Our Solar System Image credit http pds jpl

Our Solar System! Image credit: http: //pds. jpl. nasa. gov/planets/

Solar System Composition Our sun, a star Eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune (Pluto has been reclassified as a dwarf planet. ) l An asteroid belt orbiting between Mars and Jupiter l Moons orbiting these six planets: Earth, Mars, Jupiter, Saturn, Uranus and Neptune l Comets l l Image credit: http: //www. jpl. nasa. gov/solar_system/sun_index. html

Our Sun - A Star! The sun, approximately 4. 8 billion years old, is so huge that approximately one million Earths could fit into it! The sun is a gigantic ball of extremely hot glowing gases. Its surface temperature is so hot, nothing could live there. It sustains our life here on Earth by sending us light and heat, and is the source of energy for photosynthesis in plants. Image credit: http: //photojournal. jpl. nasa. gov/catalog/PIA 18167

There are billions of stars in this universe! Our sun is the star closest to Earth. It’s made up of many layers of hot gases. The diameter of the sun is about 86, 000 miles, huge in comparison with the 7, 900 mile diameter of Earth. The photo on the right shows a solar flare which is a tremendous explosion on the surface of the sun near a sunspot. The flare itself is a brilliant cloud of gas swiftly leaping from the surface of the sun. Flares release energy in different forms. Two of the forms of energy are Gamma Rays and X-Rays. Sun with solar flare Image credit: http: //www. jpl. nasa. gov/solar_system/sun_index. html

Where do planets get their light? The planets in our solar system do not have light of their own, they reflect the light of the sun. Want to know more about our sun? The spacecraft SOHO has explored it and released the photos! Check out this website. . . http: //sohowww. nascom. nasa. gov/gallery/ Photo of the sun with a flare taken from SOHO Image credit: http: //sohowww. nascom. nasa. gov

The Inner Planets The four planets closest to the sun are Mercury, Venus, Earth and Mars. These four planets are called the terrestrial planets because they have a rocky surface similar to the Earth. Mercury has little atmosphere. In contrast, the Earth, Venus and Mars have significant atmospheres. Image credit: bhc. edu

The Inner Planets The approximate distance between Mars and Jupiter is many times farther than the distance between the inner planets. The Asteroid Belt lies between Mars and Jupiter. Image credit: http: //solarsystem. nasa. gov/multimedia/display. cfn? IM_ID=72

The Outer Planets Jupiter, Saturn, Uranus and Neptune have surfaces made up of gases. Rings that consist of rock, ice and dust orbit each of these planets. Image credit: http: //solarsystem. nasa. gov/multimedia/display. cfm? IM_ID=175

Outer Planets This diagram shows the relative positions of the orbits of the outer planets and the approximate distances between the planets. Image credit: http: //solarsystem. nasa. gov/multimedia/display. cfm? IM_ID=175

Rotating or Orbiting? Which is it? When a planet rotates, it turns on its axis. Six of the planets in our solar system rotate counter-clockwise: Mercury, Earth, Mars, Jupiter, Saturn and Neptune. Two planets rotate clockwise: Venus and Uranus. One rotation is equal to one day on a planet. As a planet orbits, it travels in an elliptical path around the sun. A complete orbit is equal to one of a planet’s year.

Mercury is the closest planet to the sun. Named for the swift messenger of the gods, Mercury orbits the sun faster than any of the other Planets. One orbit takes 88 days. Its day is equal to 59 Earth days. Mercury has a rocky surface with many craters. It has a thin atmosphere containing oxygen, sodium, hydrogen. Life could not survive on its surface. The side facing the sun is Approximately 800 degrees Fahrenheit. The side facing away from the sun is approximately 290 degrees below zero Fahrenheit. Image credit: http: //www. jpl. nasa. gov/solar_system/planets_index. html-

Venus, second planet from the sun, is the HOTTEST planet in our solar system. Even hotter than Mercury? Oh, yes! A very thick blanket of clouds holds in the heat from the sun. Could we live there? It’s way too hot; its atmosphere contains poisonous sulfuric acid; its winds are extremely high; and it has extremely high surface pressure: 88 times the pressure we feel on Earth. Venus is named for the goddess of beauty. The planet is beautiful when seen in the sky. Venus is one of three planets in our solar system to rotate clockwise. A day on Venus is 243 Earth days; a year is 225 days, a short year. Image credit: http: //ww. jpl. nasa. gov/solar_system/planets/venus_index. html

Earth Yes, we know the Earth. We live here! Earth is the third planet from the sun, Our orbit is 93 million miles from the sun. Earth is the only planet in our solar system that has water and an atmosphere with the right amount of gases to support people, animals and plants. Earth photo taken from Apollo 8 Earth rotates once every 24 hours, orbits the sun once every 365 1/4 days and has one moon. If you live on the equator, you rotate with the Earth at a speed of 1, 000 miles an hour. The farther you live from the equator, the slower the speed. Image credit: http//grin. hq. nasa. gov/ABSTRACTS/GPN-2001 -000009. html

Mars, the red planet, is named for the god of war. Its red color comes from its red surface and dust storms. The Hubble view shows its two polar ice caps. Mars also has clouds, seasons, craters and volcanoes. We have explored Mars more than any planet. It is the 4 th planet from the sun. A day on Mars is 24 1/2 hours, similar to a day on Earth. It orbits the sun once every 687 days, so its year is almost twice as long as an Earth year. Mars has a thin atmosphere that may have oxygen and water vapor. Hubble’s view of Mars has two small moons. Image credit: http: //mars 4. jpl. nasa. gov/gallery/global/PIA 01249. html

