Falcon/Seahawk
Section 3
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 1. Orbit-the path of an object as it revolves around
another object in space.
 2. Force-a push or pull motion
 3. Gravity-a force that attracts all objects toward each
other.
 4. Law of Universal Gravitation-every object in the
universe attracts every other object.
 5. MASS of an object determines the force of gravity
 6. Mass- the amount of matter in an object
 7. Weight- the measure of the force of gravity on an
object
 8. Inertia-the tendency of an object to resist motion.
 9. The more mass an object has the greater the
gravity
 10. Newton’s First Law of Motion-an object at rest
will stay at rest & an object in motion will stay in
motion with a constant speed UNLESS acted on by a
force.
 11.Gravity and Inertia keep objects in motion.
 12. Mutual gravity caused these rocks to come
together, eventually to form planets, & keeps them in
close proximity to each other and not “fly” away.
 13. Accretion- This 'coming together' of material is a
process known as accretion.

Section 4

 1. Stars are classified by by a) Color, b) Temperature,
c) Size, d) Composition and e) Brightness.
 2. The color of a star reveals it’s Surface
Temperature.
 3. Cool stars are Red - 3,200 C.
 4. The hottest stars are Blue – 20,000 C.
 5. Large stars are Giant or Super Giant Stars.
Those Earth-size are White Dwarfs, and those smaller
are Neutron stars.
 6. Stars are composed of 73% hydrogen, 25% helium,
and 2 % other elements.
 7. Spectograph- a device that breaks light into colors
& produces an image of the resulting spectrum.

 8. The brightness of a star depends on both its size
and temperature.
 9. Apparent brightness/magnitude – is the
brightness of a star as seen from Earth. (the sun
seems brighter b/c it’s closer)
 10. Absolute brightness/Luminosity – is the
brightness of a star if it were at a standard distance
from Earth; it is a more accurate reading.

 11. The Hertzsprung-Russell diagram is a chart that
compares temperature and absolute brightness of
stars are related. X-axis is temperature, and Y-axis is
the absolute brightness.

 12. H-R diagram is really a chart on which stars are
graphed based on temp & absolute brightness.
Astronomers use it to CLASSIFY stars & see how
they change over time.
 13. Main Sequence – a diagonal line, where 90% of all
stars lie on the H-R diagram; the sun is one.
 14. What % of stars are main sequence stars? 90%
 On the H-R diagram, the hot stars are located on the
left side, while the cool are located on the right.
 15. The bright stars are on the near the top of the HR, while the dimmer stars are at the bottom.
Hertzsprung-Russell Diagram
The Hot are to the Top of the chart.

The hot stars
are to the
Left side.
The Cooler are to the Bottom of the chart.
The cooler
stars are to
the Right
side.