Today, our journey begins…

Coronal Hole: a low density region extending above the surface of the sun, where the solar magnetic field opens freely into interplanetary space – source locations for the solar wind and coronal mass ejections.

Deinococcus radiodurans: An example of an extremophile Deinococcus radiodurans: An example of an extremophile. This bacteria survives extreme levels of radiation, extreme temperatures, dehydration, & exposure to genotoxic chemicals. They even have the ability to repair their own DNA, usually within 48 hours.

Search for Life in the Universe How do we begin? Define terms and concepts: life universe Define the tools and techniques: Science Scientific method Scientific context of search (how nature works)

What is life? A very difficult question to answer. A variety of definitions have been proposed. We will examine them from various perspectives. We are not limiting ourselves to “intelligent” life

What is the Universe? All the matter and energy that can be detected or that can affect us. A wide range of objects occupy the universe (stars, galaxies, planets, moons, dust, gas, radiation, comets, planetesimals, exotic particles, “dark matter”, energy, …) Some of these are obvious places to search for life, some are not.

The Search for Life in the Universe Foundations of search: Physical laws are universal; nature works the same wherever you are in the universe. Organic molecules (the molecules of life, built around chains of carbon atoms) form naturally and easily in a wide range of physical conditions. Life appeared very early in the Earth’s history. Life is known to exist on Earth under a large range of physical conditions. Similar physical conditions are expected or known to common in the universe.

Images and Concepts: Fundamental connection between the two. Use pictures and images often. Will be stressed in class!

An exercise in observation and analytic thinking…

We will be conducting a scientific inquiry, so… What is science?

Thinking, not memorizing! A primary goal of class Science is a process, not a set of facts!

“Scientific Thinking” a natural part of human behavior. We draw conclusions based on our experiences & knowledge. Progress is made through “trial and error.”

Theory The Nature of Science Science seeks explanations for observed phenomena that rely solely on natural causes. Science progresses through the creation and testing of models of nature that explain the observations as simply as possible. A scientific model must make testable predictions that could force us to revise or abandon the model. Theory -- a model which survives repeated testing

The word “Theory” has a very different meaning in science than in everyday parlance

A model is only referred to as a theory when it has successfully survived testing to such an extent that it is generally accepted as a valid representation of nature. Even then, testing continues…

Theories Must be Testable Must be continuously tested Should be simple

science, nonscience & pseudoscience “Testable” - science, nonscience & pseudoscience Testing separates science from nonscience: e.g., religion is not accessible to experimental verification Testing invalidates pseudosciences: e.g., astrology fails testing.

Astronomy, Biology, Chemistry, Astrobiology, and Physics are SCIENCES. In order to make progress in our search, we need to understand science: what is it and how does it work?

There are many definitions of science There are many definitions of science. They all have in common the view that science encompasses those human endeavors that seek to understand how nature works. The aspect of nature being studied, e.g., the physical world, the biological world, human society and interactions, provides the pronoun we place before science: e.g., physical science, biological science, social science.

Why does the University consider it important for non-science majors to take a course in the physical sciences?

Science attempts to systemized knowledge through: observing (what are the “observed facts”) questioning (framing the question) hypothesizing (knowledge of how nature works) testing (hypothesis makes predictions) Thus, scientific thinking has applications to all fields of human endeavors, not just science.

We’re going to learn how to think as scientists. As you will see, it is really quite simple…

learn to question everything! Over the next few weeks, you (hopefully) will … learn to question everything! Our goal is to teach you to be creative, critical thinkers that question authority, not to groom you to take exams!

learn to question everything! Over the next few weeks, you will … learn to question everything! examine your assumptions and prejudices! be creative, but critical, in your thinking!

In some cases we need to revisit things that we “know” Our “knowledge” can be based upon misinformation or errant assumptions. Never get too wedded to your own “knowledge”, question it as well.

Where do we fit in the universe? Where do we look for life?

“home”

Typical Galaxy: roughly 1011 stars Observable Universe: roughly 1011 galaxies How much is 1011?