Essential Standard 1.1

Explain Earth’s role as a body in space.

Learning Objective 1.1.1

Explain Earth’s motion through space,

including precession, nutation, the barycenter,

and its path about the galaxy.

I Can StatementsAt the end of this lesson, you should be

able to say, with confidence:• I can explain the big bang theory and the

evidence supporting the idea that the universe is

expanding.

• I can describe the hierarchy of the Universe,

according to relative size.

• I can explain the origin of Earth’s motion based

on the origin of the galaxy and our solar system.

• I can identify and describe various structures and

phenomena found in space.

The Big Bang Theory is how astronomers explain the way

the Universe began.

The Big Bang Theory

It’s the idea that the Universe began as just a single point, about the size of a pin head.

Then, about 13.7 billion years ago, the Universe

began to expand.

Light WavesWhite light travels in waves and is made up of

several different colored light waves.

Violet and blue light waves are short with

high frequencies.

Red and orange light waves are long with low frequencies.

Red ShiftWhen a light source is moving away from or

towards an observer, the light waves change in length and in frequency.

As light moves away from an observer, the wavelengths become longer and decrease

in frequency.

The color of the light that the observer sees shifts towards the longer, low frequency red light waves.

Blue ShiftAs light moves towards an observer, the light

waves become shorter and increase in frequency.

The color of light the observer sees shifts toward the shorter, high frequency blue light waves.

Expanding UniverseIn the early 1900’s, Edwin Hubble used the

red shift / blue shift light theory to show how galaxies were not only moving away from Earth but were also moving

away from each other.

In other words, everything in the

universe was moving away from everything

else in the universe and that the universe

was expanding.

When the first Universe began it was just a mixture of tiny particles, light, and

energy.

Early Universe

As everything expanded and took up more space, it began to cool down.

Photograph of the Early Universe

Hubble was even able to use the speed at which the light shifted to deduce how fast the galaxies were moving and was able to determine how long the expansion had been

taking place – 13.7 billion years.

As the Universe cooled, the tiny particles began to collide, at

really fast speeds, causing them to group together to form atoms.

Formation of Atoms and Matter

Atoms then began to join together to form matter.

Once matter began to form, in the early universe, the force of gravity

took over.

GravityGravity is an invisible force that pulls objects towards

each other.

Albert Einstein described gravity as the bending of space

by anything that has mass.

The more mass something has, the more it is able to bend space, so the more pull it has on other objects

around it.

As gravity began to pull more and more matter together, gas clouds, called nebulae, began to form.

Formation of Stars

As a nebular gets larger and larger, it begins to collapse into

itself due to its own gravity.

As the nebular collapses, the center core heats up and a star

is born.

Fusion Reactions

Fusion reactions, within stars, are

responsible for the formation of many of the atoms present in the Universe today.

Within stars, small atoms, collide and stick together,

creating even larger atoms, in a process called fusion.

Light Energy

As atoms collide, during fusion reactions, a massive

amount of energy is released.

E = Energy M = Mass C = Speed of Light

Human eyes are able to see the energy, released by

stars during fusion reactions, as light waves.

Pressure Within StarsAs fusion reactions take place in the center of a star, heat and pressure is produced that pushes

outward on the star.

Meanwhile, the star’s gravity tries to squeeze the star into

the smallest, tightest ball possible.

Heat, pressure, and gravity balance each other out,

holding the star together.

SupernovasAfter a long period of time, a star will run out of the fuel needed to power the fusion reactions and will

begin to cool down.

As the star cools down, the pressure drops and the force of gravity causes the star to

suddenly collapse.

The collapse happens so quickly that it creates enormous shock waves that cause the outer part of

the star to explode!

Black HolesAfter an extremely large star goes supernova, the core

of the star will continue to be squeezed together by gravity into a size smaller than the tip of a pin.

The mass of all that matter squeezed into such a small

space, creates a gravitational pull so strong that nothing can escape its

force, not even light, making it appear as a black

hole.

Smaller StarsSmaller stars, like our Sun, turn into red giant stars,

which are larger but a lot colder. Later on, they collapse to become white dwarf stars.

Galaxies

Our own galaxy, called The Milky Way, consists of spiral arms and a massive black hole in its center.

A collection of stars, along with the surrounding gas, dust, and ice, form what we call a galaxy.

The Milky Way Galaxy is 100,000 light years wide and our Sun is just one of at least a billion stars within

the Milky Way.

On a very dark night, far away from city lights, you can see the dusty bands of the Milky Way.

The Milky Way

Our solar system is just one of hundreds of solar systems within our galaxy.

In the center of our solar system is the Sun. Planets, asteroids, and comets orbit around the Sun and Moons

orbit around the planets.

Solar System

Our solar system began to form about 4.6 billion years ago, when energy from a nearby supernova sent shock waves

through a nebula causing the material to spin, compress, and collapse into itself.

Formation of our Solar System

As the material spun around, it flattened out into a disk, similar to how a pizza flattens out as it is spun around.

As the disc continued to spin, gravity pulled most of the

material into the center of disc.

Formation of our Solar System

Eventually, the pressure became so great in the

center mass, that fusion reactions began, igniting

our Sun.

Sun

The lighter material collected, in a similar

fashion, to form the outer planets, often referred to

as the gas giants.

Formation of our Solar SystemAs the disc continued to spin, heavier material surrounding the Sun, began to collide and

stick together, forming the rocky inner planets.

My Very Educated Mother Just Served Us Nachos

(Order of the planets)

PlanetsA planet is a large body that orbits a star, has enough

gravity to force a spherical shape, and must be big enough that its gravity cleared away any objects of

similar size near its orbit.

Pluto was declassified as a planet because scientists

found other things in our solar system just as large as Pluto. It

is now called a dwarf planet.

MoonsMoons are large bodies or rock or ice that orbit a planet. There are 178 moons in our solar system,

most of them orbiting the gas giant planets.

AsteroidsAsteroids are large rocks that

never got large enough to form a planet but still orbit

the Sun.

Most asteroids, in our solar system, are found in the

asteroid belt, located between Mars and Jupiter.

Meteoroids and Meteors

Sometimes asteroids collide and pieces of rock break off into what

are called meteoroids.

When meteoroids enter Earth’s atmosphere, they vaporize into what we call meteors.

Meteors look like streaks of light in the sky. Some call them shooting stars, but

they aren’t.

Meteorites Not all meteors vaporize.

Those that reach the Earths surface are called meteorites.

It is thought that a large meteorite struck Earth 66 million years ago, causing severe climate change

which led to the extinction of the dinosaurs.

Scientists collect and study meteorites to learn more about

our solar system.

Hoba – Largest Meteorite

Comets Comets are large bodies of ice, dust, and a carbon-based black goo, like the charcoal residue

on a barbeque grill.

Comets orbit the Sun, but their orbits are really elongated

causing them to be very close to the Sun and also very far

from the Sun.

Anatomy of a Comet A comet’s center, called a nucleus, is like a dirty

snowball made of ice.

As a comet nears the Sun, some of the ice melts off,

along with some dust, creating a fuzzy cloud of gas and dust around the nucleus, called a coma.

As the comet travels, it develops a brightly lit tail of dust and gas.

Life on EarthEarth is the only place where we know life exists.

When scientists search for life, they look for planets or moons that have similar conditions to Earth.

They must be the right size so they can maintain an atmosphere.

They also need to be at just the right distance from a star, called the

habitable zone.

Water CycleThe habitable zone has just the right range of

temperatures so that water can exist in all three states: solid, liquid, and gas.

Water is an essential ingredient for life and is

constantly being replenished through the

water cycle.

The EndSpace Cadet