Last Update: 8-5-2004

NOTE:  None of the images displayed on this web page were taken by CCAS members.
All photos were taken by professional astronomical observatories around, and above, the Earth.

It's time for the biggest adventure of all time !

You get up in the morning, leave the comfort of your home and drive across town.  One day you drive across your state. Then the big day comes for you to drive across the immense United States, taking a number of days to make the long, tiring trip. Eventually you become very mobile and make the airplane trip of a lifetime, venturing to a another country on the other side of the Earth.  Without realizing it, in your mind you see your state, our nation and our Earth as being huge in size with people living spread out across many hundreds and thousands of miles.  You generally think of the Earth as being the biggest thing that you know of.  But is the Earth really so BIG?

Buckle Your Seatbelt !    Hold On To Your Hat !

Your frame of reference is about to make a tremendous change, a change so immense that your view of life, your knowledge of where we live and your imagination will be strained to their limits.  Suddenly you become very aware of the tiny part the Earth plays in the awesome immensity of the Universe.

This is the point where energizing music can play a huge part.  Exciting, bold, in-your-face music feeds your mind and soul with energy, creating a wonderful experience when combined with studying space exploration.  One recommended piece of orchestral music is "Godspeed!" by Stephen Melillo.  This music, and those by other outstanding directors, such as John Williams, are an integral part of life.    Now, to continue with our tour ............... 

One crystal clear night you decide to gaze upwards to look at the many points of light in the night sky.  Just a bunch of little white dots that make the night sky interesting to look at from here on Earth.  An astronomer just happens to be nearby in the darkness using a telescope.  He or she introduces you to what is "really" out among those "stars".  Once you have seen some of the objects in deep space, learn what they are and how far away they are, your mental view of our Earth quickly makes a major change.  Your imagination jumps into high gear as you start to learn about the Universe in which our Earth spins.  When you go to bed very late that night (or very early the next morning), you can't sleep because of what you have just experienced.  Visual and mental overload.

Welcome to the dark world of astronomy.  Astronomers spend many nights each year peering into the darkness of space through telescopes.  They look at many objects, but there are really just a small number of types of objects they study.  Here is a brief explanation of the basic composition of the Universe which is the foundation of astronomer's work.

Note about Images:  If you would like to see a larger image of each of the thumbnail photos below, just click on that image.  It may take a number of seconds for the larger image to open due to its larger file size.  If you wish to obtain information about a photo's subject, click on the links beneath each photo.

Note about Celestial Distances:  Much of astronomy is far from being precise.  Because of our limited technical capabilities and the vast cosmic distances to celestial objects, you may find differing figures for the distance of objects from the Earth.  Suffice it to say that astronomers do their best to approximate celestial distances.

The Universe is EVERYTHING that humans know of.  But there is an unbelievable amount yet to learn.  We have yet to find the "edge" (or end) of the Universe, being many billions of light-years away.  We have no idea where the edges might be, where the Universe ends, if there is an end to it.  Given our limited technological capabilities, the Universe is still too vast for us to see all of it or understand it all.  There are many theories about the creation of the Universe and how it operates.  These theories are continually being scrutinized, challenged and modified as we obtain increased knowledge about what is out there.

Planet Earth is located in a Solar System with the Sun being at the center of the orbits of nine planets.  In order outwards from the Sun are the planet's Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.  It is extremely important for you to understand that our Sun is the only object in our Solar System that gives off light.  The reason you can "see" our nine planets, either by your naked eye, or through telescopes, or, the reason they "give off light", is because that light is a reflection of the light coming from our Sun.  The image below is not to scale as the Sun is tremendous in size and the planets orbit at extreme distances from the Sun.

Click on the photo below for a larger image, a different view of our planets.

For quick data about the Universe and our Solar System, see CCAS Cosmic Facts

APOD: Portrait of the Solar System

Our solar system consists of the Sun, nine planets, over sixty moons, and a large number of comets and asteroids.  The inner solar system consists of the Sun, Mercury, Venus, Earth and Mars.  The outer solar system consists of  Jupiter, Saturn, Uranus, Neptune and Pluto.  For an excellent, more detailed explanation of the Solar System, see The Nine Planets.  If you wish to get a quicker overview of the Solar System, see The Nine Planets: Overview of the Solar System.   Another nice overview of our Solar System is Sea & Sky's Tour of the Solar System.

