NUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMY

See Appendix 4 & 5See Appendix 4 & 5

Hydrogen Atom

Proton

Electron

NUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMY

.00000001 cm

.0000000000001 cm

Some numbers are very smallSome numbers are very smallE.g. Diameter of Hydrogen Atom is about 0.00000001 cmE.g. Diameter of Hydrogen Atom is about 0.00000001 cm

NUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMY

Other numbers are very largeOther numbers are very largeE.g. size of galaxy 100,000,000,000,000,000,000,000 cmE.g. size of galaxy 100,000,000,000,000,000,000,000 cm

Some numbers are very smallSome numbers are very smallE.g. Diameter of Hydrogen Atom is 0.00000001 cmE.g. Diameter of Hydrogen Atom is 0.00000001 cm

100,000,000,000,000,000,000,000 cm

NUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMYNUMBERS in ASTRONOMY

The number of zeros is denoted by an exponent of 10.The number of zeros is denoted by an exponent of 10. This exponent is positive if the number is larger than 1.This exponent is positive if the number is larger than 1.

1010NN is 1 followed by N zeros is 1 followed by N zeros E.g. 100,000,000,000,000,000,000,000 is written as 10E.g. 100,000,000,000,000,000,000,000 is written as 102323

The exponent (power) is negative if the number is smaller The exponent (power) is negative if the number is smaller than 1. than 1. 1010-N-N represents a 1 in the N represents a 1 in the Nthth place after the decimal place after the decimal E.g. 0.00000001 is written as 10E.g. 0.00000001 is written as 10-8-8

Some numbers are very smallSome numbers are very smallE.g. size of Hydrogen Atom (GS) is 0.00000001 cmE.g. size of Hydrogen Atom (GS) is 0.00000001 cm

Other numbers are very largeOther numbers are very largeE.g. size of galaxy 100,000,000,000,000,000,000,000 cmE.g. size of galaxy 100,000,000,000,000,000,000,000 cm

Powers of 10 NotationPowers of 10 Notation

POWERS OF 10 NOTATIONPOWERS OF 10 NOTATIONPOWERS OF 10 NOTATIONPOWERS OF 10 NOTATION

1010NN is 1 followed by N zeros is 1 followed by N zeros

1010-N-N is a 1 in the N is a 1 in the Nthth decimal place after the decimal place after the decimal pointdecimal point

More complicated numbers are represented by More complicated numbers are represented by a combination of a power of 10 and a a combination of a power of 10 and a multiplying factormultiplying factor

101033 is 1000 is 1000 101088 is 100,000,000 is 100,000,000

1010-3-3 is 0.001 is 0.001 1010-8-8 is 0.00000001 is 0.00000001

0.000000025 is 2.5 x 100.000000025 is 2.5 x 10-8-8

64,000 is 6.4 x 1064,000 is 6.4 x 1044

NUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMYNUMBERS IN ASTRONOMY

Rule for MultiplicationRule for Multiplication

Rule for DivisionRule for Division

Multiply the factors and add the powersMultiply the factors and add the powers

E.g. 2 x 10E.g. 2 x 1044 times 3 x 10 times 3 x 1055 is is

  (2x3) x 10  (2x3) x 10(4+5)(4+5) = 6 x 10 = 6 x 1099

Divide the factors and subtract the powersDivide the factors and subtract the powers

E.g. 5 x 10E.g. 5 x 1066 divided by 2 x 10 divided by 2 x 1044 is is (5(52) x 102) x 10(6-4)(6-4) = 2.5 x 10 = 2.5 x 1022

TEST YOURSELFTEST YOURSELFTEST YOURSELFTEST YOURSELF

The mass of the Sun is: The mass of the Sun is: 1,989,000,000,000,000,000,000,000,000,0001,989,000,000,000,000,000,000,000,000,000 kg. kg. Write this mass in the powers-of-ten Write this mass in the powers-of-ten notation.notation.

Answer: 1.989 x 10Answer: 1.989 x 103030 kg kg

FLASHCARDFLASHCARDFLASHCARDFLASHCARD

The Gross National Product of Canada inThe Gross National Product of Canada in2000 was 7.6 x 102000 was 7.6 x 1011 11 Canadian Dollars. Canadian Dollars. There are 3 x 10There are 3 x 1077 people in Canada. What people in Canada. What is the amount of GNP per person?is the amount of GNP per person? A)A) 2 2.5 x 10.5 x 1033

B)B) 2.5 x 10 2.5 x 1044

C)C) 2.5 x 10 2.5 x 1055

D)D) 2.5 x 10 2.5 x 1066

FLASHCARDFLASHCARDFLASHCARDFLASHCARD

The centre of our Galaxy is 7 x 10The centre of our Galaxy is 7 x 101616 km km from us. UNBC (in Prince George) is from us. UNBC (in Prince George) is about 5 x 10about 5 x 1022 km away from us. How km away from us. How many times farther (in powers of 10 many times farther (in powers of 10 notation) is the Galactic centre from us notation) is the Galactic centre from us compared to UNBC?compared to UNBC?

