Formation of Solar System

SES1a The Origins of the Solar System

SES1. Obtain, evaluate, and communicate
information to investigate the composition and
formation of Earth systems, including the
Earth’s place in the solar system.

a. Construct an explanation of the origins of the
solar system from scientific evidence including
the composition, distribution and motion of
solar system objects.
(Clarification statement: The nebular
hypothesis should be included in this element.)

What is the Universe

The universe is everything;
planets, stars, galaxies, space,
and even time! No one knows
how big the universe is. We
used to think the universe was
infinite. Now most scientists
agree that it does have an end
and does not go on forever.

The Origin of the Universe

In 1929, astronomer Edwin Hubble
observed the redshift of the galaxies,
and knowing about the Doppler
Effect, inferred that galaxies are
moving away from each other.
Because of this observation, he
concluded that the universe must be
expanding.

Multiple Choice

According to Hubble’s law, the farther away a galaxy is,

• the faster it is moving toward us.

• the slower it is moving toward us.

• the slower it is moving away from us.

• the faster it is moving away from us.

Multiple Choice

According to the Big Bang theory,
how old is the universe?

• 6,000 years

• 65 million years

• 65 million years

• 13.7 billion years

The Big Bang Theory is the leading
explanation for how the universe
began. The universe started with an infinitely hot and dense single point that inflated and stretched, first at unimaginable speeds, and then at a more measurable rate, over the next 13.7 billion years to the still expanding cosmos that we know today.

Big Bang

Multiple Choice

The universe is

• unchanging

• shrinking

• expanding

• none of these

Big Bang Evidence - Cosmic Microwave Background Radiation

The beginning of the universe would have been
very hot and would have cooled down as it
expanded. In the 1940’s astronomers thought
there would be leftover radiation from that
expansion. This was found out by accident in
19654 as engineers were trying to find gas from
the Milky Way Galaxy. The found a lot of
background noise like static. It turns out this
static is everywhere in the universe and that
leftover “heat” is leftover from the Big Bang.

This is a whole sky Planck space telescope
image of the cosmic microwave background
(CMB), the relic radiation from the Big Bang.

Multiple Choice

What can you tell about this object's motion?

• Moving to the North (up).
• Moving to the South (down). 
• Moving to the West (left). 
• Moving to the East (right). 

We know the siren of the fire truck sounds different when it is coming toward us and when
it is moving away from us. What do you think happens to the light that we can see?

Multiple Choice

Which has the LONGEST wavelength and, therefore, the lowest frequency/energy

• Gamma Rays
• Radio Waves
• Visible Light
• Infrared rays

Big Bang Evidence - Redshift

As Edwin Hubble first observed, the
stars and galaxies are redshifted.
This indicates that they are all moving
away from us and from each other.
The farther away a galaxy is, the
faster it is moving. This shows the
Universe is expanding.

Similar to sounds from a moving vehicle, as a
star moves away from us, the light becomes
redder. As it moves towards us, the light
becomes bluer. Wikipedia

The wavelengths in the visible spectrum also shift and we can use
that information to decide if the star is moving towards us or away
from us.

Multiple Choice

The Doppler effect applies to light waves as well as sound waves. Astronomers use this to measure the motion of stars and galaxies. In 1929, Edwin Hubble discovered that light from distant galaxies was shifted away from the blue end of the spectrum and towards the red end of the spectrum. Red light has a longer wavelength (and a lower frequency) than blue light. What could Hubble conclude about these galaxies?

• The distant galaxies are growing smaller.

• The distant galaxies are moving towards the Earth.

• The distant galaxies are moving away from earth

NSSDCA Photo Gallery: Nebulae

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Multiple Choice

A cloud of gas and dust in space is called __________.

• a nebula

• a space haze

• an asteroid belt

• a galaxy

Nebular Hypothesis
Formation of Solar Systems

1.

A nebula begins to collapse and
heat up under its own gravity.

2.

The collapsing cloud begins to
spin. Then it flattens into a rotating
disk.

3.

As the material gathers in the
center, it becomes dense,
compresses, and heats up.

4.

The material grows to form a
protostar. A protostar isn’t dense
enough for nuclear fusion to start.

Multiple Choice

Once a physical force disturbed the nebula, it began to _______ and __________ into a disk.

• spin and grow.

• spin and flatten.

• shake and shatter.

• shake and grow.

Gravity

Gravity is the force that
attracts two objects
together.

The more mass an object
has the stronger gravity
that it has

Protostar becomes a star

The protostar continues to gather mater from the
surrounding disk and grow. When the protostar
becomes massive enough, dense enough, and hot
enough the process of nuclear fusion begins.

This process is what causes all stars to glow and
produce energy. Once nuclear fusion begins a solar
wind is created that drives remaining gas and dust to
the outer parts of the disk. This is where comets come
from. The young star stops gathering material.

Multiple Choice

Heat and pressure in our protostar reached limits needed for the process of _______, in which hydrogen atoms smash together to form helium.

• fission

• engine

• fusion

• matter transport

Step 5: Accretion

Since even the smallest particles
attract each other due to
gravitation the gas and dust in the
spinning nebula will attract each
other and form clumps called
planetesimals. These are larger
masses and have a larger
gravitational field which makes
them grow larger to form planets
and moons.

