How Do We Know ? Using the Electromagnetic Spectrum To Understand the Universe A nd the implications of Fermi Space Te

1. How Do We Know? Using the Electromagnetic Spectrum To Understand the Universe And the implications of Fermi Space Telescope Data on our understanding

2. How to start? • Introduce students to Epo and Alkina in the EPO Chronicles . • Have them follow their adventures and write about them in a journal for homework.

3. Catch a Ray • Talk about and explore characteristics of light energy

4. Light as Waves • Compare different wavelengths to different spring like things

5. How Do We Know • Scientists study how light and other energies interacts with different things. • From those observations they know that light, and any other kind of energy travels in waves.

6. How Do We Know • Scientists studied those waves and noticed that they had rules. • They noticed that in any one type of energy, the space between the top of one loop to the top of the next loop was always the same. • They called that space wavelength

7. How Do We Know • Scientist also noticed that every different kind of energy had a different wavelength • Because of this, scientist now had a way to tell different kinds of energy apart.

8. How Do We Know • Because each wavelength was exactly the same as the next, scientist discovered that each kind of energy moved a different amount of waves through a specific space in a specific time. • Because of this, scientist now discovered you could tell what kind of energy you had by counting the amount of waves that went by in a set amount of time. They called this measurement frequency.

9. What does the EMS tell us?(Electromagnetic Spectrum) • Transports energy • Electric and magnetic fields oscillate: that’s the “wave” • Moves at speed of light, 3 x 108 m/s • Wavelength, frequency, energy all related • Type of radiation (usually) depends on energy/temperature of object

10. How Do We Know? When we organize light waves in this type of order, we call it the “Electromagnetic Spectrum” or EMS

11. How Do We Know • Radio waves are energy that has long wavelengths and small frequencies. • They are as big as buildings and as small as a human. • They are the kind of energy we attach radio signals to broadcast them. • Stars and gasses in space also emit radio waves

12. How Do We Know • Microwaves have a shorter wavelength, about the size of a honeybee. • Cell phones and microwave ovens produce microwaves • Gasses that are collapsing into stars in space also produce microwaves

13. How Do We Know • Infrared energy has an even shorter wavelength, about the size of the head of a pin. • They are easily absorbed into molecules, heating them up, like our french fries at MacDonald's • The dust between the stars also gives off infrared energy

14. How Do We Know • Visible light rays are even shorter, about the size of a protozoan. • Visible light is the kind of energy that bounces off of me, into your eyes, and allows you to see me. • Anything you can see with your eyes is in the visible light range

15. How Do We Know • Ultraviolet wavelengths are even smaller, about the size of a molecule. That makes their frequencies very high. • A lot of waves can fit in a space, so they have a lot of energy • The sun and other stars produce ultraviolet energy • Our skin is a detector of ultraviolet energy

16. How Do We Know • X-rays are even smaller than Ultraviolet waves, about the size of an atom • so they have even more energy than ultraviolet rays • Doctors use x-rays to look at your bones. • Hot gases in space also emit x-rays

17. How Do We Know • Gamma rays are even smaller than x-rays, about the size of a nucleus of an atom. They have even more energy. • Radioactive materials, and particle accelerators make gamma rays • The biggest producer of gamma rays is our universe

18. How Do We Know • We started to make telescopes that would detect different kinds of frequencies • Some telescopes can detect visual light energy • Some can detect X-ray energy • Some can detect radio energy • Putting all this information together helps us to understand what’s going on in our universe

19. Only visible, radio and some IR and UV gets through the air! To see gamma rays, X-rays, most UV and some IR you must go to space http://imagers.gsfc.nasa.gov/ems/atmosphere.gif

20. How Do We Know? Hubble Space Telescope • Is probably the most famous of Telescopes • Three cameras, two spectrographs, and fine guidance sensors • Produces high resolution images of astronomical objects • Its images are 10 times better than the best telescope on earth. • Takes pictures of small areas in great detail

