• Stellar astronomy 
    • the study of the objects that lie beyond the solar system and the processes by which these objects interact with one another
  • Scientific Method
    • Ask a “simple” question
    • Research the question
    • Formulate a Hypothesis (An educated guess, not a theory)
    • Test your hypothesis (design an experiment)
    • Analyze your data and develop a “theory” (based on facts, evidence)
    • Must be subject to peer review 
  • Critical Thinking
    • Exploring misinformation and disinformation 
    • Extraordinary claims require Extraordinary evidence 
    • All things considered; the simplest explanation is usually the best 
    • Humans have always been terrible at understanding coincidences
    • What is your evidence? What is your source?
    • How reliable is that source? Who decides its reliability?
    • There are NO alternative facts
    • Science has always been a “work in progress”
  • The Roots of Astronomy 
    • The ancients required knowledge of the sky in order to survive
    • They used the sky:
    • As a calendar (seasons)
    • For navigation
    • For story telling
    • And then there was Curiosity
    • Most early civilizations used lunar cycles as their calendars
  • Why was understanding the sky so important for survival?
    • When to plant their crops, when to harvest
    • When herds were migrating
    • When they should migrate
    • When was it safe to travel into the mountains for hunting and gathering?
    • Understanding the timing of ocean tides for fish and travel
  • Determined Seasons using the sun 
    • Stonehenge: Summer solstice
    • Newgrange: Winter solstice
    • Chichen Itza: Equinoxes
  • Determined seasons using the stars
    • Summer and spring have different star systems
  • Navigation
    • Used Polaris as a “North, South Landmark
    • Minoans used Hydra as their “West, East Landmark”
  • Curiosity 
    • What were the wanderers? What were meteors? What were comets? Why did the moon change shape? What were eclipses?
  • Most common problems Astronomers face
    • We cannot touch what we are studying
    • The only thing we can study is its light
    • Enormous distances
    • Difficult to measure distances accurately. Without distance, there are many properties we can't understand 
    • Enormous sizes/masses/densities/speeds
    • Requires “new” physics, Special and general Relativity, Particle Physics and more 
    • Time (millions and billions of years)
    • Difficult to reconstruct histories, can only be determined by studying “populations” of objects 
  • Spectroscopy 
    • The study of an object’s light
    • Wavelength, absorption lines, hydrogen, sodium, calcium etc
  • Ground based telescopes 
  • Space telescopes
  • James Webb telescope (JWST)
  • Laboratory research
  • Measuring distances in astronomy
    • One astronomical unit (AU) is 93 million miles, average distance from the earth to the sun
    • One light year (LY)  is the distance light travels in one year
    • One parsec (PC) is 3.26 light years
    • At 65 Mph it would take 163 years to drive to the sun, 1AU
    • 100,000
  • Light travel units (LTU)
    • Speed of light is 186,000 miles a second or 300,000 km a second
    • Light second is the distance light travels in one second
    • Moon is 1.3 light seconds away
    • Light minute is the distance light travels in one minute 
    • The sun is 8.3 light minutes away
    • Light hour, light day, light year etc
  • How far can you see without telescopes (naked eye)
    • The farthest planet you can see is Uranus, 2 hours 40 light minutes
    • The farthest star you can see is 16,000 ly in Cassiopeia 
    • The farthest object you can see naked eye is the Andromeda Galaxy, 4.3 million ly
  • Where are we?
