Download universe - Northwest ISD Moodle

The Origin and History of the Universe
TEK Objective 4: The student knows how Earth-based and
space-based astronomical observations reveal differing
theories about the structure, scale, composition, origin, and
history of the universe.
Student Expectations:
a) evaluate the evidence concerning the Big Bang model such as red shift
and cosmic microwave background radiation and current theories of the
evolution of the universe, including estimates for the age of the universe;
b) explain how the Sun and other stars transform matter into energy through
nuclear fusion; and
c) investigate the process by which a supernova can lead to the formation
of successive generation stars and planets.
• How did our
universe begin?
Homo neanderthalensis
Galileo
• How old is our
universe?
• How did matter
come to exist?
• What is our place
in the universe?
True to the nature of science, a majority of these
answers have only led to more intriguing and
complex questions. Perhaps, science is all about
finding the next question, instead of the answers!
Universe
The universe is commonly defined as the totality of everything that
exists,[including all space, time, matter, energy, planets, stars, galaxies, and
intergalactic space
Galaxy
A galaxy is a massive, gravitationally bound system that consists
of stars and stellar remnants, an interstellar medium of gas, dust,
and dark matter. Our galaxy is the Milky Way, and it is a spiral
galaxy.
dark matter is matter
that is inferred (not Star, or Stellar System
actually seen) to exist. A star system or stellar system is a small number of
100 (M100)
It neither emits nor
stars which orbit each other, boundMessier
by gravitational
Spiral Galaxy
scatters light or other
attraction.
electromagnetic
Planetary, or Solar Systems
radiation (and so
A solar system consists of one or a number of stars,
cannot be directly
surrounded by a number of planets and planetary bodies
detected via optical or
held by gravitation.
radio astronomy
Universe had no beginning
or end…it was truly infinite
With the Big Bang theory,
universe is “finite”:
• 15 billion years ago, huge explosion
which started the expansion of the
universe.
• all matter, and energy of space was
contained at one point.
• this explosion filled all of space with
the particles of the young universe
rushing away from each other.
Edwin Hubble
Observed the
universe expanding
in every direction
and that a galaxy’s
velocity is
proportional to its
distance from us.
Ex: galaxies that are
twice as far from us,
move twice as fast
1) by looking for the oldest
stars; and
2) by measuring the rate of
expansion of the universe and
extrapolating back to the Big
Bang (Recessional Velocity)
This second way uses what is known as the Hubble constant to
measure of the current expansion rate of the Universe.
This mathematical derivation (calculation) can only be
correct, however, if the universe is not significantly
accelerating or decelerating its expansion rate.
If the rate of expansion is rapidly accelerating, the
universe may be older than 15 billion years.
One way to measure these ages is with the travel time of light.
Light travels incredibly fast – 300,000 kilometers per second.
8.3 minutes
from
the Sun,
We•don’t
see these
objects
as they are right now, but as they were
• 4.3
fromThe
the universe
nearest star,
when
theyears
light left.
actually works as a sort of “time
• 8500 years
from
of the
Way galaxy.
machine,”
in which
wethe
cancenter
see into
theMilky
past simply
by looking far
away.
• Speed of light ( Well known from experiments here on Earth)
• Distance of objects ( Far more difficult)
Some galaxies look much smaller and fainter than others,
showing they may be much further away.
The Andromeda galaxy is 2.3 million light years away. That is, we
are seeing it as it was 2.3 million years ago.
In recent decades, astronomers have detected galaxies located
several billion light years away. If the light has been traveling
Galaxy
is the
oldest
billions of years
toUDFj-39546284
reach us, then
the
universe must be at least
galaxy to ever be found, estimated at
that old.
13.7 billion light years from Earth.
Galaxies are not holding still in space, nor are they moving
randomly. From the time of the Big Bang, the Universe has been
expanding in a uniform manner and direction.
• Towards one another (gravity)
• Away from one another (momentum from the Big Bang)
While objects within the Universe have been expanding, for the
most part, in a uniform manner, the motion apart has not all been
at the same speed; instead it follows a pattern where galaxies that
are further apart are moving more quickly. Speed of galactic
motion is proportional to the separation between them. This,
again, is known as Hubble’s Law.
Astronomers detect a galaxy’s motion by looking at its light
spectrum.
1. Who was one of the first cosmic observers to use a telescope?
2. Describe each of the structures in the Universe, from largest to
smallest.
3. What is dark matter, and why can’t it be detected via optical
(light) or radio astronomy?
4. How old do scientists think the Universe is, and how do they
know?
5. Who can be credited with discovering the origin of the Big Bang?
6. A Galaxy’s ______ is directly proportional to its ______ from
Earth.
