Introduction to Astronomy PDF

Introduction to Astronomy EC 131 - Astronomy ENGR. ROTSEN B. LABISORES Instructor Astronomy: Definition and its Role  Astronomy and its allied fields Astronomy Study of virtually everything beyond earth Includes planets, solar system, stars, galaxies, comets, as...

Introduction to Astronomy EC 131 - Astronomy ENGR. ROTSEN B. LABISORES Instructor Astronomy: Definition and its Role  Astronomy and its allied fields Astronomy Study of virtually everything beyond earth Includes planets, solar system, stars, galaxies, comets, asteroids nebulae, moons, and the universe itself Astrobiology A relatively new field of astronomy Only speculates about the possible alien life both inside and outside of the solar system Search for Extra-Terrestrial Intelligence (SETI) Institute Part of the astronomical science community Consists of team of astronomers looking for exoplanets  Astronomy and its allied fields Astrology Non-scientific field Assumes that there is a connection between astronomical events and the human world Astrology and its astrologers were cosmos based, religious fortune tellers, and "the gods' will," messengers. Astrologers carefully studied the stars, planets, the moon, and the Sun and then tried to derive the meaning for their movements  Astronomy and its allied fields Astrophysics Branch of space science that applies physics and chemistry laws to explain the birth, life, and death of stars, planets, galaxies, nebulae and others in the universe Has two siblings sciences: Astronomy and Cosmology Cosmology Subfield of astrophysics, which studies the universe “These three fields form a family in solving and revealing the mystery of the universe”  Astronomy and its allied fields Take, for example, asking for the position of a nebula or what kind of light it emits, the astronomer might answer first. Asking what the nebula is made of and how it formed, the astrophysicist will pipe up. Asking how the data fit with the formation of the universe, the cosmologist would probably jump in. But watch out for any of these questions, two or three may start talking at once (Balter, 22 December 2017). In a most rigid sense, Astronomy measures positions, luminosities, motions, and other characteristics, Astrophysics creates physical theories of small to medium-size scale in the universe, and Cosmology does this for the most massive structures and the universe. Role and Scale of Astronomy Astronomy is the study of the universe in a large scale and a rigorous science that follows the scientific method The phenomena that occur in the sky aroused people’s interest since then Cro Magnons people made bone engravings 30,000 years ago which may depicts the phases of the moon Its role ranges from its use in agriculture to the navigation during the Renaissance Role and Scale of Astronomy Agriculture required a reasonably good knowledge of the season Since the stars seems to stay fixed, farmers or fishermen tend to remember to stars forming a specific pattern, which could be a sign of the incoming season or time for planting or harvesting Religious trials and prognostication were based on the location of the celestial bodies Hence, time reckoning became more and more accurate, and people learn to calculate the movements of celestial bodies in advance Role and Scale of Astronomy Seafaring needs a thorough knowledge of the movement of the celestial bodies (e.g., moon, stars, planets) just when voyages extend farther from the ports, the determination of a position presented some problems in which astronomy offered a practical solution Solving the problems on navigation was the most critical astronomy task in the 17th and 18th centuries when the first precise tables on the movements of the planets and other phenomena were published The basis for the developments was the discovery of the laws governing the motions of the planets by the known physicists such as Copernicus, Tycho, Brahe, Kepler, Galilei, and Newton (Karttunen et al., 2016). Role and Scale of Astronomy Modern astronomy is a fundamental science Motivated by man’s curiosity to know more about the nature and the universe It changes the man’s view of the world from geocentric, anthropocentric conceptions to the modern view of a vast universe where man and the Earth plays an insignificant role The society benefited from this science from the studies and technologies Most of it involves technology transfer (e.g., wireless local area network) Others are in the aerospace, energy, and medicine Role and Scale of Astronomy Astronomy is a science already at a large-scale Masses and sizes of astronomical objects are usually enormously large Measurements range from significantly small (10-27 or even smaller) to significantly large (1030 or even greater) It takes man long time to grasp the vast dimensions of space From Ptolemy’s geocentric model to the current size of the universe Hipparchus (200 B.C) obtained a correct value of the Moon’s distance Astronomer are able to determine the age, distance, and scale of the universe from understanding the properties of light Role and Scale of Astronomy Astronomy can be divided into different branches in several ways The division can be made according to either the methods or the objects of research It started from studying the Earth and used as basis for study in the study of exoplanets The classification of stars are based on the study of the Sun The study later expand to galaxies, black holes, nebulae, quasars, and currently gravitational waves and neutrinos It can also be classified according to the wavelength used in observations (e.g., Infrared astronomy) Scientific Notation Scientific notation is a representation of an enormously large or small numbers and it is expressed into N x 10n where N is a value at a specified number of significant figures or decimal and n is a non-zero integer. The purpose is to prevent writing a complete very large or very small numbers, thus transforming into a scientific notation without changing the original value Example: 6.55 x 106 kg= 6,550,000 kg 6.671 x 10-11 = 0.00000000006671 Some values are transformed by adding prefixes to simplify them Example: 6.55 MPa = 6.55 x 106 Pa = 6,550 kPa (Pa = Pascal) 6.671 x 10-11 m = 66.71 pm (picometer) Fundamental Quantities The following are some of the quantities and constants and the conversion that might be used. (Keeton, 2014) Fundamental Dimensions. The three key dimensions are mass, length, and time. Fundamental Quantities Other familiar quantities involve combinations of the fundamental dimensions. Fundamental Quantities We sometimes invent special units to measure certain quantities. Some of the physical units are combinations of fundamental dimensions (and their associated units): the special units might seem to be unique but in turn out to composite as well: Fundamental Quantities Temperature is often measured in Celsius, Fahrenheit, or Kelvin. A temperature in Kelvin can be converted into energy using E = kBT where kB = 1.38x10-23 JK-1 = 8.62x10-5 eV K-1 is a Boltzmann’s constant. 1. Constants of Nature. There are some special, fundamental numbers in physics: Fundamental Quantities  Fundamental Quantities 2. Astrophysical Units. Some numbers are used so frequently in astrophysics that they act as a de facto set of units. Using them can help interpret quantities quickly THANK YOU!!!