冥王星有大气吗？它如何随季节变化？
Does Pluto have an atmosphere, and how does it change with seasons?
冥王星有一层极稀薄的大气，主要成分是氮，来自表面氮冰的升华。由于冥王星轨道偏心率大、有季节变化，当它靠近太阳时大气膨胀，远离时部分气体又会冻结回表面。这种大气会随公转周期显著『呼吸』。
Pluto has an extremely thin nitrogen atmosphere from the sublimation of surface nitrogen ice. Because its orbit is highly eccentric with strong seasons, the atmosphere expands when Pluto nears the Sun and partly freezes back onto the surface when it recedes. The atmosphere thus 'breathes' over its orbital cycle.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
苏宜,《天文学新概论》第5版,科学出版社
Su Yi, Introduction to Astronomy, 5th ed., Science Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787030620477（豆瓣书目条目: 天文学新概论）
#冥王星 #大气 #氮
阋神星为什么曾威胁冥王星的行星地位？
Why did Eris threaten Pluto's planetary status?
2005年发现的阋神星质量甚至比冥王星还大，且同样位于外太阳系，这迫使天文界正视『行星』该如何界定的问题。如果冥王星算行星，阋神星及更多类似天体也该算，行星数目将失控。这一矛盾直接促成了2006年矮行星分类的诞生。
Eris, found in 2005, is actually more massive than Pluto and also lies in the outer solar system, forcing astronomers to face how 'planet' should be defined. If Pluto counted, Eris and many more would too, and the planet count would explode. This tension directly led to the 2006 dwarf-planet category.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
苏宜,《天文学新概论》第5版,科学出版社
Su Yi, Introduction to Astronomy, 5th ed., Science Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787030620477（豆瓣书目条目: 天文学新概论）
#阋神星 #冥王星 #矮行星
冥卫一卡戎与冥王星有什么特殊关系？
What is special about Pluto's moon Charon and its relationship with Pluto?
冥卫一卡戎质量约为冥王星的五分之一，两者相互潮汐锁定，永远以同一面朝向彼此，形成少见的『双矮行星』系统。它们的共同质心落在两者之外，因此更像一对互相绕转的伙伴。这一系统为研究矮行星演化和碰撞起源提供了线索。
Charon is about one-fifth of Pluto's mass, and the pair are mutually tidally locked, always showing the same face to each other, forming a rare 'binary dwarf planet' system. Their center of mass lies between them, so they behave more like partners orbiting a point in space. The system offers clues to dwarf-planet evolution and collision origins.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
苏宜,《天文学新概论》第5版,科学出版社
Su Yi, Introduction to Astronomy, 5th ed., Science Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787030620477（豆瓣书目条目: 天文学新概论）
#冥卫一 #卡戎 #相互锁定
国际天文学联合会如何定义矮行星？
How does the IAU define a dwarf planet?
矮行星需满足：绕太阳公转、自身重力使其接近球形、但未能清空轨道附近的其他天体。它比大行星少最后一条要求，所以冥王星、谷神星、阋神星等都属此类。矮行星是太阳系小天体中的重要一类。
A dwarf planet must orbit the Sun, be roughly round under its own gravity, but have failed to clear its orbital neighborhood. It lacks only the last condition of a full planet, so Pluto, Ceres and Eris qualify. Dwarf planets are an important class of small solar-system bodies.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
苏宜,《天文学新概论》第5版,科学出版社
Su Yi, Introduction to Astronomy, 5th ed., Science Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787030620477（豆瓣书目条目: 天文学新概论）
#矮行星 #行星定义 #太阳系
冥王星为什么在 2006 年被降级为矮行星？
Why was Pluto demoted to a dwarf planet in 2006?
国际天文学联合会新定义行星须清空其轨道附近区域，而冥王星未能做到，且柯伊伯带中还有类似大小天体，于是它被归为矮行星。
The IAU redefined a planet as something that has cleared its orbital neighborhood; Pluto has not, and similar-sized bodies exist in the Kuiper Belt, so it was reclassified as a dwarf planet.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
苏宜,《天文学新概论》第5版,科学出版社
Su Yi, Introduction to Astronomy, 5th ed., Science Press
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787030620477（豆瓣书目条目: 天文学新概论）
#冥王星 #矮行星 #定义