The Traveling Exhibit Science Background Part A: Intro & Family of the Sun

The Questions Behind the Exhibit How did our Solar System form? What are the giant planets like? How do scientists study far away planets?

The Big Ideas We study the giant planets of our Solar System because they tell us about the formation of solar systems, our planet, and the conditions necessary for life. Someday we may answer the age- old question of whether there is life beyond Earth. We are developing extraordinary new tools, techniques, and insights for exploring these extraordinary worlds – mini solar systems that include many moons and spectacular rings.

Welcome to the Exhibit  Family of the Sun (Our Place in Space)  Meet the Giants Front  What’s Next: Missions of Tomorrow Back The science background is organized by EXHIBIT AREA:

A. Family of the Sun KEY QUESTIONS: What is gravity? How did life on Earth depend on giant planets?

Gravity Rules Gravity is the attractive force between objects that have mass. In space, this means that a swarm of small objects eventually collects into a big one under the influence of gravity. This is how moons, rings, planets, and stars form.

Isaac Newton (1643–1727) was the first to realize that the force that makes things fall toward Earth also operates on the distant Moon, keeping it in its orbit around our planet. This force, called gravity, is a property of all matter. Newton’s universal law of gravitation describes the way gravity varies with mass (the amount of matter) and distance. Albert Einstein (1879–1955) went further to conclude that gravity is intimately connected to space and time. Space is curved by the presence of matter, which is why moons, planets, and other objects follow curved paths. What Is Gravity?

2. Planets orbit stars 3. Stars and star systems orbit the centers of galaxies 4. Galaxies orbit each other in clusters. 1.Moons orbit planets

Before entering the exhibit, fill in the blanks using the following key words. galaxy orbit solar system moon star Universe Earth Jupiter planets Sun 100 billion The Sun is a _________ located at the center of our __________________. Our home, called __________, is one of 9 planets that orbit around the _________. Earth has one _________ that orbits around it each month, showing different phases. Some planets have many moons that ___________ around them. ________________ is the largest planet in the Solar System and has 64 moons! Our sun is one of about _______________ stars contained in the spiral _____________ we call the Milky Way. Astronomers are now discovering Jupiter-sized ____________ that orbit around some of those distant stars. Outer space is even bigger yet because the Milky Way is only one of an estimated 100 billion (100,000,000,000) galaxies in the ______________! Exploring the Structure of the Universe Can You Fill in the Blanks? Click for Answers starsolar system EarthSun moon orbit Jupiter 100 billion galaxy planets Universe Copyright 2000 Cherilynn Morrow – Used with permission

Solar System Formation 1. Something (perhaps a supernova) triggers the gravitational collapse of a nearby interstellar cloud. 2. The cloud naturally heats up and spins faster as it collapses. Collisions between particles flatten the cloud into a disk. The Sun and planets start to form in this spinning, flattened disk (proto-planetary disk), with the Sun at the hottest central part. 3. In our Solar System, Earth formed in the inner region of the disk where rocky & metallic material could condense in the greater heat. Ices & hydrocarbons settled in the outer regions where gas giants like Jupiter form.

Crash Course The largest planet, Jupiter, exerted a powerful gravitational influence. If Jupiter had formed closer to the Sun, Earth and some of the other inner planets might have been thrown out of the Solar System! Jupiter, Saturn, Uranus, and Neptune formed amid a blizzard of icy particles. They swept up much of this frozen material. But much also collected into huge “iceballs.” The powerful gravity of the giant worlds flung most of the iceballs into the outskirts of the Solar System. However some were diverted toward Earth, where they crashed and deposited vast amounts of water—maybe enough to fill our oceans. Since life probably started in the oceans, we may owe our existence to these snowballs from afar.

Earth is one of 8 PLANETS in our SOLAR SYSTEM. The planets orbit a central STAR we call the SUN. Can you name the other planets? Hit for answers Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Rocky terrestrial planets of the inner Solar System. Gas & ice giant planets of the outer Solar System. Influenced by the gravity of Jupiter & Neptune, icy comets from the outer solar system likely delivered important ingredients for life to the young Earth environment (e.g. water and carbon compounds). Our Place in the Solar System

How do we explore our Solar System? Ground-based Telescopes The most readily available tools for exploring the giant worlds are ground-based telescopes. These include mammoth instruments such as the 110- foot, 500-ton Goldstone Apple Valley Radio Telescope located in California. Space Telescopes One advantage of launching telescopes into space is that they have a view unobstructed by Earth’s atmosphere. Orbiting several hundred kilometers above Earth is the Hubble Space Telescope, which has captured detailed views of the giant planets and their moons. Space Probes The best views of the giant worlds are from up close. Several space probes have made the journey to the realm of giants for “quick-look” flyby missions or for long-duration orbiting missions. Cassini-Huygens is a spacecraft that arrived in orbit around Saturn in 2004.

The Sun is the ONLY star in the SOLAR SYSTEM. Earth is the ONLY planet in our Solar System where we know for sure that life has evolved.