21. How Do We Know? GALEX Space Telescope • Relatively small satellite. It is just about six feet tall and as wide as your outstretched arms. • The two mirrors of the GALEX telescope are just a half meter (20 inches) across • Acts like a digital camera that takes pictures in the ultraviolet range of light waves • Takes broad far away shots of the sky

22. How Do We Know? GALEX Space Telescope • Orbits the earth once every 98 minutes • Takes pictures that are 2 moons wide • Has special mirrors that curve the light. • Ordinary telescopes would get images that looked like comets from such a large scan of the sky. GALEX’s mirrors change that kind of image into a flat picture • In addition to visible light GALEX has detectors that can read ultra violet light

23. How Do We Know? GALEX Space Telescope • Hubble Telescope takes very detailed pictures of a very small section of the sky • GALEX takes very large pictures of very large pieces of the sky • It’s kind of like Hubble taking close up pictures and GALEX taking landscape picture

24. How Do We Know? GALEX & Hubble Space Telescopes Working Together • Scientists take pictures from Hubble and Galax and compare and contrast the data from both telescopes • The analysis of these images and images from many more telescopes are the basis of what we know about the Universe today.

25. What We Know Size and Scale of the Universe Image courtesy of The Cosmic Perspective by Bennett, Donahue, Schneider, & Voit; Addison Wesley, 2002

26. M45 – The Pleiades Cluster X-ray: T. Preibisch Ultraviolet: MSX Visible: AAO Infrared: IRAS Radio: NVSS

27. X-ray: Chandra Multi-wavelength Crab Nebula Ultraviolet: UIT Visible: Palomar Infrared: 2MASS Radio: VLA

28. M51 – The Whirlpool Galaxy X-ray: Chandra Ultraviolet: GALEX Visible: T. & D. Hallas Infrared: ISO Radio: VLA

30. Sample Universal Objects

31. How Big? Telescope 40 feet long, 12 meters Moon 2,000 miles across, 3,200 kilometers Saturn 75,000 miles across, 121,000 kilometers Sun 875,000 miles across, 1,408,000 kilometers Pleiades 60 trillion miles across, 1 x 1014 Kilometers Whirlpool Galaxy 600 thousand trillion miles across, 1 x 1018 Kilometers Hubble Galaxies 600 thousand million trillion miles across, 1 x 1021 Kilometers

32. How Far? Telescope 350 miles above Earth’s surface, 560 kilometers Moon 250,000 miles, 402,000 kilometers Sun 93,000,000 miles, 1.5 x 108 kilometers Saturn 120,000,000 miles, 1.3 x 109 kilometers (at its closest) Pleiades 2,400 trillion miles, 4 x 1016 kilometers Whirlpool Galaxy 200 million, trillion miles, 3 x 1020 kilometers Hubble Galaxies 30 billion trillion miles, 5 x 1020 kilometers

33. How Old? Telescope A few years (launched in 1990) Pleiades 80 million years Moon 4.5 Billion years Saturn 4.5 Billion years Sun 4.5 Billion years Whirlpool Galaxy 13 billion years Hubble Galaxies 13 billion years

34. Shields and Detectors • Identify sources of EMS energies • Radio has AM & FM bands • Remote controls use infrared energy • Torch is black (UV) light and visible light

35. Shields and Detectors • Your ears detect Radio waves • Digital cameras detect infrared waves • Your eyes detect visible light waves • UV Beads detect ultraviolet waves

36. Shields and Detectors • Clear plastic • Black plastic • Aluminum foil • Copy paper • Cloth • Metal screen • Plastic screen • Wax paper • Baggie

37. Assessment You are a member of the EPO (Education and Public Outreach) team with Epo and Alkina. They are busy exploring the universe and ask you to cover a press conference for them. Epo has given you data from a new event in 5 different spectrums. You need to explain what the event is in a way that non scientists will understand. Use what you know about how the different energies react on earth to explain what is happening in the event. You may do this in any way you like, but remember your audience (the television camera men and the people that will be watching on CNN) are not scientists and do not understand how energies react as you do. You will get points based on how much and how clearly you use the data given to explain the event. You may use any format that you feel will help the public understand. Points will be granted for creativity and clarity of your message. Students are required to prepare a NASA news conference where they can use any means possible to explain to the public what the images represent. They can use power point, models, written and oral presentations as long as they make their point.

