientific notation: 8.855 × 10^8 miles

7. Uranus: Average distance = 1.8 billion miles

   • In scientific notation: 1.8 × 10^9 miles

8. Neptune: Average distance = 2.8 billion miles

   • In scientific notation: 2.8 × 10^9 miles

a. List of Distances from Each Planet to the Sun

• Mercury: 3.59 × 10^7 miles
• Venus: 6.72 × 10^7 miles
• Earth: 9.3 × 10^7 miles
• Mars: 1.42 × 10^8 miles
• Jupiter: 4.83 × 10^8 miles
• Saturn: 8.855 × 10^8 miles
• Uranus: 1.8 × 10^9 miles
• Neptune: 2.8 × 10^9 miles

b. Choose Two Distances and Add Them

Let’s add the distances from Earth and Mars:

1. Earth: 9.3 × 10^7 miles
2. Mars: 1.42 × 10^8 miles

Convert Earth’s distance to the same exponent for addition:

• 9.3 × 10^7 = 0.93 × 10^8 miles

Now, we can add: \[ 0.93 × 10^8 + 1.42 × 10^8 = 2.35 × 10^8 \text{ miles} \]

c. Choose Two Distances and Subtract Them

Let’s subtract the distance of Mercury from the distance of Venus:

1. Venus: 6.72 × 10^7 miles
2. Mercury: 3.59 × 10^7 miles

Perform the subtraction directly: \[ 6.72 × 10^7 - 3.59 × 10^7 = 3.13 × 10^7 \text{ miles} \]

d. Choose Two Distances and Multiply Them

Let's multiply the distances of Earth and Jupiter:

1. Earth: 9.3 × 10^7 miles
2. Jupiter: 4.83 × 10^8 miles

Now, perform the multiplication: \[ (9.3 × 10^7) × (4.83 × 10^8) = 44.859 × 10^{15} \]

Converting this into proper scientific notation: \[ 4.4859 × 10^{16} \text{ miles} \]

e. Choose Two Distances and Divide Them

Let’s divide the distance of Neptune by the distance of Earth:

1. Neptune: 2.8 × 10^9 miles
2. Earth: 9.3 × 10^7 miles

Now perform the division: \[ \frac{2.8 × 10^9}{9.3 × 10^7} = \frac{2.8}{9.3} × 10^{9-7} = 0.301075 × 10^2 \]

Converting this into scientific notation: \[ 3.01075 × 10^1 \text{ or } 30.1075 \]

Summary of Calculations

• Addition: 2.35 × 10^8 miles
• Subtraction: 3.13 × 10^7 miles
• Multiplication: 4.4859 × 10^{16} miles
• Division: 3.01075 × 10^1 or 30.1075

Feel free to ask if you need any further assistance!

Answer 8

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Answer 9

Certainly! Here’s the information presented without special characters:

a. List of Distances from Each Planet to the Sun

• Mercury: 3.59 × 10^7 miles
• Venus: 6.72 × 10^7 miles
• Earth: 9.3 × 10^7 miles
• Mars: 1.42 × 10^8 miles
• Jupiter: 4.83 × 10^8 miles
• Saturn: 8.855 × 10^8 miles
• Uranus: 1.8 × 10^9 miles
• Neptune: 2.8 × 10^9 miles

b. Choose Two Distances and Add Them

Let's add the distances from Earth and Mars:

1. Earth: 9.3 × 10^7 miles
2. Mars: 1.42 × 10^8 miles

Convert Earth’s distance to the same exponent for addition:

• 9.3 × 10^7 = 0.93 × 10^8 miles

Now, we can add: 0.93 × 10^8 + 1.42 × 10^8 = 2.35 × 10^8 miles

c. Choose Two Distances and Subtract Them

Let's subtract the distance of Mercury from the distance of Venus:

1. Venus: 6.72 × 10^7 miles
2. Mercury: 3.59 × 10^7 miles

Perform the subtraction directly: 6.72 × 10^7 - 3.59 × 10^7 = 3.13 × 10^7 miles

d. Choose Two Distances and Multiply Them

Let's multiply the distances of Earth and Jupiter:

1. Earth: 9.3 × 10^7 miles
2. Jupiter: 4.83 × 10^8 miles

Now, perform the multiplication: (9.3 × 10^7) × (4.83 × 10^8) = 44.859 × 10^15

Converting this into proper scientific notation: 4.4859 × 10^16 miles

e. Choose Two Distances and Divide Them

Let's divide the distance of Neptune by the distance of Earth:

1. Neptune: 2.8 × 10^9 miles
2. Earth: 9.3 × 10^7 miles

Now perform the division: 2.8 × 10^9 / 9.3 × 10^7 = 2.8 / 9.3 × 10^(9-7) = 0.301075 × 10^2

Converting this into scientific notation: 3.01075 × 10^1 or 30.1075

Summary of Calculations

• Addition: 2.35 × 10^8 miles
• Subtraction: 3.13 × 10^7 miles
• Multiplication: 4.4859 × 10^16 miles
• Division: 3.01075 × 10^1 or 30.1075

If you have any further requests or need additional assistance, feel free to ask!