Download Name

1
Name: ________________________________________ Homeroom: ____________
Chapter 11 – The Universe - Near and Far
Essential Question: What are Some Earth-Moon-Sun Interactions?
Days and Years
The spinning of the Earth, known as the Earth’s rotation, is what controls the
length of day and night. The Earth rotates on its axis, an imaginary line through Earth
that goes from the North Pole to the South Pole.
As the Earth rotates only part of the Earth’s surface faces the sun at a time. This
rotation is what causes day and night. One complete rotation takes place every 24
hours (1 day). Each planet rotates, but not at the same speed. This means that each
planet’s day lasts a different amount of time.
The planets revolve around the sun in an elliptical path. It takes one year for a
planet to revolve around the sun. In the same way the length of a day varies from
planet to planet so does the length of each planet’s year. Planets that are located
closer to the sun have a shorter year, while the planets farther from the sun have a
greater distance to travel around the sun thus have a longer year.
Seasons
The temperature changes that take place from season to season are caused by a
change in the way the sun’s rays hit Earth’s surface. When the rays hit a spot directly the
Earth’s surface absorbs a lot of energy causing air temperatures to rise. As the Earth
2
revolves the sun’s rays hit the same spot at an angle, thus less energy is absorbed and
temperatures drops.
The tilt of the Earth’s axis changes the way the rays hit the Earth’s surface. The tilt
is always the same at 23.5 degrees, but sometimes the Northern Hemisphere is titled
toward or away from the sun.
Seasons in Northern Hemisphere (where we live)
Summer
The Northern Hemisphere is titled toward sun, thus the rays hit more directly. There are
more hours of daylight and more heat is absorbed.
Fall
The Northern Hemisphere is titled away from the sun. Days and nights are equal in
length.
Winter
The Northern Hemisphere is titled even farther away from the sun. Less energy is
provided; therefore we have winter’s cool temperatures. There are also more hours of
darkness.
Spring
The Northern Hemisphere is titled away from the sun. Days and nights are equal in
length.
As the Earth orbits the sun each year the seasons change depending on how the sun’s
rays hit the Earth’s surface.
3
Eclipses
An eclipse is caused when one object passes through the shadow of another
object. A lunar eclipse occurs when the Earth blocks sunlight from getting to the moon,
therefore the moon is completely dark. A solar eclipse occurs when the moon blocks
sunlight from reaching the Earth.
NEVER look at the sun during an eclipse because the
sun’s rays can permanently damage your eyes.
Tides
Tides are the regular rising and falling of the ocean’s surface caused mostly by the
moon’s gravitational pull on Earth’s oceans. The pull causes two bulges of water, one on
the side of the Earth facing the moon and one on the opposite side.
Essential Question: What Causes the Phases of the Moon?
Phases of the Moon
The moon does not produce its own light; rather it reflects light from the sun. The
side of the moon facing the sun is always lighted by the sun. As the moon revolves
around Earth we may see all, part or none of the moon’s lighted side. That part of the
moon that we see is the moon’s phase.
What part of the moon do we see during each phase?
New Moon – dim outline of the moon’s shape
First Quarter Moon – about half of the moon’s lighted side
Full Moon – all of the moon’s lighted side (round phase)
Third Quarter Moon – about half of the moon’s lighted side
4
After 29 ½ days (about 1 month) the moon is again between Earth and the sun,
so the dark side faces the Earth. The moon has completed one lunar cycle. It takes
each phase of the moon about one week.
Other Phases in the Solar System
The moon is not the only body that has phases. Moons that orbit the other
planets also have phases. From Earth we can also see some of the phases of the
planet Venus.
Essential Question: What is in the Solar System?
The Inner Planets
The four inner planets are Mercury, Venus, Earth and Mars. The inner planets
are smaller and more dense than the outer planets. Similar to the Earth the inner
planets have three layers a crust, mantle and a core, but thickness of the layers differs
between the planets.
The inner planets are separated from the outer planets by the asteroid belt that
lies between Mars and Jupiter.
The Outer Planets and “Dwarf Planets”
The four outer planets are Jupiter, Saturn, Uranus, and Neptune. These planets
have a small solid core, but no solid surfaces and are therefore known as the gas
giants. The strong pull of gravity made these planets even larger but they are too small
to be stars.
5
The outer planets also all have satellites, a body in space that orbits a larger
body. Bodies in space that orbit the planets or planetary satellites are known as moons.
Jupiter has at least 63 moons, while Saturn as at least 33.
In 2006 the definition of a planet was changed to a large round object in a clear
orbit around a star. Since Pluto is not in a clear orbit its classification changed to a
“dwarf planet.”
Asteroids and Meteors
An asteroid is a piece of rock and metal that orbits the sun. Most asteroids are
located between the inner and outer planets in the asteroid belt.
A meteor is a piece of rock, smaller than an asteroid that enters Earth’s
atmosphere and burns up. A trail of light is produced as the meteor falls in the
atmosphere causing friction to heat it and the air around it. A piece of rock that
survives the fall through the atmosphere making it to Erath or any other body is called a
meteorite.
Most meteors are formed from a collision between asteroids. Each day up to 4
billion meteors reach Earth’s atmosphere, most are too small to ever be noticed.
Comets
A comet is a ball of ice, rock, and frozen gases that orbits the sun. A comet may
pass close by the sun or go as far as the edges of the solar system. Each time a comet
approaches the sun it changes. As some of the ice melts a cloud of dust from the
comet is released, that forms a tail always pointing away from the sun because of the
wind blowing off the sun.
6
Essential Question: What is Beyond the Solar System?
Types of Stars
A star is a huge ball of hot, glowing gases. Astronomers compare stars by color,
actual brightness, and surface temperatures using a diagram called the HertzsprungRussell diagram.
Hertzsprung-Russell Diagram
Brightest stars are at the top. Hottest stars are at the left. The hottest, brightest stars
have the greatest mass. While the coolest, dimmest stars have the least mass.
About 90% of the stars fit into the long band that runs from the upper left corner
to the lower right corner. This band is known as the main sequence, thus stars that
appear on the band are classified as main-sequence stars.
Red giants and super giants are cool red stars that are bright because they are so
large. White dwarfs are very hot and very small.
From Red Giants to Black Holes
7
Stars do not last forever. The bigger the star the shorter the stars life. A
massive star uses its hydrogen faster than a smaller star. When the hydrogen is gone,
the star dies.
Types of Galaxies
We live in the Milky-Way Galaxy. There are billions of galaxies – huge systems
of stars bound together by gravity.
Classification of Galaxies
Spiral
-
Milky Way Galaxy and 20% of all galaxies.
-
Huge, curved arms are formed by stars and gases
-
Center reddish because of the many red giants
-
Arms bluish because they contain many bright young blue stars.
Barred Spirals
-
10% of all galaxies
-
2 bar shaped clusters of stars that stretch out from the center
Elliptical
-
most galaxies are elliptical, 60% of all galaxies
-
mostly made of old stars
-
most are flat and small and do not form new stars
Irregular Galaxies
-
10% of all galaxies
-
No distinct pattern
-
Mostly young stars
8
How Did the Universe Form?
Big Bang Theory – universe began with an explosion
Big Crunch Hypothesis states that the universe may collapse on itself if its matter
reaches a certain density.