Welcome. In this "book" we explore the vast depths, the tiniest corners, and the enormous ranges of energy in the Universe.
You have some questions, I believe.
-Do I need to already know science to understand this book?
-Will I learn any science?
-Is this a science textbook?
-What is this book???
This book is: solely about one thing - to understand the scale of the Universe, and we do that by building perspective by analogy and comparison to things you already know, and to things you will learn. It is designed such that the layperson, the science enthusiast, and the science professional can enjoy it.
-Do I need to know a lot of math?
No, but those who do like and know math will also be pleased. This book is remarkably un-mathematical considering that its subject matter is The Universe. All you need bring with you is your understanding of everyday life and everyday objects. We will, of course, expand on these.
You will be introduced to Scientific Notation because it is an absolute necessity, but that is nothing more than counting zeroes. Otherwise this book can be read completely without reference to any of the mathematical footnotes or appendices. Whatever your mathematical orientation you may read the book comfortably. Just keep one point paramount in your mind: Have fun.
Some of you may want to learn more about the math used in this book. There is always the Reference page available to help you. There you will find interesting constants, formulas, and a review of math basics with some unit conversion methods thrown in. The things you use / learn there you can use to create your own perspectives if you wish.
And for those who are mathematically inclined, I invite you to join in and compute along with me, checking my work. If you do you may find that your answers do not always match mine. There can be three reasons for this:
1) Some data values are not known exactly, or have been refined over time, and perhaps we are using different values, or...
2) The answers in the body of the text are rounded off for readability. The values I use are found in the appendix reference section with their exact values, or...
3) I could have made a mistake. If anyone finds errors I would greatly appreciate being notified. My email address is in the footer at the bottom. Use the down arrow (to the left) to go there quickly.
-Ok, exactly how do we go about this then?
We use what we know as a starting point to build steps in understanding. We use these relationships to get a grasp of interstellar distances, the distances between stars. Of how the size of the Earth compares to, say, the size of the Solar System. Of how the solar system compares to the Milky Way Galaxy. Of how the galaxy compares to the known Universe...
And...We build understanding of the extraordinarily small. Of how the size of a grape relates to the size of an atom, or the atom’s nucleus. Of the absolute smallest there can be...
And...We gain an understanding of the enormous bubbling sea of Energy all around us. Of the relation of a gnat's flight energy to the lighting of a light bulb. Of the relationship of all the lightening bolts that have ever sizzled on Earth to the output of the Sun’s energy per hour. Of the equivalence of running a marathon and a small TNT explosion...
...so many interesting and dazzling subjects that I can barely wait to get started. As you read, I think you’ll see what I mean.
When contemplating the Universe it is quite easy to become bogged down by the shear immensity of it. The nearest star to us (aside from the Sun) is 40 trillion kilometers away (24.8 trillion miles). This huge distance means nothing to most people: How far is 40 trillion kilometers? Few people have a “feeling” for such an immense distance, but after you read the chapter “A Million Things to do” you might discover that you understand this distance a bit more.
When you then discovered that this distance -- 40 trillion kilometers -- is microscopic compared with the overall size of the Universe (hundreds of billion trillion kilometers) we run into a mental “wall” and the mind ceases to comprehend.
Our confused brains have no handy comparisons to make and so are powerless to understand. At this point further discussion of this immense distance loses any meaning.
Or take the size of bacteria. At around 2 millionths of a meter, it is a giant compared to an atom, about 10,000 times bigger. The same relation as a football pitch to a pearl.
Or compare the amount of energy from a “small” nuclear explosion like Hiroshima with the heat given off from 25,000 people in year and we find them having the same energy output.
The mind boggles. However, I believe it is possible to get a “feeling” of the sizes, quantities, and distances of the almost limitless space and energy contained in the known Universe. Through comparison and analogy an understanding can be gained, and it will soon become apparent that these quantities are graspable. And while this still doesn’t mean you’ll “understand” a distance like 40 trillion kilometers, nobody truly does or truly can, but we can appreciate these distances and have a “feel” for them.