Multiple Choice

The Nebular Hypothesis is the scientific explanation for the formation of __________.

• the universe.

• meteor showers.

• our solar system.

• clouds.

Do you remember the spin that gets
everything going? That turns out to be very important. The spin is working to accelerate the material off into space while gravity is pulling material inward. If the balance is just right, some of the material will stay in orbit and form planets. This is the current hypothesis but it’s kind of hard to test. Astronomers are looking for information in other galaxies.

Because Gravity

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Evidence for the Nebular Hypothesis

The nebular hypothesis was designed to
explain some of the basic features of the solar
system:

•The orbits of the planets lie in nearly the same
plane with the Sun at the center

•The planets revolve in the same direction

•The planets mostly rotate in the same direction

•The axes of rotation of the planets are mostly
nearly perpendicular to the orbital plane

•The oldest moon rocks are 4.5 billion years

In the Nebular Hypothesis, a cloud of gas and
dust collapsed by gravity begins to spin faster
because of angular momentum conservation

What causes each of these
phenomena?

What do all these things have to do
with what stars are made of?

So why?

When we see a rainbow in the sky, it is usually when the sun is behind us and it is shining through millions of tiny raindrops floating in the sky, all of which are bending the light and projecting the rainbow.

Light is a kind of wave that can bounce off things or go through them. When light hits oil on water, some of it bounces off the oil and some of it goes through the oil and bounces off the water. Then these two bounced light waves meet again and they can either add up or cancel out depending on how they line up. This makes some colors brighter and some colors darker.

Stars are different colors

Stars appear to be white at first but if we look carefully there is a range of colors. The color a star appears to our eyes can give us information about its surface temperature and where it is in its life cycle. 

Using a special tool called a spectroscope, scientists can analyze additional light emitted from a star. Each element in the periodic table gives off a unique series of bright lines. By studying these spectral lines, astronomers can determine the elements, density and mass of a star. 

Stars can be blue, blue-white, white, yellow-white, yellow, yellow-orange, and red. 

The sun is a medium-sized yellow star about halfway through its predicted lifespan of about 10 billion years.

The Hertzsprung-Russell diagram shows how size, color, luminosity, spectral class, and absolute magnitude of stars relate. Each dot on this diagram represents a star in the sky whose absolute magnitude and spectral class have been determined.

Multiple Choice

Based on this diagram which type of stars would belong to spectral class G and have the highest luminosity?

• Main Sequence Stars
• Giants
• Super Giants
• White Dwarfs

Analyzing Elements

We can look at light through a
spectroscope. It turns the light into
bands of colors. The placement of
different lines of color and black can
identify what elements are present.

Do you see the different prisms? A
prism separates light into a spectrum
of colors, creating a rainbow effect,
through a process called dispersion.

Why do you think there are black
bands in the element spectras?

Scientists can look at the light from stars and can determine what elements are on the star’s surface.

The dark line’s in a star’s spectrum indicate what energy levels are being absorbed by the elements of that star. That tells us what elements the star is made of (hydrogen, helium, etc).

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Multiple Choice

Which two element make up most of the sun?

• helium and hydrogen

• ammonia and methane

• hydrogen and oxygen

• oxygen and helium

Multiple Choice

What gases are in the unknown mixture?

• Gas B & Gas D
• Gas C & Gas B
• Gas A & Gas D
• Gas D & Gas C

Multiple Select

Choose all that apply. A star's spectra tells us what about a star.

• composition of that star (what elements make up that star)

• movement of a star (red shift or blue shift)

• brightness of a star

• temperatures of a star

Multiple Choice

The light emitted from two galaxies, A and B, is
observed and the spectral lines in each are shifted
toward the red end of the spectrum. Galaxy B is
observed to have a greater redshift than Galaxy A.
Which galaxy is moving faster away from Earth?

• Galaxy A

• Galaxy B

•  Both galaxies are traveling at the same speed away from Earth.

• Both galaxies are traveling towards Earth.

The Sun is in the Center

In 1543, Polish astronomer Nicolaus
Copernicus declared that the Sun was
the center of the solar system. Unlike
the old, Earth-centered (geocentric)
model, Copernicus' new Sun-centered
(heliocentric) model was much simpler.
The planets moved about the Sun in
predictable, simple paths.

Our solar system includes everything
that revolves around our Sun. It includes
8 planets, 5 dwarf planets, 170 moons,
over a million asteroids, and thousands
of comets.

What is a planet?

What was a planet was never a
question until recently. It was a big
round thing that circled the sun.

As telescopes got better and we
could see farther into space we saw
several planet sized objects orbiting
beyond Pluto.

Now scientists had to decide what
made something a planet.

How would you
define a planet?

Remarkably Flat

The solar system is remarkably flat
when seen edge-on. Most of the
planets are neatly spread out along
an imaginary, flattened disk.
Astronomers say they all orbit nearly
in the same plane.

How is the orbit of the dwarf planet
Pluto different from the orbits of the
planets in the solar system?

