Transcript Chapter 1 - Chabot College

Chapter 1
Our Place in the Universe
Copyright © 2012 Pearson Education, Inc.
Star
A large, glowing ball of gas that generates heat and
light through nuclear fusion
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Planet
Mars
Uranus
A moderately large object that orbits a star; it
shines by reflected light. Planets may be rocky,
icy, or gaseous in composition.
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Moon (or satellite)
An object that orbits
a planet
Ganymede (orbits Jupiter)
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Asteroid
A relatively small
and rocky object
that orbits a star
Mathilde
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Comet
A relatively
small and icy
object that
orbits a star
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Solar (Star) System
A star and all the material that orbits
it, including its planets and moons
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Nebula
An interstellar cloud
of gas and/or dust
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Galaxy
A great island of stars in space, all held
together by gravity and orbiting a
common center
M31, theM31,
Great
theGalaxy
great galaxy in
in AndromedaAndromeda
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Chapter 1: Our Place in the Universe
One difference between the terms solar system
and galaxy is that:
A. the solar system contains only one star but the galaxy
contains many billions.
B. the solar system contains planets, but the galaxy does
not.
C. other galaxies are rare, but other solar systems are
common.
D. other solar systems are rare, but other galaxies are
common.
Chapter 1: Our Place in the Universe
One difference between the terms solar system
and galaxy is that:
A. the solar system contains only one star but the galaxy
contains many billions.
B. the solar system contains planets, but the galaxy does
not.
C. other galaxies are rare, but other solar systems are
common.
D. other solar systems are rare, but other galaxies are
common.
Universe
The sum total of all matter and energy;
that is, everything within and between
all galaxies
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Key Definition: Light-Year
• The distance light can travel in 1 year
• About 10 trillion kilometers
(6 trillion miles)
Copyright © 2012 Pearson Education, Inc.
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
A. The Sun, the Milky Way, Alpha Centauri, Pluto, the
Andromeda galaxy
B. The Sun, Alpha Centauri, Pluto, the Andromeda galaxy, the
Milky Way
C. The Sun, Pluto, Alpha Centauri, the Milky Way, the
Andromeda galaxy
D. Pluto, the Sun, Alpha Centauri, the Milky Way, the Andromeda
galaxy
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
C. The Sun, Pluto, Alpha Centauri, the Milky
Way, the Andromeda galaxy
The sun – a star
~93 million miles away
~150 million kilometers
~ 8 light-minutes
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
C. The Sun, Pluto, Alpha Centauri, the Milky
Way, the Andromeda galaxy
Pluto – a “dwarf planet”
~3 billion miles away
~48 billion kilometers
~ 4.5 light hours
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
C. The Sun, Pluto, Alpha Centauri, the Milky
Way, the Andromeda galaxy
Alpha Centauri – a star
~26,000 billion miles away
~4.2 x 1013 kilometers
~ 4.5 light years
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
C. The Sun, Pluto, Alpha Centauri, the Milky
Way, the Andromeda galaxy
Milky Way – a galaxy
~200 billion stars
~100,000 light years across
~ 27,000 light years to center
Chapter 1: Our Place in the Universe
Put these objects in the correct order,
from nearest to farthest from Earth:
C. The Sun, Pluto, Alpha Centauri, the Milky
Way, the Andromeda galaxy
Andromeda – another galaxy
~400 billion stars
~2.5 million light years away
Chapter 1: Our Place in the Universe
Which is farther, the distance from San
Francisco to Los Angeles, or the distance
from you to the International Space Station,
when it passes directly overhead?
A. San Francisco – LA is further
B. The space station is further
Chapter 1: Our Place in the Universe
Which is farther, the distance from San
Francisco to Los Angeles, or the distance
from you to the International Space Station,
when it passes directly overhead?
A. San Francisco – LA is further!!
B. The space station is further
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how large
would the Earth be?
A.
B.
C.
D.
The size of an orange
The size of a marble
The size of the point of a ballpoint pen
The size of a bacterium
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how large
would the Earth be?
A.
B.
C.
D.
The size of an orange
The size of a marble
The size of the point of a ballpoint pen
The size of a bacterium
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how large
would the Earth be?
A.
B.
C.
D.
The size of an orange
The size of a marble
The size of the point of a ballpoint pen
The size of a bacterium
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
would the Earth be?
A.
B.
C.
D.
E.
6 inches
1 foot
5 feet
40 feet
1 mile
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
would the Earth be?
A.
B.
C.
D.
E.
6 inches
1 foot
5 feet
40 feet
1 mile
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
would Pluto be?
A.
B.
C.
D.
100 feet
200 feet
2,000 feet
10 miles
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
would Pluto be?
A.
B.
C.
D.
100 feet
200 feet
2,000 feet
10 miles
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
would Pluto be?
A.
B.
C.
D.