Click on each photo for a larger image.
Click on the links below each photo for information about that object.

TNP = The Nine Planets
HST = Hubble Space Telescope
APOD = Astronomy Picture of the Day
ESO = European Southern Observatory
SEDS = Students for the Exploration and Development of Space

Hubble Space Telescope Science Institute: Solar System

Note: The photo of Pluto is the best we presently have with the best equipment we have.
Pluto is the only planet not yet being directly visited by a space probe.
Plans are being developed to eventually send such a probe.

When looking into the night sky through a telescope, the objects that you see can be categorized into two categories, those that are inside the Milky Way Galaxy and those that are outside of the Milky Way Galaxy.  As explained further below, basically only other galaxies lie outside of our Milky Way.  But, within our Milky Way Galaxy are a number of different types of objects which can be seen using a telescope.  These are some of the primary targets of amateur astronomer telescopes besides other galaxies.  Aside from the Sun, planets and moons of our Solar System, and distant suns (stars) beyond our Solar System, there are some very beautiful objects to see that are located throughout any galaxy. These include star clusters and nebulae.  For an overview of stars, see Sea & Sky - Stars.

Click on the Milky Way Galaxy for a larger image and information.

Milky Way Galaxy
APOD-1   APOD-2

Star clusters, a very popular target for star party viewing, are very large groupings of stars in close proximity to each other.  Some star clusters contain as few as 30 or 40 stars, some hold hundreds of thousands of stars and some contain upwards of a million stars!  For an overview of star clusters, see Sea & Sky - Star Clusters.

Click on each photo for a larger image.
Click on the links below each photo for information about that object.

LY = Light-Year (6 trillion miles)

Hubble Space Telescope Science Institute: Star Clusters

Without a doubt, some of the most beautiful and stunning objects that exist in space are nebulae.  In reality, the grand beauty of nebulae can only be displayed by photography, not visually through a telescope.  Some of the most beautiful photo images have been captured by the Hubble Space Telescope, other orbiting telescopes and large ground based telescopes using photographic processes, special equipment and filters.  The use of film and electronic cameras dramatically captures colors and compositions that are not visible through telescopes because of the limitations of our eyes.  Our eyes only see a narrow range of colors and we can't see the various types of gases that are part of nebulae.  It is truly amazing what astrophotography has done for the world of astronomy.  Be prepared for the absolutely stunning images below.

In general, there are two categories of nebulae ... those resulting from the death of a star and those that represent star birth.  In general, a common way for a star (a sun) to die is for it to cool, expand and explode, throwing off layers of material and gas thousands of light-years into space.  In doing so, there are large amounts of material and gases that are expelled in wonderfully beautiful colors and shapes. The word nebulae is from Latin meaning "mist" or "cloud".  Nebulae that are dying stars are called Planetary Nebulae because many years ago astronomers thought they were seeing planets in the nebulae.

Nebulae are also the nurseries of star birth.  Stars, like our Sun, are born through the process of the collection of gases and material into a large mass that eventually becomes so hot as to become a sun.  Regarding the objects displayed below, these are NOT small in physical size in space.  Many of them span thousands or millions of light-years across.  But, they are so tiny in our amateur telescopes because they are at such great distances from Earth.  For an overview of nebulae, see Sea & Sky - Nebulae.

Here is a sample of the magnificent gems of our Milky Way Galaxy

Click on each photo for a larger image.
Click on the links below each photo for information about that object.

