PHYS Astronomy Dr. Phillip Anderson

PHYS Astronomy Fall 2015 –INSTRUCTOR: –Dr. Phillip C. Anderson — Room PHYS (and WSTC1.720) –TEACHING ASSISTANT: –Liu, Xu –OFFICE HOURS: –Dr. Anderson: MW 12:00 PM – 2:00 PM and by appointment –Mr Liu: F 2:00 - 4:00 PM and by appointment - location TBD

PHYS Astronomy Fall 2014 TEXT: –Foundations of Astronomy, Seeds, 12th Edition See me if you have an older edition –Slides will be available on web at GRADING: –Exams (3) 2 Exams (Oct 5, Nov 20% each = 40% Final Exam (Dec 2:00 PM)= 30% –Homework= 20% Homework will be assigned weekly and will be due a week later. Late homework will not be accepted. It is considered late after 3:45 PM seven days after assigned unless otherwise specified.. –Projects = 10% –Attendance will be taken every class period and will be used to decide whether to raise or lower grades on the cusp.

PHYS Astronomy Follow the links to each class’s notes(at They will be available at least the day before the class. Any movies in the notes will be separated out and put in a separate directory. They can be played with Quicktime or may be html animations that can be run through your web browser. The exams will only cover material discussed in class. It would behoove you to read the relevant material in the book before/after class as it may provide a different perspective on the material that will help you understand it better than the lecture and class notes alone. Note that some of the material covered in the lecture will not be in the text - it is very important to attend class.

PHYS Astronomy Project 1 1. Find a location from where you can observe either the sunrise or sunset. Note some landmarks, such as trees or light poles, etc. Make a sketch of the location and on the sketch plot the position on the horizon that the sun either rises or sets (morning or evening). Record the date and the time when you first see the sun rise or last see it set. Do this about once per week consistent with weather conditions. You MUST have at least 3 months of observations. 2. Write a three to four page paper on: A.How and where you made your observations. B.How did the sunrise or sunset position change with time? C.How fast did it change? Was the change uniform over the three month period? D.Why did the sunrise or sunset position move as you observed it. E.What problems did you encounter in doing this project and how did you solve those problems? 3.The project is to be turned at the final (Dec 14).

PHYS Astronomy Project 2 1. Plot the location and phase of moon over a complete synodic month, e.g., from new moon to new moon on an all-sky diagram as shown below. In an all-sky diagram, zenith is at the center and the edge of the circle is the horizon with the compass points indicated as in the figure. Estimate the compass direction of the moon (use a compass or the north star) and the angle of the moon above the horizon. Plot its location on the diagram using: (distance from edge of the circle to moon location)/radius = (angle above the horizon)/90 location around circle = cardinal direction (N,S,E,W)

PHYS Astronomy In the example in the diagram, the moon is in the southeast, 30 degrees above the horizon. Draw a picture of the moon at the location as it appears, in other words its phase. Do it at the same time every night. Obviously there will be times when the weather does not cooperate but there should be at least 15 nights in which you perform the observation.

PHYS Astronomy 2. Write a three to four page paper on: A.How and where you made your observations. B.How did the moon’s position and appearance change with time? C.How fast did they change? Was the change uniform over the observation period? D.Why did the moon’s position and appearance move as you observed it? E.What problems did you encounter in doing this project and how did you solve those problems? 3. The project is to be turned in at the final (Dec 14).

PHYS Astronomy SYLLABUS - Fall 2015 Chapters 1,2, & 3The Night Sky Chapter 4History of Modern Astronomy Chapter 5Newton, Einstein, and Gravity Chapter 6Light and Telescopes Chapter 7Information from Distant Objects Chapter 8The Sun Chapter 9Determining the Observable Properties of Stars Chapters 10 & 11Interstellar Medium and Star Formation Chapter 12The Evolution of Stars Chapters 13 & 14The Deaths of Stars Chapters 15 & 16Galaxies Chapter 18Cosmology Chapter 26Life in the Universe

PHYS Astronomy SCALES OF DISTANCE Astronomical Unit AUAverage distance between the Earth and the Sun Light YearLYDistance light travels in one Year 1 LY = 186,000 Miles/Second x 31,500,000 Seconds = 5.8 x Miles ParsecPCDistance of an object that would have a stellar parallax of 1 Second of Arc 1 PC = 3.26 LY = 206,000 AU AngstromAA distance of 1x10 -8 cm Visible Light has wavelengths from 4000 to 7000 A NanometernmA distance of meter or cm Visible light has wavelengths from 400 to 700 nm

