以下題目取自Professor Wu (University of Toronto) 的教材:
1. The surface of the Earth is very lightly cratered, while that of Mercury is very heavily cratered. This is because:
a) The Earth was not subject to such a heavy bombardment as Mercury, since it is not so close to the sun.
b) The Earth』s atmosphere protected it from falling bodies, while Mercury has no atmosphere.
c) The Earth is larger than Mercury.
d) None of the above.
2. What is the frost-line? Where was its rough location in the proto-planetary nebula that surrounded the Sun?
a) the distance from the Sun where temperatures were low enough for rocks to condense, between the present-day orbits of Mercury and Venus
b) the distance from the Sun where temperatures were low enough for hydrogen and helium to condense, between the present-day orbits of Jupiter and Saturn
c) the distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present -day orbits of Mars and Jupiter
d) the distance from the Sun where temperatures were low enough for asteroids to form, between the present-day orbits of Venus and Earth
e) the distance from the Sun where temperatures were low enough for metals to condense, between the Sun and the present-day orbit of Mercury
3. According to our theory of solar system formation, why do we find terrestrial planets in the inner solar system and jovian planets in the outer solar system?
a) Hydrogen compounds, which were much more abundant than rock or metal in the solar nebula, could condense into ice only in the outer solar system.
b) There was more solid material in the inner solar system, so collisions prevented large jovian planets from forming.
c) The solar nebula contained only rocky and metallic material in the inner solar system and only light gases and hydrogen compounds in the outer solar system.
d) The density of gas in the solar nebula was much greater in the outer regions, so bigger planets could form.
4. According to our theory of solar system formation, what is the origin of asteroids and comets?
a) Asteroids and comets represent material from interstellar space that was captured in the solar nebula by gravity.
b) Asteroids are chunks of pure metal that condensed in the solar nebula, and comets are chunks of pure rock that condensed in the solar nebula.
c) Asteroids and comets are both leftover planetesimals that formed between the orbits of Mars and Jupiter.
d) Asteroids are the remains of a terrestrial planet that shattered, and comets are the remains of a jovian planet that shattered.
e)Asteroids are the leftover planetesimals of the inner solar system, and comets are the left-over planetesimals that formed beyond the frost line.
5. Why do asteroids and comets differ in composition?
a) Asteroids and comets formed at different times.
b) Comets formed from the jovian nebula, while asteroids did not.
c) Asteroids formed inside the frost line, while comets formed outside.
d) Comets are much larger than asteroids.
6. Why does the plasma tail of a comet always point away from the Sun?
a) The solar wind blows the ions directly away from the Sun.
b) The conservation of the angular momentum of the tail keeps it always pointing away from the Sun.
c) Gases from the comet, heated by the Sun, push the tail away from the Sun.
d) Radiation pressure from the Sun』s light pushes the ions away.
7. Comets with extremely elliptical orbits, like comets Hyakutake and Hale-Bopp,
a) come from the asteroid belt.
b) come from the Kuiper belt.
c) are captured by Jupiter.
d) come from the Oort cloud.
AKOW 011 - 天文問答．太陽系篇
我又估:
1. The surface of the Earth is very lightly cratered, while that of Mercury is very heavily cratered. This is because:
d)
2. What is the frost-line? Where was its rough location in the proto-planetary nebula that surrounded the Sun?
c) the distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present-day orbits of Mars and Jupiter
3. According to our theory of solar system formation, why do we find terrestrial planets in the inner solar system and jovian planets in the outer solar system?
b) There was more solid material in the inner solar system, so collisions prevented large jovian planets from forming.
4. According to our theory of solar system formation, what is the origin of asteroids and comets?
e)Asteroids are the leftover planetesimals of the inner solar system, and comets are the left-over planetesimals that formed beyond the frost line.
5. Why do asteroids and comets differ in composition?
c) Asteroids formed inside the frost line, while comets formed outside.
6. Why does the plasma tail of a comet always point away from the Sun?
a) The solar wind blows the ions directly away from the Sun.
7. Comets with extremely elliptical orbits, like comets Hyakutake and Hale-Bopp,
b) come from the Kuiper belt.
1. The surface of the Earth is very lightly cratered, while that of Mercury is very heavily cratered. This is because:
d)
2. What is the frost-line? Where was its rough location in the proto-planetary nebula that surrounded the Sun?
c) the distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present-day orbits of Mars and Jupiter
3. According to our theory of solar system formation, why do we find terrestrial planets in the inner solar system and jovian planets in the outer solar system?
b) There was more solid material in the inner solar system, so collisions prevented large jovian planets from forming.
4. According to our theory of solar system formation, what is the origin of asteroids and comets?
e)Asteroids are the leftover planetesimals of the inner solar system, and comets are the left-over planetesimals that formed beyond the frost line.
5. Why do asteroids and comets differ in composition?
c) Asteroids formed inside the frost line, while comets formed outside.
6. Why does the plasma tail of a comet always point away from the Sun?
a) The solar wind blows the ions directly away from the Sun.
7. Comets with extremely elliptical orbits, like comets Hyakutake and Hale-Bopp,
b) come from the Kuiper belt.
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david_kmng
- 白矮星
- 文章: 960
- 註冊時間: 週五 11 7月, 2003 00:10
- 來自: 草根階層
1) b. The atmosphere not only help us to burn the meteors but also create weathering effect.
2) c. Frost-line is a new word to me. I believe it is c)
3) a and c are so close. The reason is that metal have a higher melting/boiling point and heavier atomic weight. So the inner solar system provides a better environment to form Earth-like planets. It also relates to the The escape velocity of gases as they have lighter atomic/molecular weight. I choose a.
4) e.
5) c.
6) d.
7) d.
bcaecdd
Regards,
David
Happy new year!!!!!
2) c. Frost-line is a new word to me. I believe it is c)
3) a and c are so close. The reason is that metal have a higher melting/boiling point and heavier atomic weight. So the inner solar system provides a better environment to form Earth-like planets. It also relates to the The escape velocity of gases as they have lighter atomic/molecular weight. I choose a.
4) e.
5) c.
6) d.
7) d.
bcaecdd
Regards,
David
Happy new year!!!!!
不愧為啟明兄, 答中了...六題!
惟一錯的一題是第6題: 正確答案是a.
Comets usually have 2 tails: the dust tail & the plasma tail.
Radiation pressure from solar light pushes dust grains away from the comet, forming the dust tail.
Solar wind blows ions away, forming the plasma tail.
E.g. Comet Hale-Bopp
It has a white dust tail and blue plasma tail.
大家知道為甚麼離子尾(ion tail)是藍色的嗎?
P.S. 新年快樂!! ^^
惟一錯的一題是第6題: 正確答案是a.
Comets usually have 2 tails: the dust tail & the plasma tail.
Radiation pressure from solar light pushes dust grains away from the comet, forming the dust tail.
Solar wind blows ions away, forming the plasma tail.
E.g. Comet Hale-Bopp
It has a white dust tail and blue plasma tail.
大家知道為甚麼離子尾(ion tail)是藍色的嗎?
P.S. 新年快樂!! ^^
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