Course Course Website: – Textbook: –Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. You also will need a calculator.

Office Hours Mine Tuesday, Thursday - 1:15-2:15pm Lederle Graduate Research Tower C 632 Neil Tuesday, Thursday - 11 am-noon Lederle Graduate Research Tower B 619-O

Homework We will use Spark owebcthttps://spark.oit.umass.edu/webct/logonDisplay.d owebct Homework will be due approximately twice a week

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

Homework #2 (due Tuesday) 10 questions In Assessment on Spark

Why should we learn about the Solar System? the-tv.phphttp:// the-tv.php

Metric System 1 kilometer = 1,000 meters 1 meter = 100 centimeters 1 centimeter = 10 millimeters

Distances An Astronomical Unit (AU) is the average distance between the Sun and Earth 1 AU = 150 x 10 6 km = 150 x 10 9 m 1 light-year is the distance light travels in a year 1 light-year = 9.5 × meters

Scientific Notation = = = = = = 10 -7

How do you write numbers? 31,700,000 = 3.17 x ,770,000 = 2.77 x = 5.6 x = 7.8 x 10 -6

How do you do multiply? 10 6 x 10 8 = 10 (6+8) = x 10 3 = 10 (-5+3) = (3 x 10 4 ) x (4 x 10 5 ) = 12 x 10 (4+5) = 12 x 10 9 = 1.2 x 10 10

How do you divide? 10 8 /10 6 = 10 (8-6) = /10 -4 = 10 (-6-(-4)) = (3 x 10 8 )/(4 x 10 3 ) = ¾ x 10 (8-3) = 0.75 x 10 5 = 7.5 x 10 4

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

When we are looking at stars or galaxies We are looking into the past Light-year is the distance light travels in a year.

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

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

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

Answer Number of stars in universe = (100 x 10 9 ) x (100 x 10 9 ) = x = 1 x = 10,000,000,000,000,000,000,000 This is about the same number of grains of sand in every beach in the world

Questions: How many of these stars have planets? How many of these planets have life?

My Very Eager Mother Just Served Us Nine Pizzas

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

Does anyone play basketball?

Assume That the sun is the same size as a basketball Basketball diameter = 24.4 cm Sun’s Diameter = 1.4 x 10 9 m = 1.4 x cm Scale Factor = 1.74 x Multiply scale factor by actual diameters of planets to get their approximate size

Mercury Diameter = 4.88 x 10 6 m Multiply by scale factor (1.74 x ) Relative Diameter = 8.5 x m = 0.85 mm

Mariner 10 Messenger

Venus Diameter = 1.21 x 10 7 m Multiply by scale factor (1.74 x ) Relative Diameter = 2.1 x m = 2.1 mm

Mariner 10

Earth Diameter = 1.28 x 10 7 m Multiply by scale factor (1.74 x ) Relative Diameter = 2.2 x m = 2.2 mm

Apollo 17

Mars Diameter = 6.80 x 10 6 m Multiply by scale factor (1.74 x ) Relative Diameter = 1.2 x m = 1.2 mm

Hubble Space Telescope

Jupiter Diameter = 1.43 x 10 8 m Multiply by scale factor (1.74 x ) Relative Diameter = 2.5 x m = 25 mm = 2.5 cm

Voyager 1

Saturn Diameter = 1.21 x 10 8 m Multiply by scale factor (1.74 x ) Relative Diameter = 2.1 x m = 21 mm = 2.1 cm

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). Cassini

Uranus Diameter = 5.18 x 10 7 m Multiply by scale factor (1.74 x ) Relative Diameter = 9.0 x m = 9 mm

Voyager 2

Neptune Diameter = 4.95 x 10 7 m Multiply by scale factor (1.74 x ) Relative Diameter = 8.5 x m = 8.5 mm

Voyager 2

Pluto Diameter = 2.30 x 10 6 m Multiply by scale factor (1.74 x ) Relative Diameter = 4.0 x m = 0.4 mm

Hubble Telescope

Scientific method

What is a constellation?

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

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.

What is this constellation?

Orion Bigger the star, the brighter it is

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.

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

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

Originally considered part of Leo’s tail

Named after Queen Berenice II of Egypt, wife of Ptolemy III Euergetes (246 BC 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.

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.

Question: Why do all the planets seem to follow the same path?

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

Why don’t all the constellations have ancient names?

Ancient cultures such as the Greeks and Egyptians could not see the constellations in the Southern Hemisphere

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

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

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.

Question: How can do know that the sun is travelling along the zodiac since you can’t see stars during the day?

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.

Any Questions?