Asteroid Belt 25, 000 asteroids have been estimated to orbit the sun in the Asteroid Belt, the huge space between Mars and Jupiter. Asteroids are difficult to see in space because they are dark, and like the planets, they have no light of their own. Asteroids are made of chunks of rock and metal. Scientists think asteroids may be pieces of planets that never formed. Photo of asteroids taken from the Voyager spacecraft Image credit: http: //www. jpl. nasa. gov/solar_system/asteroids_comets_index. html

Jupiter, the 5 th planet from the sun, is the largest gas planet in our solar system. Unseen in this photo are three rings orbiting Jupiter. More than 61 moons orbit Jupiter, so it is sometimes called a“mini solar system. ” Bands of color encircle the gaseous surface of Jupiter. Its Great Red Spot, shown by the green arrow, is a 300 -year-old storm, including hurricane force winds, that is almost the size of three Earths! Its diameter is eleven times the diameter of Earth. True color photo of Jupiter taken from the Cassini spacecraft Jupiter has a short, 10 -hour day because it rotates so fast, 29, 000 mph at its equator. A year on Jupiter is equal to 12 Earth years. Its atmosphere is about 90% hydrogen and 10% helium. Image credit: http: //www. jpl. nasa. gov/solar_system/planets/jupiter_index. html

Saturn is the 6 th planet from the sun, the second largest of the planets in our solar system. Saturn is called a gas giant and is made up mostly of hydrogen and helium. It takes up 755 times as much space as Earth. It’s known for its enormous, complex, ring system, made up of icy particles that are held in orbit by Saturn’s magnetic field. The width of Saturn with its rings would just fit in the distance between Earth and our moon. 31 known moons are also held in orbit around Saturn. Clouds and haze in Saturn’s Atmosphere Winds five times faster than Earth’s fastest hurricane winds, along with heat rising from Saturn, make the colored bands on Saturn visible. Saturn’s day is about 10 Earth hours; a Saturn year is approximately 30 Earth years. Image credit: http: //www. jpl. nasa. gov/solar_system/planets/saturn_index. html

Rings of Saturn This photo of the colorful rings of Saturn was taken from Voyager 2. The colors in the rings were enhanced to show the possible variations in the chemical composition of its rings. Image credit: http: //photojournal. jpl. nasa. gov/catalog/PIA 01486

Uranus Eleven rings and 15 moons orbit the smallest gas planet Uranus, the 7 th planet from the sun. Uranus seems to rotate sideways because its axis is tipped more than 90°. It rotates clockwise, opposite from 6 other planets. Methane gas above its layers of clouds gives it a blue/green color. A day on Uranus is 17 hours; a year is about 84 Earth years. Uranus with its four major rings taken by the Hubble infrared telescope Image credit: http: //photojournal. jpl. nasa. gov/catalog/PIA 02963

Neptune, the 8 th planet from the sun, is the 3 rd largest of the four giant gas planets that have no solid surfaces. It takes up the same amount of space as 44 Earths. Neptune has two thin and two wider rings. Eight known moons orbit Neptune. Its “Great Dark Spot, ” is thought to be a hurricane and is big enough to contain Earth. Neptune has 8 moons, the largest, Triton, orbits Neptune in the opposite direction from Neptune’s orbit and is the coldest known body in our solar system. Neptune with dark spot on left side A day on Neptune is 19 Earth hours; its year 164 Earth years. Its atmosphere contains hydrogen and helium. Methane gives Neptune its bluish color. The winds on Neptune are faster than winds on any other planet. Inage credit: http: //www. jpl. nasa. gov/solar_system/planets/neptune_index. html

Pluto - reclassified Pluto is no longer considered to be the ninth planet in our solar system, In 2006 it was reclassified as a dwarf planet. It has one moon and is very cold and dark. Pluto and moon, Charon Image credit: http: //www. jpl. nasa. gov/solar_system/planets/pluto_index. html

Comets are infrequent and spectacular sights. A comet’s head is made up of rocks, dust and frozen gases. Its tail appears as the comet nears the sun when the gases in its head melt and change into water vapor. Its tail can be thin and partially transparent. Comets travel through our solar system in elliptical orbits, curve around the sun, then go back out through the solar system. Image credit: http: //www. fiz. uni-lj. si/astro/comets/

The Orbits of Comets Many comets travel in long, rather narrow Ellipses, and may take a thousand years or so to come from the outer solar system to travel around the sun. Image credit: http: //deepimpact. jpl. nasa. gov/gallery/orbits 3. html

Credits Welcome to the Planets Jet Propulsion Laboratory, NASA California Institute of Technology http: //pds. jpl. nasa. gov/planets/ Solar System Jet Propulsion Laboratory, NASA California Institute of Technology http: //www. jpl. nasa. gov/solar_system/ The Hubble Site http: //hubblesite. org/

NASA Planetary Photojournal http: //photojournal. jpl. nasa. gov/index. html SOHO Exploring the Sun http: //sohowww. nascom. nasa. gov/ Crni Vhr Observatory in Western Slovenia Comets and Asteroids http: //www. fiz. uni-lj. si/astro/comets/ Deep Impact Comet Project Jet Propulsion Laboratory, NASA http: //deepimpact. jpl. nasa. gov/gallery/orbits 3. html