Transcript Linking Asteroids and Meteorites through Reflectance Spectroscopy

Astronomy 101
The Solar System
Tuesday, Thursday
2:30-3:45 pm
Hasbrouck 20
Tom Burbine
[email protected]
Course
• Course Website:
– http://blogs.umass.edu/astron101-tburbine/
• Textbook:
– Pathways to Astronomy (2nd Edition) by Stephen Schneider
and Thomas Arny.
• You also will need a calculator.
Office Hours
• Mine
• Tuesday, Thursday - 1:15-2:15pm
• Lederle Graduate Research Tower C 632
• Neil
• Tuesday, Thursday - 11 am-noon
• Lederle Graduate Research Tower B 619-O
Homework
• We will use Spark
• https://spark.oit.umass.edu/webct/logonDisplay.d
owebct
• Homework will be due approximately twice a
week
Astronomy Information
• Astronomy Help Desk
• Mon-Thurs 7-9pm
• Hasbrouck 205
•
The Observatory should be open on clear Thursdays
• Students should check the observatory website at:
http://www.astro.umass.edu/~orchardhill for updated
information
• There's a map to the observatory on the website.
Final
• Monday - 12/14
• 4:00 pm
• Hasbrouck 20
HW #12 and #13
• Due today
HW #14
• Due Tuesday at 2:30 pm
Exam #3
• Next Thursday
• Covers material from October 15th – November 5th
• Formulas
Density = mass/volume
Volume = 4/3r3
• Luna 2 - impact on the surface of the Moon (1959) (USSR)
• Luna 3 - first photos of the far side of the Moon (1959)
(USSR)
• Apollo - Six manned landings on the Moon with sample
return 1969-72.
– (The seventh landing, Apollo 18, was canceled for
political reasons)
• Luna 16 - automated sample return from the Moon (1970)
(USSR)
• Clementine - a joint mission of the Ballistic Missile Defense
Organization and NASA (1994)
• Lunar Prospector - the first NASA mission to the Moon in
almost 30 years (1998-1999)
• SMART-1 - The European Space Agency’s (ESA) spacecraft
orbited the Moon and then crashed into the Moon in
(September, 2006)
Currently
• Japanese SELENE mission (also known as Kaguya) orbited the
Moon
• Goal was "to obtain scientific data of the lunar origin and evolution
and to develop the technology for the future lunar exploration"
http://www.selene.jaxa.jp/en/about/image/img_equipment_001_e.jpg
Pythagoras Crater from SMART-1
http://cdn2.libsyn.com/astronomy/moon_show20.gif?nvb=20081110153501&nva=20081111153501&t=0b619a8f8100c5f7820f5
http://www.space.com/imageoftheday/image_of_day_060626.html
Pythagoras Crater from Selene
Diameter 130 km, Depth 5.0 km
http://wms.selene.jaxa.jp/data/en/hdtv/006/hdtv_006_3/hdtv_006_3_l.jpg
• http://space.jaxa.jp/movie/20080411_kaguya_mo
vie01_e.html
• India's national space agency launched Chandrayaan-1,
an unmanned lunar orbiter, on October 22, 2008.
• Estimated cost is $80 million
• The probe revolved around the Moon for ~1 years (no
longer working)
• Its scientific objectives were to prepare a threedimensional atlas of the near and far side of the moon
and to conduct a chemical and mineralogical mapping
of the lunar surface.
http://upload.wikimedia.org/wikipedia/en/8/89/Chandrayaan1_Spacecraft_Discovery_Moon_Water.jpg
Chandrayaan-1
http://en.wikipedia.org/wiki/Image:Chandrayaan_1.jpg
• A total of 382 kg of rock samples were returned
to the Earth by the Apollo and Luna programs.
