1. How are the planets alike and/or different? What factors exists on Earth that make life possible here, but unlikely on any other planet? Which planets in the solar system are called the “gas giants” and why? In general, what condition on the planets is MOST affected by its distance from

3. The Planets Earth’s atmosphere is about 78% nitrogen, 21% oxygen. Liquid water, moderate temperature, and an atmosphere rich in oxygen make Earth the only planet that can support life as we know it. The planets, Jupiter, Saturn, Uranus, and Neptune, are called the “gas giants.” This is because they are so much larger than Earth and they do not have well defined surfaces. The condition on the planets that is most affected by its distance from the sun is the temperature. The farther away they are from the sun, the lower the temperature on the planet.

4. The planets that are much closer to the sun are classified as inner planets: Mercury, Venus, Earth, Mars –Inner planets have rocky, dense surfaces….terrestrial planets The planets that are much farther from the sun are classified as outer planets: Jupiter, Saturn, Uranus, Neptune –Outer planets are larger and composed of gas…. Gas giants Pluto is a dwarf planet – it is not included in the outer planets group because it has different characteristics

5. The Inner Planets Also known as the “Terrestrial Planets” Mercury Venus Earth Mars

6. Mercury closest planet to the sun only Pluto is smaller rocky surface with many craters very thin atmosphere high temperature no life; Distance from the sun58,000,000 km Diameter4,880 km Year Length (Earth Years)88 days Gravity (X Earth’s00.38 Moons0

7. Venus Distance from the Sun108,000,000 km Diameter12,100 km Year Length (Earth Years)225 days Gravity (X Earth’s)0.91 Moons0 2 nd planet from sun same size as Earth rocky surface atmosphere is very thick with carbon dioxide gas traps heat under it no life;

8. Earth Distance from the Sun 150,000,000 km Diameter = 12,760 km Length of Year = 365.25 days Gravity = 1 Moons = 1 3 rd planet from sun surface is rocky covered with plains, valleys, mountains, plateaus, active volcanoes ¾ surface covered with water, atmosphere 78% nitrogen, 21% oxygen water, moderate temperature, and oxygen makes Earth only planet supporting life

9. Mars Distance from the Sun228,000,000 km Diameter6,790 km Year Length (Earth Years)687 days Gravity (X Earth’s)0.38 Moons2 4th planet from the sun, called “red planet”, half the size of Earth, rocky and dusty surface, hills, plains mountains, extinct volcanoes, craters, largest volcano in solar system, ice caps north and south poles, may have had water at one time, thin atmosphere with carbon dioxide, life may have existed at one time;

10. The Outer Planets “Gas Giants” Jupiter Saturn Uranus Neptune *No solid surfaces to walk upon*

11. Jupiter Distance from the Sun 778,000,000 km Diameter143,000 km Yea Length (Earth Years)119 years Gravity (X Earth’s)2.53 Moons63 5th planet from sun, largest planet, “gas giants" no solid surface, slushy ball of liquid hydrogen, atmosphere mostly helium and hydrogen gases, large red spot ( gigantic storm or hurricane), circled by very thin rings, no life;

12. Saturn Distance from the Sum1,427,000,000 km Diameter120,500 km Year Length (Earth Years)29.4 years Gravity (X Earth’s)1.14 Moons47 6th planet from sun, complex ring system, second largest planet, structure similar to Jupiter, atmosphere is hydrogen and helium gases, no life;

13. Uranus Distance from the Sun2,871,000,000 km Diameter51,100 km Year Length (Earth Years)84 years Gravity (X Earth’s)0.9 Moons27 blue-green color from poisonous methane 7th planet from sun third largest planet surface completely covered with water, methane, and ammonia 11 rings circle planet rotates on its side poles point toward and away from sun, extremely cold temperature, no life;

14. Neptune Distance from the Sun4,498,000,000 km Diameter49,500 km Year Length (Earth Years)165 years Gravity (X Earth’s)1.14 Moons13 8th planet from the sun, fourth largest planet, glows blue-green with methane gas clouds, icy ocean of water, methane, ammonia, and hydrogen, six rings orbit planet, no life on planet;

15. Quick Check Which planets in the solar system are called the gas giants? a.Mercury, Venus, Earth, Mars b.Saturn, Uranus, Neptune, Pluto c.Jupiter, Saturn, Uranus, Neptune d.Earth, Venus, Pluto, Mars

16. Quick Check Which is the current and correct model of our solar system? a.The Big Bang Theory b.The Geocentric Theory c.The Pythagorean Theory d.The Heliocentric Theory

17. Quick Check What three factors exist on Earth that make life possible here, but unlikely on any other planet? A. liquid water, moderate temperatures, atmospheric oxygen B. liquid water, moderate temperatures, atmospheric nitrogen C. liquid waters, moderate size of Earth, atmospheric oxygen D. solid water, moderate temperatures, atmospheric oxygen

18. Quick Check Which planet is MOST LIKELY to support life as we know it? A. Mercury B. Venus C. Jupiter D. Mars

19. Quick Check In general, what condition is MOST affected by its distance from the sun? A. size B. temperature C. atmosphere D. surface composition

20. Quick Check The force of gravity on a planet determines the weight of objects on the planet. If you weighted 30 kg (66 pounds) on Earth, what would you weigh on Jupiter? A. 11.4 kg (5.2 pounds) B. 30 kg (66 pounds) C. 34.2 kg (75.4 pounds) D. 75.9 kg (167.3 pounds)