38. Assessment

39. Fermi - Gamma Ray Large Area Space Telescope Implications of Fermi Data on our understanding of the universe

40. Launch! The Fermi Observatory Was Loaded into the payload of a DELTA 7920H Rocket

41. Launch! And launched from Cape Canaveral Air Station June 11, 2008 at 12:05 PM EDT

42. The Observatory Large Area Telescope -LAT Gamma-ray Burst Monitor - GBM

43. GBM Collaboration National Space Science & Technology Center University of Alabama in Huntsville NASA Marshall Space Flight Center Max-Planck-Institut für extraterrestrische Physik

44. Data Processing Unit (DPU) GBM Instrument Design: Major Components 2 Bismuth Germanate (BGO) Scintillation Detectors 12 Sodium Iodide (NaI) Scintillation Detectors Characteristics • 5-inch diameter, 0.5-inch thick • One 5-inch diameter PMT per Det. • Placement to maximize FoV • Thin beryllium entrance window • Energy range: ~5 keV to 1 MeV Major Purposes • Provide low-energy spectral coverage in the typical GRB energy regime over a wide FoV • Provide rough burst locations over a wide FoV • Characteristics • Analog data acquisition electronics for detector signals • CPU for data packaging/processing • Major Purposes • Central system for instrument command, control, data processing • Flexible burst trigger algorithm(s) • Automatic detector/PMT gain control • Compute on-board burst locations • Issue r/t burst alert messages • Characteristics • 5-inch diameter, 5-inch thick • High-Z, high-density • Two 5-inch diameter PMTs per Det. • Energy range: ~150 keV to 30 MeV • Major Purpose • Provide high-energy spectral coverage to overlap LAT range over a wide FoV

45. LAT Collaboration Principal Investigator: Peter Michelson (Stanford University) ~270 Members (~90 Affiliated Scientists, 37 Postdocs, and 48 Graduate Students) construction managed by Stanford Linear Accelerator Center (SLAC), Stanford University • France • CNRS/IN2P3, CEA/Saclay • Italy • INFN, ASI, INAF • Japan • Hiroshima University • ISAS/JAXA • RIKEN • Tokyo Institute of Technology • Sweden • Royal Institute of Technology (KTH) • Stockholm University • United States • Stanford University (SLAC and HEPL/Physics) • University of California at Santa Cruz - Santa Cruz Institute for Particle Physics • Goddard Space Flight Center • Naval Research Laboratory • Sonoma State University • Ohio State University • University of Washington

46. What Makes Fermi Special? Fermi surveys the whole sky every three hours. Taking advantage of the huge fields of view of the GBM and the LAT, Fermi is operated in a scanning mode that monitors the sky regularly. The reason this survey mode is important is that the gamma-ray sky is dynamic, showing changes on time scales ranging from milliseconds to years.

47. Large Area Telescope First Light! The EGRET map was a compilation of 18 months of data. The full gamma-ray sky projected onto a surface This map represents just 4 days of Fermi data! But it looks like the Energetic Gamma Ray Experiment Telescope map. What’s new?

48. LAT 1st Catalog: >9000 sources possible Many More Sources Expected The 271 sources in the third EGRET catalog involved considerable manual processing. The LAT analysis will rely much more heavily on automated processing.

49. Pulsars – rapidly spinning neutron stars with enormous magnetic and electric fields Milky Way – Gamma rays from powerful cosmic ray particles smashing into the tenuous gas between the stars. What’s going on in the gamma-ray sky? Some gamma-ray pulsars took years for EGRET to see. The LAT confirmed all the EGRET pulsars in a matter of days and is now looking for more.

50. PKS 1502+106 - a blazar 10 billion light years away, never detected by EGRET, flared up overnight to become one of the brightest things in the gamma-ray sky. 3C454.3 - LAT saw it flare up 5 times brighter than EGRET ever measured. Blazars – supermassive black holes with huge jets of particles and radiation pointed right at Earth. What is new in the gamma-ray sky?