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Asteroids
APOD – 11/12/12
Explanation: Which feature takes your
breath away first in this encompassing
panorama of land and sky? The
competition is strong with a waterfall,
meteor, starfield, and even a moonbow all
vying for attention. It is interesting to first
note, though, what can't be seen -- a rising
moon on the other side of the camera. The
bright moon not only illuminated this
beautiful landscape in Queensland,
Australia last June, but also created the
beautiful moonbow seen in front of
Wallaman Falls. Just above the ridge in the
above image is the horizontal streak of an
airplane. Toward the top of the frame is the
downward streak of a bright meteor, a
small pebble from across our Solar System
that lit up as it entered the Earth's
atmosphere. Well behind the meteor are
numerous bright stars and nebula seen
toward the center of our Galaxy. Finally, far
in the background, is the band of our Milky
Way Galaxy, running diagonally from the
lower left to the upper right in the image but
also circling the entire sky.
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APOD November 13, 2012
Explanation: Some people are so
inspired by solar eclipses that they
quilt. Pictured above is a resulting
textile from one such inspiration.
The 38x38 inch quilt offers
impressions of a total annular
eclipse, when the Moon is too far
from the Earth to cover the entire
Sun, witnessed in Spain in October
of 2005. Today, however, a full total
solar eclipse will occur, although it
will only be visible to eclipse
chasers and those who live in a thin
swath of Australia. For a few
minutes, those near the center of
the eclipse path will see the entire
Sun blocked by the Moon, causing
the day to become unusually dark.
Just before -- and just after -- totality
occurs, sunlight may stream
between mountains on the Moon's
edge creating a diamond ring effect.
The next total eclipse of the Sun will
occur in November 2013.
Three different types of asteroids:
• C- type: Carbonaceous (stony and darker
than coal)
• S- type: Silicaceous (bright, stony bodies
which contain metal)
• M-type: Metallic (exposed metallic cores
of much larger bodies)
Lutetia (C – type)
M-type
Eros (S-type) – closest to Earth
Ceres – largest of the asteroids
found in 1801, now considered a
dwarf planet (C-type)
950 km wide, it resides in the Main
Belt of Asteroids
Asteroid Classes
• Asteroid Belt (between Mars and Jupiter)
• Trojan Asteroids (60o before or 60o after
Jupiter – in the same orbit)
• Apollo Asteroids (cross the orbit of Earth)
• Amor Asteroids (cross the orbit of Mars)
Meteors, Meteoroids, Meteorites
• Meteor – bright streak in the sky (“shooting star”)
• Meteoroid – chunk of debris before it hits the
Earth’s surface
• Meteorite – the part of the meteoroid that
reaches the Earth’s surface
• Crater – bowl shaped depression resulting from
the collision of debris with a planet’s surface
Craters on the Moon
Craters on Mercury
Craters on Earth
Barrington Crater
• Arizona
• Measuring 1.2 km across and 175 m deep
• Formed about 50,000 years ago