• Our Sun is one of more than 100 billion stars in our galaxy.
• The Sun is, at present, about 70% hydrogen and 28% helium by mass. Everything else ("metals") amounts to less than 2%.
• There are nine planets and a large number of smaller objects orbiting the Sun.
• Mercury is the closest planet to the Sun and the eighth largest.
• Mercury has no known satellites.
• Mercury is often visible with binoculars or even the unaided eye.
• Temperature variations on Mercury are the most extreme in the solar system ranging from 90 K to 700 K.
• Venus is the second planet from the Sun and the sixth largest.
• Venus' orbit is the most nearly circular of that of any planet.
• Venus probably once had large amounts of water like Earth but it all boiled away. Venus is now quite dry.
• Venus has no satellites and is usually visible with the unaided eye.
• Earth is the third planet from the Sun and the fifth largest.
• Earth is the only planet whose English name does not derive from Greek/Roman mythology.
• The Earth is the densest major body in the solar system.
• 71 Percent of the Earth's surface is covered with water.
• Earth has only one natural satellite, the Moon.
• Mars is the fourth planet from the Sun and the seventh largest.
• Mars' orbit is significantly elliptical.
• The average temperature on Mars is about 218 K.
• Mars has two tiny satellites which orbit very close to the martian surface.
• Jupiter is the fifth planet from the Sun and by far the largest.
• Jupiter is more than twice as massive as all the other planets combined.
• Jupiter is about 90% hydrogen and 10% helium.
• Jupiter has 63 known satellites.
• Saturn is the sixth planet from the Sun and the second largest.
• Saturn's rings are extraordinarily thin: though they're 250,000 km or more in diameter they're less than one kilometer thick.
• Saturn has 30 named satellites plus one discovered in 2003 and is unnamed as of yet.
• Uranus is the seventh planet from the Sun and the third largest (by diameter).
• Uranus is composed primarily of rock and various ices.
• Uranus has 11 known rings which are all very faint.
• Uranus has 21 named moons and six unnamed ones.
• Neptune is the eighth planet from the Sun and the fourth largest.
• Neptune has an internal heat source - it radiates more than twice as much energy as it receives from the Sun.
• Neptune's rings are very dark but their composition is unknown.
• Neptune has 13 known moons.