1 Passport Science Space Unit – Part 1 of 3 PowerPoints (Textbook reference Chapters 12, 13, 14, 15 and 16)

What is astronomy?

Stars Nebula Planets The Sun The Great Andromeda Galaxy by George Greaney Star clusters Galaxies Galaxy clusters Dark matter Black holes

What is astronomy? Astronomy is a science that attempts to understand the make-up and the history of the universe. Galaxy M83 in Hydra by George Greaney

M33, The Pinwheel Galaxy in Triangulum by George Greaney What is astronomy? M33, The Pinwheel Galaxy in Triangulum by George Greaney

Basically, if its off this planet its a study of some realm of astronomy. As one might imagine that covers an awful lot of subjects, even more than we know right now. NGC 253, galaxy in Sculptor by George Greaney

Key Ideas Galaxies: clusters of stars; different shapes Stars: Sun; differ in size, temperature and color; source for all bright objects Gravity: planets, stars, solar system Know the appearance, composition, position and size, and motion of objects in our solar system Astronomical units for measuring 7

What is a Meteor? What is a Comet? What is a Star? What is a Nebula? What is an Open Cluster? What is a Black Hole? What is a Quasar? ? ? ? ? ? ?

Galileo Galilei ( ) What is an astronomer ? A night watchman with a college education?

Galileo Observatory in Italy An astronomer is a scientist, skilled in mathematics, physics, and astronomy. Most professional astronomers work for universities or government agencies. Source: The Berkeley Cosmology Group

Astronomer Serena Kim at work At Cerro Tololo in Chili Few astronomers spend much time looking through a telescope. Most operate telescopes from a control room or even from their computer at home via the Internet. Typical astronomers only spend one or two weeks each year observing, and the rest of their research time analyzing their data. Source: Applied Theoretical and Computational Physics Division Los Alamos National Laboratory

Amateurs and their tools What is an amateur astronomer?

Although the term has different meanings for different people, a basic definition would include anyone who looks into the sky, and wants to see or learn more.

What is space like? No air No gravity-when you’re not very close to a planet, sun, or moon No wind No friction No real “up” or “down” No pressure

15 The Expanding Universe 15-5 The Big Bang Theory

What is a “galaxy”? (Textbook reference 15-4) A large group of stars outside of our own Milky Way Made of billions to trillions of stars –Also may have gas and dust Spiral, or elliptical, or irregular shaped –The Milky Way Galaxy is a spiral galaxy. Image at

Spiral galaxy--Andromeda NOAO/AURA/NSF Images at and

Elliptical Galaxies Images at and

Irregular Galaxies NASA and NOAO/AURA/NSF Images at and

Our Galaxy: the Milky Way has about 200 billion stars, and lots of gas and dust is a barred-spiral (we think) about 100,000 light-years wide (a measure of distance) our Sun is halfway to the edge, revolving at half a million miles per hour around the center of the Galaxy takes our Solar System about 200 million years to revolve once around our galaxy

The Milky Way Image at

Mapping the Milky Way We can see –stars –star clusters –nebulae –galaxies How do we know what our galaxy looks like?

23 Reviewing Galaxies Groups of stars, planets, and space debris Irregular, Elliptical, Spiral Milky Way is our galaxy

What Is a Star? Image of the Sun from Goddard Space Flight Center

What is a Star? Our Sun is the closest star. At the simplest, a star is just a ball of gas that has condensed out of interstellar material. The largest part of its lifetime is spent as a main sequence star during which hydrogen is being converted to helium balancing gravitational contraction so that the radius and energy output remain almost constant. Source: The British Astronomical Association

26 Stars (Textbook reference 15-2 and 15-3) Bodies of gases that give off tremendous amounts of radiant and heat energy Constellations are patterns of stars used for navigation, storytelling, honoring heroes Life Cycle of a Star Video

Image courtesy of Dave Dockery Astronomical Society of Las Cruces Source: The British Astronomical Association Nearby Stars: Name Distance from Earth Sun 93 million miles (8 light minutes) Proxima Centauri 4.22 Light Years Alpha Centuri A,B 4.39 Light Years Barnards Star 5.94 Light Years Wolf Light Years Lalande Light Years Sirius A,B 8.6 Light Years

28 Evolution of Stars

29 How do Black Holes form?

30 Black Holes Remains of a neutron star that has collapsed due to intense gravity

31 Hertzsprung-Russell Diagram The Doppler Effect: Red Shift – stars moving away from Earth Blue Shift – stars moving toward Earth Video on the Hertzsprung-Russell Diagram Spectroscopy Video

Hertzsprung-Russell Diagram Images from and The coolest stars are blue- white in color.

Using a Star’s Spectrum We can use a star’s spectrum to classify it. NOAO/AURA/NSF image at