    • Earth in Sol’s system, located in the solar neighborhood, high is a group of stars located in the Milky Way galaxy
    • Diameter: 140,000 light years across 
    • Around 1.5 trillion masses (100-400 billion stars)
    • The sun is located around 30,000 ly from the center of the galaxy 
    • Milky Way is located in the “local group” of galaxies
    • Approximately 80 galaxies
    • The area between galaxies is called “intergalactic space”
    • Galaxy groups are organized into galaxy clusters
    • Our local group is located in the Virgo cluster 
    • Clusters are organized into superclusters 
    • The Virgo cluster is located in the Virgo supercluster (laniakea)
    • Superclusters are organized into filaments and walls 
    • Visible universes
    • 5% of the universe is made out of visible matter 
    • 27% is made out of dark matter
    • 68% is made out of dark energy

      Deep Sky Objects       The Constellations       Areas of the sky       Pareidolia       Illusion of. Recognizable image where none exists       The face on the surface features of the moon       Asterism       An asterism is a recognizable pattern of stars       Big Dipper, Little Dipper, Orion       The classical constellations       48 classical constellations were described by Ptolemy in “Almagest” which was written in 120 AD       Pallets of marker-3200 BC       The oldest known constellations       Bayer Catalogue: southern sky       Some defunct constellations… Felis (the cat) noctura (the owl)       Using constellations       Mnemonics       Navigational aids       Art       Rituals and calendars       As storytelling mnemonics       The story of Perseus and Andromeda       Navigation       Urea Major: the Drinking Gourd- Polaris is North       Art       Altas- Palace of Farnese, Rome       Starry Night- Van Gogh       Astronomical Alignments       Lakota Medicine Wheel       Mayan Celestial Alignments       Modern Constellations       A constellation is an area of the sky       The sky is divided into 88 official constellations. Most are based upon the constellations of the Ancient Greek tradition and contains the signs of the zodiac       The 13 constellations of the Zodiac are called the Zodiacal Constellations       Star names       Individual stars can have many names       Naming the stars       Star names and designations       Proper names       Bayer designations       Flamsteed designations       Proper names of stars       Most bright star names are Arabic       They begin with “Al”, which means “the”       Algol-the ghoul, Alioth-the black horse, Alkaid-the leader of the recession of mourners, Alnilam-the string of pearls Alnitak-the belt       Bayer designations       All stars have other names       The Bayer designation uses the Greek alphabet to designate the stars. The brightest star is the alpha star, the second brightest is the beta star, etc       The Greek letter can then be followed by “in” and the constellation name, or the constellation’s genitive (possessive name)       Example the brightest star in Orion would be (alpha) in Orion       Alpha, beta, gamma, delta, epsilon, zeta, eta, theta, iota, kappa, lambda, mu, nu, xi, omicron, pi, rho, sigma, tau, upsilon, phi, chi, psi, omega       Flamsteed designation       Stars can also have a “Flamsteed number”       25 in Orion; 25 Orionis       Drake Equation       N=R*. Fp x ne x fl x fi x fc x L       N= number of civilizations with which humans could communicate       R*= mean rate of star formation       Fp= fraction of stars that have planets       Ne= mean number of lancets that could support life per star with planets       Fl= fraction of life supporting planets that develop life       Fi= fraction of planets with life where life develops intelligence       Fe= fraction of planets with life where life develops intelligence       Fe= fraction of intelligent civilizations that develop communication       L= mean length of time that civilizations can communicate       Charles Messier 1730-1817 (will be on quiz)       Comet hunter       Nicknamed the Comet Ferret       August 1758, discovery of Messier Object #1       Commonly called M1       Galaxies       The largest entities in the universe       Huge accumulations from several million to hundreds of trillions of stars       Nebulae-4 types       Clouds of dust and gas, remnants of dying or dead stars       Emission Nebula       Emits light and glow as newly formed stars ionize the gases       The red color is caused by the ionization of hydrogen gases       The “birthplaces” of new stars       Evolve to become “open clusters”       Reflection Nebula       The bluish white light is created as light from newly formed stars is reflected off left over dust grains       Absorption Nebula       Also called “dark nebula”, are dust clouds which block light       Orion Nebula, Horsehead Nebula       Planetary Nebula       Ejected envelopes of red giant stars       Appear as expanding, symmetrical clouds of gas with shapes similar to “smoke rings”       Supernova Remnants       Remnants of a massive star, greater than 8 solar masses, which has violently exploded       The Fate of a Star, whether or out it ends its life as a Planetary Nebula, SuperNova, Neutron Star, Black hole, etc, is determined by its MASS       M1 The Crab Nebula       A bright supernova recorded by Chinese and Arab astronomers in 1054       Located at a distance of about 6.5k light years       Star Clusters       Two categories of Clusters       Globular Clusters       Ancient stars: 10-12 billion years old as old or older than the galaxies       Cool “red” stars       Population 10k-1 million stars       Separated by light weeks/months       Found in the “halo” of the galaxy       Open Clusters       Also called Galactic Clusters       Young, newly formed stars… “blue and white” stars       Population: 10-300 stars       Found within the plane of the galaxy       Binary Star Systems       Star system made up of two gravitationally bound stars       Messier 40, double star M40 (WNC 4) in Ursa Major       The celestial sphere       A rotating crystalline sphere to which the celestial bodies are attached       The belief that everything revolves around the Earth       Celestial Equator       Imaginary line that divides the celestial sphere into Northern and Southern Hemispheres       Meridian       Imaginary line that runs from the north to the south and divides the Celestial Sphere into East and West Hemispheres       North/South Celestial Poles (NCP)-(SCP)       The north and south celestial poles are the two magi army points in the sky where the Earth’s axis is extended out onto the celestial sphere       Ecliptic       Apparent path of the Sun, Moon and planets through the background stars of the Zodiacal constellations