ASTR101 Textbook Notes .docx - Week 1 (August 28 -...

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Week 1(August 28 - September 3): A BeginningText(OpenStar Astronomy) -Sections 1.0-1.5Introduction, The Nature ofAstronomy, The Nature of Science, The Laws of Nature, Numbers inAstronomy, & Consequences of Light Travel Time.(Chapter 1: Science and the Universe: A Brief Tour)1.0 IntroductionStars are the fundamental building blocks of the universe, decoding themessage of starlight has been a central challenge and triumph of modernastronomy. By the time you finish reading this text, you will know how toread that message and how to understand what it is telling us.1.1 The Nature of AstronomyAstronomy:the study of the objects that lie beyond Earth and theprocesses by which these objects interact with one another.-Humanity’s attempt to organize what we learn into a clear history ofthe universe, from the instant of its birth in the Big Bang to the presentmoment.Emphasis thatScienceis aProgress Report:one that changesconstantly as new techniques and instruments allow us to probe moredeeply.Cosmosevolve:considering the history of our universe, cosmoschange in profound ways over time.1.2 The Nature of ScienceThe ultimate judge in science:always what nature itself reveals basedon observations, experiments, models, and testing.Scienceis not merely a body of knowledge, but amethodby which weattempt to understand natureand how it behaves. This method begins with many observations overa period of time. From the trends found through observations,scientists can model the particular phenomena we want to understand.Such models are always approximations of nature, subject to furthertesting.New models and idea are consideredhypothesesahypothesismust be a proposed explanation that can betested.Experiment results match the hypothesis = acceptance of
hypothesis as a useful description of nature.Experiment results are inconsistent with hypothesis = ascientist must discard the hypothesis and develop analternative.Example(based from observation & philosophical belief):1.Earth is the center of the universe and everything around it orbited ina circular motion2.Above model is updated and additional circles of orbit were added fordifferent planets - with Earth at its center3.As instruments improved, the Sun was later considered the center ofour universe.astronomyis sometimes called anobservational science; we oftenmake our tests by observingmany samples of the kind of object we want to study and noting carefullyhow different samples vary. Newinstruments and technology can let us look at astronomical objects from newperspectives and in greater detail. Our hypotheses are then judged in thelight of this new information, and they pass or fail in the same way we wouldevaluate the result of a laboratory experiment.

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Term
Fall
Professor
Orozs

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