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Solar System Astronomy ASTR 111 – Summer 2010. Welcome to Astronomy Professor Jack Brockway Reed 121 250-6941

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Presentation on theme: "Solar System Astronomy ASTR 111 – Summer 2010. Welcome to Astronomy Professor Jack Brockway Reed 121 250-6941"— Presentation transcript:

1 Solar System Astronomy ASTR 111 – Summer 2010

2 Welcome to Astronomy Professor Jack Brockway Reed 121 250-6941 brockway@radford.edu www.radford.edu/brockway Office Hours: MWF 10-12

3 Welcome to Astronomy ASTR 111 – Solar System Astronomy Lecture McGuffey 203 2:00 – 2:50 MWF Laboratory Curie 145  7:00 – 9:00 Monday  9:00 – 11:00 Monday  8:00 – 10:00 Wednesday

4 Welcome to Astronomy ALWAYS ASK QUESTIONS!

5 Welcome to Astronomy There are problems to whose solution I would attach an infinitely greater importance than to those of mathematics, for example touching ethics, or our relation to God, or concerning our destiny and our future; but their solution lies wholly beyond us and completely outside the province of science. — Carl Friedrich Gauss (1777-1855)

6 Why Science? I have a theory… Water causes cancer Only water causes cancer  Not cigarettes…  Not UV radiation…  Not nothing else… Who/how it affects cannot be predicted  Now or ever

7 Why Science? I have a theory… Water causes cancer Only water causes cancer Who/how it affects cannot be predicted Evidence: Every single cancer victim has been exposed to water Rebutting evidence to the contrary: Not every lung cancer victim smokes Not every smoker gets lung cancer

8 Why Science?

9

10 What is Science? Science is a system of knowledge that is based on empirical evidence and testable explanations Empirical – we can observe and measure Testable – we can support or disprove A theory must be falsifiable A theory – of any sort – that cannot conceivably fail any test is not science

11 What is Science? In science we do not teach… What might be true What we believe to be true Perhaps not even things that are true We search for, find, and teach the best explanations for nature we can find

12 What is Science? Science is NOT any conjecture chosen to justify belief – not even popular or widely-held belief

13 What is Science? Science is an exploration Guided by natural law Explanatory by reference to natural law Testable against the empirical world Conclusions are tentative It is falsifiable

14 Science vs Authority Authority often works by suppressing inquiry favors (or even depends upon) the status quo Science is subversive Old ideas can be falsified and rejected New ideas must be supported by evidence Scientific authority can be overthrown by new or better evidence Nature is the arbiter of science. It decides what ideas are good or bad

15 Science vs Authority Science provides tools For separating truth from fiction Science can only suffer under ideological requirements Galileo vs Church Scopes trial AIDS research Global Warming USSR/China – Lysenko

16 Accepting Science Many reject science Astrology crystal healing Hostility to Modern Medicine Vaccines cause autism… or kill Smoking Rejection of climate change findings

17 Accepting Science Science is not “natural” The brain is an ever-turning “belief engine” Full moons are dangerous 13 is unlucky Health insurance providers are our friends

18 Accepting Science Science is not “natural” Science requires doubt and skepticism Society holds unshakeable faith to be a virtue People seek security and certainty  Faith delivers  Science doesn’t Science enables us to recognize (and turn away from) incorrect beliefs To be fair, let’s not assume that scientists are without bias, nor are they always right…

19 Scientific World View Which of the following would be a scientific way of viewing nature? a) All ideas are equally valuable and should be equally respected b) Well established ideas should never be checked or tested c) Nature informs us about the usefulness of our ideas

20 Scientific Method Knowedge from Science We think we understand empirical phenomena when a satisfactory theory explains how the phenomena work, what regular patterns they follow, or why they appear to us as they do Scientific explanations are in terms of natural phenomena rather than supernatural phenomena science itself requires neither the acceptance nor the rejection of the supernatural

21 Scientific Method Scientific “facts” and theories many scientific theories, initially, are often little more than guesses based on limited information mature and well-developed scientific theories systematically organize knowledge and allow us to explain and predict wide ranges of empirical events

22 Scientific Method Science Conclusions are a posteriori Theory follows observation Theories are conclusions  a position, opinion, or judgment reached after consideration Measurable predictions Key to falsifiability Falsifiable We can distinguish between accurate and inaccurate predictions (Precambrian rabbits) Reproducible

23 Scientific Pretenders Pseudoscience Set of ideas based on theories put forth as scientific when they are not scientific They are missing one or more of the characteristics of scientific disciplines/theories

