Download THE SIZE AND DISTANCE SCALE OF THE UNIVERSE

Our place in space
Since the entire Solar System, including our Earth,
was created about the same time (about 4.6 billion
years ago), our understanding of the origin and
properties of the Solar System, the Sun, and its other
members are important to our understanding of Earth
itself.
What makes up the universe?
• Earth is one of eight planets that orbit the sun,
which is a star.
Stars are grouped together in structures known as
galaxies. Gravity keeps the stars in the galaxy
from moving away from eachother. Inertia keep
everything in motion.
What makes up the universe?
• There are an estimated 100 billion galaxies in the
universe.
• The universe is space and all the matter and
energy in it.
Unit 2 Lesson 1 Structure of the Universe
What makes up the universe?
• Earth is a special place because it has just the
right combination of conditions to support life.
• The presence of air and water supports the growth
and development of plants and animals.
• The atmosphere contains an ozone layer that
absorbs harmful solar radiation and other gases
that keep Earth warm enough for life to exist.
What makes up the universe?
The solar system is the collection of large and
small bodies that orbit our central star, the sun.
• The solar system has eight bodies called planets,
which are generally larger than the other bodies.
A planet is a spherical body that orbits the sun.
The sun is our central star.
 A satellite is a a small object orbiting a larger one. There are
many electronic objects that orbit the Earth.
A comet is a small, frozen mass of dust and gas
revolving around the sun.
Asteroids
Meteorite
What do we know about asteroids?
 An asteroid is a small, irregularly shaped, rocky
object that orbits the sun.
 Most asteroids are located in the asteroid belt
between the orbits of Mars and Jupiter.
• The asteroid belt contains hundreds of thousands
of asteroids, called main-belt asteroids.
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What do we know about asteroids?
 The composition of asteroids varies.
Hydrocarbons are materials that are found in
asteroids.
• Some are rich in carbon.
• Others are rocky, with cores of iron and nickel.
• Some have a rocky core surrounded largely by
ice.
Copyright © Houghton Mifflin Harcourt Publishing Company
What do we know about asteroids?
• Some asteroids appear to be piles of rock loosely
held together.
• Others contain economic minerals such as gold,
iron, nickel, cobalt, and platinum.
Copyright © Houghton Mifflin Harcourt Publishing Company
Burned Out
What do we know about meteoroids,
meteors, and meteorites?
 A sand grain- to boulder-sized rocky body that
travels through space is a meteoroid.
 A bright streak of light that results when a
meteoroid burns up in Earth’s atmosphere is
called a meteor.
 A meteorite is a meteoroid that reaches Earth’s
surface without burning up.
Copyright © Houghton Mifflin Harcourt Publishing Company
What do we know about meteoroids,
meteors, and meteorites?
 Meteoroids that burn up in the atmosphere that
are close enough to see are often referred to as
shooting stars.
• Meteoroids come from the asteroid belt, Mars, the
moon, and comets.
• Most meteoroids that enter Earth’s atmosphere do
not reach Earth’s surface. Many explode in the
upper atmosphere; others skip back into space.
• Large meteoroids that enter Earth’s lower
atmosphere or strike Earth’s surface can be
destructive.
Copyright © Houghton Mifflin Harcourt Publishing Company
What makes up the universe?
The four planets that orbit nearest to the sun are
called terrestrial planets.
The terrestrial planets are Mercury, Venus, Earth,
and Mars.
 The terrestrial planets are rocky, dense, and
relatively small.
What makes up the universe?
• The four planets that orbit farthest from the sun
are called gas giant planets.
• The gas giant planets are Jupiter, Saturn, Uranus,
and Neptune.
• The gas giant planets have thick, gaseous
atmospheres; small, rocky cores; and ring
systems of ice, rock, and dust.
• The asteroid belt separates the inner planets and
gas giant planets
What makes up the universe?
• Orbiting most of the planets are smaller bodies
called moons. Earth has only one moon, but
Jupiter has more than 60.
• The solar system has other small bodies, including
dwarf planets, comets, asteroids, and meteoroids.
• Altogether, there are up to a trillion small bodies
in the solar system.
What makes up the universe?
A star is a large celestial body that is composed
of gas and emits light.
• Most stars are composed almost entirely of
hydrogen and helium.
What makes up the universe?
A galaxy is a large collection of stars, gas, and
dust held together by gravity.
 Small galaxies, called dwarf galaxies, may
contain a few billion stars. Giant galaxies may
contain more than 1 trillion stars.
 Our solar system is located in the Milky Way
galaxy. The Milky Way is classified as a spiral
galaxy.
What makes up the universe?
• Spiral galaxies are shaped like pinwheels. They
have a central bulge from which two or more
spiral arms extend.
• Elliptical galaxies look like spheres or ovals and do
not have spiral arms.
