Transcript B. Origin of Name

I. Comets
Comets and Asteroids
A. What is a Comet?: It is a small body orbiting the Sun that
develops a ______ (a fuzzy atmosphere) and/or a ____ as it
approaches the Sun. Comet nuclei range from _____________
__________.
B. Origin of Name: Latin “cometes” and Greek “komē” meaning
“_______________".
C. Composition: Comets are composed of _____, _____, ______
___, and ____________ such as carbon monoxide, carbon
dioxide, methane and ammonia. They are often popularly
described as “_____________", though recent observations
have revealed dry dusty or rocky surfaces, suggesting that the
ices are hidden beneath a crust
D. Orbital Periods: Comets have orbital periods ranging from a _____
years to ____________________ of years. Some comets pass
through the inner Solar System only once before being thrown out
into interstellar space.
1. Short-period comets originate in the ___________, a disk
of small rocky, icy bodies orbiting the Sun beyond the orbit
of Neptune.
2. Long-period comets come from the ___________, a
spherical collection of bodies outside of the Kuiper Belt that
are left over from the formation of the Solar System.
3. The trip inward towards the Sun begins with gravitational
interactions with the ____________ (in the case of Kuiper
Belt objects) or nearby ______ (in the case of Oort Cloud
objects) or can be a result of collisions between objects
within these regions.
4. Comets do not orbit forever. Comets have been observed
to regularly crash into ________. After many orbits, comets
become _________ after they lose all of their volatile
materials and become just orbiting hunks of rock.
E. Number of Known Comets: Currently ______ and increasing every
year.
F. Size of Coma and Tail: The coma may be larger than _______,
and ion tails have been observed to extend ______ (150 million km)
or more
G. Shape of Nuclei: Because of their low mass, comet nuclei have
_________ shapes.
H. Tails: The streams of dust and gas each form their own distinct
tail, pointing in slightly different directions. The tail of dust often
forms a _______ tail. The gases form an ____ tail that always
points _______________________.
I. Meteor Showers: In their orbits, comets leave a trail of ____
______ behind them. It is this debris that results in a meteor
shower when ______________________________. The
Perseid meteor shower occurs every year between August 9 and
August 13, when Earth passes through the orbit of the Swift–
Tuttle comet. Halley's comet is the source of the Orionid shower
in October.
J. Rosetta: In ______, an ESA (_European Space Agency_)
spacecraft will begin to ______ the comet 67P/ChuryumovGerasimenko for a period of ________. It will also carry a lander
to set down on its surface.
II. Asteroids
A. Also Known As: ____________
B. Characteristics: Made of _____________. No coma or tail.
C. Size: Objects in the main asteroid belt vary greatly in size, from a
diameter of ________ for the dwarf planet Ceres down to rocks
just _____ of meters across. A few of the largest asteroids are
roughly _________, but the vast majority are much smaller and
________.
D. Location: The vast majority are located in the ____________
between the orbits of _________________ in relatively circular
orbits. The asteroid belt is estimated to contain between _____
___ million asteroids larger than 1 km in diameter and millions of
smaller ones.
E. Mass: The mass of all the objects of the asteroid belt is
estimated to be about ___ percent of the mass of the Moon. The
dwarf planet, Ceres, alone makes up ____ percent of the total.
Adding in the next three largest asteroids brings this figure up to
51%.
F. Earth-Crossing Asteroids: There are _____________
________, of asteroids that intersect the orbit of the Earth.
99942 Apophis will approach the Earth so closely in ______ that
it will pass under the orbit of Earth's geostationary satellites. The
Earth will change the trajectory of Apophis and the result may be
an even closer approach on April 13, 2036 (Friday the 13th!!).