Cosmic Odyssey Script
The Beginning
Early Man
Long before any written language or agriculture or cities and towns, humans have been looking up at the sky in wonder. What is out there? Why is it out there? How far away are these things we see?
Stories & Patterns
First, they tried to remember the locations of the stars as they appeared to slowly move across the night sky. This was hard to do but every culture did it and they all used the same trick, they imagined the stars were in groups which we call constellations.
Mysteries of the Sun Moon & Stars
Native Americans used the stars as a basis for a rich storytelling tradition. Polynesians used their named constellations to navigate across the Pacific. People also noticed that some stars did not move with the others but instead wandered across the sky. The word wanderer in Greek is …..planet. Along with the stars, people understood the phases of the moon and the seasonal changes to the angle of the sun. They applied all this to their religions as well as used it to determine when to plant and harvest their crops.
Early Astronomers
From Myths to Measurements
Nearly 2000 years ago the Alexandrian astronomer Ptolemy set up a model of the solar system with the Earth as the center, and the Sun, planets and stars moving around the Earth. 1500 years later the Polish astronomer Nicolaus Copernicus proposed a new model of the solar system in which the Earth revolved around the Sun. For nearly a hundred years, people ignored Copernicus and his crazy idea that the Earth moves.
Later Astronomers
Introduction to the telescope
In 17th century Italy, Galileo constructed a telescope, pointed it up at the night sky and told people what he saw. He saw moons circling Jupiter. He saw that Venus had phases, just as the moon does, which proved it revolves around the Sun. These ideas were so unpopular at the time that Galileo spent the last nine years of his life under house arrest. Then a German astronomer named Johannes Kepler realized the shape of the planets’ orbit was not a circle but an ellipse. That was the final piece of the puzzle on how the planets moved. As astronomers looked closer at the sky with better telescopes they noticed things that were neither planets nor stars. They called these nebulae which means cloud or fog.
Twentieth Century
In the early 1900’s Henrietta Levitt at the Harvard Observatory received little credit for her research on variable stars called Cephieds. But then Harlow Shapley and Edwin Hubble used her discovery to estimate the size of our Milky Way galaxy and realized many of these nebulae were in fact other galaxies far outside our own.
Then Hubble, looking at the colors of the stars, came to the startling conclusion that nearly all the galaxies are moving apart from each other. If all the galaxies are moving away from each other, then long ago they all must have been very close. Fred Hoyle, thought this was so ridiculous he referred to it as the “Big Bang” and the name stuck. In 1964 Arno Penzius and Robert Wilson were looking for other celestial objects with a giant metal telescope and no matter where they pointed it they kept seeing the same thing. They finally realized that what they were seeing were echoes of the BIg Bang.
Telescopes
Since Galileo’s time, telescopes have gotten bigger and better. Some modern telescopes on Earth have lenses nearly as big as the stage you are standing on and have been placed on the tops of mountains to get a better view. Some telescopes are as large as a valley and look at very long wavelengths of light. Other telescopes have been launched at various planets to get closeup views. The Hubble Space Telescope is orbiting the Earth and the newer James Webb Space Telescope is much further from us and orbiting the Sun along with the Earth
Exporing the Solar System
The Sun
We begin our exploration of the Cosmos with our Sun. It is a giant gas ball made up of mostly Hydrogen and Helium with an immense gravitational pull. That gravity means the Hydrogen and Helium are squeezed together so hard in the center that energy is released, lighting up the Sun. The photosphere, or top layer of the sun, looks grainy and appears to be constantly bubbling up from below. Sometimes a solar flare can erupt high above the surface.
The Sun, on to Mercury
As we leave our Sun to explore the rest of the solar system we encounter the first of the inner 4 rocky planets… Mercury. It is the smallest planet, only about 1 and a half times larger than our moon
Mercury
Mercury’s daytime side is very hot but the nighttime side is quite cold. With the proper equipment you could land on the nighttime side and survive. But don’t plan to stay in one spot for very long because….in just 1 to 2 Earth months you would be rotated into the hot sunshine.