A)A) 3 3.5 x 10.5 x 101919

B) 1.4 x 10B) 1.4 x 1088

C)C) 1.4 x 101.4 x 101414

D) 7.1 x 10D) 7.1 x 10-15-15

FLASHCARDFLASHCARDFLASHCARDFLASHCARD

The mass of our Galaxy is about 7 x 10The mass of our Galaxy is about 7 x 101111 times the mass of our Sun. There are times the mass of our Sun. There are about 10about 101111 galaxies in the Universe. If an galaxies in the Universe. If an average star weighs about half that of average star weighs about half that of our Sun, about how many stars are there our Sun, about how many stars are there in the Universe?in the Universe?

A)A) 7 7 x 10 x 10121121

B)B) 14 x 10 14 x 102222

C)C) 7 x 10 7 x 102222

D)D) 7 7

POWERS of TEN EXAMPLESPOWERS of TEN EXAMPLESSizes in MetersSizes in Meters

POWERS of TEN EXAMPLESPOWERS of TEN EXAMPLESSizes in MetersSizes in Meters

UNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMY

Mass: Mass: kilograms (kg)kilograms (kg) Time: Time: seconds (s) or years (y)seconds (s) or years (y)

A A light yearlight year is the distance light travels in one is the distance light travels in one yearyear Speed of light = 3 x 10Speed of light = 3 x 1055 km/s km/s There are 3 x 10There are 3 x 1077 seconds in a year seconds in a year Thus a lightyear is (3 x 10Thus a lightyear is (3 x 1055) x (3 x 10) x (3 x 1077) = 9 x 10) = 9 x 101212 km km

Distance: Distance: meters (m), kilometers (km), light meters (m), kilometers (km), light years (ly), or Astronomical Units (AU)years (ly), or Astronomical Units (AU)

An An Astronomical UnitAstronomical Unit is the mean distance is the mean distance between Earth and the Sun (1.5 x 10between Earth and the Sun (1.5 x 1088 km) km)

UNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMY Light year:Light year:

Astronomical Unit:Astronomical Unit:

Solar MassSolar Mass

This is the distance which light will travel in the This is the distance which light will travel in the period of 1 yearperiod of 1 year

The speed of light (c) is 3 x 10The speed of light (c) is 3 x 1055 km/s km/s There are 3 x 10There are 3 x 1077 seconds in a year seconds in a year Thus, a light year is (3 x 10Thus, a light year is (3 x 1055) x (3 x 10) x (3 x 1077) = 9 x 10) = 9 x 101212 km km Note: the star nearest the Sun (Proxima Centauri) Note: the star nearest the Sun (Proxima Centauri)

lies at a distance of 4.26 ly (or 38 million million km!)lies at a distance of 4.26 ly (or 38 million million km!)

This is a convenient unit to use for mass and is This is a convenient unit to use for mass and is equal to the mass of our own Sun (1.9891 x 10equal to the mass of our own Sun (1.9891 x 103030 kg) kg)

Your instructor weighs in at a hefty 4 x 10Your instructor weighs in at a hefty 4 x 10-29-29 solar solar massesmasses

This is the mean Earth-Sun distance, and is about This is the mean Earth-Sun distance, and is about 1.5 x 101.5 x 1088 km ( 150 million km) km ( 150 million km)

UNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMYUNITS in ASTRONOMY Temperature:Temperature:

Use Degrees Kelvin (K)Use Degrees Kelvin (K) K = C + 273K = C + 273 C water freezes at 0C boils at 100CC water freezes at 0C boils at 100C K water freezes at 273K boils at 373KK water freezes at 273K boils at 373K Room Temperature about 300KRoom Temperature about 300K 0K = - 273C is absolute 00K = - 273C is absolute 0

ANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENT

0°360 degrees

90 degrees

180 degrees

270 degrees

ANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENT360 degrees in a full circle

1 degree = 60 minutes1 minute = 60 seconds

ANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENTANGULAR MEASUREMENT

FLASHCARDFLASHCARDFLASHCARDFLASHCARD

WHAT IS THE ANGULAR SIZE OF THE WHAT IS THE ANGULAR SIZE OF THE MOON AS SEEN FROM THE EARTH?MOON AS SEEN FROM THE EARTH?

A)A) 0.5 degree0.5 degree

B)B) 5 degrees 5 degrees

C)C) 10 degrees 10 degrees

D)D) 50 degrees 50 degrees