The Scale of the Universe Notes Test – Thursday, 1/16 Textbook & Online Resources: Chapter 3 – Lesson 1: Scale of the Universe Chapter 3 – Lesson 2: Star Systems and Galaxies Chapter 3 – Lesson 3: Gravity and Motion Chapter 4 – Lesson 5: Small Solar System Objects

Astronomy The study of stars, planets, galaxies… everything in space

NOT ASTROLOGY Fortune telling The zodiac

Regular Telescope

Really BIG, really expensive telescope

Hubble Space Telescope

Distances in the universe can be measured in two ways

Light Year The distance that light can travel in a year TRILLION kilometers *** A light year is a unit of DISTANCE NOT TIME!!! *** The speed of light is 670,616,629 mph 300,000,000 meters in 1 second

Light Year Fun Facts You could travel from the Earth to the Moon in 1.3 light SECONDS

Light Year Fun Facts You could travel from the Earth to the Sun in 8 light MINUTES

The most distant space probe, Voyager 1, was about 17 light-hours away from the Earth as of December Even though it is traveling about 38,000 mph, it will take about 17,500 years to reach one light-year. Before 2015, this will become the first manmade object to leave the Solar System.

Light Year Fun Facts Proxima Centuari, the nearest star, is about 4.22 light years away.

Light Year Fun Facts The center of our galaxy is about 26,000 light years away. You are here

Astronomical Unit (AU) The distance from the Earth to the Sun About 150,000,000 km

AU Distances from the Sun Mercury AU Venus – 0.72 AU Earth – 1 AU Mars – 1.52 AU Jupiter – 5.20 AU Saturn – 9.54 AU Uranus – AU Neptune – AU

Because distances are often so large in space, they are often expressed in scientific notation.

Scientific Notation 2.4 X 10 5 = 1 Light Year = 9,460,000,000,000,000 m 240, X 10 15

Relative Size Objects that are closer appear larger Objects that are farther away appear small.

Relative Distance Distance in reference to a certain point.

Astronomers calculate relative distance using parallax

Parallax The apparent change in position of an object when you look at it from different places.

Universe All of space and everything in it

The Universe is made up of BILLIONS of galaxies!

Galaxy A huge system of stars, star systems, dust, and gas held together by gravity. *** There are over 100 Billion galaxies in the universe!

A galaxy is made up of BILLIONS of stars

Our galaxy is called the Milky Way The Milky Way has 300 Billion Stars

The Milky Way as seen from Earth

Nebula A large cloud of gas and dust in space New stars can form inside Nebulae The Helix Nebula

The Witch Head Nebula

The Red Spider Nebula

The Horsehead Nebula

Cat’s Eye Nebula

Eagle Nebula

Jellyfish Nebula

Solar System (AKA – Star System) A star and all of the planets and other objects that revolve around it.

Galaxy vs. Solar System

Our solar system is made up of the sun, planets, and ALL other objects that orbit the sun

The parts of a solar system can include…

Star Made of gases (H & He) and produces its own light & heat through nuclear fusion

A group of stars that appear to form a pattern in the sky is a constellation Examples: Big/little dipper, Draco

Planet 1)An object that orbits a star 2) Is large enough to have become rounded by its own gravity 3) Has cleared the area of its orbit. Can be rocky or gas

Our solar system has 8 planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, & Neptune

A good way to remember this… My Very Educated Mother Just Served Us Nachos.

Dwarf Planet A spherical object that orbits the sun, but has NOT cleared the area of its orbit.

There are also 5 dwarf planets: Ceres, Pluto, Eris, Haumea, and Makemake

Moon An object that orbits a planet. A planet can have many moons, one moon, or no moons

Comet Small body of ice, rock, & dust that orbits the sun. Has a “tail” because the sun’s heat melts ice, & creates gas Halley’s Comet – 1986 Will return in 2061

Comet Hale-Bopp

Comet Lovejoy – December 2013

Asteroid Large rocky object that orbits the sun. Asteroids make up the Asteroid Belt which is found between Mars & Jupiter.

Meteor Piece of dust, rock, or debris that travels through space.

Meteor Meteors are sometimes called “shooting stars” but they are not stars They glow when they are passing through the atmosphere, because of friction

Everything in the universe has gravity. The amount of gravity that an object has depends on its mass and distance from other objects

The sun has the most gravity in our solar system Large-mass planets have more gravity than smaller- mass planets Your weight on other planetsYour weight on other planets

Remember… Weight – The amount of gravity (changes) Mass – The amount of matter (doesn’t change)

Planets and stars are formed by accretion, gravity bringing material together

Small planet – little gravity Pulls in more dust, ice, & gas Grows to be a Large planet – More gravity Pulls in more dust, ice, & gas