For instance, having lived for a while you are familiar with the length of a year. You have a “feel” for a year. Most readers will have lived at least several decades. Now most of us will never “understand” a millenium (1000 years) in the sense of living and experiencing that entire length of time, but with the sense of a year and a decade we grasp the concept of a century and from that a millenium.
By relating to things we are familiar with our sense of wonder we have concerning the Universe will increase a thousandfold. I promise that you will find that your mind will not butt against some invisible mental wall.
Prepare yourself for the journey of your life. In the web pages that follow you will fly to the furthest reaches of the Universe, peer inside atoms, investigate stars, peek into and contemplate the vast, cold emptiness of space, and bathe in the enormous sea of energy bubbling all about you.
Everything you need to know to understand a section is presented as needed. There is a need, however, to read the book in order, at least on the first reading, since some of the information presented earlier is used later. And in particular the first three chapters present the basic knowledge needed to understand this book.
At points throughout the book I give you opportunities to skip sections you may already know. All of these are clearly indicated with links to use.
While new knowledge will certainly be gained, the book is written with an eye towards entertainment and mental stimulation not instruction. However, it will be necessary to discuss some background here and there so that you can understand the relationships we will be forging. In order to understand the Universe we need to discuss aspects of energy, chemistry, and astrophysics. These subjects are by no means examined exhaustively. Just enough is presented to gain the primary objective: understanding of the scale involved and a “grasping” of the Universal perspective.
We will be working with distances, weights, quantities, volumes, and more. These will be presented in metric units since the language of science is metric in nature, for the most part, and since it is a simpler system to understand. English units will also be provided at select points to help people familiar with those units ease into the metric world.
There is much more to the story I tell here. These details are described abundantly in many popular science and semi-technical books (see the extensive Reference Page and in the Bibliography, both of these links will open in a new tab/window). But here the objective is to understand what science has discovered not how it has discovered it, and to give you some mental yardsticks to use.
We begin the journey shortly. Following immediately here is a brief summary of the methods of science and how we can know what we think we know. If you are already familiar with the Scientific Method and scientific philosophy feel free to go on to the first chapter.
Focus : A Method to the Madness
What is science? It is curiosity. The urge to know, coupled with the will to find out.
Why is the sky blue? How does a tree grow? How does the eye see? What is a shooting star? Why, when we fall, do we fall down and not up?
Everyone at one time or another wonders about things like this. The scientist goes about finding the answers to such questions using what is called the scientific method. Trying to make sense out of the innumerable natural phenomena surrounding us is a daunting task and the development of the scientific method made the process simpler and more foolproof.
In its basic form the scientific method requires:
1) an hypothesis
2) a controlled experiment
The hypothesis is simply a question generally designed and asked in such a way that it can be answered yes or no.
The associated experiment is then designed to provide the answer to the specific question posed. Key is that the experiment is “controlled”; that is, it is designed to rule out all (or as many as possible) potential errors or misleading results (see the discussion of Redi below). Or, put another way, the experiment will be designed to isolate the phenomenon in question and find its basic, underlying causes.
The element of reproducibility simply means that if the conclusion drawn from the experiment is true it should be true for all scientists everywhere. And any scientist should be able to repeat (reproduce) the experiment and come up with the same results.
The hypothesis posed is answered by the scientist with an educated guess about the possible outcome. It is determined on completion of the experiment whether the hypothesis, and the guessed answer, was correct or incorrect. But in either case another fact has been determined. And another small piece of the “truth”, so far as “truth” can be known, has been found.
Classic experiments, meaning experiments done with good controls and inescapable conclusions, have changed our world view for centuries now. An Italian scientist named Francesco Redi performed a classic experiment several centuries ago that changed a world view.
In those times people believed that insects, worms and such were spontaneously created from garbage. It was a known “fact”, dating from the times of Aristotle, that flies formed spontaneously from rotting meat because only as the meat was rotting could the people see the young flies, or maggots.
Redi believed otherwise. He believed that flies could only come from other flies, just as cats from cats, or horses from horses, or, more generally, that life could only come from existing life. This was his hypothesis. And he devised an experiment to prove it.