• Irregular galaxies appear as splotchy, irregularly
shaped “blobs.”
• Quasars
What is the structure of the universe?
The universe can be defined as space and all the
matter and energy in it.
• Throughout the universe, there are areas where
galaxies are densely concentrated.
• These areas are called clusters and superclusters.
What is the structure of the universe?
• Clusters contain as many as several thousand
galaxies.
• Superclusters can be made up of 10 or more
clusters of galaxies.
• The universe also contains huge spherical areas
where very little matter exists. They are called
voids.
How Big Is Big?
How are distances in the universe
measured?
• Distances between most objects in the universe
are so large that astronomers measure distances
using the speed of light.
A light-year is the distance that light travels
through space in one year.
Light travels through space at about
300,000 km/s, or about 9.5 trillion kilometers
(km) in one year.
EARTH AND THE SOLAR SYSTEM
The Size and Distance Scale Of The Solar System
• We consider the size of our Earth to be very large, in
comparison with most sizes and distances we deal with in
our daily lives.
• However, the size of the Earth is very small compared to the
size of the Solar System, which consists of the Sun and its
family of planets.
•
Earth is only about average in size.
The Size and Distance Scale Of The Solar System
• In turn, the size of our Solar System is very large compared
to the size of our Earth, or even the largest planet, Jupiter.
• The distance from our Earth to the Moon is about 238,000
miles or 384,000 kilometers (nearly 100 times Earth’s
diameter, or about 30 times the distance around the Earth
at its equator).
• The distance from our Earth to the Sun is about 93,000,000
miles or 149,600,000 kilometers (more than 390 times the
distance to the Moon).
• The most distant major planet from the Sun, Neptune, is 30
times Earth’s distance from the Sun.
SIZES AND DISTANCES IN THE SOLAR SYSTEM
Sizes
Diameters of Solar System Members:
Sun =
1,392,000 km
Mean Distance from Sun
Mercury =
Venus =
Earth =
Mars =
Jupiter =
Saturn =
Uranus =
Neptune =
Pluto =
4,878 km
12,104 km
12,756 km
6,794 km
142,984 km
120,536 km
51,118 km
49,530 km
2,304 km
57,900,000 km = 0.387 AU
108,200,000 km = 0.723 AU
149,600,000 km = 1.000 AU
227,900,000 km = 1.524 AU
778,300,000 km = 5.203 AU
1,427,000,000 km = 10.07 AU
2,871,000,000 km = 19.19 AU
4,497,000,000 km = 30.06 AU
5,914,000,000 km = 39.53 AU
Earth’s Moon =
3,476 km
Mean Distance from Earth = 384,400 km
Earth and Moon to Scale
Sizes and Distances in the Earth-Moon System
Relative Sizes of Planets in Our Solar System
The Planets of Our Solar System
The Inner Planets
Sizes to Scale
Mercury
Venus
Earth and Moon
Mars
The Planets of Our Solar System
The Gas Giants
Jupiter
Saturn
Earth Included for Scale.
Uranus
Pluto
Neptune
Size Comparisons In Our Solar System
THE SIZE AND DISTANCE SCALE OF THE SOLAR SYSTEM
• The distances between the members of our Solar System are much
larger than the sizes of the members (even the Sun).
• The largest planet, Jupiter, is 5 times Earth’s distance from the Sun,
and 11 times Earth’s diameter (1/10 of the Sun’s diameter).
• The most distant major planet, Neptune, is 30 times Earth’s distance
from the Sun.
• The region beyond the orbit of Neptune, called the Kuiper Belt,
contains a large number of smaller objects (including Pluto), all (as
yet known) smaller than our Moon.
• The Kuiper Belt objects known to date can reach distances of more
than 90 times Earth’s distance from the Sun.
SIZES AND DISTANCES IN THE SOLAR SYSTEM
Sizes
Diameters of Solar System Members:
Sun =
1,392,000 km
Mean Distance from Sun
Mercury =
Venus =
Earth =
Mars =
Jupiter =
Saturn =
Uranus =
Neptune =
Pluto =
4,878 km
12,104 km
12,756 km
6,794 km
142,984 km
120,536 km
51,118 km
49,530 km
2,304 km
57,900,000 km = 0.387 AU
108,200,000 km = 0.723 AU
149,600,000 km = 1.000 AU
227,900,000 km = 1.524 AU
778,300,000 km = 5.203 AU
1,427,000,000 km = 10.07 AU
2,871,000,000 km = 19.19 AU
4,497,000,000 km = 30.06 AU
5,914,000,000 km = 39.53 AU
Earth’s Moon =
3,476 km
Mean Distance from Earth = 384,400 km
Orbits of the Inner Planets
Orbits of Jupiter and Saturn
Orbits of the Outer Planets