100 feet
200 feet
2,000 feet
10 miles
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
should you put another grapefruit to represent
Alpha Centauri, the next nearest star?
A.
B.
C.
D.
E.
10 feet
1,000 feet
1 mile
10 miles
1,500 miles
Chapter 1: Our Place in the Universe
In a scale model solar system that used a
grapefruit to represent the Sun, how far away
should you put another grapefruit to represent
Alpha Centauri, the next nearest star?
A.
B.
C.
D.
E.
10 feet
1,000 feet
1 mile
10 miles
1,500 miles
How can we know what the universe was
like in the past?
• Light travels at a finite speed
( 186,000 miles/second = 300,000 km/s).
Destination
Light travel time
Moon
1 second
Sun
8 minutes
Sirius
8 years
Andromeda Galaxy
2.5 million years
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How can we know what the universe was
like in the past?
• We see objects as they were in the past:
The farther away we look in distance,
the further back we look in time.
Look far enough away, and we look back in time to
when the universe was much younger…
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Example:
This photo shows the Andromeda Galaxy as it looked
about 2 ½ million years ago.
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• At great distances, we see objects as they were
when the universe was much younger.
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How big is the universe?
• The Milky Way is one of about 100 billion galaxies.
• 1011 stars/galaxy  1011 galaxies = 1022 stars
It has as many stars as grains of (dry) sand on all Earth’s beaches.
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How is Earth moving in our solar system?
• Contrary to our perception, we are not “sitting still.”
• We are moving with the Earth in several ways, and at
surprisingly fast speeds.
Copyright © 2012 Pearson Education, Inc.
Chapter 1: Our Place in the Universe
Earth rotates on its axis:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 250,000 years
Chapter 1: Our Place in the Universe
Earth rotates on its axis:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 250,000 years
How is Earth moving in our solar system?
Earth rotates around its
axis once every day.
Copyright © 2012 Pearson Education, Inc.
Chapter 1: Our Place in the Universe
Earth revolves around the Sun:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 250,000 years
Chapter 1: Our Place in the Universe
Earth revolves around the Sun:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 250,000 years
Earth orbits the Sun (revolves) once every year…
• at an average distance of 1 AU ≈ 150 million km.
• with Earth’s axis tilted by 23.5º (pointing to Polaris).
• and rotates in the same direction it orbits, counterclockwise as viewed from above the North Pole.
Copyright © 2012 Pearson Education, Inc.
Chapter 1: Our Place in the Universe
The Moon revolves around Earth:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 250,000 years
Chapter 1: Our Place in the Universe
The Moon revolves around Earth:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a moonth
Once a year
Once every 250,000 years
Chapter 1: Our Place in the Universe
Earth revolves around the Milky Way Galaxy:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 230 million years
Chapter 1: Our Place in the Universe
Earth revolves around the Milky Way Galaxy:
A.
B.
C.
D.
E.
Once a day
Once a week
Once a month
Once a year
Once every 230 million years
Our Sun moves randomly relative to the other stars
in the local solar neighborhood…
• at typical relative speeds of more than 70,000 km/hr
• but stars are so far away that we cannot easily notice
their motion
… and it orbits the galaxy every 230 million years.
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Are we ever sitting still?
Earth rotates on axis: > 1,000 km/hr
Earth orbits Sun: > 100,000 km/hr
Solar system moves among stars: ~ 70,000 km/hr
Milky Way rotates: ~ 800,000 km/hr
Milky Way moves
in Local Group
Universe
expands
Copyright © 2012 Pearson Education, Inc.
Chapter 1: Our Place in the Universe
Why do we not feel or sense the various
motions of Earth in the universe?
A. They are not real, they are just models
B. They are too slow to sense
C. They are nearly uniform, and you can not sense
uniform velocity, only acceleration, which is a change
of velocity or direction
Chapter 1: Our Place in the Universe
Why do we not feel or sense the various
motions of Earth in the universe?
A. They are not real, they are just models
B. They are too slow to sense
C. They are nearly uniform, and you can not sense
uniform velocity, only acceleration, which is a change
of velocity or direction
Chapter 1: Our Place in the Universe
Suppose that, at this very moment, students are
studying astronomy on planets in Andromeda.
Could they know that we exist here on Earth?
A. Yes, because we can see stars in Andromeda, so they can see us in
the Milky Way.
B. No, the light from the solar system has not yet reached Andromeda.
C. No, the light from the solar system that has reached Andromeda came
from a time before Earth had formed.
D. No, radio signals from terrestrial civilizations have not yet reached
Andromeda.
E. Yes, in principle. With sufficiently powerful telescopes, they should be
able to see man-made features such as the Great Wall of China on
Earth’s surface.
Chapter 1: Our Place in the Universe
Suppose that, at this very moment, students are
studying astronomy on planets in Andromeda.
Could they know that we exist here on Earth?
D. No, radio signals from terrestrial civilizations have not yet
reached Andromeda.