He obtained eight jars and put an equal amount of fresh and varied types of meat in each of them. Four of the jars he left open to the air, and the other four were covered with Muslin, a fine meshed cloth. The experiment was “controlled” in that everything was the same except that four jars were screened off. The varied meats were paired off: each variety was put on an open to the air jar, and the other in a covered jar.
His hypothesis was that maggots would only be found in the open to the air jars where flies could freely enter. The covered jars allowed air in but not flies. His hypothesis was seen to be correct. The outcome of the experiment was that maggots only appeared on the meat in the uncovered, completely open jars. The meat in the covered jars also rotted but no maggots were found on the meat.
And by this Redi proved that flies lay eggs, just as chickens and turtles do, and in order to do so must land on, and touch, the meat. This outcome certainly changed the perspective of the people of that time and of future scientists who embraced the carefully controlled scientific method.
Science looks for verifiable, and consistent, causes and relationships. By isolating phenomena and performing experiments the scientist roots out underlying elements. Each of these elements is a “fact.” From thousands of experiments all the elements are collected together in a consistent, verifiable, whole called the “truth.” But this “truth” is constantly changing and in flux as new facts are discovered, or new theories better explain natural phenomena.
Scientists have been able to determine Universal laws that do dictate the behaviour of things as different as receding ambulance sirens and receding galaxies; a floating log and moving continents; a falling apple and the course of the Moon; a beam of light and the structure, and possible fate, of the entire Universe.
We will investigate these relationships and more. But, just as science itself is a slow progression, we must progress by steps. We must begin at the beginning, building on our knowledge all the while.
Facts are fragile things. Today they can be true, and tomorrow false. Another aspect of the scientific method is the willingness to give up our favourite “facts” when a good experiment shows the “fact” to be false after all.
The facts presented in this book are part of a spectrum. Some of them are so well established that there is minimal probability that they will change. Other “facts” are somewhat less certain and are held as “working values” while they have use and have not been found to be false. Finally, some of the facts in this book are on the cutting edge of knowledge and will certainly be modified and updated as new information through experiment is found, or tossed away and replaced when something is found that better explains the phenomena in question.
This is why the frontiers of science and knowledge can be so exciting -- people are forging new truths or debunking old myths each day! It is through reproducible, verifiable experiments that facts are changed.
The Astronomer and the Astrophysicist, the types of scientist who study the Universe beyond our air atmosphere, are at a disadvantage here. They cannot create a Sun in the laboratory and experiment with it. They cannot sample a star and analyse it. They cannot send a survey crew out to the edge of the known Universe to measure it.
How then can we know very much about the Universe? No one has journeyed away from the Earth farther than the Moon and yet we pretend to understand how stars work, how many there are, and their distance from us.
This knowledge is gathered from inference from things we know to be “true,” in the scientific sense of truth, and by using every deductive and observational trick we have.
Our inferences are considered to be true because of a fundamental assumption of science. This assumption is that what we can find to be true in laboratories on Earth will be true throughout the Universe. In other words, it is assumed that physics and chemistry operate on the same principles everywhere in the Universe. We gather knowledge of our Sun and use it to understand and estimate how other suns behave.
The astrophysicists can’t take a sample of the Sun but they can examine its light which tells an amazing amount of information. Using these, and other, observational methods, together with theory from physics, allows scientists to extend their knowledge.
Of course, none of this is taken for granted. Every scientific idea is subject to dispute and must be defended and proved. And every scientist has the duty to be critical of experimental, or theoretical, results and to expect honesty and accuracy to be associated with any claim of discovery.
Scientists also use mathematical models and logic to deduce the working principles of the Universe. The highest quality possible is ensured by submitting these models to very rigorous criticism from other scientists. Even though the modelling guesses scientists make are very educated, and probably mostly correct, there will be scientists who gain deeper insights providing more accurate thoughts, explanations, and experiments who will thereby change our perspective and alter our “truth.”
And with that it is time to move on to Chapter 1.