Astronomy 101 Section 020 Lecture 1 John T. McGraw, Professor Laurel Ladwig, Planetarium Manager

Introduction n The syllabus –The success of this class depends upon your success! –Responsibility n for assignments n to attend class n to prepare interesting, educational lectures and activities n to talk to someone when something isn’t right

A Brief Tour of the Universe n Our tour starts from our Earth, the only planet known to harbor life.

n Earth and its moon are almost a “double planet.”

n Mars is a “rocky,” or terrestrial planet that once had surface water.

n The sun and planets to scale. Is our multi-planet solar system unique?

n Comets and asteroids also orbit the sun.

n The Sun, a normal star, is the heart of our solar system.

n All of the stars we see at night are in our Milky Way Galaxy.

n So are all the nebulae that mark star birth and star death.

n The Milky Way - self-portrait.

n The Milky Way - detail. (with apologies to Gary Larson)

n Our tour continues with a visit to the nearest galaxies - here the Large Magellanic Cloud.

n Many galaxies are spirals, similar to our Milky Way.

n The most numerous galaxies are ellipticals.

n We’ll visit galaxies in collision - or worse!

n Most galaxies tend to cluster - or even supercluster!

n A quasar (it’s the “star” on the right) - pretty boring until you get close. But not too close!

n The most distant reaches of the universe are populated by galaxies and quasars.

n Galaxies map the structure of the universe.

n The Earliest Observable Universe – And Structure is Present

News of the universe! … (make your own “clack, clack, clack” wire service sounds here) n 90% of the Universe is missing! n We all know that the Universe is expanding – but now it is accelerating! n Particles from the center of the sun bombard Earth – but what flavor are those particles? n Stay tuned for more – much more!