Introduction to the Universe
The Solar System is a collection of planets, moons, asteroids and comets and other rocky objects orbiting the Sun. The Solar System is believed to extend out to at least 150 000 million km from the Sun, although the planets are all found within about 6000 million km.
Our Solar System is thought to have formed 4.6 x 109 years ago from a vast, rotating cloud of gas and dust known as the solar nebula. As the solar nebula rotated, its gravity began to attract gas and dust towards the centre, eventually forming our Sun.
The Sun is the powerhouse of the Solar System. Without it, life on Earth simply would not exist. Despite burning its hydrogen fuel for the best part of 5 billion years, the Sun is still only half way through its life cycle.
The study of the Sun, its environment and how the material it discharges interacts with other worlds in the Solar System is of great interest to us all. ESA has a number of mission that analyse various aspects of this solar emission.
| SOHO || Joint mission with NASA at Lagrange 1 || An observatory viewing and investigating the Sun from its deep core, through its outer atmosphere (the corona) and the powerful solar wind. |
| Ulysses || Highly elliptical Sun centred polar orbit || The main scientific goal of the joint ESA-NASA Ulysses deep-space mission is observing the unexplored region of space above the Sun's poles, a first for solar observatories. |
| Cluster || Four spacecraft flying in formation near the Earth || The Cluster mission is currently investigating the structure (in three dimensions) of the Earth's plasma environment, such as those involved in the interaction between the solar wind and the magnetospheric plasma. |
| Double Star || Joint mission with the Chinese one spacecraft in equatorial and one in polar orbit || Double Star follows in the footsteps of ESA's ground-breaking Cluster mission by studying the effects of the Sun on the Earth's environment. Conducting joint studies with Cluster and Double Star should increase the overall scientific return from both missions. |
||Planets and Moons
Last Update: 16 May 2013