Name: _____________
Nebula Theory
______________ ____________− scientists who study the composition,
formation, and motion of planets − think that the ___________ ______________
formed from a giant rotating cloud of dust and gas called the solar
____________. According to the______________ _____________, about 4.6 billion
years ago something happened that caused the nebula to start to collapse.
SEQUENCE OF EVENTS
1. As the rotating cloud started to collapse, it began to spin faster. More and
more of the dust and gas spiraled in, pulled toward the center by
_______________ . Collisions between the gas particles caused the core
of the collapsing nebula to heat up. As more material poured into the
center, the temperature continued to _______________.
2. Once the center of the solar nebula was hot enough to undergo
_______________ fusion and ______________ fusion, the glowing ball in the
center stopped collapsing inward and a new star –_______________– was
born.
3. However, not everything from the nebula was pulled into the sun.
_________________ pulled some of this material together to form smaller
objects called ____________________.
4. Planetesimals collided with each other and slowly built up into the
_____________ inner rocky planets. Farther out from the sun, gas, ice, dust,
and planetesimals orbited.
5. These materials_______________ and grew quickly into the four giant gas
and ice planets—Jupiter, Saturn, Uranus, and Neptune—we have today.
6. Once all the gas and dust had been ________________ up into the planets,
blown away by _____________, or ______________ from the Solar System,
the new Solar System settled down into the arrangement we have today.