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Astronomy 1020-HSpring_2015
Day-4Stellar Astronomy
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3X5 card question• Name (legible!legible!):
• What scientist (living or not) would you most like to meet?
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Course Announcements• Smartworks Chapter 1: Start on –
Grades will be downloaded sometime after Friday.
• SW-2 … hop to it.
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A Scientific Result: We Are Stardust
Our bodies contain many types of atoms.Except for the hydrogen in water (H2O), 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.
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Science Is CreativeScience 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.
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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
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Scientific Method• To be accepted as
valid, an idea must be testable and falsifiable.
• This separates “fact” from “faith”.
• We use the “Scientific Method”
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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
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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)
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New Concept:Cold Dark Matter
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A Strange Universe
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Cute and Science
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Colored Card QuestionThink-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.
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An Important AssumptionThe 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.
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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
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Scientific Notation4,500,000,000,000,000 = 4.5x1015
0.000000000000000028 = 2.8x10-17
On calculators…look for the “EXP” keyor the “EE” key
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centi = 0.01 = 10-2 (c)
milli = 0.001 = 10-3 (m)
micro = 0.000001 = 10-6 ()
nano = 0.000000001 = 10-9 (n)
kilo = 1,000 = 103 (k)
mega = 1,000,000 = 106 (M)
giga = 1,000,000,000 = 109 (G)
tera = 1,000,000,000,000 = 1012 (T)
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