mass = 0.06 M , radius = 2439 km, orbit = 0.39 AU, year = 0.24 years, day = 1408 hours

• Named after the roman god of travel as it moves swiftly in the sky.
• Visited by Mariner 10 in 1974
• Very eccentric orbit, 46 - 70 million km
• Revolves very slowly so temperature varies greatly, 90K - 700K
• Virtually no atmosphere, surface like our Moon's.

mass = 0.82 M , radius = 6052 km, orbit = 0.72 AU, year = 0.62 years, day = 5832 hours

• Named after the roman goddess of love as it is so bright in the sky
• Shows phases when viewed from Earth
• Magellan recently produced very detailed maps of its surface using radar to look through the dense atmosphere
• Rotates very slowly, 243 Earth days
• Very dense, high pressure carbon dioxide atmosphere
• Greenhouse effect makes planet very hot, 740K
• Very few craters, several volcanoes

mass =  M, radius = 6400 km, orbit = 1 AU, year = 1 year, day = 24 hours

• The name Earth comes from old English
• 70% of surface covered with water
• Atmosphere sustains life

mass =  0.11 M, radius = 3400 km, orbit = 1.52 AU, year = 1.88 years, day = 24.6 hours

• Named after the god of war as it is red
• Mars Expedition Rovers arrived in 2004 and have explored the surface
• temperature from -133C to 20C
• Surface features include mountains, canyons and craters. Evidence of erosion.
• Very thin atmosphere, mostly carbon dioxide
• has two tiny moons

mass =  318 M, radius = 71,500 km, orbit = 5.2 AU, year = 11.9 years, day = 9.9 hours

• named after the king of the gods as it is the largest planet
• Giant gas planet, 90% hydrogen, most of the planet is liquid metallic hydrogen
• When Galileo studied the orbit of 4 of its moons it led to his conclusions about a heliocentric solar system
• The bands we see are high velocity winds flowing in opposite directions
• The giant red spot is a 300 year old storm

mass =  95 M, radius = 60,000 km, orbit = 9.5 AU, year = 29.5 years, day = 10.7 hours

• named after the roman god of agriculture
• Giant gas planet mostly hydrogen and helium, bulk is liquid metallic hydrogen
• Very distinct rings A and B, separated by the Cassini Division, then C. Made up of small particles from 1cm to 1m in size. Rings about 1 km thick.
• Very squashed sphere shape due to high rotational speed
• 34 named satellites. Some "shepherd moons" help to maintain the ring structure

mass =  14.5 M, radius = 26,000 km, orbit = 19.2 AU, year = 84 years, day = 17 hours

• Discovered by William Herschel in 1781 who was surveying the sky with a new telescope that was powerful enough to see a disc rather than a point of light. It had been mistaken for a star in the past.
• Visited by Voyager 2 in 1986
• Spins on an axis almost parallel to the ecliptic so its south pole faces the Sun
• A gas giant mostly hydrogen and helium, blue colour due to presence of methane. Bulk is liquid metallic hydrogen
• 5 large and 10 small moons

mass =  17 M, radius = 25,000 km, orbit = 30 AU, year = 165 years, day = 16 hours

• named after the roman god of the sea
• The existence of Neptune was predicted by Le Verrier after observing its gravitational effect on the orbit of Uranus. It was first observed in 1846 by Galle and d'Arrest at a location that was predicted mathematically.
• Visited by Voyager 2 in 1989
• Composition probably very similar to that of Uranus
• 13 known moons

mass =  0.002 M, radius = 1160 km, orbit = 39 AU, year = 249 years, day = 153 hours

• named after the roman god of the underworld
• First observed by Clyde Tombaugh in 1930 by accident. The presence of a planet was predicted (gravitational effects) by Percival Lowell. The planet was found despite the fact that the calculations turned out to be wrong.
• Has never been visited
• Has one moon, Charon
• Some argue that Pluto should not be classed as a planet. It is one of many objects in the Kuiper belt. Several objects have been found which are larger than Pluto.
• Orbit is very inclined compared with the other planets. Sometimes it is closer to the Sun than Neptune.