Download Chapter 19 Notes- Planets I. Inner planets – the four inner planets

Chapter 19 Notes- Planets
I. Inner planets – the four inner planets closest to the sun.
- Inner planets all have a metal core and rocky surfaces.
- Have similar geologic features as Earth does, including mountains,
canyons, and craters
A.) Mercury- closest planet to the sun
- Covered in craters
- Almost no atmosphere and no water
- very extreme temperatures= 720K during the day and 120K at night
- Short years (88 earth days) because it is so close to the sun
B.) Venus - Very thick atmosphere made up of mostly carbon dioxide and sulfuric acid
- Greenhouse effect that makes the climate on Venus very hot (over 700K)
- Spins on its axis VERY slowly and in the opposite direction of the other
planets
C.) Earth – Only planet that supports life
- An atmosphere that moderates the temperature and protects us from
harmful radiation from the sun as well as space debris
- Only planet with large amounts of liquid water on the
surface(hydrosphere)
- Distance from a planet to the sun: measured in terms of how far Earth is
from the sun. This distance is called an astronomical unit (AU).
- 1AU =150,000,000 Km
D.) Mars – Mars appears red because of the iron oxide in the soil
- Very thin atmosphere which allows objects from space to impact the
surface
- Olympus Mons- volcano and the largest mountain in the solar system
- Has polar ice caps with frozen CO2 and small amounts of water, but
surface features suggest liquid water may have flowed across Mars in the
past.
II. Between Mars and Jupiter is the asteroid belt
- Asteroids are small objects made up of metal and rock in orbit around
the sun that range from 3Km to 700Km across
III. Gas Giants – the four outer planets furthest from the sun
- Large planets with thick gaseous atmospheres
- Gas giants contain many satellites and rings
A.) Jupiter- Our solar system’s largest planet
- Spins on its axis very quickly. One day on Jupiter is only 10 Earth hours
- Has more than 60 moons
- Thick and complex atmosphere made up of hydrogen, helium, methane,
and ammonia
- Has giant storm systems such as the Great Red Spot
B.) Saturn- most extensive ring system made up of dust, rock, and ice
- Radiates three times more energy than it receives from the sun
- Over 40 moons
- Scientists believe that the helium in Saturn’s outer layers is condensing
and falling inward towards the core. Due to this fact, Saturn is considered
to still be forming
C.) Uranus – considered a blue giant
- Gaseous atmosphere made up of hydrogen, helium, and methane.
Methane gives Uranus a bluish tint
- Tilted on its axis at 98˚ which causes the seasons on Uranus to be very
extreme
D.) Neptune- also considered a blue giant
- Similar atmosphere, size, and color to Uranus
- Complex storm system similar like Jupiter
- Very windy: up to 1,100 Km/hour
IV. Beyond Neptune is the Kuiper Belt.
- Composed of many celestial bodies made up of ice and rock.
- Includes bodies such as dwarf planets like Pluto and Eris, as well as some
comets that have escaped from the Oort cloud.
- This region of space is actively being explored by Astronomers