Transcript Astronomy Review Document

How do Rockets Work?
• A rocket or space shuttle moves forward when
gases shooting out the back of the rocket/space
shuttle push it in the opposite direction.
What are artificial satellites?
What are they used for?
• Manufactured objects
that orbit Earth or some
other body in space.
• Used in weather
forecasts, telephone
calls, navigation of ships
and aircraft, monitor
crops and other
resources, and military
activities.
What are space stations?
What are they used for?
• Large artificial satellites on which people can
live and work for long periods.
• Used to conduct long-term observations and
experiments in space.
The Moon
The Moon does not make its own
light. We see it the same way we see
mountains in the daylight.
The moon’s surface reflects
sunlight.
Temp:
130°C in direct sunlight
-180°C at night
How does the amount of gravity on
the moon compare to the amount of
gravity on Earth?
• 1/6 that of Earth’s gravity. Mass is the
same on earth and moon, but we weigh
less on the moon
How was the moon formed?
• A planet-sized object collided with Earth
debris from collision formed moon.
Explain each of the moon’s surface
features.
• Craters: large round pits
• Highlands: Light colored features on
moons surface were mountains.
• Maria: Hardened rock formed from huge
lava flows.
What is so special about the
amount of gravity that the sun has?
• Gravitational force of the sun is strong
enough to hold all of the planets and many
other distant objects in orbit.
What is the sun’s interior like?
• Giant furnace.
• Sun’s energy from nuclear fusion
• Hydrogen atoms fuse together to form
helium
Explain the 3 layer’s of the sun’s
atmosphere.
• Core: Center of the sunwhere sun’s energy is
produced
• Radiation zone: Middle
layer -very dense
• Convection zone: outer
layer - hot gases rise
from the bottom.
What are:
Sunspots and prominences?
• Sunspots: areas of gas on
the sun’s surface that is
cooler than the gas around it
• Prominence: huge reddish
loops of gas
What is an Astronomical
Unit? (AU)
Astronomical Unit (AU) = average distance from Earth to the
Sun …so earth to sun is 1 AU
1AU = 150 million kilometers
Used to measure distance between the Sun and all planets
and other stars
Why are the four inner planets
called the terrestrial planets?
• Small, dense, and have rocky surfaces.
Mercury
• Smallest Planet
• not much larger than the moon
• Virtually no atmosphere
• Side facing sun 430°C and -170°C on the
other side
Venus
• Size: Earth’s twin-similar in size and
mass to earth
• Atmosphere: thick and always
cloudy-sulfuric acid
• Interesting Rotation:7.5 Earth
Months to revolve around the sun
and 8 months to rotate on its axis
Earth
• Size: Largest of the inner planets
• Atmosphere: 20% is oxygen; rest is nitrogen
with small amounts of argon & CO2
• Only Place with Living things that we know
of.
• 70% is covered by H20
• Rotation: 1Day
• Revolution: 1 year
Mars
• Size: Bigger than Mercury
• Atmosphere: 95% CO2
• Red planet: Breakdown of iron-rich rockscreates a rusty dust over the surface
• Seasons: Mars has seasons because it
tilts on its axis like Earth.
Why are the first four outer planets
called gas giants?
• Much larger than Earth
• Don’t have a solid surface
Jupiter
• Size: Most massive
• Atmosphere: Thick made up of hydrogen and
helium
• Red Spot: Giant area of swirling clouds many
times bigger than Earth
• Moons 63
Saturn
• Size: 2nd largest planet
• Atmosphere: Thick-mostly of hydrogen and
helium
• Rings: Chunks of ice and rocks orbiting Saturn
Uranus
• Size: 4x Earth; much smaller than Jupiter or
Saturn
• Rotation: Top to bottom instead of side to side.
–hit by an object
Neptune
• Atmosphere: Contains visible clouds of
methane gas
• Great Dark Spot: giant storm
• Orbit: 20 years out of 248 years-Pluto and
Neptune change orbits
Pluto
• Size: Less than 2/3 that of Earth
• Atmosphere: Rocky cold surface with
frozen methane, nitrogen, and CO2
• Orbit: Takes 248 years; not exactly round,
so changes places with Neptune for 20
years.
• 2006-Scientists changed the definition of a
planet and because of Pluto’s size and
orbit it didn’t fit in
Comet
• Chunks of ice and dust whose orbits are
usually very long, narrow ellipses.
• Nickname: dirty snowball
• Famous comet: Haley's Comet
• Orbit the sun and can be seen for days,
weeks or months
Asteroid
• Objects (rocks) too small and numerous to be
planets
• Most are found revolving around the sun
between Mars and Jupiter-asteroid belt
Meteoroid, meteor, meteorite
• Meteoroid: chunk of rock or dust in space
• Meteor: When meteoroid enters the Earth’s
atmosphere(shooting stars)
• Meteorites: Meteoroids pass through the
Earth’s atmosphere and hit the Earth’s
surface
Galaxy
• Giant cluster of stars,
gases, and dust held
together by gravity
• Milky Way: where our
solar system is located
• Billions of galaxies in
our universe
3 Types of Galaxies
Spiral
Elliptical
Irregular
Main Characteristics to Classify Stars
• Color: Red, red-orange, yellow, white, and
blue or blue-white
• Temperature: red = 3,200°C, yellow =
5,000°C; white = 8,000°C, blue >
20,000°C
• Size: Supergiant, Giant, medium-sized,
white dwarf, and neutron
Brightness of Stars
• Apparent magnitude: brightness as
seen from Earth
• Absolute magnitude: brightness a star
would have if it were a standard
distance from Earth
Hertzsprung-Russell Diagram
Graph with temperatures of stars
on x-axis and brightness on yaxis
• Main sequence: surface
temperatures ↑ as brightness ↑
How Long Do Stars Live?
• Small stars with less mass live longer as
they use their fuel slowly
• Medium sized stars like the sun live for
about 10 billion years. Sun is estimated to
be 4.6 billion years old.
When Stars Die!
White Dwarf
Neutron
Black Hole
Spectrograph
• A device that breaks
light into colors and
produces an image of
the resulting spectrum
• Determines how
much of each element
is in a star
• Found in large
telescopes
Light Year
• Used to calculate
distances between
stars or galaxies
• It is the distance light
travels in one year =
9.5 million million
kilometers
Light
• Stars are the source
of light for all bright
objects in space and
that the Moon and
planets shine by
reflection of the sun’s
light