Venus
The second planet is Venus. Other than the Moon, Venus is often the brightest object in our night sky. Covered in a thick atmosphere of heat trapping carbon dioxide gas, the surface temperatures can be over 800 degrees.
Venus, The Surface
Until recently we had no view of the surface of Venus, but now through radar imaging we can observe its fascinating rocky landscape.
Earth Moon System
We now soar towards our own home, the third planet from the sun, Earth. Special in many ways, possibly the most important feature of Earth’s location is that its perfect placement allows the existance of water as a liquid on the surface. Earth is now the only body in our solar system with liquid water on the surface. We believe liquid water is essential for the development of life as we know it.
Earth Images
These images of Earth showcase it’s beauty as a planet.Earth to Moon Transition
How did we get our large Moon? Not all planets have similar sized moons. The most likely explanation is that early in Earth’s history our planet was hit by an object nearly as big as Mars. Some people refer to this as “The Big Splat”. Debris was thrown into space and some of that debris was pulled together by gravity to form the Moon.
Man on the Moon
In the early 1960’s President John F Kennedy explained why we needed to go to the Moon. Audio clip of JFK speech . He did not survive to see his dream come true but in 1969 astronaut Neil Armstrong became the first human to set foot on the moon as part of the Apollo 11 mission. Audio clip of Neil Armstrong.
On to Mars
We now soar from the earth’s moon to Mars. Other than our moon, Mars is the most explored heavenly body in our solar system. As we speed towards the surface of Mars we pass its small inner moon Phobos.
Mars
Mars has been viewed in many different ways for centuries from simple eyesight to sophisticated telescopes. Our best images now come from spacecraft that orbit Mars as well as numerous robotic missions which have landed on Mars.
Mars on the Surface
While what we see are images of a dry barren surface, this is not what Mars always looked like. Earlier in the history of our solar system we know that Mars had liquid water on its surface and a thicker atmosphere. Some people believe life forms could have survived on Mars several billion years ago. Searching for evidence of that past microscopic life is the focus of many of the space missions we have sent to Mars.
Ceres and the Asteroid Belt
As we move past Mars we next encounter the wonder of the asteroid belt. Here, there are over one million large asteroids in an area so big it is still mostly empty space. The largest asteroid is the dwarf planet Ceres, which is so large gravity has forced it into the shape of a sphere.
Jupiter and Moons
Having successfully passed through the stunning display of asteroids, we have now reached the first and biggest of our gas giants. The colorful planet Jupiter is an enormous ball of gas, on its surface a storm, called the great red spot, has lasted for centuries with winds approaching 900 miles per hour. If you landed on Jupiter its enormous gravity would rapidly pull you into its depths. Jupiter’s four large moons, first discovered by Galileo, can be vividly seen here from the Voyager spacecrast. First is Ganymede…a moon larger than the planet Mercury. Then Calisto, whose surface is the oldest and most heavily cratered object in the Solar System. Next is Europa, covered with an ice crust with liquid water underneath. If there are other life forms in our Solar System, Europa would be the place to look. Finally there is Io, a moon with over 400 active volcanoes.
Saturn Rings and Moons
Saturn is the second gas giant with its famous rings composed of rock and ice. Saturn’s largest moon is Titan. Here, with its low gravity and thick atmosphere, if you strapped wings on your arms you could fly through the air — a magical experience many humans have dreamed about.
Uranus and Moons
Uranus is one of the strangest planets. Another gas giant with many moons and rings … but it rotates on an unusual horizontal plane … as if something knocked it on its side.
Neptune and Moons
The fourth and final gas giant is beautiful blue Neptune where clouds of frozen methane can blow at over 1000 miles per hour. Along with Neptune we see it’s largest moon, Triton.
Pluto and Charon
When I was a child, Pluto was the ninth planet. Then other equally large objects were discovered in the area we now call the Kuiper Belt. All of these large objects including Pluto are now called dwarf planets. Pluto has a remarkably large moon Charon. It is so large that Pluto and Charon can be better thought of as two dwarf planets revolving around each other. Our best images of Pluto, Charon and the other small moons of Pluto come from the New Horizons spacecraft which flew past Pluto in 2015.
