Intro to the Planets Flashcards
(24 cards)
planets all orbit in the ____ plane called the…
same; Ecliptic Plane
planets orbit in what direction
same
which way does the sun rotate
The sun rotates in the same direction that the planets orbit
What orbit do the planets have?
The planets all have elliptical orbits
The closer the planet is to the sun, the ____ it orbits
faster
(e.g. Mercury fast, Neptune slow)
Mercury
Closest planet to the sun
No atmosphere (gets cold at night)
Highly cratered surface
Rocky exterior with a huge iron core
Temp fluctuates between -170C and 425C
No moons
Only 2 probes:
Mariner 10 (1974-1975)
Messenger (2011-2015)
Venus
Same size as Earth
Lots of volcanoes
Thick CO2 atmosphere (hard to walk through)
Runaway greenhouse effect
Makes it hotter than Mercury
Always 460C everywhere
Rains acid
No moons
Rotates slow and backwards
Many probes and landers
Earth
Same size as Venus
Lots of volcanoes
O2 and N2 atmosphere
Large oceans regulate CO2
Surface heavily affected by life
Has large moon
23.4 deg orbital tilt produces significant seasons
Mars
No distinct volcanoes
Thin CO2 atmosphere
No evidence for life
2 small moons
Polar ice/dry-Ice caps
Planet wide dust storms
25.2 degree orbital tilt produces significant seasons
May probes and landers
Terrestrial Planets
Small, rocky
Thin or no atmosphere
Few moons and made from heavy elements (iron cores, rocky crusts)
Jupiter
Largest planet in solar system
Thick gaseous atmosphere surrounds giant ball of liquid hydrogen
Faint rings
Many moons (more than 60)
Several probes have visited
Saturn
2nd largest planet in solar system
Structure is like Jupiter
Has spectacular rings
Many moons
Several probes have visited
Uranus
Coldest planet
Small, rocky core
Thick water, ammonia and methane mantle
Thick H2/He atmosphere
Rotation axis tilt 98 degrees (doesn’t spin in ecliptic plane)
Thin rings and lots of moons
Neptune
Furthest planet from sun
Structure very similar to Uranus
Rotation axis tilted 28 degrees
More surface feature than Uranus
Strongest winds in the solar system up to 2,100 km/h
Jovian Planets
Jupiter, saturn, uranus, neptune
Large, gas and liquid mantle, small rocky core
Many moons and made from light elements
Earth moon
Takes 28 days for moon to go around Earth once
Rocky, like the Earth
No atmosphere
Cratered surface
No geological activity
Looks similar to mercury
Jupiter moon
4 large moons, orbit in same direction as Jupiter (over 60 known moons)
High ice content
I0 is most geologically active in solar system (large volcanic activity)
Saturn moon
Ring system is in same orbit as sun
Over 60 known moons
5 over 1000 km diameter
High ice content
Orbit in same plane and direction as the rings
Uranus moon
Over 60 known moons
4 over 1000 km diameter
High ice content
Orbit in same plane as Uranus’ rotation
Tipped 97 degrees from ecliptic plane
Neptune moon
14 known moons
Only 1 over 1000 km diameter
Orbit not same plane or direction as Netune’s rotation
Surface is frozen Nitrogen (main component of air)
Dwarf planets
9 identified, may be hundreds
Only Pluto and Ceres have been visited by probes
Pluto has high ice content
Asteroid belt
Around a million asteroids larger than 1 km in diameter
Total mass is around 3% of the moon’s
Some asteroids have been visited by probes
Kuiper belt
Vast collection of small icy videos beyond the orbit of Neptune
Includes several of the Dwarf Planets, including Pluto
Total mass around that of the Earth’s moon
2 objects visited by the New Horizons probe (NASA)
Comets
Smaller icy bodies from the outer solar system
Highly elliptical orbits
Emit tails when they get close to the sun
