topic 11 Flashcards
what is the name of the dwarf planet not located in the kupier belt and where is it located?
ceres - located in asteroid belt
what does eccentricity of a comet tell you?
how squashed the ellipse is. 1 is a circle and going down is more squashed
what is a planet (3)
- orbits a star
- its gravity is strong enough to pull it into a sphere
- It has cleared it’s region of space of smaller bodies
what are the two tails of a comet?
ion and dust
explain the ion tail of a comet
trail of plasma streaming back from solar wind - points in exactly opposite direction of sun
explain the nucleus of a comet
solid comet core, ma be hidden by coma
explain the coma of a comet
vapour cloud surrounding the nucleus
explain the hydrogen envelope of a comet
invisible, irregular cloud surrounding the coma
explain the dust tail of a comet
prominent trail of dust and gases that curves backwards
describe short period comets (3)
- likely origin in kupier belt
- orbit < 200 y
- periods in hundreds of years
describe long period comets (3)
- likely origin in oort cloud
- orbit > 200y
- periods in thousands of years
what are comets orbits often like and what does this suggest? (4)
1) very eccentric (not circular)
2) very inclined to the ecliptic
3) retrograde
^ these suggest an origin outside of the solar system
describe the kupier belt (3)
- outer solar system, from orbit of neptune onwards
- 30 - 50 AU
- similar to asteroid belt, but mostly comets, centaurs, and dward planets
describe the heliosphere(2)
- upto a distance of 80-100 au in the direction the sun moves through interstellar space, many times that distance in the opposite direction
- termination shock: radiation from the sun reaching maximum distance around due to gravity
describe the oort cloud(3)
- in interstellar space (space between stars)
- 2000 au to 200k au
- mostly consisting of comets, with 1-2 % asteriods
describe mercury(3)
- no atmosphere
- appearance similar to our moon
- not much bigger than our moon
describe venus(4)
- thick carbon dioxide atmosphere
- the hottest planet in the solar system
- similar size to earth
- a day is longer than a year
describe earth(2)
- the only planet with liquid water
- only place in the universe (THAT WE KNOW) supports life
describe mars(4)
- evidence of water eriosion on the surface
- polar ice caps
- very thin atmosphere of mostly carbon dioxide
- 2 small moons, probably captured asteroids
describe jupiter(4)
- the largest planet
- a gas giant, mostly hydrogen and helium
- giant red spot is a storm that has lasted 400 years
- more than 75 moons-
the 4 galilean moons are historically important
describe saturn(3)
- another gas giant
- prominent ring system first seen by galileo - the remains of a moon that broke into pieces
- at least 53 moons including titan (only jupiter’s moon ganymede is bigger)
describe uranus(4)
- discovered in 1781 by william herschel
- mostly icy water, methane and ammonia with a hydrogen helium outer layers
- rotates on its side
- at least 27 moons, many named after shakespeare characters
describe neptune(4)
- another icy giant very similar to uranus
- its existence was predicted due to observed gravitational effects on neptune
- 14 moons including triton
- its retrograde orbit suggests that is was probably captured from the kupier belt
what is an astronomical unit?
the mean distance between the earth and sun