SOIAR SYSTEM

SUN Diameter : 1,384,000 km. Age:4.5 billion years . Satellites :9 planets. A rather ordinary ,middle-age star ,the gaseous sun may reach a temperature of 27 million degrees celslus at its core . Its 11- year cycle is now approaching a solar maximum ,a period mark ed by frequent sunspots and flares. On earth ,some radio waves will be disturbed and the amazing sky streamers called northern lights will appear.

MERCURY Diameter:4,849.6km Moons: none. Average distance to the sun;57.6 km Time to orbit the sun:88 days.

VENUS Diameter: 12,032km. Moons: none. Average distance to the sun: 107.52 million km. Time to orbit the sun: 225 days.

EARTH Diameter:12,739.2 km. Moons:1 Average distance to the sun:148.8 million km. Time to orbit the sun:365 days

MARS Diameter : 6,755.2 km . Moons :2. Average distance to the sun : 225.6 million km. Time to orbit the sun :678 days . The Viking probes fail to find any sing of life . Beneath its thin atmosphere, mars is barren, covered with pink soil and boulders. Long ago it was more active ; the surface is marked with dormant volcanoes and deep chasms where water once freely flowed .

JUPITER Diameter:141,968 km. Moons: 16. Average distance to the sun: 772.8 million km. Time to orbit the sun: 11.9 years.

SATURN Diameter: 119,296 km. Moons: 20 or more. Average distance to the sun: 1,417.6 million km. Time to orbit the sun: 29.5 years.

NEPTUNE Diameter: 49.000 km. Moons: 8. Average distance to the sun: 4,497 million km. Time to orbit the sun: 165 years.

PLUTO Diameter: 3,040 km. Moons: 1. Average distance to the sun: 5,865.6 million km. Time to orbit the sun: 248 years.