-According to Aristotle, larger, heavier objects were supposed to fall to the ground faster than smaller, lighter objects. Galileo performed a number of experiments to Aristotle’s pronouncements, that two objects of different weight dropped from the same height fall down at exactly the same rate. -Copernicus published his findings in 1 543, the same years as his death, in a text entitled (On the Revolutions of the Celestial Spheres). Heliocentric theory was proposed by Aristarchus of Samos, Ptolemy created the Geocentric theory -Occams Razor: discard the more complex heory and choose the simpler one -should two theories of unequal complexity be equally successful modern version of Oc Razor tell us discard more complex theory – The geocentric theory was accepted primarily because the Ptolemaic view with its system of orbits and “suborbits” or “epicycles” did a better Job of “saving the phenomenon” -Quantum mechanics, which was developed only a few decades ago to describe the behavior of phenomena at the atomic or microscopic level of nature – The principle of universality states that the basic principles and laws governing the ehavior of the physical world do not change with time or one’s location in the universe. also universality principle states experiments can be reproduced at any time or location -Theory must be expanded on, amended, or changed, but only in accordance with a rule of the scientific method called the correspondence principle – Correspondence principle pt 2: any new or revised theory must not only account discrepancy between experimental results and predictions of old theory but must be successful where old theory was successful -All of the observations were collected by Galileo into a short but impressive work entitled Sidereus Nuncius (The Starry Messenger). Galileo did (Dialogue on the Two Chief World Systems) -Greek and Hellenistic views of nature were found to be lacking in saving the phenomena, -Pythagroas believe that fundamental relationship exist between number and physical world -when we draw point or straight line, such drawing can only “represent” that point or line -Plato: felt such representations were totally inadequate in determining the “true” nature of the universe. Such a determination could only be properly done at the “higher plane” of pure thought and reason.
Conclusions drawn from observations and measurements made by the “eye of the body’ were imperfect and not to be trusted, while conclusions drawn from the thought and reason of the “eye of the soul” were regarded as the essence of truth – Copernicus had managed to resurrect the idea of a heliocentric planetary system and place it on an equal intellectual footing with the geocentric system of Ptolemy -He found to his dismay that the Ptolemic scheme of orbits and epicycles had become extremely complicated. -More than 75 “wheels” were required by the Ptolemic ystem to describe, and imperfectly at that, the motions of seven objects in the sky. For Copernicus this was an intolerable situation and he set about the task of developing a less tedious method for his calculations. -Soon Copernicus was able to demonstrate that a somewhat simpler system was to be had by assuming that the Sun and not the Earth marked the center of the planetary system -Democritus proposed tne atomlc tneory (tnlngs are mace up 0T atoms) out was superseaea Dy Aristotles simple view of everything made up of earth, water, air, and fire -Basic
Assumptions: everything in life can be represented as numbers, use of models, occams razor, save the phenomenom, principle of universiality, correspondence principle, -Scientific observations: electronic observation, cheap, versatile, flexible, -Angular diameter (measured in arcseconds) = (2. 06 x 105) x (linear diameter)/ distance Measurable quantities scientists use to describe the physical world: time, length, mass -The most commonly used coordinate system in astronomy is the equatorial or right ascension-declination system -RA: angular distance between the prime hour circle and the hour circle of the object. astronomical longitude”. Ranges from Oh to 24h where lh of RA= 150 -DEC: shortest angular distance between the celestial equator and the object. “astronomical latitude”.
Ranges from +900 at the north celestial pole to 00 at the celestial equator to -900 at the south celestial pole CH 5 -Apparent Brightness = total power received/ total area (luminosity of the source/4pi dA2 -Energy of a Photon = (Planks constant= 6. 63 x IOA-34) x frequency of the photon -(bl (compare two objects 1 and 2, dimming distance effect) – Strong nuclear interaction: Serves as an atomic “glue” that is strong enough to vercome the repulsive electrostatic forces in the nucleus, thereby holding the nucleus together -Bohr’s claims: As long as an electron stays in one of the orbits or “energy levels” it does not have to radiate electromagnetic energy as one would expect from an oscillating charge -It must change its position by making discrete “Jumps” between energy levels -Stefan- Boltzmann Law: Intensity total = o (Kelvin o is a constant- 5. 7 *10-8 (watts/m2)/(Kelvins)4 -Albedo = total temperature)4 reflected light/ total incident light Object’s observed radial velocity’= speed of light (observed wavelength of a given pectral line- lab wavelength of that same line) / (lab wavelength of that same spectral line) -If the observed wavelength of an object is longer than the laboratory wavelength, then the relative motion of the source is away from the observer, the radial velocity has a positive value, and the object’s spectrum is said to be red- shifted. -If the observed wavelength of an object is shorter than the laboratory wavelength, then the relative motion of the source is toward the observer, the radial velocity has a negative value and the object’s spectrum is said to be blue-shifted. CH 6
Theoretical Resolving Power= trp (spyglass)/ trp (eye) also.. [diameter (telescope 1)/ diameter (telescope 2)] Eye 1/5 TRP(theoretical resolving power)= diameter/ wavelength of object being observed Image brightness = (total power collected by telescope)/ (area of image formed by telescope) Magnification= (focal length of primary lens/mirror)/ (focal length of the eyepiece) Photographic exposure= image brightness x exposure time Optical illusions fool the eye. The eye is linked to the brain and therefore falls to the brain’s subjectivity in which observer “sees” an object not as it actually exists, but as hat observer expects or wants to see it E. E. Bernard claimed canals did not exist. G. V.
