chapter 12

Question 1

Pluto

Answer 1

When Pluto was discovered in 1930 it was immediately classified as a planet.
Nothing farther out was discovered for more than half a century (except Pluto’s
major moon, Charon), but in 1992 a small object (later called Albion) was
discovered in an orbit with a semi-major axis of about 44 AU. Then in 2002
Quaoar was discovered, followed by Eris, Haumea, and Sedna in 2003 and
Makemake in 2005. Albion is very small (about 100 miles in diameter), but
Eris is the same size as Pluto, and the others at least half of Pluto’s diameter.
At present, more than 2300 objects have been discovered beyond the orbit of
Neptune. Image #3 shows you some of this array of objects. Note that a
number of them have moons. So, are these all planets? In 2006 the
International Astronomical Union re-defined what we mean by a planet.
 It orbits the Sun (or some other star, in the case of an exoplanet) directl

Question 2

Lowell Observatory

Answer 2

Pluto was discovered in 1930 with the 24” refractor at Lowell Observatory in
Flagstaff, Arizona (Image #6). This observatory has an interesting history.
Perceival Lowell was a wealthy Bostonian who was also an avid amateur
astronomer. He constructed this observatory to study what he believed to be
canals on Mars (Image #7). Mars and Earth were particularly close in 1877,
and during this time the Italian astronomer Giovanni Schiaparelli observed
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what he described as canali (natural waterways) on Mars. This was
misinterpreted by some as “canals” (artificial water courses). Lowell believed
these had been built by Martian civilizations to carry water from the polar caps
for irrigation. This set off a flurry of “Martian” excitement (Images #8 & #9).
The idea of a canal system on Mars has been thoroughly discredited by our
close observations and landings over the past half century. But a study of the
“observation” of canals on Mars might be the object of a psychology project, if
you should ever need one. Some people could see them quite clearly; some
could not see them at all.

Question 3

Mass

Answer 3

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Question 4

Discovering- classification

Answer 4

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Question 5

Blink compactor

Answer 5

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Question 6

New horizons

Answer 6

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Question 7

results

Answer 7

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Question 8

Clean

Answer 8

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Question 9

ceres and the asteroid

Answer 9

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Question 10

discovery

Answer 10

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Question 11

dawn

Answer 11

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Question 12

other asteroids

Answer 12

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Question 13

appollo asteroids

Answer 13

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Question 14

kinlawood gape

Answer 14

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Question 15

trojan asteroids

Answer 15

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