The Kuiper Belt and Oort Cloud

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The Kuiper Belt and Oort Cloud Eric Berglund
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Why?

• Kuiper, Oort?
• Is Pluto a planet?
• Sedna, Chiron, Quaoar?
• Comets?

All reasons why the Kuiper Belt and Oort Cloud
have been such an interesting topic today.
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A Brief Introduction
In the most simplest sense Kuiper Belt 35,000
objects with diameters larger than 60 miles
orbiting the sun beyond Neptune. Oort Cloud
A theory that an unknown number of icy objects
(comets) surround the solar system, weakly bound
to the sun.
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Such Strange Names

• Gerard Kuiper
• Dutch-born American astronomer.
• 1905 1973
• Father of modern planetary science..
• Studied surface of the Moon.
• Discovered a moon around Neptune and Uranus.
• Mentioned the idea of something like the Kuiper
  Belt as it is known today (1951).

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Some Historical Discrepancies

• It should be noted that Kuiper did not really
  predict the idea as it is known today
• His paper mentioned objects scattered out beyond
  Pluto (not Neptune) that were thrown there by
  Pluto.
• Another person, Kenneth Edgeworth, wrote a paper
  about the same objects before Kuiper.
• They were mentioned in an obscure paper even
  earlier by Frederick Leonard in 1930.

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Such Strange Names, Part II

• Jan Hendrik Oort
• Dutch astronomer.
• 1900 1992
• Main focus of his work was on the rotation of our
  galaxy.
• Studied comets on the side.
• Theory of the Oort Cloud (1950).

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Kuiper Belt, In Depth
Beginning in 1992 astronomers started discovering
small objects orbiting the sun from Neptunes
distance and out.
4,647,794,380 miles
Neptune (30 AU)
Past Plutos orbit (50 AU)
These small bodies are members of Kuiper Belt and
include what are known as trans-Neptunians.
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Kuiper Belt, In Depth (continued)
Here are some of the larger, known Kuiper Belt
objects
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Kuiper Belt, In Depth (continued)
It was observed that the objects were clustered
around the ecliptic.
This suggests that they lie in band, or belt,
around the sun, much like the orbit of one of the
planets. Thus giving way to the name, Kuiper
Belt.
This would also suggest that they might have
formed like a planet would have as well
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Kuiper Belt, In Depth (continued)
When the solar system was just a cloud of dust
and gas, it was obviously more dense in the
middle which caused the sun and planets to form.
The outer, less dense areas formed more slowly
into small fragments.
However, other modern simulations show the
objects forming along with the planets and
getting lightly thrown out by larger objects
during the creation of the Solar System.
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Kuiper Belt, In Depth (continued)
It is also thought that the Kuiper belt is the
origin of many comets with short periods.
They are thought to be formed by collisions
inside the Kuiper belt.
In fact, it was the number of short-period comets
that caused Kuiper to question Oorts theory of
the origin of comets (more on that in a bit).
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Pluto, What Is It?
Some astronomers suggest that it formed much like
the other Kuiper Belt objects, or was a moon that
escaped Neptune.
Its eccentric orbit is not unlike many of the
Kuiper Belt objects. Also, its physical
characteristics are similar to some of the larger
objects.
However, it will always be the ninth planet for
historical and emotional reasons.
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With That Said
Why not just send a probe out to finally visit
Pluto and maybe take a swing through the Kuiper
Belt afterwards? New Horizons will do just
that, assuming it still has funding when it
launches early 2006.
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Oort Cloud

• Jan Oort noticed that
• No comet has an orbit that would take it through
  interstellar space.
• The farthest point in the comets orbit was
  usually around 50,000 AU.
• They come from any direction.

Subsequently, he proposed they resided in a cloud
on the outer regions of the Solar System.
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Oort Cloud (continued)
Simulations suggest that there may be as many one
trillion comets in the proposed
cloud. 1000000000000 Its formation is theorized
to be from objects formed closer to the sun and
tossed out of the Solar System, but failing to
escape the suns gravity entirely. The Oort Cloud
is still a hypothesis as we have no direct
evidence.
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Oort Cloud (continued)
It is thought to extend about 3 light years from
the edge of the planetary system. Because
of these large distances, passing stars and the
tidal forces of the Milky Way galaxy effect the
objects inside the Oort Cloud.
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Current Events, Sedna
Recently, an object known as Sedna was discovered
3 times as distant as Pluto.

• Roughly 1200 mile diameter.
• Red in color.
• Discovered on Palomar Mountain March 15th of this
  year.

Who cares, weve been through this before
(Quaoar, etc.)?
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Current Events, Sedna (continued)

• It is very interesting for the following reasons
• The orbit is very strange, putting it somewhere
  between the Kuiper Belt and Oort cloud.
• It is large.
• It should have a moon, but does not.

So what is it? It could be one of the first Oort
Cloud objects, or an inner Oort Cloud object
stay tuned.
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http//www.ifa.hawaii.edu/faculty/jewitt/kb.ht
ml http//www.gps.caltech.edu/mbrown/sedna/moon
http//www.nineplanets.org/kboc.html http//www.so
larviews.com/eng/oort.htm
The End, Sources
All which are linked from http//www.astronomyinfo
.net and also where you can download this
presentation. Have any questions?