Shiaparelli claimed canals did exist -Heliocentric: Aristarchus(thought of It)ucopernlcus(resurrectea IVslmpllTlea It)UC5allleo created telescope ana ooservea sun was bigger than earth therefore claimed earth orbits the sun0Kepler saved the phenomenon Practice Problems: Design telescope which will detect point source objects with an apparent which will detect point source objects with an apparent brightness as faint as 2XIOA-1 5 watts square meter if the telescope produces an image area of 3XIOA-12 suqare meters nd the detection system requires an image brightness equal to 5XIOA-2 watts/ squaremeter what area in square meters should the telescope primary lens/mirror have? -Telescope want to detect a object with an apparent brightness of 2X1 on-1 5 -Image brightness = 5*10A-2 -Image area = 3XIOA-12 -What is the area of the telescope? Need to find total power first -Image brightness= Total power/ image area -Total power collected = image brightness X image area -(5X10A-2) X 15M power collected -Power Collected by telescope= Apparent Brightness X Area of Primary Lens 1 5XIOA-14=2XIOA-15 X Area of Primary lens Oust fucking divide and boom answer) Fort Collins is located at a latitude of 41 N if the observers horizon is defined as the circle on the celestial sphere which is everywhere 90 degrees from the observer’s zenith or overhead point and below which objects are not visible to that observer… 1) What range of right ascensions are visible from Fort Collins at sometime or other? 2) What range of declinations are visible from Fort Collins at sometime or other? )ln principle all the limes of the Right Ascension pass though your location everyday 2) 1-900-49 therefore range is from -49 to 90 Currently in the predawn sky, the planet Venus, with an apparent magnitude equal to -4. 1 is located side by side with the bright Leo star Regulus which ahs an apparent magnitiude of +0. 9 if the apparent brightness of regulus is equal to IXIOA-8 watts/sq meter l)what is the apparent brightness in watts/square meter of the planet venus 2) If the distance between the earth and regulus were increased by four times what apparent brightness would be seen for Regulus from this new distance 1) . 9-(-4. 1)=5 = 100 Then get 100* 1. X10A-8 )B1 /B2 = (Ll 1/16 1/16*1X10A-8 Keplers Law: planetary motion did a far better Job of mathematically representing the phenomenon of planetary motion and reduced the number of required orbits in the system to a total 0T seven, one eacn Tor sun, moon, Tlve naKea eye planets -stars nave been used for navigation, time keeping, religious practices, and orientation -caroline islanders of the central pacific navigated by means of this star compass in which 32 points on the horizon were defined by rising and setting points of bright starts and constellations -one cycle around ecliptic is 365. 42 days and 29. 530 lunar phases and 12. 368 lunar phases in a year -Systematic observation of the heavens reveal that there exist a number of correspondences between celestial events and confgurations and natural phenomena on earth -one ecliptic revolution is every 18. years and used this to predict lunar and solar eclipses More information (CH 5) -realization that light behave as particle led to amazing conclusion that light exhibits sort of wave particle duality, can behave both as a particle and wave but not simultaneously -Difficulties with atomic model all positive charges in nuclei of atoms with atoms with two or more protons are hed together when they should fly apart from electrostatic repulsive forces explained via Strong nuclear interaction -second difficultly is electrons are able to avoid electrostatiscially plunging into positive charged nucleus -Ground state: electron that is in lowest possible energy level can occupy within a given atom -excited state: any other electron levels -a 6th magnitude star is fainter than a 4th magnitude star, and a 12th magnitude star is fainter than a 6th magnitude star, and so on