Other Kuiper Belt Objects
There are a number of other Kuiper Belt objects including the dwarf planets Eris, Makemake and Haumea. The only one we have been able to see clearly is the double potato shaped Arrokoth which was observed by the New Horizons spacecraft as it flew past
Passing Voyager
As we approach Voyager 1 we can see its antenna pointed back towards Earth. This spacecraft was launched nearly 50 years ago. It has gone farther than any other man made object and in 2024 was still transmitting data. Each piece of data travels at the speed of light and takes nearly a day to get to Earth. Most of the pictures you saw of Jupiter, Saturn, Uranus and Neptune were taken by Voyager 1 or it’s sister, Voyager 2. As we pull up alongside Voyager we are traveling at a speed of 10 miles per……second. And Voyager carries a special gift — a record containing pictures, music, sounds…..a greeting from planet Earth, intended for whoever may find it in the future.
Comets and the Oort Cloud
And on we travel … far from our home but still in our solar system. We are in the land of billions of rocky, icy objects called the Oort Cloud. They happily remain here slowly revolving around the Sun. On rare occasions one gets jostled a bit and begins to fall towards the Sun. When this dirty snowball gets close to the Sun it produces a spectacular show that can be seen in our night sky…a comet.
The Milky Way Galaxy
Stars, double and triple
As we leave the solar system behind we see countless stars in what we call the Milky Way. While at a distance they each look like single stars, if we could get closer we would see that many of them are actually double or triple star systems. These are stars held together by gravity and revolve around each other. Recent discoveries have shown planets are common thus most of these stars have planets
Globular Clusters
As we look through our Milky Way we see many large clumps of stars held together by gravity. These groups are called globular clusters. They can contain a million older stars.
New Stars and Solar Systems
Not all stars are as old as those in the Globular clusters. Many newer star groups have been observed. The Pleiades may be the most famous.
Formation of Stars
If there are young stars, they must have been born. Let’s go visit a stellar nursery in an area seen as just below the belt in the constellation Orion. This is called the Orion Nebula and it is one of many places in our galaxy where gravity pulls gas and dust together to form new stars.
Remnants of old Stars
Do stars last forever? The answer is no. They can expand and contract and usually just burn out. But sometimes the end of a large star can be a spectacular explosion called a Nova. These Novas are the source of many of the atoms in our bodies. In this way, we are from the stars.
Beyond the Milky Way
Andromeda
Leaving the Milky Way, we encounter the large galaxy Andromeda. It is a spiral galaxy similar to our Milky Way. In our Milky Way, you would find the Sun and Earth far out towards the end of one of the spiral arms.
Shapes of other Galaxies
Galaxies come in many different shapes other than spirals. Each of these galaxies may contain 100 billion or more stars.
Interacting Galaxies
There are so many galaxies that sometimes they hit each other. But there is so much empty space between the stars that the stars themselves rarely collide. However, gravity can twist and pull these celestial bodies, changing the shape of the galaxies.
Deep Space Field
Here is one of the most famous images of galaxies called the Hubble Deep Space Field. The telescope was pointed at a tiny dark area of the sky where they expected to see very little. After taking a very long exposure, this is what they saw. Each of those fuzzy spots is an entire galaxy containing billions of stars. We live in a Universe with an almost unimaginably vast number of stars.
Black Holes
You have probably heard of black holes, but what are they? These are such massive objects with so much gravity that no light can escape, so they look black making them very difficult for astronomers to see. Here is an image of the edge of a black hole that is in another galaxy in Virgo. Along the edge, some light and particles miss being captured and can be seen in this image. This black hole has a mass as large as 6 billion of our Suns.
Ending
Profusion of Stars to Life on Earth
As our journey through the cosmos draws to a close, we bring our thoughts back to the precious blue gem we call home. Unique among planets in our solar system for its singular features, including the liquid water that creates its blue aura and makes our very life possible, Earth has an etheral beauty that reflects and sustains its broad diversity of life. Perhaps our planet is just a tiny part of the Milky Way and the dark skies around it but it is everything to us. Earth is a gem indeed, a treasure to be cherished and protected for a future we can only imagine in a universe we continue to explore.