What was the decision

These are the three things that
scientists decided an object must
meet to be a planet:

1.

It must orbit the sun.

2.

It must be massive enough for
gravity to compress it into a
round shape and small enough
that it isn’t a star.

3.

It must have cleared the area
surrounding its orbit.

Pluto

This third requirement
resulted in the removal
of Pluto from the list of
known planets. Pluto's
orbit is heavily
influenced by Neptune's
gravity, and Pluto passes
very near other, smaller,
objects that are also
orbiting the sun.

Multiple Choice

Which is NOT one of the criteria to be a planet?

• It must orbit the sun.

• It must be big enough for gravity to squash it into a round ball.

• It must have at least one moon.

• It must have cleared other objects out of the way in its orbital neighborhood.

Pluto

From the time it was discovered in
1930 until the early 2000s, Pluto was
considered the ninth planet. When
astronomers first located Pluto, the
telescopes were not as good, so
Pluto and its moon, Charon, were
seen as one much larger object. With
better telescopes, astronomers
realized that Pluto was much smaller
than they had thought.

Better technology also allowed astronomers to discover
many smaller objects like Pluto that orbit the Sun. One of
them, Eris, discovered in 2005, is even larger than Pluto.

Even when it was considered a planet, Pluto was an oddball. Unlike the other outer planets in the solar system, which are all gas giants, it is small, icy, and rocky. With a diameter of about 2,400 km, it is only about one-fifth the mass of Earth’s Moon. Pluto’s orbit is tilted relative to the other planets and is shaped like a long, narrow ellipse. Pluto’s orbit sometimes even passes inside Neptune’s orbit.

In 1992, Pluto’s orbit was recognized to be part of the Kuiper
belt. With more than 200 million Kuiper belt objects, Pluto
has failed the test of clearing other bodies out its orbit.

Multiple Choice

Why was Pluto thought to be a planet when it was first observed through a telescope in 1930?

• Pluto was found to be a star

• Pluto and its moon, Charon, appeared as one much larger object

• Pluto was larger, but it has been struck by so many meteorites that it’s gotten smaller

• Pluto was thought to be spherical but it was found not to be

Dwarf Planets

The dwarf planets of our solar system are exciting proof of how much we are learning about our solar system. With the discovery of many new objects in our solar system, astronomers refined the definition of a dwarf planet in 2006.

According to the IAU, a dwarf planet must:

●Orbit a star.

●Have enough mass to be nearly spherical.

●Not have cleared the area around its orbit of
smaller objects.

●Not be a moon.

Multiple Choice

What is NOT characteristic of a dwarf planet?

• Has cleared the area of its orbit of smaller objects

• Is big enough to be roughly spherical due to gravity

• Orbits a star

Why are planets round?

As dust in the galaxy
attracted more dust
planetesimals formed. As
early planets grew larger
through accretion, gravity
pulled from the center to
the edges. This forms a
sphere.

From the Earth to the Moon

Our Moon is a long distance
from Earth. A jet plane, which
takes about 5 hours to fly from
New York to London, would
take about 1 month to fly to
the Moon.

The Moon is also quite large
relative to Earth. It's almost
one-third the diameter of the
Earth. The Earth and Moon
are sometimes called a double
planet.

Distances in the Solar System

The distances to the Sun
and planets are much
larger than the distance
to the Moon.

Where the Moon was
hundreds of thousands of
kilometers from the Earth,
the Sun is hundreds of
millions of kilometers
from the Earth.

Planet Distances

The solar system is big. You
and I are tiny compared to
even the smallest planet, but
the planets are very small
compared to the huge
distances between them.

1 kilometer (km) = 0.621371
miles

A Vast Solar System

To help us understand these
great expanses of space, it's
convenient to use a
measurement called the
astronomical unit, or AU for
short. An AU is the average
distance between the Earth and
the Sun—about 150 million
kilometers (93 million miles).

Multiple Choice

Distances in space are too large for the mathematical units we use on Earth. We need a special unit for space. This unit is the astronomical unit. What is the basis of the astronomical unit?

• the distance from the Moon to Earth

• the distance from the Sun to Earth

• the distance from the Earth to Venus

• the distance from the Earth to Mars

How far to Neptune?

The planets in our solar system are not evenly spaced apart. Many diagrams don’t show the distance accurately. The distances between the planets become larger the further away from the solar system one travels. The distance between
Mercury and Venus is approximately
50,000,000 km, while the distance between Uranus and Neptune is over 1.6 billion km - over three times as far apart as Mercury and Venus!

Multiple Choice

Using the information from the chart, choose the most reasonable distance between Pluto and the Sun.

• 7 AU

• 15 AU

• 25 AU

• 49 AU

NASA's Voyager 1 spacecraft was launched in 1977.
In 2012 it became the first human-made object to
enter interstellar space by crossing the edge of the
heliosphere. That's the boundary beyond which most
of the sun's ejected particles and magnetic fields
dissipate.

According to NASA, "if we define our solar system
as the Sun and everything that primarily orbits the
Sun, Voyager 1 will remain within the confines of the
solar system until it emerges from the Oort cloud in
another 14,000 to 28,000 years."