The Sun is the only star in the SOLAR SYSTEM, but it is one of over 100 billion stars in the GALAXY we call the Milky Way. Our Solar System is located about 2/3 of the way out from the galaxy’s center. Astronomers think that most of the stars in the Milky Way galaxy could also have planets orbiting around them. These are called “extra-solar planets”. Artist’s Concept of our Milky Way Galaxy Our Place in the Galaxy

2. “Milky Way” = the band of light and dust that stretches across a dark night sky.* This is just a portion of one of the spiral arms that we can see from Earth. The term “Milky Way” is used in two ways. For purposes of this presentation, we mean the whole galaxy. 1. “Milky Way” = our entire galaxy of 100 billion stars.* Our whole Solar System orbits once around the galaxy’s center every 225 million years or so. * The image above is of another spiral galaxy that may be a lot like our own Milky Way. It would not be possible to make such an image of our own galaxy from within it. This galaxy is called NGC * The image above is a long exposure photograph, showing much more contrast than we would see with our naked eye. To the eye, the “Milky Way” looks like a faint, whitish band with a few dark patches.

Of course, the Sun is really 10 billion times bigger than a grapefruit with a 14 cm diameter. Q1. About how big would planet Earth be on this scale? [ Show size with your hands or an object. for answer.] Assume the Sun is the size of a large grapefruit: A1: About the size of a pencil tip Q2: On this scale, how far away would pencil-tip “Earth” be from the grapefruit “Sun”? A2: About 15 meters (50 ft) away. Pluto would be about ½ mile away. Q3: On this scale, how far away would the nearest star in the Milky Way galaxy be? A3: About 5000 km (3000 miles). The East-West distance across the US!

So in this scale model, the space between the Sun and the NEAREST STAR in the Milky Way galaxy is like having one grapefruit on the Golden Gate bridge in San Francisco, and another grapefruit on the Brooklyn Bridge in New York. Images of spiral galaxies make it seem like stars are crammed closely together, but in reality there are vast distances between them.

Our galaxy is only one of more than 100 billion galaxies in the Universe! All but 4 specks in this “Hubble Deep Field” image are entire galaxies, each of them with 100 billion stars.

Gravity is the attractive force between objects that have mass. This is how moons, rings, planets, and stars form. Earth is one of 8 PLANETS that orbit a STAR we call the SUN [“3 rd rock from the Sun”] The Sun is at the center of the SOLAR SYSTEM and is the ONLY star in the Solar System. Our SUN is one of over 100 billion STARS in the GALAXY we call the Milky Way Our GALAXY is one of over 100 billion galaxies in the UNIVERSE! A. Family of the Sun SUMMARY

Test yourself on “Earth’s Place in Space” by taking a few minutes to play TWO ASTRONOMY GAMES OR Skip ahead to PART B: Meet the Giants

Two Astronomy Games Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

On a sheet of paper, make two columns like the ones below: “Small and Large”“Near and Far” Smallest Largest Closest Farthest Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

Game # 1: RThe next slide will show 9 images ROrder the objects in these images from the smallest object (number 1) to largest object (number 9). Use the first column in the table you created. RWrite the letter as well as the name of the object in the column. This way, you will have a list that you can consult later. Are you ready? Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

A. THE SUN B. EARTHC. SPACE SHUTTLE D. THE MOON E. THE SOLAR SYSTEM G. MARS H. A GALAXYI. JUPITER F. BEARS Press ENTER for a HINT Mars has no oceans and the same LAND area as Earth Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

The Solution Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

7A. THE SUN 5B. EARTH 2C. SPACE SHUTTLE3D. THE MOON 8E. THE SOLAR SYSTEM 1F. BEARS 4G. MARS6I. JUPITER 9H. A GALAXY Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

Game # 2: RThe next slide will show 9 images. ROrder the objects in these images from the object that is nearest to the surface of Earth (number 1) to the object that is farthest from the surface of Earth (number 9). Use the second column in the table you created. RIt would be best to write the letter as well as the name of the object in the column. This way, you will have a list that you can consult later. Are you ready? Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

A. THE SUN B. A GALAXY C. AURORAS D. THE MOON E. JET AIRPLANE F. HUBBLE TELESCOPE G. AN EAGLE H. STARS OF THE BIG DIPPER I. SATURN Auroras occur in Earth’s uppermost atmosphere Stars we see are within the Milky Way galaxy If we see a whole spiral, it can’t be our own galaxy. Saturn is 10 times farther from the Sun than Earth The Space Shuttle can visit Hubble, but not the Moon Press ENTER for HINTS Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

The Solution Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

G. AN EAGLE E. JET AIRPLANE C. AURORAS F. HUBBLE TELESCOPE D. THE MOON A. THE SUN I. SATURN H. STARS OF THE BIG DIPPER B. A GALAXY Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission

These games are available on-line in multiple modalities: 1.As you see it here in PowerPoint 2.As a downloadable card game for the exhibit floor 3.As an on-line interactive 4.As a classroom activity Go to Click on “Traveling Exhibition” then “Education Program” then “Activities” Two Astronomy Games Copyright 2004 Cherilynn Morrow – Used with permission