Formation Of Comets
Date: Prior to 1993
As far as comets are concerned, what is the area outside of our
solar system called and how does it relate to the formation of comets. Also,
how many known comets are on record; which is the largest, smallest, etc.
There is a region (still considered in our solar system) well
beyond the orbit of Pluto called the Oort Cloud. This is where most comets
spend most of their time because they have highly elliptical orbits. I am not
sure how many periodic (returning) comets are on record -- certainly hundreds,
maybe thousands. The most famous and one of the largest is Halley's Comet.
Their is no limit on how small a comet can be, but very small comets have to
get very close to the sun to be detected. As for comet formation, most
astronomers believe they are remnants of the formation of the solar system.
The Oort Cloud (note: singular tense) is the theoretical region associated
with our solar system where most comets spend most of their time. This is
possible because most comets have highly elliptical orbits. Look for a
college undergraduate text book on astronomy. This may be beyond the level of
a high school student, but a possible project might be to use the orbital
parameters of known reappearing comets to calculate the dimensions of the Oort
Cloud. It would also be interesting to learn more about Prof. Oort and how he
came up with the idea.
The best write-up on the Oort cloud of the astronomy texts I have
is in "Exploration of the Universe" by Abell, Morrison, and Wolff. Some
astronomers believe that in addition to the Oort cloud, there is another
reservoir of comets (the source of "short-period" comets) called the Kuiper
belt. I consulted the online Reader's Guide and found some magazine articles
that, from the abstracts, look promising: Sky and Telescope Jan. '93 p. 15,
p. 26-9; Sky and Telescope Apr. '93 p. 44-5 <-- about Jan Oort; Astronomy
Sept. '92 p. 40-7; Discover Feb. '91 p. 8
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Update: June 2012