How Do We Know? Using the electromagnetic spectrum To map the
universe And the Implications of fermi data That endeavor
Slide 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.
Slide 3
Catch a Ray Talk about and explore characteristics of light
energy
Slide 4
Light as Waves Compare different wavelengths to different
spring like things
Slide 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.
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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
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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.
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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.
Slide 9
What does the EMS tell us? (Electromagnetic Spectrum)
Transports energy Electric and magnetic fields oscillate: thats the
wave Moves at speed of light, 3 x 10 8 m/s Wavelength, frequency,
energy all related Type of radiation (usually) depends on
energy/temperature of object
Slide 10
How Do We Know? When we organize light waves in this type of
order, we call it the Electromagnetic Spectrum or EMS
Slide 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
Slide 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
Slide 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
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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
Slide 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
Slide 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
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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
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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
whats going on in our universe
Slide 19
http://imagers.gsfc.nasa.gov/ems/atmosphere.gif To see gamma
rays, X-rays, most UV and some IR you must go to space Only
visible, radio and some IR and UV gets through the air!
Slide 20
How Do We Know? 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
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How Do We Know? 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
Slide 22
How Do We Know? 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. GALEXs mirrors change that kind
of image into a flat picture In addition to visible light GALEX has
detectors that can read ultra violet light
Slide 23
How Do We Know? 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 Its kind of like Hubble taking
close up pictures and GALEX taking landscape picture
Slide 24
How Do We Know? 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.
Slide 25
Size and Scale of the Universe Image courtesy of The Cosmic
Perspective by Bennett, Donahue, Schneider, & Voit; Addison
Wesley, 2002 What We Know
Slide 26
M45 The Pleiades Cluster X-ray: T. Preibisch Ultraviolet:
MSXVisible: AAO Infrared: IRASRadio: NVSS
M51 The Whirlpool Galaxy X-ray: ChandraUltraviolet:
GALEXVisible: T. & D. Hallas Infrared: ISORadio: VLA
Slide 29
Slide 30
Slide 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 10 14 Kilometers Whirlpool Galaxy 600
thousand trillion miles across, 1 x 10 18 Kilometers Hubble
Galaxies 600 thousand million trillion miles across, 1 x 10 21
Kilometers
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How Far? Telescope 350 miles above Earths surface, 560
kilometers Moon 250,000 miles, 402,000 kilometers Sun 93,000,000
miles, 1.5 x 10 8 kilometers Saturn 120,000,000 miles, 1.3 x 10 9
kilometers (at its closest) Pleiades 2,400 trillion miles, 4 x 10
16 kilometers Whirlpool Galaxy 200 million, trillion miles, 3 x 10
20 kilometers Hubble Galaxies 30 billion trillion miles, 5 x 10 20
kilometers
Slide 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
Slide 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
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Shields and Detectors Your ears detect Radio waves Digital
cameras detect infrared waves Your eyes detect visible light waves
UV Beads detect ultraviolet waves
Slide 36
Shields and Detectors Clear plastic Black plastic Aluminum foil
Copy paper Cloth Metal screen Plastic screen Wax paper Baggie
Slide 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.
Slide 38
Assessment Assessment Rubric For NASA Press Conference
Performance Assessment Category25 points20 points10 points
Understanding Comprehension (possible 25 points) Student is able to
accurately answer all questions posed by classmates and instructor
based on information from the unit. Student is able to answer
questions posed by classmates and instructor about the topic, but
is not sure of the accuracy of his answers. Student is not able to
back answers to questions posed by classmates and instructor with
information from the unit. Answers are garbled and/or confused.
Understanding content (Possible 25 points) The student can
accurately identify at least 1 characteristic in all 5 pictures The
student can accurately identify at least 1 characteristic in 3 of
the pictures provided The student can accurately identify at least
1 characteristic in two of the pictures provided Performance
(Possible 25 Points) The student can accurately explain the
significance of at least 1 characteristic in all 5 pictures. The
student can accurately explain the significance of at least 1
characteristic in 3 of the pictures provided. The student can
accurately explain the significance of at least 1 characteristic in
2 of the pictures provided. Performance (total possible points 25)
The student provides at least one example of the energy analyzed as
it exists on earth. (one example of x-ray energy, one example of
ultraviolet energy, one example of visible light energy, one
example of infrared energy, one example of radio energy) The
student provides at least one example of the energy analyzed as it
exists on earth for three different energy sources. (one example of
x-ray energy, one example of ultraviolet energy, one example of
visible light energy, one example of infrared energy, one example
of radio energy) The student provides at least one example of the
energy analyzed as it exists on earth for two different energy
sources. (one example of x-ray energy, one example of ultraviolet
energy, one example of visible light energy, one example of
infrared energy, one example of radio energy) Total Possible points
100
Slide 39
Fermi - Gamma Ray Large Area Space Telescope Implications of
Fermi Data on our understanding of the universe
Slide 40
The Fermi Observatory Was Loaded into the payload of a DELTA
7920H Rocket Launch!
Slide 41
And launched from Cape Canaveral Air Station June 11, 2008 at
12:05 PM EDT
Slide 42
The Observatory Gamma-ray Burst Monitor - GBM Large Area
Telescope -LAT
Slide 43
University of Alabama in Huntsville in HuntsvilleNASA Marshall
Space Flight Center Max-Planck-Institut fr extraterrestrische
Physik National Space Science & Technology Center GBM
Collaboration
Slide 44
GBM Instrument Design: Major Components 12 Sodium Iodide (NaI)
Scintillation Detectors 2 Bismuth Germanate (BGO) Scintillation
Detectors Data Processing Unit (DPU) 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 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
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
Slide 45
LAT Collaboration 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 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
Slide 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.
Slide 47
Large Area Telescope First Light! The full gamma-ray sky
projected onto a surface But it looks like the Energetic Gamma Ray
Experiment Telescope map. Whats new? The EGRET map was a
compilation of 18 months of data. This map represents just 4 days
of Fermi data!
Slide 48
Many More Sources Expected LAT 1 st Catalog: >9000 sources
possible The 271 sources in the third EGRET catalog involved
considerable manual processing. The LAT analysis will rely much
more heavily on automated processing.
Slide 49
Milky Way Gamma rays from powerful cosmic ray particles
smashing into the tenuous gas between the stars. Pulsars rapidly
spinning neutron stars with enormous magnetic and electric fields
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.
Slide 50
Blazars supermassive black holes with huge jets of particles
and radiation pointed right at Earth. What is new in the gamma-ray
sky? 3C454.3 - LAT saw it flare up 5 times brighter than EGRET ever
measured. 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.
Slide 51
The Pulsing Sky Pulses at tenth true rate Finding Pulsars
Slide 52
Gamma Ray Bubble at the center of the Milky Way
Slide 53
Thunderstorms create antimatter!
Slide 54
The speed of energy
Slide 55
We have only scratched the surface of what the Fermi Gamma-ray
Space Telescope can do. The gamma-ray sky is changing every day, so
there is always something new to learn about the extreme Universe.
Some results from both the GBM and the LAT are starting to be made
public through the Fermi Science Support Center. Fermi science
teams are cooperating with many other missions and observatories to
maximize the scientific return. Follow the latest news at the
Project Scientists blog, http://blogs.nasa.gov/cm/blog/GLAST What
Next for Fermi?