Our Universe

1. Our Universe

2. Universe Objectives (8.8)  Science concepts. The student knows characteristics of the universe. The student is expected to: (8.8A)  describe components of the universe including stars, nebulae, and galaxies. (8.8B)  Recognize that the Sun is a medium sized star near the edge of a disc-shaped galaxy of stars and that the sun is many thousands of times closer to Earth than any other star. (8.13C)  Explore how different wavelengths of the electromagnetic spectrum such as light and radio waves are used to gain information about distances and properties of components in the universe. (8.8D) Model and describe how light years are used to measure distances and sizes in the universe.

3. Refracting Telescopes a set of lenses (curved glass) gather and focus light. The light bends as it passes through a curved objective lens.

4. Reflecting Telescope Mirrors gather and focus light to magnify image. Astronomers use this type since they are larger and gather more light.

5. Reflecting Telescope

6. Radio Telescope Radio Waves! What type of electromagnetic wave do these telescopes gather?

7. Radio Telescope Because radio waves are so big! Why are these Radio telescopes so large?

8. McDonald Observatory is located in the Davis Mountains, 450 miles west of Austin, Texas. There is a log of light pollution around cities Why are telescopes usually far from cities?

9. X-Ray Telescope Why is this telescope more powerful than the radio or visible telescope? X-rays have a higher frequency (more energy)

10. Reflecting Telescope Where is the hubble space telescope? Orbiting the Earth outside of it’s atmosphere? Why? Clouds and air can not interfere with image.

11. The Universe Consists of all space and the matter space contains. Astronomy is the study of all physical objects beyond Earth.

12. The Universe contains: • Galaxies • Stars • Comets • Quasars • Nebulas or Nebulae (Nebula)

13. Galaxies Large groups of stars Astronomers estimate from the size and brightness of the galaxy how many sun-sized stars it might have.

14. How many galaxies can be seen here? At least 15. How many stars are in each galaxy? Millions. The bigger and brighter – the more stars.

15. Galaxies There are three main types: Spiral Elliptical Irregular

16. Galaxies Spiral • Characterized by a bulge at the center and spiral arms • Spiral shape is caused by the rotation of the galaxy Example

17. Galaxies How many stars are in this picture? Spiral MILLIONS! This is not our solar system. This is millions of stars very close together.

18. Galaxies Elliptical • Characterized by a very bright centers and very little dust and gas • Appear elongated or spherical and are basically massive blobs of stars • Composed of mostly old stars If you rotated an elliptical shape, what would it look like from the end? A Circle Side View End View Example

19. Galaxies Irregular • Galaxies that do not fit into any other class • As their name indicates they have irregular shapes Example

20. Contents of Galaxies Billions and billions of stars! Some planetary systems too! Comets Gas clouds or nebulas Star Clusters Quasars

21. Stars • Huge, Dense, Hot, Bright balls of gas trillions of km away from Earth • Made up of different elements in the form of gasses

22. Comets dirty ice, dust, and gas balls with huge elliptical paths. Comets range in their orbital Periods from orbiting every 3 years to orbiting just once in 10,000 years! Hale-Bopp comet

23. Gas Clouds • Nebulas or Nebulae - Latin for “Cloud” • Giant clouds of gas and dust • Where new stars are formed • Found in spiral galaxies; not in elliptical galaxies • May glow, absorb light or reflect starlight

24. Star Clusters Globular clusters: • Groups of older stars • Looks like a ball of stars • Found in a spherical halo or ring that surrounds spiral galaxies (such as the Milky Way) and giant elliptical galaxies. Omega Centauri

25. Open Clusters • Groups of stars that are usually located along the spiral disk of a galaxy. • Bright, blue stars are found in newly formed open clusters Pleiades

26. Would a spiral, elliptical, or irregular galaxy be more likely to contain open clusters? Why? • Spiral – because they are newer/younger galaxies than elliptical or irregular.

27. Origin of Galaxies Quasars • star like sources of light that are the most distant objects from Earth • among the most powerful energy sources • may be the core of young galaxies

28. How far away is it? This is how it looked 6 billion years ago • 6 billion light–years away • A light year is equal to the distance that light travels through space in 1 year • How far is that? • 9.46 trillion km per year You are looking back in time 6 billion years!

29. Formation of the Universe Cosmology is the study of the origin, structure, and future of the universe. To understand how the universe formed, scientists study the movement of galaxies. Most galaxies are moving apart.

30. The Big Bang Theory • All matter once existed in 1 small, extremely dense spot. • The universe began with a tremendous explosion. • Now everything in universe is expanding .

31. Looking through the center of the Milky Way Which color do you see more of in this picture of the stars? http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html

32. Which wave is longer; red or blue? • If a star is moving towards you what color will it be? • If a star is moving away from you, what color will it be? Blue Shift Red Shift http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html

33. Looking through the center of the Milky Way So what does the color of these stars tell us about their movement? Doppler Effect - Wavelength changes due to motion http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html