LY = Light-Year (6 trillion miles)

Hubble Space Telescope Science Institute: Nebulae

Our Solar System is located in the Milky Way Galaxy which is just an average galaxy in the Universe which contains hundreds of billions of galaxies.  Our Milky Way Galaxy is approximately 100,000 light-years across and roughly 7,000 light-years thick at the center bulge.  A light-year is the distance it takes for light to travel in one year traveling at 186,000 miles per second (like circling the Earth seven times a second) (or 670,000 miles per hour), approximately 6 trillion miles in one year.  The Milky Way Galaxy looks like many other galaxies in the Universe, being a Spiral Galaxy having "arms" that twist around the center bulge.  Some of the largest galaxies are three times larger than the Milky Way.  Some galaxies exist alone and others are part of clusters of galaxies.  Scientists theorize that black holes are at the heart of galaxies.  Our Solar System is located about 2/3 the way out from the center bulge in one of these arms.  For an overview of galaxies, see Sea & Sky - Galaxies.

Click on each photo for a larger image.
Click on the links below each photo for information about that object.

These are just a few of the hundreds of billions of galaxies
that lie far beyond our Milky Way Galaxy

LY = Light-Year (6 trillion miles)

Other APOD Galaxy Links:   Waves of Galaxies     Three Galaxies in Draco

Hubble Space Telescope Science Institute:  Nearby Galaxies

Click on each photo for a larger image.
Click on the links below each photo for information about that object.

Hubble Space Telescope Science Institute: Distant Galaxies

When you look up at the clear night sky, you generally see a maximum of about 3,000 stars from your half-side of the Earth, so around the entire Earth people can see a total of about 6,000 stars with unaided eyes.  Our Sun, being about 4.5 billion years old and about 109 times the size of Earth, is an average star.  Other stars can be larger or smaller than our Sun, some being larger than our entire Solar System.  When looking at the night sky using only your unaided eyes, with the exception of other galaxies that can generally only be seen through telescopes, all of those points of light in the sky are other stars, nothing else.  In other words, they are all other suns!  Not only that, with the exception of the other galaxies, all of the stars you see, including those through telescopes, are ALL within our Milky Way Galaxy, no matter where you stand on Earth.

Knowing that all of the stars are other suns, this means that our Solar System is not the only solar system in the Milky Way Galaxy.  It is estimated that there are from 200 billion to 400 billion stars (suns) in our Milky Way Galaxy, many of which could be other solar systems.  As of mid-2001, astronomers had discovered about 60 planets (described as extrasolar planets) orbiting other distant stars (suns).  Therefore, is Earth the only planet having life in the Milky Way Galaxy or in the Universe?  As of mid-2001, nobody knows.  That is one of the key areas of research that astronomers and scientists are involved in, attempting to discover life beyond the Earth.  That is the business of SETI, the Search for Extra Terrestrial Intelligence. 

Reality Check - Space Travel Times:  The common unit of distance used in presentations on astronomy and space travel is the light-year, 6 trillion miles, the time it takes light to travel in one year.  As you may have realized in studying the images above of our planets, star clusters, nebulae and galaxies, traveling at the incredibly fast speed of light would take spacecraft hundreds or thousands or millions of years to reach those objects.  Obviously this presents mankind with an unbelievably monumental challenge of how we hope to perform deep-space travel in the future.  At the present speed of our spacecraft, in the range of 17,000 miles per hour, travel to other planets and beyond is currently unrealistic, taking far too many years for a crew of humans to endure.  But, as a major step to space exploration, we are pondering a manned mission to Mars around the year 2025 or later.  So, seeing the past (and the future?) through our telescopes is all that we will realistically be able to do for many years to come until we develop means to travel at far greater speeds than is presently possible.  This is mankind's most profound hurdle in its exploration of space, to "Boldly Go Where No Man Has Gone Before".

This concludes our brief Tour of the Universe.  Thank you for joining us on this short trip around the cosmos.  We hope you have found this to be a good starting point for learning more about astronomy and what is in the night sky.  Several excellent sources of astro photos and information are:

Astronomy Picture of the Day
Hubble Space Telescope Science Institute
University of Alabama Messier Picture Gallery
SEDS Messier Object Gallery
Sea & Sky's Cosmic Wonders

Selected Spectacular Photos from the Hubble Space Telescope

Enjoy!

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