Mystery of odd Wisconsin rock formations solved
Juliet Williams,КAssociated Press
April 27, 2004CRATER0427
ROCK ELM, WIS. -- The muddy b rown h ill s and rolli ng farml and at first look li ke
typical Wisconsin. Farm fields and a bubb ling brook yield to rocky ou tcrops and rows of
trees.
But scientist s yea rs ago saw so mething d iff erent abou t tho se rock s and conc luded that an
anc ient catastrophic even t had o ccur red, alt hough wha t it was remained a mystery.
Now they be li eve they know : A 650- to 700-foot-wide meteorit e crashed to Earth at
speeds as h igh as 67,500 mil es per hour 450 milli on ye ars ago .
The im pact dislodged rocks and created a massive ho le about 4 mil es in d iameter and 600
feet deep in an area called Rock Elm, 70 mil es southea st of the Twin C iti es, thre e
scientists state in an article pub lis hed in the G eologi cal Society of America Bull etin.
Over tim e, shale, dir t and sedim ent fill ed the c rater to make the sit e virt uall y
indistingu ishable from t he surround ing land. I t's beli eved that a shall ow sea cove ring
Wis cons in at the time of the im pact probably blunt ed the meteorite's effect.
Meteorite caused rock uphea vals
Janet Hostetter
Associated Press
Bit of Administration ….
• Washburn Observatory
– Wednesday, after dusk for a few hours
• Reading
– Chapter 24, Chapter 14 recommended
• Discussion Section
– Web-lecture in advance of section
• 2 pts extra credit for evaluation
• 3 pt extra credit quiz
• responsible for material
THE EXTRA-SOLAR PLANET PROJECT
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Phase 1: Last week’s quiz.
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Phase 2 : A Web-Lecture on Extra-Solar Planets.
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Learn about extra-solar planets and have opportunity to earn 5 pts extra credit.
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A computer with connection to the Internet.
Computer speakers or headphones.
The software requirements for viewing the lecture are:
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Preparation for next week’s discussion sections (5/3-5/7).
Access: http://eteach.engr.wisc.edu/meibom/espp/index.html
Speed: 300 Kbps, 100 Kbps, and 37 Kbps.
The hardware requirements for viewing the lecture are:
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2 pts for evaluation questions
3 pts for success on quiz
Windows Operating System.
Internet Explorer version 5.5 or later.
Power Point 2002 or later ("Power Point Animation plug-in").
Campus computer-labs:
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http://www.doit.wisc.edu/computerlabs/index.asp
Bring headphones!
Asteroids, Comets, Meteors, and Pluto
Oort Cloud
Primordial Icy Planetesimals
Jupiter Forms
Icy Planetesimals
Rocky Planetesimals
Kuiper Belt
Fragmented Icy Planetesimals (KBOs)
Sedna
Asteroids, Comets, Meteors, and Pluto
• Summary
• Asteroids
• Rocky Planetesimals
• Comets
• Long - Period = Icy Planetesimals
• Short - Period = Fragmented KBOs
• Pluto, Sedna, Triton, Kuiper Belt Objects
• Icy Planetesimals
• Meteors
• Processed Iron and Stony Meteorites
Fragmented asteroids
• Meteor Showers
Fragmented comets
• Primitive Meteors = Rocky Planetesimals
Asteroids, Comets, Meteors, and Pluto
Asteroids, Comets, Meteors, and Pluto
• Meteors
• Showers - debris of old comets
Earth orbit
Past Comet
Asteroids, Comets, Meteors, and Pluto
• Meteors
• Types - Processed Meteorites
• Stony Meteorites
• 93%
• Just like crust of Earth
• Iron Meteorites
•6%
• Crystallization patterns => long cooling times
Asteroids, Comets, Meteors, and Pluto
• Meteors
• Types - Primitive Meteorites
• Stony, with trace of pure metallic flakes
• Carbonaceous chondrites
• Carbon compounds, and even water
Life in the Solar System
• Arguments for Life as High Probability
• Organic molecules form easily
• Carbonaceous Chondrites
• Allende Meteorite 2/8/69, 1:05 AM
Chondrules
(Amino Acids)
Calcium-Aluminum
Inclusions (CAIs)
Life in the Solar System
• Arguments for Life
• Organic molecules form easily
Life in the Solar System
• Arguments for Life as High Probability
• Organic molecules form easily
• Life occurred quickly on Earth - < 3.85 billion years
3.5 billion yr old
Stromatolites (cyanobacteria)
Life in the Solar System
• Arguments for Life as High Probability
• Organic molecules form easily
• Life occurred quickly on Earth - < 3.85 billion years
4.4 billion yr old zircon
high oxygen isotope ratios
cool water on Earth!
Life in the Solar System
• Arguments for Life as High Probability
• Organic molecules form easily
• Life occurred quickly on Earth - < 3.85 billion years
• Life can exist in a wide range of conditions
Life in the Solar System
• Life on Mars ?
• Flowing water and warm conditions for ≈ 1 byr
magnetite crystals
• Extensive volcanos
• Martian meteorites
• ALH84001
Life in the Solar System
• Life on Mars ?
• Flowing water and warm conditions for ≈ 1 byr
• Extensive volcanos
• Martian meteorites
Life in the Solar System
• Life on Europa ?
• Icy crust
• Tidal heating
Liquid oceans
Volcanic vents
Life in the Solar System
• Life on Europa
• Icy crust
• Tidal heating
Liquid oceans
Volcanic vents