• Apollo - 381.69 kg
Apollo 16
• Luna – 300 g
Luna 16
http://en.wikipedia.org/wiki/Image:Apollo_16_LM.jpg
http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1970-072A
Apollo 15 sample
“Genesis Rock”
Very ancient sample
4 billion years old
http://en.wikipedia.org/wiki/Image:Apollo_15_Genesis_Rock.jpg
Rocks and More Moon
• Mineral – A naturally occurring, homogeneous
inorganic solid substance having a definite
chemical composition and characteristic crystal
structure
• Rock - naturally occurring aggregate of minerals
Forming Different Mineralogies
• Can be on a planet-scale
• Or a few meters to kilometers
Some minerals form
before other minerals
http://www.gly.fsu.edu/~salters/GLY1000/8Igneous_rocks/Slide16.jpg
What minerals form?
• Depends on the composition of the magma
• Depends how quickly the magma cools
Types of Rocks
• Igneous – rock that solidified from molten or
partially molten material
• Metamorphic - rock that has changed in
composition, mineral content, texture, or structure
by the application of heat or pressure
• Sedimentary – rock formed from material that
was deposited as sediment by water, wind, or ice
and then compressed and cemented
Igneous Rock
http://en.wikipedia.org/wiki/Image:Magma.jpg
Metamorphism
Quartzite
http://en.wikipedia.org/wiki/Image:Quartzite.jpg
Sedimentary
• Examples of two types of sedimentary rock: limey
shale overlaid by limestone
http://en.wikipedia.org/wiki/Image:Limestoneshale7342.jpg
• Rock formed from sediments covers 75-80% of
the Earth's land area
Lunar Meteorites
•
•
•
•
~60 are known
only 1 in 1200 meteorites are lunar
Lunar meteorites are expensive
http://www.meteorites.tv/298-buy-a-lunarmeteorite
• By comparison, the price of 24-carat gold is about
$20 per gram and gem-quality diamonds start at
$1000-2000/gram.
http://epsc.wustl.edu/admin/resources/moon_meteorites.html
Mare
Lunar Highlands
http://epsc.wustl.edu/admin/resources/moon/howdoweknow.html
http://en.wikipedia.org/wiki/Image:Lunar_Ferroan_Anorthosite_60025.jpg
• Highlands – contain Al-rich material
– Plagioclase feldspar - CaAl2Si2O8
• Mare – contain Fe-rich material – basaltic eruptions
– Olivine - (Mg, Fe)2SiO4
– Pyroxene – (Mg,Fe)SiO3
– Ilmenite - FeTiO3
Fe-rich
Al-rich
http://epsc.wustl.edu/admin/resources/moon_meteorites.html
Magma Ocean
How do you form the Moon?
Definitions
• Volatile – evaporates easily
• Refractory – does not evaporate easily
Need to account for these things
• The Moon's low density (3.3 g/cc) shows that it does not
have a substantial iron core like the Earth does.
• Moon rocks contain few volatile substances (e.g. water),
which implies extra baking of the lunar surface relative to
that of Earth.
• The relative abundance of oxygen isotopes on Earth and
on the Moon are identical, which suggests that the Earth
and Moon formed at the same distance from the Sun.
Oxygen Isotopes
• There are three stable isotopes of oxygen
• They have masses of 16, 17, and 18 atomic mass units
%
• 16O
~99.762
• 17O
~0.038
• 18O
~0.200
• The oxygen isotopic ratios (17O/16O and 18O/16O of
silicate rocks from the Earth and Moon are the same
and are different from most meteorites and Mars
http://www4.nau.edu/meteorite/Meteorite/Images/MeteoriteOxygen9.jpg
Giant impact Hypothesis
• Formation of the Moon as a result of a collision between
the young Earth and a Mars-sized body
• Evidence
– oxygen isotope ratios of Moon identical to those of Earth.
– A large portion of the Moon appears to have been once
molten, and a giant impact scenario could easily have
supplied the energy needed to form such a magma ocean.
– The Earth has a large iron core, but the moon does not. This
may be because Earth's iron had already drained into the core
by the time the giant impact happened. Therefore, the debris
blown out of both Earth and the impactor came from their
iron-depleted, rocky mantles.
Atmosphere
• Not much of an atmosphere since the Moon’s gravity is
so small
Did We Land on the Moon
• http://www.youtube.com/watch?v=Y5MVVtFYTSo
Any Questions?