I. Powers of Ten NotationAstronomers use the powers of ten notation for very large or very small numbers in order to save space/create a shortcut.Format: ± a.bc × 10^ ± dPlus (+) = large numberMinus (-) = small number“a” represents a digit 1-9“bc” ranges from 00-99Exponent “d” is any integerThe average distance between the Sun and the Earth is called an Astronomical Unit (A.U.)One A.U. is equal to about 150,000,000 kilometers (km) or 1.50 × 10 ^ 8One A.U. is equal to about 93,000,000 miles (mi) or 9.30 × 10 ^ 7 miExamples of powers of ten notation:For small numbers, we use a minus sign in front of the exponent0.0000000067 = 6.70 × 10^ -9Usually only two decimal places are needed with the number representing “a” in the format ± a.bc × 10^ ± d6.695823441 × 10^ -9 = 6.70 × 10^ -9II. The Metric SystemWhat do we mean by the “size” of an object?The distance across an object = “size” of an objectMeters (m) and kilometers (km)1 m is equal to about 1 yd (about 40 in)1 km is equal to about 1000 m (about 0.6 mi)Example: the asteroid Ceres has a diameter that is equal to about 1000 km × (0.6 mile ÷ 1 km). For every km, there are 0.6 of a mile.Centimeters (cm) and millimeters (mm)1 cm is equal to about 0.4 in1 mm is equal to about 0.039 inFundamental Unit of MassWhat is mass?Mass is how much material an object contains1 kilogram is equal to about 2.2 pounds (very rough estimate)Kilograms measure massPounds measure weightMass and weight are NOT the same. Weight depends on where the object is in space. An object on the surface of the Moon will have 1/6 the weight on Earth, but it will have the same mass.III. Introduction to Discovering the Night SkyIllusions in the night sky1st illusion: the night sky is filled with apparent patterns of stars called “constellations”These stars are NOT all the same distance from us. Only in terms of angular separation, not physical separation (distance).Constellations are named in honor of people, animals, and objects. Few have resemblance to their names.There are 88 official constellations named by the International Astronomical Union.The Naming of StarsThere are given names for the brightest stars: Vega, Regulus, BetelgeuseThere are Greek letter designations for the brightest and intermediately bright stars: alpha Lyrae, alpha Leonis, alpha OrionisThere are catalog numbers for the brightest stars, intermediately bright, and dimmer stars: HR 7001, HD 39801).AST 115 1st Edition Lecture 1Outline of Current Lecture I. Powers of Ten Notationa. The Astronomical UnitII. The Metric Systema. What do we mean by the size of an object?b. Metric Conversionsc. The Fundamental Unit of MassIII. Intro to Discovering the Night Skya. Illusions in the night skyb. The Naming of StarsCurrent LectureI. Powers of Ten Notation- Astronomers use the powers of ten notation for very large or very small numbers in order to save space/create a shortcut.- Format: ± a.bc × 10^ ± do Plus (+) = large numbero Minus (-) = small numbero “a” represents a digit 1-9o “bc” ranges from 00-99o Exponent “d” is any integer- The average distance between the Sun and the Earth is called an Astronomical Unit (A.U.)o One A.U. is equal to about 150,000,000 kilometers (km) or 1.50 × 10 ^ 8o One A.U. is equal to about 93,000,000 miles (mi) or 9.30 × 10 ^ 7 mi- Examples of powers of ten notation:o For small numbers, we use a minus sign in front of the exponent 0.0000000067 = 6.70 × 10^ -9o Usually only two decimal places are needed with the number representing “a” in the format ± a.bc × 10^ ± do 6.695823441 × 10^ -9 = 6.70 × 10^ -9II. The Metric System- What do we mean by the “size” of an object?o The distance across an object = “size” of an object- Meters (m) and kilometers (km)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o 1 m is equal to about 1 yd (about 40 in)o 1 km is equal to about 1000 m (about 0.6 mi) Example: the asteroid Ceres has a diameter that is equal to about 1000 km × (0.6 mile ÷ 1 km). For every km, there are 0.6 of a mile.- Centimeters (cm) and millimeters (mm)o 1 cm is equal to about 0.4 ino 1 mm is equal to about 0.039 in- Fundamental Unit of Masso What is mass? Mass is how much material an object containso 1 kilogram is equal to about 2.2 pounds (very rough estimate)o Kilograms measure masso Pounds measure weight Mass and weight are NOT the same. Weight depends on where the objectis in space. An object on the surface of the Moon will have 1/6 the weighton Earth, but it will have the same mass.III. Introduction to Discovering the Night Sky- Illusions in the night skyo 1st illusion: the night sky is filled with apparent patterns of stars called “constellations” These stars are NOT all the same distance from us. Only in terms of angular separation, not physical separation (distance).  Constellations are named in honor of people, animals, and objects. Few have resemblance to their names. There are 88 official constellations named by the International Astronomical Union.- The Naming of Starso There are given names for the brightest stars: Vega, Regulus, Betelgeuseo There are Greek letter designations for the brightest and intermediately bright stars: alpha Lyrae, alpha Leonis, alpha Orioniso There are catalog numbers for the brightest stars, intermediately bright, and dimmer stars: HR 7001, HD