Astronomy 1020-H Stellar Astronomy Spring_2015 Day-4

3X5 card question legible! Name (legible!): What scientist (living or not) would you most like to meet?

Course Announcements Smartworks Chapter 1: Start on – Grades will be downloaded sometime after Friday. SW-2 … hop to it.

A Scientific Result: We Are Stardust Our bodies contain many types of atoms. Except for the hydrogen in water (H 2 O), all the atoms were made in stars. Stars generate energy by making heavier elements out of light ones. They eject the material into space. New stars and planets (and humans) form out of the ejected material.

Science Is Creative Science is one of many creative human activities. It has its own rules for deciding what is right and wrong. It is an important way for achieving knowledge and insight. There are also other valuable ways to achieve understanding.

Science Is a Process Science is a method for learning about nature. The scientific method works like this: Ideas are tested against nature. Tests come from observation or calculation. The tests falsify some ideas and support others. All scientific knowledge is provisional. Science involves Exploration & Discovery HST Curiosity

Scientific Method To be accepted as valid, an idea must be testable and falsifiable. This separates “fact” from “faith”. We use the “Scientific Method”

Scientific Revolutions The scientific processes and investigations can be slow: many small steps and tweaks. Every now and then, there is a revolution and progress is very rapid in both new knowledge gain and understanding the implications and effects. Newtonian Mechanics Quantum Mechanics Evolution

Challenges to Science Science is subversive. Old ideas can be falsified and rejected. New ideas must be supported by evidence. Authority often works by suppressing inquiry. Scientific authority can be overthrown by new or better evidence. Nature is the arbiter of science. It decides what ideas are good or bad. (Occam’s Razor)

New Concept: Cold Dark Matter

A Strange Universe

Cute and Science

Colored Card Question Think-Pair-Share The Milky Way is: A) A nutty candy bar B) A spiral galaxy C) An elliptical galaxy D) Haven’t got a clue.

To make sense of what we see: The Cosmological Principal

An Important Assumption The cosmological principle: “There is nothing special about our place in the universe.” On one level: Our view from the Earth is not special or unique. Distant objects should be like nearby ones which we can study in detail. On another level: Matter and energy obey the same physical laws everywhere.

Math Review page 16 – Math Tools 1.1 box. You should feel comfortable working at this level. You’ll need at least these skills just to live in the modern world. Scientific Notation Ratios Geometry Algebra Proportionality

Dealing with very large and small numbers Scientific Notation 4,500,000,000,000,000 = 4.5x = 2.8x On calculators…look for the “EXP” key or the “EE” key

Common Prefixes Don’t let the units confuse you. centi = 0.01 = (c) milli = = (m) micro = = (  ) nano = = (n) kilo = 1,000 = 10 3 (k) mega = 1,000,000 = 10 6 (M) giga = 1,000,000,000 = 10 9 (G) tera = 1,000,000,000,000 = (T)