Comets and the Stardust Mission

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Cometsand theStardust
Mission

• Whats in oursolar systems freezer?

UCRL-PRES-228777
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Hope Ishii, Ph.D.Research ScientistLLNLwithT
om SheflerScience TeacherGranada High School
This work were performed in part under the
auspices of the U.S. Department of Energy,
National Nuclear Security Administrationby the
University of California, Lawrence Livermore
National Laboratory, contract No. W-7405-Eng-48.
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Comet McNaught mid-January 2007
Ken Tatebe and Ed Wishnow, Berkeley
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Comet McNaught mid-February 2007
Minoru Yoneta, Queenstown, New Zealand
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Imagine you lived 500 years ago.
What objects are normal in the night sky?
How are comets different?

• harder to predict timing Halley 76
  years Hale-Bopp 2500 years

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Historically, comets were FEARED
Woodcut (Nuremberg Chronicle)
Comet of 1556 earthquake in Constantinople
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Modern Comet Hysteria

• On closest approach,Hale-Bopp was farther from
  Earth than the SUN is!

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Oh no!!
Oooh!Ahhh!
KNOWLEDGE
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your KNOWLEDGE
INCREASE

• NASAs Stardust mission
• How comet dust was captured
• Whats firing up researchers today

http//heasarc.gsfc.nasa.gov/docs/cosmic/earth.htm
l
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How do Comets Size Up?
Images NASA
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How do Comets Size Up?
MOON
CHARON
PLUTO
0.5-10 miles
COMET NUCLEUS
Images NASA
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Comet Anatomy

• Ices H2O, CO, CO2, CH4, NH3, N2, H2CO, HCN
• Minerals (rocks and dust)
• Organics carbon-rich CHON

• Ionized gas

• Atmosphere of gas fromsublimed ices
• Ionized by solar wind (e- removed)
• gt100,000 miles across for a bright comet

• Dust released as ices sublime

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Comet Anatomy
NUCLEUS
COMA
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Comet Anatomy Tails
comet orbit
1 AU
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Lets make a comet!
15 min.
Comet
Prep Time
Dish
2 cups water (H2O) 2 cups dry ice (CO2) Dash
ammonia (NH3) 2 spoons dirt (rocks) Dash of Karo
syrup (organics)
ices
Wear work gloves and safety glasses!
Line a large plastic mixing bowl with a garbage
bag. Mix together water, syrup, ammonia and dirt
in mixing bowl with a large wooden spoon. Place
3 garbage bags inside each other, add dry ice and
crush with hammer. Add crushed dry ice to bowl
while stirring. When mixture is nearly frozen,
lift out of bowl using garbage bags and pack
together comet like a snowball until firm.
Unwrap!
http//www.noao.edu/education/crecipe.html
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Why do we study comets?
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Solar System Formation
interstellar cloud
painting by Kazuaki Iwasaki
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HOT
COLD
rocky bodies
Comets hold starting ingredients for
planets...including STARDUST!
Comets Frozen Time Capsules
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Comets delivered basis for LIFE?

• Today, Earths atmosphere protects from most
  impacts
• Early Earth bombarded by comets, asteroids

Meteor Crater in AZ
1 mile
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Mission to a Comet
STARDUST

• 1st sample return from a known comet for
  detailed study on Earth

• NASA Discovery Class Mission lt300M

• 1st U.S. solid sample returnsince Apollo 17 in
  1972

• Record 3 billion milestotal distance for
  asolar-powered spacecraft
• Record 2.72 AU from Earth

Image NASA
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StardustLaunch
February 17, 1999
Image NASA
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Stardust Launch
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Encounter Lucky Comet Wild 2
Deflected in 1974by Jupiters gravity inner
solar system orbit

• Intercept 1.86 AU
• Wild 2 circled sun only 5x -- fresh!

Really cool website! http//www.windows.ucar.edu
/tour/link/comets/comet_model_interactive.html
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Wild 2 up close and personal
lt150 miles of nucleus

• _at_
• 13,700 miles / hourrelative speed

3 miles
Images (top left) NASA, (bottom left) Harold
Eggerton, (right) NASA/JPL
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AEROGEL Catching comet dust

• transparent

• 99.8 holes

NASA
Ultra-low density glass foam worlds
lightest solid
Dust particles slow down g r a d u a l l
y
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Stardust Returns
January 15, 2006 Utah desert 28,000 mph
NASA
NASA
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Media Coverage
On the news, on the Daily Show, in cartoons
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Wild Times Studying Stardust
Images (top left) Ishii, (others) NASA/Stardust
PET
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Tiny Samples!
comet particle
human hair
5 microns
HOW CAN WE STUDY SUCH TINY OBJECTS?
Image Ric Felten, Smartech
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Powerful X-rays
Track Chemical Maps
Microscope image
4 mm
X-ray chemical maps
Images SSRL/LLNL/Stardust Preliminary
Examination Team/ NASA
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Powerful X-rays
Track Shapes
Track Chemical Maps
Microscope image
Microscope image
Shape reconstruction by X-ray tomography
4 mm
X-ray chemical maps
Images SSRL/LLNL/Stardust Preliminary
Examination Team/ NASA
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Ion Microscopes
Isotope maps
Images McKeegan et al, Science 314, 1724.
Evidence for stardust in Stardust comet dust
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Electron Microscopes
Identify minerals inStardust comet particles
Images LLNL/Stardust Preliminary Examination
Team/NASA
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but what does it all MEAN?
but also
some stardust
HOT rocks in thesolar systems DEEP FREEZE!
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The End