There's an enormous universe out there with wonders to discover

“The world is full of magical things, waiting only for us to see them.�

— Sidney X. Shore

Cosmology is a study of the universe — all of it. Cosmologists are astronomers who want to know what happened in the past and what will happen in the future. They discover things out in space, draw conclusions, and often change their conclusions as they discover more and more material in space.

How big is our universe? Is it possible that there are more universes? How was our planet formed? How were the other planets formed? What is there up in the sky? How many stars are up there? Who discovered how far away the stars are from Earth? What is a galaxy, and how many of them are there in space? Are there any other planets like our Earth, where living people exist? If these people exist, are their religions similar to those here on Earth?

These were only a few of the questions I used to ask myself. I am beginning to get answers.

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Astronomy started thousands of years ago, when people looked up at the sky and saw dots of light, some flickering and some steady. They started to name the spots based upon religion and fantasy. It was the great Galileo Galilei who constructed the first telescope to view the sky, the stars, the planets, the moon and whatever else he could see up there. He built it and put it to work in the year 1609. His telescope was about 2 inches in diameter and magnified the stellar objects by 13 times. It was nothing like what we have now, and will have in the next 10 years, and far beyond. But for astronomy it was a wonderful breakthrough.

At Galileo’s time, that was a great improvement for seeing whatever was up in the sky. But the planets were still small and the stars never looked any bigger than before. Galaxies were unknown then, looking like tiny smudges of white or color, often referred to as nebulae.

What is a galaxy? It is primarily a collection of stars, some of which are like our sun. Galaxies contain lots of dust and gaseous elements such as hydrogen and helium. Gravitational powers caused the dust to collect, to solidify, and to form the stars, and also the solar systems and the planets. And it takes millions to billions of years for the stars to form.

Galaxies have several shapes, depending upon their size and the length of time it took them to form. Some are spiral in shape like our Milky Way. Some are elliptical, and some are called “irregular� because their shapes vary in many different ways. And some are called lenticular. These are short galaxies, where stellar formation stopped long ago.

All the components of galaxies are held together by the force of gravity, and as time goes by the components of the galaxies close in on themselves. This process takes billions of years.

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Our galaxy was named the Milky Way because of the white dust that formed around the edges of the collection of stars seen in the sky. It has a disk diameter of 100,000 light years. What is a light year? It is the distance that light travels in one year.

Since light travels at the rate of 186,282 miles per second, a light year is a mighty long distance. Multiply 186,282 by 60 and you have the distance light travels in one minute, 11,176,920 miles. Multiply that number by 60 and you have the distance that light travels in one hour, 670,615,200 miles. Multiply that number by 24 and you have the distance that light travels in one day, 16,094,764,800 miles. Multiply that number by 365 and you have the distance that light travels in one year, 5,874,589,152,000 miles!  

When you deal with numbers while exploring distances or sizes or times in our universe, you are dealing with giant amounts. Millions, billions, trillions, quadrillions, quintillions and more. Light travels more than 5 trillion miles in one year.

How many stars are there in the Milky Way? It has been an interesting search over the years, and every year seems to deliver an increase in the number. I remember when the Milky Way was supposed to have “only� 100 million stars. Then the number was raised to 1 billion. Now it has been raised to between 200 billion and 400 billion. Which of those numbers is correct? We really do not know because it is an extremely difficult task to count the numbers of things in space, especially when they are so far away and when there are these super quantities of them.

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I’d like you to look at these numbers again — 100,000 light years in diameter; 200 to 400 billion stars in the galaxy. Astronomy deals with numbers of this size and more. They are certainly not normal or usual in our regular lives. But the numbers are closer to being true than not.  Astronomers have some wonderful tools to check these numbers, and a lot more.

 In the next columns you will learn about the discoveries of astronomers like Charles Messier, Edwin Hubble, the wonderful lady astronomer, Henrietta Swan Leavitt and more. The study of cosmology will go on and on, as long as there is life on our planet. And new things are discovered every year.

(This is the first of a multi-part series on the cosmos. More to follow.)

Sidney X. Shore is a scientist, inventor and educator who lives in Sharon and holds more than 30 U.S. patents.