7. What is a simpler way to describe the above?
This is the name given to the phenomenon of galaxies
moving farther away from each other.
As light approaches
Earth from different
galaxies, the space
between that distant
galaxy and Earth
increases. This leads
to wavelengths of the
light being stretched.
Why red???
This movement would tend to
make objects (or galaxies) that we
are most distant to appear
“reddish”
Remember…the longer wavelengths of the visible light
spectrum include the reds and oranges. The shorter
wavelengths of the visible light spectrum include the indigos
and violets, so the farther away the stars become, the “more
red” they appear
When a galaxy is carried away by the expansion of space, its light
waves are stretched out, making it appear redder. This red shift
can be used to calculate the galaxy’s velocity.
From the measurements of many galaxies, astronomers can
accurately measure the expansion rate of the universe as a
whole. Hubble's Law
The age of universe can be determined by imaging what the
universe looked like in the past, “rewinding” the expansion. In the
past the galaxies must have been closer together, and in the
distant past they would have been packed together in a tiny point.
If we assume that the expansion rate is constant over time, the
age for the universe as a whole is about 10 billion years.
Astronomers have been working over the last 20 years to determine how the
expansion rate changes with time. We now know that early in the universe the
expansion was slowing down, but now it is speeding up. Using careful
measurements of this change in expansion rate, the age of the universe is now
known quite precisely to be 13.7±0.13 billion years
is thermal radiation filling the observable universe
almost uniformly. It is radiation left over from an early
stage in the development of the universe, and its
discovery is considered proof of the Big Bang model
of the universe.
Scientists use
very small
radio telescope
arrays to listen
to CMBR.
https://youtu.be/1OpNI5DjxC0
9. Why do objects (or galaxies) tend to appear reddish when they are
farther away?
10. In the electromagnetic spectrum, the longer wavelengths of visible light
are the ____ and ____, while the shorter include the _____ and _____.
11. Using the above information, what color would you expect the closest
galactic objects (galaxies) to be when viewed through a telescope?
12. On the EM spectrum, what forms of low frequency energy are found
below the visible light spectrum?
13. What high frequency energy forms are found above the visible light
spectrum?
14. What is CMBR, and how do scientists use it as proof of the Big Bang?
15. What does the Big Bang sound like to you?
Our sun is in the “main
sequence” of its life.
The layers of the Sun show
temperature highest at the core and
progressively decreasing as we move
out towards the exterior.
The whole of solar mass is gaseous
and mostly composed of hydrogen
and helium. As the hydrogen is
replaced by helium (nuclear fusion),
these numbers flip-flop during its
life.
At birth, the star has plentiful hydrogen. As it consumes hydrogen through
fusion, helium increases.
At its core, the Sun fuses 620 million metric tons of hydrogen each second. At
this average distance, light travels from the Sun to Earth in about 8 minutes
and 19 seconds, and is largely emitted by the photosphere.
The only time we truly get to see the sun’s corona (atmosphere) is when there is
a solar eclipse.
The sun represents a source of light and heat upon
which all living things depend for their survival.
This light and heat radiated by the sun is the result
of fusion energy.
Fusion converts matter to energy. Fusion is the
joining of two small elements to form one larger
one. In the process, energy is lost, in the form of
light and heat.
The main fuels used in nuclear fusion are
deuterium and tritium, both heavy isotopes of
hydrogen.
This energy, once it reaches the Earth, is then utilized by plant life to build tissue, and
repair injury, as well as maintain homeostasis.
Then animals and microscopic consumers eat the plants, delivering the energy to
their bodies. Consumers use this energy for the same purposes as plants.
A supernova is a stellar
explosion that is more energetic
than a nova. It represents the
“death” of a star.
The explosion expels much
or all of a star's material[ at
a great velocity driving a
shock wave into the
surrounding space. This
shock wave sweeps up an
expanding shell of gas and
dust called a supernova
remnant.
It is this remnant, or stellar “dust” which has the potential to
form new stars and even planets.
Supernovas may occur in two ways:
• After the core of an aging massive star (red giant) stops creating energy
from nuclear fusion, it may undergo sudden collapse into what they call a
neutron star or black hole, releasing gravitational potential energy that
heats and expels the star's outer layers.
• Alternatively, a white dwarf star may accumulate sufficient mass from a
stellar companion (through accretion, or merger) to raise its core
temperature high enough to undergo runaway nuclear fusion, completely
disrupting it.
16.What is the energy source of stars?
17.What two main isotopes fuel our Sun’s energy?
18.How does life on Earth rely upon the Sun’s energy?
19.Describe how a Supernova can be the end, and the
beginning.
20.In what two ways may supernovas occur?