24 Scientific Pretenders Pseudoscience Conclusions are a priori Observations made (often chosen) to confirm theory Theories are assumptions  Reached without consideration  Conclusions are not conclusions! Not Falsifiable Not reproducible No measurable predictions Predictions allow competing theories to be compared

25 Scientific Method Science makes conclusions Based on weight of evidence All the data must be considered Pseudoscience makes assertions Not supported by most of the data Though it might be supported by some of it I’m being tendentious – look it up

26 Our Criteria A priori or a posteriori? Did you conclude or did you assume? Falsifiability Is it possible to collect contradicting evidence? Is contradicting evidence considered when available? Reproducibility Observable predictions Science is a tool, not a rationalization

27 Benefits of Science What benefit has science provided? Vaccines Computers Anesthetics Spacecraft Hydrogen bombs Women surviving childbirth Greatly Increased life expectancy Social/economic prosperity…

28 Benefits of Science What benefit has science provided? Cell Phones Toilets Books

29 Benefits of Rejecting Science Ignorance Gullibility

30 Benefits of Rejecting Science Astrology “You’re not going to marry him because she’s a Taurus??” “You’re quitting your job because Mercury is in Cancer??” Intelligent Design ID is an attack against science Gardisil Debate

31 Gardisil is a vaccine against HPV virus HPV is believed to be a necessary factor in the development of nearly all cervical cancer cases Fifth most deadly cancer in women Nearly 4000 will die from it this year in the US

32 Gardisil Debate Critics say it’s unnecessary or dangerous: They say the body’s immune system is sufficient 90% of the time, that it only protects against 4 of over 100 strains of HPV, that there are serious side effects, that Gardisil has killed people, that HPV hasn’t been proven to cause cervical cancer

33 Gardisil Debate Facts suggest otherwise: the body’s immune system is sufficient 90% of the time..and fails 10% of the time It protects against 4 (of over 100 strains) of HPV there are side effects People have died that were taking Gardisil HPV hasn’t been proven to cause cervical cancer

34 Gardisil Debate Facts suggest otherwise: the body’s immune system is sufficient 90% of the time It only protects against 4 (of over 100 strains) of HPV But 2 of those 4 are responsible for over 70% of cases 38% effective against 10 other strains (>2/3 remaining cases) there are side effects People have died that were taking Gardisil HPV hasn’t been proven to cause cervical cancer

35 Gardisil Debate Facts suggest otherwise: the body’s immune system is sufficient 90% of the time it protects against 4 (of over 100 strains) of HPV there are side effects About half of the adverse effects that most drugs have People have died that were taking Gardisil HPV hasn’t been proven to cause cervical cancer

36 Gardisil Debate Facts suggest otherwise: the body’s immune system is sufficient 90% of the time it protects against 4 (of over 100 strains) of HPV there are side effects People have died that were taking Gardisil People have also died that were taking Tylenol, were sleeping, or were sitting in chairs  No evidence has shown a link between the drug and the deaths (at least not yet) About 40 people out of 40 million recipients have died HPV hasn’t been proven to cause cervical cancer

37 Gardisil Debate Facts suggest otherwise: the body’s immune system is sufficient 90% of the time it protects against 4 (of over 100 strains) of HPV there are side effects People have died that were taking Gardisil HPV hasn’t been proven to cause cervical cancer But the link is far stronger than for smoking and lung cancer… Each year in the US Nearly 4000 die from cervical cancer Gardisil can prevent over 3000 of those deaths

38 Benefits of Rejecting Science Astrology Intelligent Design Gardisil Debate Population control

39 Fact vs theory This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully, and critically considered. – sticker in Cobb County GA

40 Fact vs Theory No real difference… Theories are typically considered to be less developed/established In science, “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional assent.” – Stephen Gould

41 Scientific “fact” This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully, and critically considered. – sticker in Cobb County GA

42 Scientific “fact” This textbook contains material that states smoking can lead to cancer. That is a theory, not a fact, regarding the dangers of smoking. This material should be approached with an open mind, studied carefully, and critically considered. – my sticker for Cobb County

43 Evolution & Natural Selection Scientific “facts” and theories mature and well-developed scientific theories systematically organize knowledge and allow us to explain and predict wide ranges of empirical events

44 Science vs Ideology Trofim Lysenko Director of Soviet biology under Stalin Rejected Mendelian genetics Inheritability of acquired characteristics  Plucking a plant’s leaves can reduce leaves on offspring… Genetics stigmatized ‘bourgeois science’ or ‘fascist science’ Stalin disliked fascist Germany’s embrace of genetics Gregor Mendel himself was a priest  Religion considered backward and evil