PHYS Astronomy Our Place in the Cosmos

PHYS Astronomy From Earth to the Moonour natural satellite1.25 seconds From Earth to the Sunthe centre of our Solar System8.3 min From the Sun to Jupiterthe largest planet41 min From the Sun to Saturnthe furthest naked eye planet85 min From the Sun to Pluto5.5 hr From the Sun to Alpha Centaurithe nearest star to us4.3 yr From the Sun to Siriusthe brightest star in our sky8.6 yr Distance where the Sun would no longer be visible to naked eye60 yr From the Sun to Polaristhe north pole star650 yr From the Sun to the Galactic centre the centre of our Galaxy31,000 yr Galactic diameterthe diameter of our Galaxy81,500 yr To the Andromeda Galaxythe nearest large galaxy2,200,000 yr Extinction of the dinosaurs65,000,000 yr To Q typical quasar4,500,000,000 yr Formation of the Earth and Sun4,700,000,000 yr To remotest quasarsdiscovered in ,000,000,000 yr Edge of Universelimit of observable Universe15,000,000,000 yr Light Travel Time

PHYS Astronomy 1.25 s

PHYS Astronomy The Solar System 8.3 min 41 min 85 min 5.5 hr

PHYS Astronomy

Alpha Centauri - closest star LY Our Milky Way Galaxy

PHYS Astronomy The Milky Way

PHYS Astronomy Spiral Galaxies Similar to the Milky Way View from above Edge view

PHYS Astronomy The Milky Way The Sun is located on the Orion spiral arm about 30,000 LY from the galactic center It takes about 230 million years for the sun to complete one orbit around the galactic center

PHYS Astronomy Other Galaxies in Our Local Group The Andromeda Galaxy 2.3 million LY away A Ring Galaxy

PHYS Astronomy Deep field view - about 10 billion LY away

PHYS Astronomy  In our galaxy there are about 200 billion stars  In our universe there are over 100 billion galaxies There are more stars in the universe than there are grains of sand on the Earth

PHYS Astronomy If the Universe was one year old (instead of 13.7 billion years) The Cosmic Calendar (Carl Sagan)

PHYS Astronomy meters = 1000 yottameters 100 Billion Light Years This image represents the size of the known universe -- a sphere with a radius of 13.7 billion light years.

PHYS Astronomy meters = 100 yottameters Ten Billion Light Years Light from galaxies on the edge would require 5 billion years to reach the center. Observers at the center are seeing light that was emitted by these galaxies before the solar system formed. The largest scale picture ever taken. Each of the 9325 points is a galaxy like ours. They clump together in 'superclusters' around great voids which can be 150 million light years across.

PHYS Astronomy meters = 10 yottameters One Billion Light Years Astronomers have determined that the largest structures within the visible universe - superclusters, walls, and sheets - are about 200 million light years on a side.

PHYS Astronomy meters = 1 yottameter 100 Million Light Years Clusters of Galaxies

PHYS Astronomy meters = 100 zettameters 10 Million Light Years Within the Virgo Cluster

PHYS Astronomy meters = 10 zettameters 1 Million Light Years The Local Group - Our galaxy with the Magellanic Clouds - two companion galaxies on the right.

PHYS Astronomy Our galaxy - the Milky Way - looks rather like a whirlpool. It has spiral arms curling outwards from the center and rotates at about 900 kilometres per hour. It contains about 200 billion stars meters = 1 zettameter 100,000 Light Years

PHYS Astronomy meters = 100 exameters 10,000 Light Years Our Spiral Arm

PHYS Astronomy meters = 10 exameters 1,000 Light Years The Stars of the Orion Arm

PHYS Astronomy meters = 1 exameter 100 Light Years Stars within 50 Light Years

PHYS Astronomy meters = 100 petameters 10 Light Years The Nearest Stars

PHYS Astronomy meters = 10 petameters 1 Light Year The Oort Cloud

PHYS Astronomy meters = 1 petameter 0.1 Light Year Sol - our Sun

PHYS Astronomy meters = 100 terameters Our Sun and a few rocks

PHYS Astronomy The solar system. Only the orbit of Pluto is off the picture meters = 10 terameters

