Download Document

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Astronomical spectroscopy wikipedia, lookup

Outer space wikipedia, lookup

Expansion of the universe wikipedia, lookup

Shape of the universe wikipedia, lookup

Nucleosynthesis wikipedia, lookup

Big Bang nucleosynthesis wikipedia, lookup

Redshift wikipedia, lookup

Big Bang wikipedia, lookup

Cosmic microwave background wikipedia, lookup

UNIT NINE: Matter and Motion
in the Universe
 Chapter 26 The Solar System
 Chapter 27 Stars
 Chapter 28 Exploring the Universe
Chapter Twenty-Eight:
Exploring the Universe
 28.1 Tools of Astronomers
 28.2 Galaxies
 28.3 Theories about the Universe
Section 28.3 Learning Goals
 Explore theories about the origin of the
 Discuss the evidence in support of the Big
Bang theory.
 Describe planetary systems.
28.3 Doppler Shift
 In the 1800s, Christian
Doppler discovered that
when the source of a
sound wave is moving, its
frequency changes.
 The change in sound you
hear is caused by a
Doppler shift.
 Doppler shift is related to
the net change between the
source of the waves and
the observer.
28.3 Doppler Shift
 Doppler shift also
occurs with
waves, such as
visible light, X-rays,
and microwaves.
 This phenomenon is
an important tool
used by astronomers
to study the motion
of objects in space.
28.3 The expanding universe
The faster the source
of light is moving
away from the
observer, the greater
the redshift.
The opposite
(blueshift) happens
when an object is
moving toward the
28.3 The expanding universe
Edwin Hubble
discovered that the
farther away a galaxy
was, the faster it was
moving away from
This concept came to
be known as the
expanding universe.
28.3 The Big Bang theory
The theory that the universe was
expanding implies the universe must have
been smaller in the past than it is today.
It implies that the universe must have had a
Astronomers today believe the universe
exploded outward from a single point.
This idea is known as the Big Bang theory.
28.3 The Big Bang theory
The Big Bang theory says the
universe began as a huge explosion
between 10 billion and 20 billion years
According to this theory, all matter
and energy started in a space smaller
than the nucleus of an atom.
28.3 Evidence for the Big Bang theory
In the 1960s, Arno Penzias
and Robert Wilson were
trying to measure
electromagnetic waves
given off by the Milky
The “noise” these
scientists found was the
cosmic microwave
background radiation
predicted by the Big Bang
28.3 Evidence for the Big Bang theory
The proportion of hydrogen to helium is
consistent with the physics of the Big Bang.
If the universe were significantly older, there
would be more heavy elements present
compared with hydrogen and helium.
28.3 Planetary systems
 A star with orbiting planets is called a
planetary system.
 Scientists now believe that planets are a
natural by-product of the formation of stars.
28.3 How the solar system formed
 Scientists think that the solar system was
formed out of the same nebula that created the
28.3 Binary stars
 A binary star is a
system with two stars
that are gravitationally
tied and orbit each
 About half of the 60
nearest stars are in
binary (or multiple)
star systems.
Optional* Investigation 28C
The Time Machine
 Key Question:
How long does it take for starlight to reach Earth?
Searching the Cosmos
 Astrophysicist Dr. Hakeem
Oluseyi (Oh-lu-SHAY-ee) is
fascinated by stars. A
physics and space science
professor at the Florida
Institute of Technology, he
has invented several new
instruments to give
astronomers a closer look at
the cosmos.