| Solar System Worlds and Orbits | ||
| Planet | Average Distance from Sun (km) | Orbital Period (Earth Year/Earth Days) |
| Mercury | 57,900,000 | 0.24 Earth year (88 Earth days) |
| Venus | 108 million | 0.62 Earth year (226.3 Earth days) |
| Earth | 149 million | 1 Earth year (365.25 days) |
| Mars | 227 million | 1.88 Earth years (686.2 Earth days) |
| Jupiter | 779 million | 11.86 Earth years (4,380 Earth days) |
| Saturn | 1.425 billion | 29.5 Earth years (10,767.5 Earth days) |
| Uranus | 2.85 billion | 84 Earth years (30,660 Earth days) |
| Neptune | 4.5 billion | 165 Earth years (60,225 Earth days) |
| Pluto | 5.06 billion | 248 Earth years (90,520 Earth days) |
| Composition of Earth’s Atmosphere | |
| Nitrogen | 78.084% |
| Oxygen | 20.9% |
| Argon | 0.9340% |
| Carbon dioxide | .0394% |
| Neon | 0.0018% |
| Helium | 0.0005% |
| Methane | 0.00018% |
| Krypton | 0.00011% |
| Hydrogen | 0.00005% |
| Nitrous oxide | 0.000032% |
| Other elements: 0.079 plus water vapor. | |
| Current and Near-Future Moon Missions | |||
| Name | Mission Goals | Country | Status |
| Lunar Reconnaissance Orbiter | Surface mapping | USA | Working |
| Chang’e 2 | Lunar studies, now studying asteroid Toutatis | China | Working |
| LADEE | Study lunar atmosphere and surface | USA | Launch in 2013 |
| Chang’e 3 | Soft lander, perform UV astronomy | China | Launch in 2013 |
| GLXP | Moon Express lander, rover | Private competition | Launch ~2013 |
| Luna-Glob | Robotic lunar base/orbiter combo | Russia | Launch ~2014 |
| Chandrayaan-2 | Robotic rover, orbiter combo | India | Launch ~2016 |
| Best Times to Observe Mercury | |||
| Time | Date | Elongation | Magnitude |
| Evening (after sunset) | 2013 Oct 9 | 25.3°E | +0.2 |
| Morning (before sunrise) | 2013 Nov 18 | 19.5°W | -0.3 |
| Evening (after sunset) | 2014 Jan 31 | 18.4°E | -0.3 |
| Morning (before sunrise) | 2014 Mar 14 | 27.6°W | +0.4 |
| Evening (after sunset) | 2014 May 25 | 22.7°E | +0.7 |
| Morning (before sunrise) | 2014 Jul 12 | 20.9°W | +0.6 |
| Evening (after sunset) | 2014 Sep 21 | 26.4°E | +0.3 |
| Morning (before sunrise) | 2014 Nov 1 | 18.7°W | -0.3 |
| Evening (after sunset) | 2015 Jan 14 | 18.9°E | -0.4 |
| Morning (before sunrise) | 2015 Feb 24 | 26.7°W | +0.3 |
| Evening (after sunset) | 2015 May 7 | 21.2°E | +0.5 |
| Morning (before sunrise) | 2015 Jun 24 | 22.5°W | +0.7 |
| Evening (after sunset) | 2015 Sep 4 | 27.1°E | +0.5 |
| Morning (before sunrise) | 2015 Oct 16 | 18.1°W | -0.3 |
| Evening (after sunset) | 2015 Dec 29 | 19.7°E | -0.3 |