PHYS Astronomy Within the orbit of Jupiter - the orbits of the inner four planets : Mercury, Venus, Earth and Mars. All four have rocky crusts and metallic cores meters = 1 terameter

PHYS Astronomy Six weeks of the Earth's orbit. The orbits of Venus and Mars are just visible on either side meters = 100 gigameters

PHYS Astronomy Four days of the Earth's orbit meters = 10 gigameters

PHYS Astronomy The moon's orbit around the Earth, the furthest humans have ever traveled meters = 1 gigameter

PHYS Astronomy 10 8 meters = 100 megameters Earth

PHYS Astronomy North and Central America 10 7 meters = 10 megameters

PHYS Astronomy 10 6 meters = 1 megameter California

PHYS Astronomy 10 5 meters = 100 kilometer The San Francisco Bay Area

PHYS Astronomy 10 4 meters = 10 kilometers San Francisco

PHYS Astronomy 10 3 meters = 1 kilometer Golden Gate Park

PHYS Astronomy Japanese Tea Garden - one hectare (10,000 m 2 ) 10 2 meters = 100 meters

PHYS Astronomy A pond with lily pads 10 1 meters = 10 meters

PHYS Astronomy A one-meter square 10 0 meters = 1 meter

PHYS Astronomy meters = 10 centimeters A bee on a lily pad flower

PHYS Astronomy A bee's head meters = 1 centimeter

PHYS Astronomy A bee's eye meters = 1 millimeter

PHYS Astronomy Pollen meters = 100 micrometers

PHYS Astronomy Bacteria meters = 10 micrometers

PHYS Astronomy Virus on a bacterium meters = 1 micrometer

PHYS Astronomy A virus meters = 100 nanometers

PHYS Astronomy The structure of DNA meters = 10 nanometers

PHYS Astronomy The molecules of DNA meters = 1 nanometer

PHYS Astronomy Carbon's outer electron shell meters = 100 picometers

PHYS Astronomy The inner electron cloud meters = 10 picometers

PHYS Astronomy Within the electron cloud meters = 1 picometer

PHYS Astronomy The nucleus meters = 100 femtometers

PHYS Astronomy The nucleus of carbon meters = 10 femtometers

PHYS Astronomy A proton meters = 1 femtometer

PHYS Astronomy Within the proton meters = 100 attometers

PHYS Astronomy Quarks and gluons meters = 10 attometers

PHYS Astronomy Constellations Constellations - groupings of stars named after mythical heroes, gods, and mystical beasts - made up over at least the last 6000 years - maybe more - used to identify seasons: - farmers know that for most crops, you plant in the spring and harvest in the fall. - in some regions, not much differentiation between the seasons. - different constellations visible at different times of the year - can use them to tell what month it is. For example, Scorpius is only visible in the northern hemisphere's evening sky in the summer. - many of the myths associated with the constellations thought to have been invented to help the farmers remember them - made up stories about them

PHYS Astronomy Picture at right shows a start chart of the region around the constellation Orion. Picture at the left is an ornate star chart printed in shows the great hunter Orion. He is holding a lion's head instead of his traditional bow or shield. He is stalking Taurus, the Bull in the upper right hand corner. Behind him, his faithful dog, Canis Major, is chasing Lepus, the Hare.

PHYS Astronomy In modern world - constellations redefined so now every star in the sky is in exactly one constellation. In 1929, the International Astronomical Union (IAU) adopted official constellation boundaries that defined the 88 official constellations that exist today. asterisms - less formally defined groupings - Big Dipper - part of Ursa Major - Start clusters - Beehive, Pleiades, etc - Orion’s belt - Northern Cross - formed by the leading stars of the constellation Cygnus Constellations Western culture constellations originated in Mesopotamia over 5000 years ago- added to by Babylonian, Egyptian, and Greek astronomers - current list is based on those listed by the Roman astronomer, Claudius Ptolemy (~140 AD)

PHYS Astronomy The Orion Nebula

PHYS Astronomy Nebulae Nebula - an interstellar cloud of dust, hydrogen gas and plasma. One of the most beautiful sights in the universe Birthplaces of stars

PHYS Astronomy The Orion Nebula Located in the sword of the constellation Orion.

PHYS Astronomy The Orion Nebula

PHYS Astronomy Proplyds or Proto Solar Systems in the Orion Nebula

PHYS Astronomy Gaseous Pillars - Stellar Nursery