Course

1
Course

• Course Website
• http//blogs.umass.edu/astron101-tburbine/
• Textbook
• Pathways to Astronomy (2nd Edition) by Stephen
  Schneider and Thomas Arny.
• You also will need a calculator.

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Office Hours

• Mine
• Tuesday, Thursday - 115-215pm
• Lederle Graduate Research Tower C 632
• Neil
• Tuesday, Thursday - 11 am-noon
• Lederle Graduate Research Tower B 619-O

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Homework

• We will use Spark
• https//spark.oit.umass.edu/webct/logonDisplay.dow
  ebct
• Homework will be due approximately twice a week

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Homework 1 (Due today)

• Find an article concerning a topic concerning the
  Solar System and write about why you found it
  interesting.
• Include the name of the article and where it was
  published.
• Submit using Spark

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Homework 2 (due Tuesday)

• 10 questions
• In Assessment on Spark

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Why should we learn about the Solar System?

• http//www.thisistheend.com/2009/08/the-ihc-on-the
  -tv.php

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Metric System

• 1 kilometer 1,000 meters
• 1 meter 100 centimeters
• 1 centimeter 10 millimeters

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Distances

• An Astronomical Unit (AU) is the average distance
  between the Sun and Earth
• 1 AU 150 x 106 km 150 x 109 m
• 1 light-year is the distance light travels in a
  year
• 1 light-year 9.5 1015 meters

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Scientific Notation

• 10000 104
• 100000000 108
• 10000000000 1010
• 100000000000000000000 1020
• 0.001 10-3
• 0.0000001 10-7

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How do you write numbers?

• 31,700,000 3.17 x 107
• 2,770,000 2.77 x 106
• 0.00056 5.6 x 10-4
• 0.0000078 7.8 x 10-6

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How do you do multiply?

• 106 x 108 10(68) 1014
• 10-5 x 103 10(-53) 10-2
• (3 x 104 ) x (4 x 105) 12 x 10(45) 12 x 109
  1.2 x 1010

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How do you divide?

• 108/106 10(8-6) 102
• 10-6/10-4 10(-6-(-4)) 10-2
• (3 x 108)/(4 x 103) ¾ x 10(8-3) 0.75 x 105
  7.5 x 104

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What is a galaxy?
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What is a galaxy?

• Is a massive, gravitationally bound system
  consisting of stars, gas and dust, and dark
  matter. Galaxies can contain between ten million
  and a trillion stars
• Dark matter is matter that does not emit or
  reflect enough radiation to be seen, but whose
  gravitation effects can be felt

http//en.wikipedia.org/wiki/ImageNGC_4414_28NAS
A-med29.jpg
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When we are looking at stars or galaxies

• We are looking into the past

Light-year is the distance light travels in a
year.
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Milky Way Galaxy

• Milky Way is 100,000 light-years in diameter
• There are 200 billion stars in the Milky Way
  (estimates from 100-400 billions stars)

http//www.venusproject.com/ecs/images/photos/gala
xy.jpg
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What is the Universe?
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What is the Universe?

• Sum total of all matter and energy all galaxies
  and everything between them
• Observable universe portion of the universe
  that can be seen from Earth, probably only tiny
  portion of the whole universe

93 billion light-years wide
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How many stars in the Universe

• Say there are 100 billion galaxies
• Each galaxy has 100 billion stars
• So how many stars in the universe

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Answer

• Number of stars in universe
• (100 x 109) x (100 x 109) 10000 x 1018
  1 x 1022 10,000,000,000,000,000,000
  ,000
• This is about the same number of grains of sand
  in every beach in the world

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Questions

• How many of these 1022 stars have planets?
• How many of these planets have life?

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• My Very Eager Mother Just Served Us Nine Pizzas

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• My - Mercury
• Very - Venus
• Eager - Earth
• Mother - Mars
• Just - Jupiter
• Served - Saturn
• Us -Uranus
• Nine -Neptune
• Pizzas - Pluto

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Does anyone play basketball?
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Assume

• That the sun is the same size as a basketball
• Basketball diameter 24.4 cm
• Suns Diameter 1.4 x 109 m 1.4 x 1011 cm
• Scale Factor 1.74 x 10-10
• Multiply scale factor by actual diameters of
  planets to get their approximate size

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Mercury

• Diameter 4.88 x 106 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 8.5 x 10-4 m 0.85 mm

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Mariner 10
Messenger
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Venus

• Diameter 1.21 x 107 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 2.1 x 10-3 m 2.1 mm

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Mariner 10
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Earth

• Diameter 1.28 x 107 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 2.2 x 10-3 m 2.2 mm

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Apollo 17
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Mars

• Diameter 6.80 x 106 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 1.2 x 10-3 m 1.2 mm

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Hubble Space Telescope
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Jupiter

