|
where did the solar system come from |
the cloud that gave birth to our solar system was the product of recycling of gas through many generations of stars within our galaxy. this material consisted of 98% hydrogen and helium and 2% everything else combined. |
|
what caused the orderly patterns of motion in our solar system? |
a collapsing gas cloud naturally tends to heat up, spin faster, and flatten out as it shrinks in size. thus our solar system began as a spinning disk of gas and dust. the orderly motions we observe today all come from the orderly motion of this spinning disk |
|
why are there two major types of planets? |
the two types of planets formed from two different types of solid seeds that condensed from gas in the solar nebula. within the frost line temperatures were so high that only metal and rock could condense, beyond the frost line cooler temperatures also allowed more abundant hydrogen compounds to condense into ice |
|
how did the terrestrial planets form? |
terrestrial planets formed inside the frost line, where accretion allowed tiny, solid grains of metal and rock to grow into planetesimals that ultimately merged to make the planets we see today |
|
how did the jovian planets form? |
accretion built ice-rich planetesimals in the outer solar system and some of these icy planetesimals grew large enough for their gravity to draw in hydrogen and helium gas, building the jovian planets |
|
what ended the era of planet formation |
the young sun had a strong solar wind, which ultimately swept away material not yet accreted onto the planets. once the solar nebula was cleared away, planet formation ceased because there was little material left to accrete |
|
where did asteroids and other comets come from? |
asteroids are the rocky leftover planetesimals of the inner solar system, and comets are the ice rich leftover planetesimals of the outer solar system |
|
how do we explain exceptions to the rules? |
most of the exceptions probably arose from collisions or close encounters with leftover planetesimals especially during the heavy bombardment that occured early in the solar systems history |
|
how do we explain the existance of our moon? |
our moon is probably the result of a giant impact between a mars-size planetesimal and the young earth. the impact blasted material from earths outer layers into orbit, where it reaccreted to form the moon |
|
how does radioactivity reveal an objects age? |
Radiometric dating is based on carefully measuring the proportions of radioactive isotopes and their decay products within rocks. the ratio of the two changes with time and provides a reliable measure of the rocks age |
|
when did the planets form? |
the planets began to accrete in the solar nebula about 4.5 billion years ago. |
|
how many of the planets orbit the sun in the same direction that earth does |
all |
|
what fraction of the moons of the planets orbit in the same direction that their planets rotate |
most |
|
The solar nebula was 98 % |
hydrogen and helium. |
|
Which of the following did not occur during the collapse of the solar nebula? |
concentrating denser materials nearer the Sun |
|
What is Jupiter’s main ingredient? |
hydrogen and helium |
|
Which lists the major steps of solar system formation in the correct order? |
collapse, condensation, accretion |
|
Leftover ice-rich planetesimals are called |
comets. |
|
Why didn’t a terrestrial planet form at the location of the asteroid belt |
Jupiter’s gravity kept planetismals from accreting |
|
What’s the leading theory for the origin of the Moon? |
It formed from the material ejected from Earth in a giant impact |
|
about how old is our solar system |
4.5 billion years |
Share This
Flashcard