45 Science vs Ideology Trofim Lysenko Stalin insisted on applying Lysenkoism to human genetics Geneticists were fired, sent to labor camps, or executed ‘Scientific’ arguments were made based on conformity to Marxist ideology Serious, long-term harm to Soviet biology  Massive crop failures, famine, millions of deaths  Economic disintegration  Crippled advances in biology and biochemistry

46 Science vs Ideology Soviet Sciences While USSR invested heavily in science Strictly persecuted deviations from communist ideology Introduced party control over sciences In general, ideologically-offensive disciplines and scientists were suppressed Notable exception was nuclear physics  “Stalin was crazy, but he wasn’t stupid”

47 Science vs Ideology Where is science subordinated to ideology? Nazi Germany USSR China American schools

48 What’s my point? Science is profoundly important in our society Only effective tool for understanding nature Biology Medicine Physics Fossil Fuel alternatives Chemistry Geology Engineering Informed decisions are impossible without some understanding of science

49 What’s my point? Science is a way of evaluating propositions It provides mechanisms for distinguishing between true and false

50 Science and Mathematics

51 Science discovers patterns and rhythms in nature. Most phenomena work regularly and predictably. Mathematics is the language of patterns. Mathematics works when used to describe nature and its patterns.

52 Back to Astronomy… Earth is a small planet… Orbiting a medium-size star… In a galaxy of 100 billion stars… Which is one of billions of galaxies… In a universe that is 13.7 billion years old. We’re going to measure EVERTHING!

53 Measurements – metric & more… Système International d'Unités (SI) International System of Units mks system meter kilogram second cgs system centimeter gram second

54 Metric System meter 1/40,000,000th of the polar circumference of the Earth length of a particular bar of platinum-iridium alloy now defined as the distance traveled by light in a vacuum during 1/299,792,458 of a second

55 Metric System kilogram Originally one liter of pure water at standard pressure and 3.98° Celsius definition was hard to realize accurately  density of water depends slightly on the pressure  pressure units include mass as a factor  circular dependency in the definition! since 1889, equal to mass of the international prototype made from an alloy of platinum and iridium  39 mm height and diameter kept at the Bureau International des Poids et Mesures

56 Metric System second currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom cesium atom at rest at a temperature of 0 K

57 Metric System Temperature Kelvin An absolute temperature scale Absolute zero* (definition) Water's freezing point triple point of water* Water’s boiling point 0 K 273.15 K 273.16 K 373.1339 K –273.15 °C 0 °C 0.01 °C 99.9839 °C −459.67 °F 32 °F 32.018 °F 211.9710 °F

58 Metric System What parts of the world use (or don’t use) the metric system?

59 Units are for convenience Mass Solar Mass Earth Mass Distance Astronomical Unit Time… Temperature Kelvin

60 A Vast Universe We need to handle great distances and long times We can do this through the travel time of light Light travels 300,000 km every second 299,792,458 m/s 186,000 miles per second We often use time to denote distance e.g. we may say a friend’s house is two hours away

61 A Vast Universe Travel time of light 300,000 km/s 1¼ seconds to arrive from the Moon. 8.3 minutes to arrive from the Sun. 5.5 hours to get to Pluto from the Sun. 4.3 years (yr) to get to the nearest star. 100,000 yr to cross the galaxy. 2.9 million yr to get to the nearest big galaxy. 10 billion yr to come from distant galaxies.

62 Nearby Distances Moving outward through the Universe at the speed of light, Earth is like a snap of your fingers… The Moon is a little more than a second away… The Sun’s distance is like a quick meal…

63 Longer Distances …and the diameter of the Solar System is a long night’s sleep. The distance to the nearest star is like the time you spend in college… Hopefully

64 The Longest Distances …and the distance between galaxies is like the time since earliest human ancestors walked on Earth.… The radius of the Galaxy is like the age of our species…

65 The Longest Distances The size of the universe is like three times the age of the Earth… Comparing the size of the universe to the size of Earth is like comparing the age of the planet to a snap of your fingers – times three Scales will be a conceptual handicap

66 Campus scene (16m × 16m) 16 meters across

67 City View 1 mile

68 Pennsylvania 100 miles

69 Earth 12,756 km diameter

70 Earth & Moon 384,000 km

71 Earth & Sun 150 million km = 1 AU or 1 ua

72 Solar System 100 AU

73 Empty Space 10,000 AU

74 Solar Neighborhood 17 light-years

75 Astronomical Scales – 1 billion Jupiter is about 1 billion kilometers away ~600 million miles How big is one billion? What was happening 1 billion minutes ago? How much do 1 billion dollar bills weigh?

76 Our first day of Astronomy… Applause


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