Vocabulary:

Asteroids Celestial Objects (planets, moons, and asteroids) Counterclockwise Earth Galaxies Gravitational force

Instruments (Earth- and space-based) Milky Way Galaxy Moon Orbital motions Orbits Pattern

UNIT 4: ASTRONOMYEARTH’S PLACE IN THE UNIVERSE

SCIENCE 8MRS. GILL-KLESARISNOTE PACKET #5

NAME:__________________ CLASS:_______ DATE: ________

And you think I’m BIG!!! …

P.S. I’m Delilah

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Planets Scale Scale properties

Distance from Sun Diameter Surface features (e.g. volcanoes) Structure Composition (e.g. ice versus rock versus gas)

Seasons Solar Eclipse Solar system stars Sun Universe

2

What is Astronomy?Astronomy is the scientific study of matter in outer space, especially the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial objects and phenomena. (phenomena: is something observable and explainable by science)

There are many different Celestial Objects in our UniverseThe Universe refers to all the celestial objects in space and the space and energy between them. Celestial objects appear in the sky during day and night. They include:-The Sun -The Moon- Planets -Stars-Comets -Asteroids

-Meteorites

When and where did the Universe originate?- The universe began with a period of extreme and rapid expansion known as the Big Bang. -According to the Big Bang Theory, all the matter in the universe started out as a_____________________! This single point was extremely dense. It became unstable and exploded outward. -This Big Bang, which actually sounded more like a low hum, is estimated to have occurred around 13.8 billion years ago!!! -Today the universe continues to expand from this single point of origin, and distant galaxies are getting further apart from one another.

What do you wonder about Astronomy? Imagine that you are about to take off in this space shuttle and take a long journey to the edge of our universe. Make a list some questions that you might seek to answer about astronomy?__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Scale Properties in the Universe

3

How big is the Universe?It is very humbling to contemplate the size of our Universe because it is unbelievably BIG and therefore it can make you feel VERY small. However it’s also impressive that our civilization has acquired such great knowledge, and it reminds us that we as people are a part of larger system. It is important for us to respect the natural equilibrium of our planet and the universe to which it belongs. We must work to limit our environmental impact and continue to educate our peers about the delicate balance of this system.

Measuring Distance: In order to grasp and describe the vast size of our Universe, we must first develop a measurement standard.

Distances between celestial objects are extremely large. Rather than miles, astronomers refer to a ____________________ as a

standard unit of distance.One light-year is the distance light travels in one year.

The speed of light is 186,000 miles per hour (that’s fast!) Thus, one light-year is about 6 trillion miles. The nearest star to us (Proxima Centauri) is 4.2 light-years away.

Astronomical unit: Another unit of distance is the _________________________ (AU). One AU is the distance from the Earth to the Sun (93 million miles) Distances to other objects in the solar system are given in multiples of AU.

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

4

Have you ever heard someone say that you’re seeing the past when you look up at the stars? It sounds romantic and perhaps even silly, but it is correct. For example, when an astronomer views the Andromeda galaxy, he/she is seeing how it was 2.5 million years ago. This is because it has taken that long for the light to reach us here, offering a window into the past that no history book ever could!

Components of our Universe.The best definition of the Universe is: EVERYTHING!We are all a part of the universe along with everything else you can think of.

Outside of the edge of the universe is nothing. This is confusing because it’s hard to imagine “nothing”. The universe is expanding into nothing because

nothing is in its way. All matter makes up the universe. I like to think of the components like a system of “Russian Dolls.” These components are organized from largest to smallest and they fit inside of each other:

The universe is made of billions of GalaxiesGalaxies are made of billons of Solar SystemsIn the center of Solar Systems are starsRevolving around stars are planets, Smaller than planets are moons, asteroids and meteorites.Planets moons comet, asteroids and meteorites are made of matter.Systems within the universe are held together by gravity.GalaxiesThe solar system is part of the Milky Way Galaxy, which is one of many billions of galaxies.

A ______________ is a collection of millions or billions of stars. Galaxies can be spiral, elliptical, spherical or irregular in shape.

The Sun is part of the MILKY WAY galaxy, which is a spiral galaxy. The Sun is located on one of the spiral arms, far from the galactic center.

When you look up on a clear night there is a hazy lighter band that runs across the sky. When you look at this band you are looking at the side of the spiral arm that is adjacent to the arm that our sun is in. Each arm is made of millions of stars. The stars themselves are too far away to see individually, but together their light combines to make the sky lighter in that area.

Did you know…A light year is the distance light travels in a single year – 9,460,528,000,000 km. So the light we see coming from Proxima Centauri left the star 4.2 years ago. Even being the nearest star, Proxima Centauri is incredibly far away. It would take our fastest spacecraft more than 50,000 years to make the journey.

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Scale Properties in the Solar System

Gravity and Motions in Space5

A. Which is bigger: Our Solar System or Our Sun?Naturally our ____________________ is bigger since the sun is apart of it. An object must always be bigger than something it includes. For example, a shoebox must always be bigger than the shoes. And your shoe must be big enough to fit your foot.

