Chap 12 Flashcards
How is the distance between the planets n the sun determined
- astronomical unit and light years are used to measure the relative distances between the planets and the sun
explain astronomical unit (A.U.)
- is the average distance between the earth and the sun ( which is approx 93 million miles or 150 million km)
- 1 A.U. = 1.5 x 10^8 km
explain light years (ly)
- refers to the distance travelled by light in one year
- light moves at a velocity of 300 000 km every second
- 1 light year = 9.5 x 10^12km
What r the planets in solar system (in order)
-mercury
-venus
-earth
-mars
-jupiter
-saturn
-uranus
-neptune
Explain about mercury
- the closest planet to the sun , approx 57.9 mil km
-it is the smallest planet in the solar system
-smaller than jupiter’s moon , Ganymede ‘ and saturn’s moon, titan - surface is similar to the surface of the moon, w asteroid craters n cliffs which r tens of km high
- Sky appears dark in outer space bcuz light cannot be scattered in the absence of atmosphere
Explain Venus
- second closest planet to the sun
- known as the greenhouse planet bcuz of the high content of carbon dioxide in its atmosphere
-also rotates from east to west, which differs from other planets which rotate west to east, this causes the sun to rise from the west on venus - the size n age of venus is the same as the earth, but its climate is far more challenging , w a temp of approx 460 C
Explain about the earth
-third planet frm sun
- only place in the universe that is inhabited by living things
- has a layer of air known as the atmosphere , which protects the surface of the earth from solar wind, harmful ultraviolet rays and radiation from outer space
-more than 71% of the earth is covered in water n 29% land
Explains about mars
- the fourth planet from the sun n is also known as the “red planet”
- has two moons , phobos n demos
- has a surface area that is only 25% that of the earth n its mass is 10% that of the earth
- if observed from earth, the atmosphere of mars can be divided into 2 diff areas
- the brighter area is covered in dust n reddish sand, while the poles contain frozen water n carbon dioxide
Explain about jupiter
- fifth planet frm the sun
-largest planet - mass is almost 320 times that of earth, twice the amount of all the planets in the solar system
- said to be the protector of the earth, able to deflect huge objects from hitting earth w its strong gravity
Explain about saturn
- sixth planet frm the sun n the 2nd largest planet
- classified as a giant gas planet
- has a ring system which mostly comprises of ice w a small amount of rocky material n dust
- 62 moons hv been found to orbit this planet
Explain about uranus
- seventh planet frm the sun n third biggest planet
- first elements in the interior of uranus r ice n rock
- astronomers often refer to it as a giant gas planet
- has a ring system similar to saturn, but its thinner n darker
- has many moons
- is unique bcuz its axis of rotation is tilted, almost parallel to its orbit and the sun
- takes 84 years (time of earth) to orbit the sun
explain neptune
- eighth planet from the sun
- classified as a giant gas planet
- takes almost 165 years (time on earth) to orbit the sun
Explain the relationship between temp of a planet that do not hv an atmosphere n the sun
Mercury: -surface will cause the area that faces the sun to be extremely hot, more than 427 C
- darker area is extremely cold, temp can drop to -173 C
Explain the relationship between temp of a planet that hv an atmosphere n the sun
Earth: - has clouds that reflect sunlight back into outer space but the atmosphere traps some of the heat, which causes greenhouse effect
Venus: has thick clouds that can reflect sunlight back into outer space, but the atmospheric layers consist carbon dioxide which cause greenhouse effect. More heat is trapped n surface temp can reach up to 462C
Mars: surface pressure of atmosphere is extremely low compared to that of earth, causing minimal effect on the surface temp
the surface temp fluctuates between -143C to 35 C
Explain the relationship between temp of giant planets n the sun
Jupiter, Saturn, Uranus, Neptune:
- surface if these planets covered in gas
- receive very little sunlight
-surface temp r extremely low
the gravity on the surface of a planet depends on
its mass and density
the gravity of earth is
9.8 ms-2
give a few facts about gravity in our solar system
- gravity of mercury n mars is lower than earth bcuz their masses r lower than earth
-gravity of venus is almost the same as earth bcuz its mass is almost the same as earth’s mass
-gravity of jupiter is much higher compared to earth bcuz its mass is extremely high although it has a low density - although saturn, uranus n neptune hv very high mass, their gravity is not as high as the gravity of earth bcuz these giant gas planets hv low density.
The further a planet is from the sun, :
the more time it needs to orbit the sun
Explain abt the rotational direction of planets
- all planets rotate on their axis at diff angles
-all planets rotate from west too east except venus n uranus
-venus rotates from east to west while uranus rotates on its side
What happens if the rotation of the earth slows down or stops completely?
- longer day and night duration in 2 diff parts of the earth
- change in high and low tides
- temp will drop in areas of the earth that do not receive sunlight
- more desert areas in parts of the earth that faces the sun
whats natural satelites
- objects that move around planets on their own orbit
-moon is the only natural satellite of the earth
why would the moon be facing the earth at all times
- this is bcuz the moon also moves around the earth on its orbit, and the duration taken is also the same – 27 days.
What r the few factors that allows earth to support life
-presence of water
-minerals
-temperature
-atmospheric content
state the characteristics of earth
- has alot of water for all living processes
- has high oxygen content for respiratory process
- has a suitable temp range, not too hot or cold
- its atmosphere blocks harmful ultraviolet rays from reaching the earth
-receives sunlight for plants to conduct photosynthesis - has gravity that keeps object from floating
meaning of ecological footprint
-the measure of the ability of water n land to provide the basic needs of humans aswell as the ability of the earth to absorb all human wastes n reproduce resources after they have been used by humans.
ecological footprint is the ratio measurement for six areas, which are
- carbon dioxide waste treatment areas
- construction areas
-forests
-agricultural areas - farming areas
-fishing areas
if the ecological footprint exceeds the ability of the earth to renew its resources,
the earth will be depleted of all its resources
ecological footprint is different between
countries
Why isnt mercury the hottest planet in the solar system
- mercury has very weak atmosphere so it cannot hold anything