• Diameter 1.43 x 108 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 2.5 x 10-2 m 25 mm 2.5 cm

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Voyager 1
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Saturn

• Diameter 1.21 x 108 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 2.1 x 10-2 m 21 mm 2.1 cm

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Cassini
Six moons are in the picture Titan (5,150
kilometers across), Janus (179 kilometers
across), Mimas (396 kilometers across), Pandora
(81 kilometers across), Epimetheus (113
kilometers across) and Enceladus (504 kilometers
across).
http//en.wikipedia.org/wiki/FileSaturn_during_Eq
uinox.jpg
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Uranus

• Diameter 5.18 x 107 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 9.0 x 10-3 m 9 mm

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Voyager 2
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Neptune

• Diameter 4.95 x 107 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 8.5 x 10-3 m 8.5 mm

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Voyager 2
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Pluto

• Diameter 2.30 x 106 m
• Multiply by scale factor (1.74 x 10-10)
• Relative Diameter 4.0 x 10-4 m 0.4 mm

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Hubble Telescope
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Scientific method
https//www.msu.edu/course/isb/202/snapshot.afs/ts
ao/images/scientific_method01.gif
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What is a constellation?
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Constellations

• People refer to constellations as a pattern of
  stars
• Astronomers refer to constellations as specific
  regions of the sky
• In 1928, the IAU (International Astronomical
  Union) decided there were 88 constellations
• Many of the constellation names go back thousands
  of years

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Constellations

• The constellations are totally imaginary things
  that poets, farmers and astronomers have made up
  over the past 6,000 years (and probably even
  more!).
• The real purpose for the constellations is to
  help us tell which stars are which, nothing more.

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What is this constellation?
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Orion
Bigger the star, the brighter it is
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Orion was the son of the god of the sea,
Poseidon and a great hunter. One story is that he
made an enemy of Hera who sent a scorpion to
sting him. Orion was restored to health by
Ophiuchus, the first doctor of medicine.
Another story is that Artemis was tricked by by
Apollo to shoot an arrow at Orion. When he
died, Poseidon asked Zeus to put him among the
stars.
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Ursa Major

• Ursa Major, the Great Bear, was identified with a
  bear by native American Indians of the
  Northeastern United States and the ancient
  Greeks.
• The name common in Britain, the Plough,seems to
  have a medieval origin,
• Another common name among northern European
  cultures is the Wain, a shortened form of wagon

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What are the constellations named after

• 14 men and women
• 9 birds
• 2 insects
• 19 land animals
• 10 water creatures
• 2 centaurs
• one head of hair
• a serpent
• a dragon
• a flying horse
• a river
• 29 inanimate objects

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• Originally considered part of Leos tail

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• Named after Queen Berenice II of Egypt, wife of
  Ptolemy III Euergetes (246 BC - 221 BC)
• Around 243 BC, the king undertook a dangerous
  expedition against the Syrians, who had murdered
  his sister.
• Berenice swore to the goddess Aphrodite to
  sacrifice her famous long hair if her husband
  returned safely.
• He did, she had her hair cut, and placed it in
  the goddess' temple.
• By the next morning, the hair had disappeared.
• To appease the furious king and queen (and save
  the lives of the temple priests), the court
  astronomer, Conon, announced that the offering
  had so pleased the goddess that she had placed it
  in the sky.
• He indicated a cluster of stars that at the time
  were identified as Leo's tail, but now have been
  called Berenice's Hair.

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Zodiac

• The zodiac is an imaginary belt in the heavens
  extending approximately 8 degrees on either side
  of the Sun's apparent path (the ecliptic), that
  includes the apparent paths of the Moon and the
  planets Mercury, Venus, Mars, Jupiter, Saturn,
  Uranus, and Neptune.

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Question

• Why do all the planets seem to follow the same
  path?

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Answer

• The planets, the Earth, and the Sun all tend to
  fall in the same plane called the ecliptic

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Why dont all the constellations have ancient
names?
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• Ancient cultures such as the Greeks and Egyptians
  could not see the constellations in the Southern
  Hemisphere

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Question

• Why is the path of the constellations on the
  zodiac not on the celestial equator?

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Answer

• The rotation axis of the Earth is inclined with
  respect to the ecliptic

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• Polaris is called the North Star
• Brightest star in the constellation Ursa Minor.
• 48th brightest star in the night sky
• It is very close to the north celestial pole,
  making it the current northern pole star.
• Polaris' altitude, or height above the horizon,
  is equal to an observer's latitude.

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Question

• How can do know that the sun is travelling along
  the zodiac since you cant see stars during the
  day?

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Answer

• One can however figure out where the sun is on
  the zodiac by noting which is the last
  constellation of the zodiac to rise ahead of the
  Sun or the first to set after it.

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Any Questions?