Introduction to Astronomy

Science in General

Chapter index in this window — — Chapter index in separate window

This material (including images) is copyrighted!. See my copyright notice for fair use practices.

Scientific knowledge is based on observations of nature. From observations of many different events and situations, scientists try to find patterns and create generalizations as to the underlying fundamental processes involved. Then they experiment again to see if the right guess was made of what the rule is that nature follows under a given situation. Experiments determine scientific truth. The scientist usually learns about nature by using controlled experiments in which only one thing at a time is varied to determine whether or not a particular situation, feature, or circumstance can be determined to be the cause of an observed effect. The experiments can be repeated by anyone as many times as they want to verify that the effect is reproducible. The astronomer cannot do controlled experiments. They cannot even examine things from a variety of angles. What astronomers do is collect light and other radiation from celestial objects and use all of their information and creativity to interpret the signals from afar. They look for the experiments nature has set up for us and hone on a few basic characteristics at a time.

Scientific Models and Scientific Theories

Scientists will create models (simplified views of reality) to help them focus on the basic fundamental processes. In this context a model is an abstract construct or idea that is a simplified view of reality, not something made out of paper, wood, or plastic (or some good-looking person). "Theory" in the scientific use of the word is different than the everyday language usage today. Most people today use "theory" as just a hunch, guess, belief, or proposal. Science uses the original meaning of "theory": a logical, systematic set of principles or explanation that has been verified—has stood up against attempts to prove it false. Scientific models and theories must make testable predictions. Like any scientist, the astronomer makes observations, which suggest hypotheses. These speculations are made into predictions of what may be observed under slightly different observing and/or analysis circumstances. The astronomer returns to the telescope to see if the predictions pan out or if some revision needs to be made in the theory. Theory and observation play off each other.

Often the evidence for a particular hypothesis is indirect and will actually support other hypotheses as well. The goal is to make an observation that conclusively disproves one or more of the competing theories. Currently unresolvable questions may be resolved later with improved observations using more sophisticated/accurate equipment. Sometimes new equipment shows that previously accepted theories/hypotheses are wrong!

Scientific models and theories must make testable predictions. If an explanation is offered that has no concrete test that could disprove the explanation in principle, it is not a scientific one. This characteristic of scientific explanations is often the distinguishing one between scientific and other types of theories or beliefs (religious, astrological, conventional wisdom, etc.). Do understand that a scientific theory can be incorrect but still be considered a good scientific theory because it makes a testable prediction of what will happen under a given set of observing or analysis circumstances.

Go back to previous section -- Go to next section

Go to Astronomy Notes home

last updated: November 26, 2021

Is this page a copy of Strobel's Astronomy Notes?

Author of original content: Nick Strobel