Test Flashcards
(37 cards)
what are the atmospheres of the terrestrial planets like?
- made of rocky substances
- metallic core composed of mostly iron with a surrounding silicate mantle (mercury venus earth mars)
- have common surface features like canyons, creaters, mountains, volcanoes
- have secondary atmospheres which are gnereated through volcano or comet impact
- more dense than jovian
where did the water for earths oceans come from
-water came from comets and icy objects bombarding the earth
why dont venus and mars have oceans
- mars is too cold, low temperatures water wouldnt be stable in liquid phase
- venus is too hot to sustain water
how do the jovian planets differ from earth? why are they so different?
- made of gas
- jupiter and saturn contain almost entirely hydrogen and helium
- different because of formation of solar system: formed behind frost line where hydrogen could condense into ice - formed farther from sun
- jovian planerts are larger than earth & terrestrial planets - less dense
how do we know that earth formed from the accretion of smaller rocky objects
- craters on earths surface
- iron meteorite and stony meteorite
- moon and mercury show evidence through meteorites
where are most comets located? how do we explain the origin of comets
- comets are located in the oort cloud - 10,000x farther away from sun then earth
- they originate from the oort cloud and Kupier belt
- oort cloud - has icy bodies and a star can pull one out letting it fall to earth as a comet
- kupier belt - composed of icy bodies (short period comets)
why is the solar system flat?
- based on current obsevations, we can see solar systems beyond our own
- the solar system is flat because of angular momentum
what is the nebular hypothesis?
- the nebular hypothesis ocurred when the gravity contracted the solar nebula na dmost of the material collected in the center to from the protosun
- remaining materials formed a thick, flattened, rotating disk within which matter gradually cooled and condensed into grain of clumps and icy, rocky material
- repeated collisions resulted in the material clumping together into planets
what seven wanderers did the ancient greek astronomers identify in geocentrism
- moon
- mercury
- venus
- sun
- mars
- jupiter
- saturn
what did the Ptolemaic (geocentric) model include and why ?
- earth was the center of the solar system - motionless
- believed all celestial objects orbited erath
- assumed each planet moved on a small sphere of circle called an epicycle
what discover made by galileo led to the downfall of geo-centrism? why?
- the discovery of the phases of venus
- ptolemaic system argues that the crescent phases of venus should never be seen from earth
- we are able to see phases, therefore copernican view of sun centered universe is more accurate
what is retrograde motion?
- the westward motion of planets. Since Earth moves much faster than the other planets, the slower moving planets appear as if theyre going in reverse
- earth moves faster than mars so when it passes mars it looks like mars is moving backwards
How was retrograde motion explained in both the Ptolemaic (geocentric) and Copernican (heliocentric) models?
- geocentric: used epicycles to explain the retrograde motion - the center of the epicycle moves in large circl called a deferent
- heliocentric: planets further from sun move more slowly. As earth laps mars, mars appears to go bakcward as seen by observer on earth
what is keplers three laws of planetary motion?
a. Elliptical orbits (all planets move about sun in elliptical orbits) - planets are sometimes closer to sun and go fast. further away and go slow
b. equal areas in equal times - describes the speed of a planet traveling in an elliptical orbit around the sun. Line between sun and planet sweeps equal areas in equal times
c. period squared = distance cubed - planets in solar sytem have no linear relationship between planets orbit and distance around sun
what discovery by newton verified keplers laws?
when he proposed the law of univeral gravitation. Gravitational force was the cause of Kepler’s laws
what are the phases of the moon? Is the moon ever visible during the day? Start with new moon
New moon: The moon is between sun and earth - back lit
waxing crescent: sunlit portion is increasing but still less than half (right side lit)
first quarter: half of the moon is lit. right side
waxing gibbous: more than half is lit (left side is unlit)
full moon: earth sun and moon are in approximate alignment - entire sunlit part is facing us
waning gibbous: light decreases, more than half lit (right side unlit
third quarter: half moon is lit - left side is lit
waning crescent: more is dark lit, only part of left side is lit
- the moon can be seen during the day when it is in New moon as it moves away from the sun
what are the differences between the crescent moon visible after sunset and the one visible before sunrise?
After sunset: moon appears very low in western sky, has low surface brightness, ddrawn curved to the right
before sunrise: points eastward - drawn curved to the left
what is the connection between lunar phases? why don’t eclipses happen every month?
- solar eclipses only happen when moon is in new moon phase: plane of moons orbit is aligned with earth’s orbit around sun - only happens once or twice a year
- lunar eclipses only occur when moon in in full phase - planes have to align
- They dont happen every month because the moon does not orbit in the same plane as earths orbital plane
- more likely to see lunar eclipse
what do we know about the suns visible surface and outer atmosphere & how do we know it
outer atmosphere: photosphere, chromosphere, and corone
Photosphere: very active, gives off visible light strongly, has sunspotss which emerge when suns magentic field breaks through the surface
Chromosphere: emits a reddish glow as hydrogen burns off. Plays a role in heat from interior to corona
Corona: thrid layer of suns atmosphere. hotter than photosphere. only visible during a solar eclipse.
-studied through solar exlipses and satellite devices
what do we know about the suns interior and how do we know it
-suns interior is opaque
-core: pure helium
-radiation zone: hydrogen
Convection zone: doesnt transmit light
-observed throug hhelioseismology which studies suns movement/swinging. these movements are caused by sound waves
how big is the sun and how does it compare to other stars
- the suns circumference is about 2,700,000 miles - you could line up 109 earths across the face of the sun
- suns diameter is 100 times wider than earth, gaseous, not very dense
- stars are 700 times bigger than our sun - our sun is ver y average
what are the two most abundant chemical elements in the sun? How are they related to the source of the suns energy
-hyrdogen and helium - hydrogen nuclei crash together and form helium in nuclear fusion - releases gamma waves which turn into visible light
what are the seven regions of the electromagnetic spectrum? what are their similarities and differences
highest energy - lowest (shortest - longest wavelength)
a. gamma rays
b. x ray
c. ultraviolet
d. visible
e. infared
f. microwave
g. radio wave
why are radio telescopes placed in desert valleys? why are optical telescopes placed on mountain tops? why are some telescopes put into orbit?
Desert valleys: humans dont emit radio waves in deserts & can get away from human interference, possible to do day or night
Mountain tops: less atmosphere pollution, easier to see, less light interference from cities
orbital telescopes: study visible light from space and ultraviolet telescopes study very hot stars, these lights can only be studied from space bc theyre . blocked from our atmosphere
