The Size and Scale of the Universe Guided Notes (1) (AutoRecovered)
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Dec 6, 2023
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Guided Notes – The Size and Scale of the Universe
Name
Leah Walker
The Solar System Scale
The solar system consists of
8
planets and many
smaller
bodies.
The person given the scientific credit for convincing enough people to hold the assessment that Earth
orbits the Sun is Nicolas Copernicus
A dwarf planet is something too small to count as a planet, i.e. Pluto.
About 99.8% percent of the solar system is the Sun
The two largest planets that account for most of the other small percentage of the solar system are
Jupiter & Saturn.
Two types of objects that orbit the Sun (other than planets and dwarf planets) are Asteroids and comets.
A moon is a body orbiting a planet, a dwarf planet, or a smaller body. All of the planets have moons
except for Mercury and Venus.
Test Yourself – Solar System
Our solar system consists of: A
Your Turn – Solar System Object
What can you say about the picture shown? What would you like to know about it? (Please be sure to
answer in complete sentences and explain your thoughts clearly.)
The picture appears to be taken with a high-definition camera of is a rendering done though someone's
observation. The picture shows the rings around Saturn seem to be lighting up and expanding far beyond
he planet. I would like to know if the light shining out is due to the sun bouncing off the debris in the
rings or something. Else.
The Stellar Scale
A star is made of hydrogen and helium and held together by Gravity
A light year can be described as distance light travels in one year, and its value is distance not time.
Describe what the speed of light is and what it means: The distance light can travel in space within one
year, i.e. the distance from the earth to the sun would be
Test Yourself – Sound – minute
Sound travels at a speed of 300 meters per second. In analogy to the light-year, what does 1 sound-
minute equal?
D
The Nearest Stars
The nearest star to our Sun is Proxima Centauri and is approximately 4 light years away.
Most of the stars we see in the sky can be up to 10,000-100,000 of light years away.
Most stars have 3 properties that make it so you wouldn’t see them unless you were very close.
These
properties are:
1.
small
2.
faint
3.
cool
The Sun is a mid sized star
Stars Evolve – Starbirth
Stars are born in molecular clouds.
Stellar Death – Planetary Nebula
Smaller stars (like the Sun) emit a ultra violet light, which is a planetary Nebula when they die.
For our
Sun, this will occur in about 6 billion years
Test Yourself – Planetary Nebula
If our Sun is expected to last about 6 billion years longer, then turn to be a planetary nebula for several
thousand years, about how much of the rest of its life will our Sun be a planetary nebula?
a.
A tenth
b.
A hundredth
c.
A millionth
d.
A billionth
Your answer: C
Based on your answer, would you expect planetary nebulae to be common or rare, and why?
Your answer: I would believe a planetary nebulae to be a common occurrence in happen but because
our lifespans are so short compared to the life of a star it would seem more like a rare occurrence to us.
Stellar Death – Supernovae
A supernova is an explosion of a star.
One example of a supernova was observed around 1000 years ago by Chinese observers, who called the
supernova a “guest star”.
Today, what’s left over from this explosion is called crab nebula.
Stellar Corpses
The three possibilities for what a star can become when it reaches the end of its life are:
1.
White Dwarfs
2.
Neutron Star
3.
Black Hole
Test Yourself – Supernovae
Stars massive enough to make supernovae are much rarer than the stars that make planetary nebulae.
Also, supernovae last months, while planetary nebulas last thousands of years.
Compared to planetary nebulae, supernovae are:
A.
More common
B.
About equally common
C.
A little rarer
D.
Much, much rarer
Your answer: D
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Stellar Ecology
Stars leave behind gas when they die.
This forms the basis for new stars and planets. This is important
for us, because heavy elements are what just about everything around us is made of.
Test Yourself – Stellar Generations
We’ve talked about star birth and star death almost as if stars are alive. Does it make sense to talk about
stars that form earlier and stars that form later as “generations” of stars? In what way?
A.
Perfect analogy.
B.
No. What I get from biological ancestors is inheritance. Genes. Money if I’m lucky. But my body is
not made out of atoms from their bodies. Yuck!!!!!
C.
Sort of. Stars in the early Universe changed the matter that later stars can be made of.
D.
I can think of a better way to say it. (What?)
Your answer: A
Part 3: Galaxies: The Milky Way is a Galaxy
In the 20
th
century, Astronomers came to realize that the Milky Way is a huge Galaxy of stars, which
we see as a in a band
Edwin Hubble showed that our galaxy is just one of many galaxies in space
Size of the Milky Way galaxy
Our galaxy is about 100,000 light years across, and about 1,000 light years thick. We are about
280,000 light years from the center of the galaxy.
There are about 200 billion stars in the Milky Way
Your Turn – Milky Way Distances
Since this is a drawing, you should do it on your own, but you do not need to turn it in for the
Guided Notes.
Other Galaxies: Many Sizes and Shapes
There are almost 100 billion galaxies in our observable Universe
The shapes of galaxies mentioned here are:
1)
Disk or balls
2)
Spirals or rings
Test Yourself – How Many?
Fill in the blank: The number of stars in our galaxy is _______________ the number of galaxies in the
observable Universe.
A.
Orders of magnitude smaller than
B.
About the same as
C.
Orders of magnitude larger than
Your answer: B
We are in the Local Group
The Local Group is a small group of galaxies with about 30 members
The Local Group is on the outskirts of the Virgo Cluster, which has 1,000 of members
Clusters combine into Superclusters
The Universe is expanding.
Therefore, in the past, the Universe started at a single point, almost 14
billion years ago.
We can’t see back to the start of the Universe, but we can see the earlier hot, dense phase, which
was around 400,000 years after the Big Bang
Your Address
Your cosmic address, going from smaller to bigger, is:
1)
Earth
2)
Solar Systme
3)
Milky Way
4)
The Local Group
5)
The Local Supercluster
Test Yourself – Scales
Arrange the following items according to size, from the smallest to the largest.
a.
Earth, Sun, galaxy, solar system, giant star
b.
Earth, Sun, giant star, galaxy, solar system
c.
Earth, giant star, Sun, galaxy, solar system
d.
Earth, Sun, giant star, solar system, galaxy
Your answer: D
Making Sense of the Universe
Scale
Typical Light Travel Times
Objects
Solar System
Click or tap here to enter text.
Click or tap here to enter text.
Stellar
Click or tap here to enter text.
Click or tap here to enter text.
Galactic
Click or tap here to enter text.
Click or tap here to enter text.
Timescales
The Universe is approximately 14 Billion years old.
The Solar System is approximately 4.6 billion years old.
Life on Earth started approximately 3.5-4 billion years ago.
Humans have been on the planet for approximately 200,000 or 0.0002 billion years
Written human history has existed for approximately 0.000006 billion or 6,000 years.
Your Turn – Milky Way
Does this make sense: “A recently launched NASA spacecraft will soon let us see pictures of the
Milky Way from outside of the galaxy”?
Describe why or why not this makes sense: The system does not make sense as the amount of time
it takes to travel to the Milky Way would vastly exceed
the human life span and we don’t have the
technology to launch a craft to travel that far of a distance.
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