The Launch Pad Tuesday, 8/31/10 What will be the ultimate fate of our Sun?

 We will have our first test of the year this Friday. There will be a self-paced review on Thursday.  You should now have your Science Binder with its Table of Contents and all of the paperwork that you have received put into it.  As soon as you have your ID, please fill out your yellow paper and get your laptop.

Attention Juniors and Seniors: If you have not picked up your laptop, be aware that Time is running out! Your scheduled time is before and after school Mon, Tues, and Wed of this week ONLY. The last day for your scheduled pick up time is Wednesday 8th period – 4:30pm. Any junior or senior who has not picked up a laptop after that day will not be allowed to get a laptop until September 11th, after 9th and 10th grade laptop distribution is completed.

Assignment Currently Open Pages Date of Notes on Website Date IssuedDate Due Information SheetN/A 8/238/24 Class Procedures and Expectations 1-4N/A8/238/25

How the Universe Works – The Big Bang - Gravity How the Universe Works – The Big Bang – Everything Starts with the Big Bang How the Universe Works – Black Holes

 The Color and Temperature of Stars † Hot Stars †Stars with a temperature above Kelvins emit short-wavelength light and therefore appear blue. † Medium Temperature Stars †Stars with a temperature between and Kelvins emit medium- wavelength light and appear yellow, like our Sun. † Cool Stars †Stars with a temperature less than Kelvins emit longer-wavelength light and appear red.

Binary Stars and Stellar Mass Binary stars are t wo stars orbiting one another and held together by mutual gravitation. Both stars orbit around a common center of mass.

 Parts of an H-R Diagram Main-Sequence Stars 90% of all stars are main-sequence. These band through the center of the H-R diagram. Our Sun is in the main sequence. Giants (or Red Giants) Red Giants are very large and very luminous. These are in the upper-right on the H-R diagram.

Figure 24.7

 Between stars is the “vacuum of space”, which actually contains varying amounts of “interstellar matter.”  A nebula is a large cloud of dust and gases.  There are two major types of nebulae:  Bright nebulas glow if they are close to a very hot star.  There are two types of bright nebulae:  Emission nebulae  Reflection nebulae

Figure 24.9

 Between stars is the “vacuum of space”, which actually contains varying amounts of “interstellar matter.”  A nebula is a large cloud of dust and gases.  There are two major types of nebulae: Dark nebulae are not close to any bright star, therefore they appear dark Dark nebulae contain the material that forms stars and planets.

 Our Own Milky Way Galaxy The Milky Way’s structure was determined by using radio telescopes. It is a large spiral galaxy about 100,000 light- years across. It’s thickness at the galactic nucleus is about 10,000 light-years. The Milky Way has three spiral arms of stars. Our Sun resides about 30,000 light-years from the center of the galaxy.

 Our Own Milky Way Galaxy The individual stars of the Milky Way revolve around the galactic nucleus. The outermost stars revolve the slowest. Our Sun revolves around the galactic nucleus once about every 200 million years. A halo surrounds the galactic disk. The halo is spherical in shape and is composed of very tenuous gas The Milky Way’s halo contains numerous “globular clusters.”

 Other Galaxies The existence of galaxies other than our own was first proposed in the mid-1700s by Immanuel Kant. The are four basic types of galaxies in our known Universe: Spiral galaxies Spirals have arms extending from their nucleus. About 30% of all galaxies are spirals. They can have large diameters up to 125,000 light-years Spirals contain both young and old stars. The Milky Way is a spiral galaxy.

Figure 24.20

 Other Galaxies The are four basic types of galaxies in our known Universe: Barred Spiral Galaxies In this type of galaxy, the stars are arranged in the shape of a bar. Barred spirals are generally quite large About 10% of all galaxies are barred spirals.

Figure 24.22

 Other Galaxies The are four basic types of galaxies in our known Universe: Elliptical Galaxies These galaxies have an ellipsoidal shape. About 60% of all galaxies are ellipticals. Most are smaller than spiral galaxies; however, they are also the largest known galaxies.

Figure 24.22

 Other Galaxies The are four basic types of galaxies in our known Universe: Irregular galaxies Irregular galaxies lack symmetry. About 10% of all galaxies are irregulars. Irregulars contain mostly young stars Our local companions the Magellanic Clouds are irregular galaxies.

Figure 24.22

 Galactic Clusters Galactic clusters are group of galaxies, some containing thousands of galaxies. Our Local Group We live in a galactic cluster, which contains at least 28 galaxies. Superclusters Superclusters are huge swarms of galaxies, and these may be the largest entities in the Universe.

Figure 24.22