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Characteristics of the Universe

Characteristics of the Universe. Created by the Lunar and Planetary Institute For Educational Use Only LPI is not responsible for the ways in which this powerpoint may be used or altered. Welcome!. Please complete the pre-assessment It’s for us—it’s not about you.

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Characteristics of the Universe

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  1. Characteristics of the Universe Created by the Lunar and Planetary Institute For Educational Use Only LPI is not responsible for the ways in which this powerpoint may be used or altered.

  2. Welcome! • Please complete the pre-assessment • It’s for us—it’s not about you

  3. What are we going to cover? • Our Place in the Universe • Scale and Distance • The Electromagnetic Spectrum • Classifying Stars • Classifying Galaxies • History of the Universe

  4. First up… • Our Place in the Universe • What is our Universe made of? • How big are things? How far away? • How do we know?

  5. Activity!! • Use the Venn diagrams to place the stickers—where does everything go? • After you’re finished, let’s discuss…

  6. Examining the Components • Stars • Gas and dust (Nebulae) • Star clusters • Galaxies

  7. Different types of stars

  8. Types of Stars • Big • Small • Red • Blue • Yellow • In groups • Alone • More later

  9. What is a “star cluster”? • stars formed together at same time • stars may be gravitationally bound together • two types: open (galactic) and globular

  10. Open Clusters • dozens to thousands of young stars • located in the spiral arms of a galaxy • example: Pleiades

  11. Globular Clusters • millions to hundreds of millions of stars, clumped closely together • old! 6 to 13 billion years • surround our disk as a halo

  12. What is a “nebula”? • A cloud in space • Made of gas and dust • Can have stars inside • Most of the ones we see are inside our Milky Way Galaxy • Many different types, sizes, composition

  13. What is a “galaxy”? • 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

  14. Next Up • Our Place in the Universe • Scale and Distance • The Electromagnetic Spectrum • Classifying Stars • Classifying Galaxies • History of the Universe

  15. Measuring Distances • What is a Light Year? • A light year is the distance light travels in a year. Light moves at a velocity of about 300,000 kilometers (km) each second; how far would it move in a year? • About 10 trillion km (or about 6 trillion miles). • Why do we use light years? • Show me how far 5 centimeters is. • Now show me 50 centimeters. • Now tell me (without thinking about it, or calculating it in meters) how far 500 centimeters is? 2000? 20,000? • We need numbers that make sense to us in relationship to objects; we scale up and use meters and kilometers for large numbers.

  16. Measuring Distances • Parallax (let’s model it) • As Earth orbits the Sun, we see nearby stars move relative to more distant stars • How many degrees did the plate move, relative to the background? • The angles involved for strellar observations are very small and difficult to measure. Proxima Centauri, has a parallax of 0.77 arcsec. This angle is approximately the angle subtended by an object about 2 centimeters in diameter located about 5.3 kilometers away.

  17. Mapping the Milky Way How do we know what our Galaxy looks like? We can see stars • star clusters • nebulae • Galaxies • Let’s try to Map our Galaxy

  18. 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 • 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

  19. The Milky Way

  20. Next Up • Our Place in the Universe • Scale and Distance • The Electromagnetic Spectrum • Classifying Stars • Classifying Galaxies • History of the Universe

  21. Let’s check your knowledge • Please draw an electromagnetic spectrum on a sheet of paper, and label the parts. • You can work in groups.

  22. Radiation • There are lots of types of light (radiation), including visible and invisible Electromagnetic spectrum http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/what_is_ir.html .

  23. Let’s Observe A Spectrum • Now let’s examine the invisible parts—using our cell phones and a solar cell.

  24. Radiation • All stars emit radiation • Radio, infrared, visible, ultraviolet, x-ray and even some gamma rays • Most of the sunlight is yellow-green visible light or close to it The Sun at X-ray wavelengths Image and info at http://imagine.gsfc.nasa.gov/docs/teachers/gammaraybursts/imagine/page18.html .

  25. Using a Star’s Spectrum • We can use a star’s spectrum to classify it.

  26. Stellar Evolution

  27. Time to Create a Stellar Graph • Everyone will receive several “stars” • Place them on the large paper, according to their color and their brightness • This is a version of the Hertzsprung-Russell diagram.

  28. Hertzsprung-Russell Diagram Images from http://www.nasa.gov/centers/goddard/news/topstory/2007/spectrum_plants.html and http://sunearthday.gsfc.nasa.gov/2009/TTT/65_surfacetemp.php

  29. Young stars form in nebulae

  30. A Star is Born Movie at http://www.stsci.edu/EPA/PR/95/44/M16.mpg

  31. Regular/ Small Star On the “Main Sequence”

  32. Red Giant

  33. White Dwarf Small, but very hot

  34. Massive Stars On the “main Sequence” but not for long

  35. Betelgeuse—Red Supergiant

  36. Supernova—Massive Star Explodes

  37. Neutron Star or Pulsar Image at http://hubblesite.org/newscenter/archive/releases/nebula/supernova-remnant/2002/24/results/50/

  38. Black Hole

  39. Galaxies • come in different sizes (dwarf, large, giant) • come in different shapes and classifications • Spirals • Ellipticals • Lenticulars • Irregulars • are fairly close together, relative to their sizes

  40. Collisions! • We now think that galaxies in groups and clusters often collide • The Milky Way is moving at 300,000 mph toward the Andromeda Galaxy • They may collide in about 5 billion years • Stars don’t usually collide • New orbits, gas piles up to form new stars

  41. Galaxies

  42. Spiral galaxy--Andromeda

  43. Elliptical Galaxies

  44. group of galaxies

  45. interacting

  46. Interacting

  47. Cluster

  48. Origin of the Universe • Big Bang • Dominant scientific theory about the origin of the universe • Occurred ~13.7 billion years ago • How do we know???? http://www.esa.int/esaCP/ESAKD7G18ZC_FeatureWeek_1.html

  49. Infinitely dense point not governed by our physical laws or time All matter and energy contained in one point Building a Universe .

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