Download 19.3 Notes

Formation of the Solar System (19.3) Notes
Astronomy-
The Greek philosopher, ________________, explained the phase of the moon and eclipses by using a
The Original
model of the solar system with _________________ in the center called the _______________ model.
Science
This model was expanded by _______________ in 140 CE. He thought that the sun, moon, and planets
orbited the __________________ in perfect ________________. His model was used for over a
thousand years.
In 1543, Nicolaus Copernicus proposed a _____________________ model. In this new model, Earth and
the planets orbited the ____________ in perfect circles. In 1605, Johannes Kepler improved the model by
proposing that the orbits around the sun are _______________, or ovals, rather than circles.
In 1687, Isaac _____________ explained that the force that keeps planets in orbit around the sun, and
satellites in orbit around planets is _________________. His theory also states that every object in the
universe exerts a gravitational ____________ on every other object. Newton was the first to propose that
everything in the universe follows the ________ rules and acts in ___________________ ways.
The Nebular
According to the dating of ____________, scientists believe that the solar system is approximately
Model
______ ________________ years old.
A ____________ is a large cloud of dust and gas in space. The most widely accepted model of the
formation of the solar system is the _________________ model. According to this model, the sun, like
every star, formed from a cloud of gas and dust that collapsed because of _______________.
As the cloud collapsed, it formed into a flat, __________________ disk. In the center, where the material
became ____________ and _____________, a star began to form.
Planetesimals, or particles that become _____________, began to form in the disk through the process of
_______________, the accumulation of matter.
______________ may have formed around gas giants in the same way planets formed around the sun.
Another possibility is that the planetesimals were captured by the ___________________ pull of the gas
giants. __________________ and other small rocks are most likely leftover planetesimals from the solarsystem formation.
Rocks in
Most asteroids can be found between ____________ and __________________. Meteoroids are small
Space
pieces of rock that enter the Earth’s _______________________. Most meteoroids burn up in the
atmosphere, and we see them as _________________ streaking through the night sky. If a meteoroid
survives the atmosphere and hits the ground, it is called a ______________________. ____________ are
probably composed of leftover material from when the solar system formed.
Comets are composed of ___________ and of ___________ made from methane, ammonia, carbon
dioxide, and water. When a comet passes near the sun, solar radiation heats the ice so the comet gives off
gases in the form of a long _________.
Planetesimals that remained in the nebular disk formed the ______________ belt beyond the orbit of
Neptune. ___________ may simply be the largest object in this belt.
Meteor showers can occur when Earth passes through a _____________ tail, but larger rocks that make it
through our atmosphere come from ____________________.
Many scientists believe that an asteroid or comet that was 10-15 km wide struck Earth about __________
million years ago caused the extinction of the _______________________.
How the
When the Earth was still forming it was _______________, or heated to an almost liquid state. A Mars-
Moon
sized body struck the Earth at an angle and was deflected. At impact, a large part of Earth’s mantle was
Formed
blasted into space. The debris began to clump together to form the ________________.
The moon has an _____________ core.