The Solar System includes: The solar system consists of the sun and a collection of objects

of varying sizes and conditions—including planets and their moons—that are held in orbit around the sun by its gravitational pull on them.

The Sun, a ______________size, middle-aged star The eight planets and associated moons ________________chunks of rock found mostly in a belt between

Mars and Jupiter __________________– mass of frozen gas and rock All of these objects are called __________________ which appear in

the sky during day and night. D. The Formation of Our Solar System:

______________________ large disk of gas, ice & dust existed It began to contract & slowly rotate due to gravity

E. The Parts of Our Solar System: The ______ is the center of the Solar

System _______________, also called

___________: (meaning earth-like) the first four planets

__________________: band of rocks orbiting the sun between mars and Jupiter

________________, also called ___________: the four planets farthest from the sun.

Size Comparison Jovian vs. Terrestrial

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Hints: Good models include labels or a key to label objects Arrow should indicate motions and or forces in your model Word bubbles are a good way to explain your drawings Note the scale and identify the limitations of your model

Gravity

6

How do the Planets move around the Sun? All planets revolve around the sun in nearly circular path called an orbit All planets move in the same plane (a large imaginary flat surface) The planets move in a counter clockwise direction around the sun

Is gravity always the same? Gravity– the force of attraction between 2 objects Gravity increases with the mass of an object. In other words, bigger

objects have more gravity then smaller objects. Gravity also depends on the distance between the two objects. Gravity

decreases as the distance between objects increase.

Draw a model in this box to represent how the planets move around the sun using the information above.

*Did you include the force that is keeping the planets in orbit? What is holding the system together? _______________________________

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Let’s examine the two models of a solar systems below. Each model shows a planet orbiting a star at a certain distance from the planet. In the models, a larger circle represent a larger mass. Solid arrow represent distance, with longer arrows indicating greater distance. White arrow represent gravity, thicker symbols represent stronger gravity. MODELS ARE NOT DRAWN TO SCALE.

1. Which model above shows a stronger gravitational attraction between the planet and the star? State your Claim-Evidence-Reasoning (CER) below: Claim: Model _______ shows a stronger gravitational attraction between the planet and the star. Evidence: In the model, it can be observed that ____________________________Reasoning: When objects are ___________________, then the gravitational attraction is ___________________. 2. How could you increase the gravity between the star and the planet in Model B without changing the distance between them? Draw a model in the box below to explain. __________________________________________________________________

Using the same key asAbove, draw your model hereGravity and Motions in space: If gravity is an attractive force, then why don’t all the planets get sucked into the sun?

7

Model how orbits work: Draw a model that could explain your understanding of how planets stay in orbit around the sun. Hint: Using the important vocabulary words below

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Planets: A planet is a large round body that is in orbit around the Sun. Planets in order from the closest to the sun are: MERCURY, VENUS, EARTH, MARS, JUPITOR, SATURN, URANUS, NEPTUNE

8

Terrestrial Planets: Four ___________ planets of the solar system Relatively __________ in size and mass (Earth

is the largest and most massive) __________ surface

List the terrestrial planets:_____________, _________, _________, _______________

Jovian Planets: Much _____________ in mass and size than

terrestrial planets Much lower average ___________________ Mostly _________; no solid surface Also known as Gas Giants because they are

made of mostly hydrogen and helium List the Jovian planets: ___________,

____________, ____________, __________

Important Vocabulary: Revolution – the movement of an object around another object Orbit – the path taken by a revolving object Gravity: The attractive force between objects Inertia – the tendency of an object in motion to continue in motion

along a straight path

Class Model:After the class discussion redraw your model based on the class consensus. Reflect on how your level of understanding has changed.

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

Based on the chart above, what is the relationship between the distance from the sun and the period of revolution of the planets? As distance from the sun _____________, the ______________________________________________________________.Which have more moons, Jovian planets or Terrestrial planets? _________________.

9

Asteroids Rocky objects with round or irregular shapes Most orbit in a wide belt between _________ and

____________ The total mass of all the asteroids is less than

that of the Moon Photographed by Galileo probe

Comets: Are only visible when they are close to the

sun have highly elliptical orbits, occasionally

coming close to the sun Comet Composition: Dust, rock, frozen

methane, ammonia, and water Comets normally look like dirty snowballs When they get close to stars, they begin to

vaporize & and form a tail called a coma

Meteoroids, Meteors & Meteorites:Meteoroids: chunks of randomly moving through space. Usually leftover comet or asteroid debrisMeteor: Meteoroid that collides with Earth, evaporates in the atmosphere producing streaks of visible light (“shooting stars”) Most burn up before reaching the surfaceMeteor Shower: Many meteors at one time Meteorite: Meteor that does not totally burn up, & strikes the Earth’s surface. The impact creates a crater

“Satellite” a fancy science word for moon.

Astronomy Note Packet Science 8- Mrs. Gill-Klesaris

10