Solar System Facts
- The solar system is around 4.6 billion years old.
- There are eight major planets and over 100 moons in the solar system.
- Other objects in the solar system include dwarf planets, asteroids and comets.
- Many bodies in the solar system are visible to the naked eye.
- Mercury, Venus, Earth and Mars are the small rocky planets. Jupiter, Saturn, Uranus and Neptune are the gas giants.
- The sun is by far the largest object in the solar system.
- All the planets orbit the sun in an eliptical, oval shaped path.
- The solar system is in the galaxy known as "The Milky Way".
- Astronomers have found many other stars in our galaxy which have planets orbiting around them. There are around 200 billion stars in the milky way.
- The Voyager 1 spacecraft is the furthest man-made object in the solar system, it is around 11 billion miles (18 billion km) from the sun and is still sending data back to Earth.
Birth of the Solar SystemOur solar system began as part of a massive nebula cloud of molecular hydrogen and dust around 4.6 billion years ago. In a region of this dark cloud conditions allowed gravity to begin condensing the hydrogen until a substantial mass began to grow ever larger and hotter, eventually this mass collapsed in on itself, forming the early stage of a star called a protostar. The gravitational pull of the embryonic star caused a large disc of gas and dust to begin forming around it. Over millions of years pressure began to build up inside the protostar as it became hotter and denser until eventually nuclear fusion began in its core, giving birth to the sun as we know it. During this time the disc of gas and dust that had formed around the star had also began condensing into ever growing orbiting bodies. In time they would go on to form the planets, moons and other objects in our solar system.
Our Home PlanetThe Planet Earth and Sun as seen from the Space Shuttle
View From Another WorldAmazing image of the sun setting on Mars
The nearest planet to the sun is Mercury, aptly named after the swift footed messenger god it orbits the sun in only 88 days, quicker than any other planet in the solar system. Next comes Venus, often referred to as Earth’s sister planet but underneath her thick clouds lies a hellish oven baked landscape with temperatures hot enough to melt lead. Third planet from the sun lies Earth, a striking blue sphere covered with oceans of liquid water and the only planet known to us which harbors life. The last of the rocky inner planets is Mars, consisting of a thin atmosphere this red body was once covered in oceans just like Earth but is now a desert where dust storms can engulf the entire planet. Almost 800 million kilometers from the sun we find the first of the gas giants, Jupiter, enormous in its size it would take over a 1,000 Earths to fill its volume. Saturn is the second of the gas giants and is unlike any other planet in the solar system with its spectacularly colorful rings made from dust and ice particles. Then comes the first of the planets known as ice giants, Uranus, this large turquoise ball of gas lies tilted on its side with freezing atmospheric temperatures of -371 Fahrenheit. At 4.5 billion kilometers from the sun we find the last of the planets, Neptune, a blue ice giant where winds in the atmosphere reach over 2,000 kilometers per hour.As mankind explores space we have found that some of the moons in our solar system are equally and at times even more fascinating than the planets themselves. Jupiter’s wonderfully colored moon Io is the most volcanically active object in the solar system, Saturn’s moon Titan has a thick nitrogen based atmosphere which rains methane producing liquid lakes on its surface. Another of Saturn’s moons Enceladus has volcanoes which erupt with water ice and possibly has a liquid ocean underneath its icy surface. Then there is the ice world of Europa, another of Jupiter’s fascinating moons, underneath its surface lies a vast ocean of liquid water which is 100 km deep and possibly teeming with life.At the center of the solar system is our sun, a massive ball of hydrogen and helium over a hundred times larger in diameter than Earth producing immense heat and enormous explosions which jettison solar winds millions of miles into space. Between the orbits of Mars and Jupiter lies the Asteroid Belt, millions of rocks reside in this area some as large as 60 miles (100 km) in diameter. Beyond Neptune we reach the Kuiper Belt where we find most of the dwarf planets including Pluto, at one time considered the ninth planet in our solar system this tiny body orbits the Sun at an average distance of almost 6 billion kilometers. Comets originate in the Kuiper Belt or the even more far flung Oort Cloud, a massive spherical cloud of icy bodies that surrounds the solar system.
Learn about stars, galaxies, nebulae and exoplanets by visiting the Universe section.
|The Planets in Scale of Size - Click here for larger image|
Surface of Mars
Ice Moon Europa
Jupiter's Red Spot
Surface of Titan (Artist's Impression)