Astronomy Series
A Short History Of Astronomy
Ever since mankind began walking upright and moved into a cave he has spent some part of his evenings looking up at the sky. What is all of this? What is it made of? How does it move? All of these questions have bothered early man for thousands of years.
We still study the heavens today from both the earth and from space.
While out in the wilderness somewhere, it is a grand time for us to do the same thing.
It tends to place a little perspective in our lives by realizing how small we really are.
Early Observers
As time went by and mankind advanced into various civilizations more and more watching turned into very methodical observations. Mathematics developed through the centuries and added to the collective knowledge about the heavens.
Much of the early studies were attached to both religion and emotion of the times. Still actual scientific study and notations were made and laid the foundation for all of modern astronomy.
Star charts were drawn up, constellations named and various theories about everything in the visible sky began to develop. Strange stars, now known to be planets, wandered through the night sky.
Their path totally defied the rest of the orderly sky movement. They were known as the "guest stars".
In time, mankind was able to predict events and built great monuments to help note events.
Stonehenge in England noted the exact time of the equinoxes. Various other locations around the world also did this and more.
The Babylonians were able to mathematically state the period of some of the visible planets.
Both the Incas and Mayans also were very active in astronomy and merged it into their cultures. The Mayan culture considered the sun a god and noted its movement constantly.
Aztecs considered every point of light in the heavens to be a divine being with the sun the greatest. They too built fixed observation points in their temples noting the equinoxes and other events.
The famous Aztec calendar has 365 days. It describes the days and rituals related to the seasons. This was an aid to their agricultural year.
The Chinese too developed a strong science. They determined the earth was round, plotted planetary motion and began recording greatly accurate solar observations.
They were the first to note an exploding star, what is called a Super Nova.
Modern astronomers have figured out which one it was and thus were able to know its exact age and the amount of change over a given time.
As agricultural societies developed, the fore knowledge of when to plant became valuable. Great religious practices were also attributed to the heavenly movement. The sun, moon and the stars were all involved in many different cultures religions.
The Egyptians were very involved in this and even aligned their famous pyramids with heavenly bodies. They also integrated much of it into their culture and religion.
The Renaissance
The earliest astronomers all believed that the Earth was the center of the universe with the Sun, the Moon and the stars rotating around it.
This is known as the geocentric model of the universe. From only earth based observation, this is an easy belief to accept. This model persisted until the period of the Renaissance.
Until the 16th century, the standard belief was that everything revolved around the earth.
The stars revolved in an orderly fashion around a single point of light. However, execpt for the North Star they also seemed to change from month to month only to return the next year. And then there were those pesky "Guest Stars" that wandered across the heavens in an apparent strange movement.
Then Nicholas Copernicus developed his theory that the Earth actually revolved around the sun. This theory better explained the movements of the planets, or "Guest Stars". Most learned men of the day accepted this view while the masses still believed in the geocentric model.
Almost a hundred years later both Galileo and Kepler were able to expand on and sometimes corrected the original Copernicus model. The development of the telescope in this time period greatly aided these men in both observing and began new discoveries that continue on today.
Another century would pass by before Sir Isaac Newton came along and through his theories of gravity finally explained the motion of the planets. His theories were also quite accurate and have merely been improved upon through today.
Modern Astronomy
It was in the 20th century that the greatest advance in astral knowledge has occurred. This was through the ability of modern engineering to make very large ground based telescopes for observations into deep space.
It allowed the discovery that here on Earth we live in what is called the "Milky Way" galaxy.
The existence of many other galaxies similar to ours are scattered all over the observable universe.
All types of different stars began to be identified like quasars and pulsars.
Theories of "Black Holes" and explanations of Novas were formulated. The vast expanse of space was being looked at and studied with new enthusiasm and energy. All forms of new theories were developed. Many are still being proved, disproved or modified.
More planets were discovered including that little one, now in dispute, named Pluto. Its orbit around the sun takes 128 earth years so since its discovery in 1928, we have only seen it through about one-quarter of its orbit.
Telescopes
Ground based telescopes are still in wide use and provide great information.
The grand Mount Wilson telescopes in California, one 60 inch and the other 100 inch mirror are still in operation but due to the bright lights that come from the huge urban sprawl below they are not as effective as they once were. Their two solar observatories on the same site are at work every day.
There are campgrounds all over the San Gabriel Mountains that place you within a very short drive to Mt. Wilson. Hiking trails are all over the place. They offer grand views of the local mountains and the Los Angeles basin all the way to the ocean. Visitors are welcome at the Mt. Wilson Observatory at all times.
Mount Palomar in San Diego County brought forth the 200 inch telescope and launched an entire new wave of discovery. There is a campground on Mt. Palomar within walking distance to the observatory and visitors are welcome. It is also a great place to view Meteor Showers.
Today, the world's largest observatories are located on Mauna Kea Peak in Hawaii. Not only are they aided by having no urban light to hamper observations, the surrounding ocean actually stabilizes the atmosphere. The mountain top is extremely dry and there are hardly any clouds to interfere with observations. They get more viewing nights than any other observatory.
There are thirteen working telescopes on the mountain top today with a combined optical strength of fifteen times that of Palomar. Most work with visible light and others work in different wavelengths.
Radio telescopes allowed even deeper penetration into space without looking. A wide variety of objects are observable at radio wavelengths, including supernovae, interstellar gas and pulsars. These telescopes can be either one single dish or a collection of them scattered all over acting as one very big dish.
Space
Today we have several different types of telescopes in space, all in orbit around the Earth. Scientists waited decades for the ability to observe without the earths atmosphere interfering and now they have it.
We have all heard of the great Hubble space telescope and a lot have seen some of the wondrous photographs it has provided the science community.
The Hubble is quite versatile but mostly works in the visible light spectrum, which is the light that we all can see.
The Hubble has now been joined in orbit by the Compton Gamma Ray Observatory, the Chandra X-Ray Observatory and the Spitzer Space Telescope. The Spitzer operates in the infra-red light spectrum.
On the Hubble website they offer quite a collection of photographs. They also make great wallpaper on your computer screen. NASA offers these photographs to anyone who wishes to download them.
I am sure that it will take until the end of the 21st century to unravel some of the discoveries these great space telescopes make. I can hardly wait!