极光是怎么形成的？
How do auroras form?
太阳风带来的带电粒子被地球磁场引导到两极上空，与高层大气中的氧、氮原子碰撞使其激发。这些原子回到基态时放出红、绿、蓝等颜色的光，形成极光。因此极光多出现在高纬度地区。
Charged particles from the solar wind are steered by Earth's magnetic field toward the poles, where they collide with oxygen and nitrogen atoms in the upper atmosphere and excite them. As those atoms return to lower energy they emit red, green and blue light, forming auroras. That is why auroras appear mainly at high latitudes.
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
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#极光 #太阳风 #磁场
地球的磁场是怎么产生的？
How is Earth's magnetic field generated?
地球外核是高温液态的铁镍，因热量对流和地球自转产生环流，形成类似发电机的效应，称为地磁发电机。它产生包裹地球的磁层，偏转太阳风、保护大气和生命。磁场还会缓慢漂移甚至偶发倒转。
Earth's outer core is hot liquid iron and nickel whose convection, combined with Earth's rotation, acts like a dynamo and generates the magnetic field. It creates a magnetosphere that deflects the solar wind and shields the atmosphere and life. The field also drifts slowly and occasionally reverses.
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
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#地球 #磁场 #外核
温室效应对地球是好事还是坏事？
Is the greenhouse effect good or bad for Earth?
适度的温室效应是必要的，大气中的二氧化碳和水蒸气留住部分热量，使地表平均温度约15摄氏度，适宜生命。问题在于人类活动排放过多二氧化碳，增强了这种效应，导致全球变暖。所以温室效应本身不可或缺，过强才有问题。
A moderate greenhouse effect is essential: carbon dioxide and water vapor trap some heat, keeping Earth's average temperature near 15 degrees Celsius, suitable for life. The problem is that human activity emits too much carbon dioxide and strengthens the effect, driving global warming. So the greenhouse effect itself is necessary; only an excessive one is harmful.
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
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#地球 #温室效应 #气候
为什么南半球和北半球的季节正好相反？
Why are the seasons opposite in the northern and southern hemispheres?
地球自转轴倾斜约23.4度，公转过程中两个半球轮流更正对阳光。北半球朝向太阳时，那里是夏天，同一时刻南半球受到的是斜射阳光，正处于冬天。半年之后情况刚好互换。
Earth's axis is tilted about 23.4 degrees, so as the planet orbits the Sun the two hemispheres take turns leaning toward the light. When the north leans sunward it has summer, while the south receives slanting light and has winter. Half a year later the situation is exactly reversed.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#季节 #地轴倾斜
地球在太空里跑得有多快？
How fast does Earth travel through space?
地球绕太阳公转的速度约每秒30公里，比子弹快得多。因为身边没有可以对比的参照物，我们一点也感觉不到。
Earth races around the Sun at about 30 kilometres every second, far faster than a bullet. We never feel it because there is nothing nearby to compare our motion with.
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
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#地球 #公转
从太空看地球为什么是蓝色的？
Why does Earth look blue from space?
地球表面约71%被海洋覆盖，液态水对阳光中的蓝光散射和反射较强。大气分子也会散射短波的蓝光，使地球边缘呈现蓝色光晕。因此地球在太空中看起来是一颗蓝白相间的『蓝色弹珠』。
About 71 percent of Earth's surface is covered by oceans, and liquid water strongly scatters and reflects the blue part of sunlight. Air molecules also scatter short-wavelength blue light, giving the planet a blue rim. So from space Earth appears as a blue-and-white 'blue marble'.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#地球 #海洋 #大气散射
极昼和极夜是怎么形成的？
What causes the midnight sun and the polar night?
由于地轴倾斜，夏季极圈以内的地区整天都处在被阳光照到的一侧，太阳整夜不落，这就是极昼。半年后同一地区整天位于背光一侧，于是出现极夜。纬度越高，极昼极夜持续得越久。
Because Earth's axis is tilted, in summer places inside the polar circles stay on the sunlit side all day long, so the Sun never sets and daylight lasts through the night. Half a year later the same places sit on the shaded side all day and the polar night begins. The higher the latitude, the longer each one lasts.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#极昼极夜 #极圈
为什么不同季节能看到不同的星座？
Why do we see different constellations in different seasons?
地球绕太阳公转，夜晚背向太阳的那片天区一年之中不断改变。冬夜正对着的星空，到了夏天恰好被白昼的太阳挡在后面。所以猎户座是冬季夜空的主角，夏天则轮到天蝎座。
As Earth travels around the Sun, the patch of sky on our night side keeps shifting through the year. The region we face on winter nights ends up behind the daytime Sun in summer. That is why Orion dominates winter evenings while Scorpius takes over in summer.
难度 入门 · 适合 小学高段(9-12)
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）
#星空 #地球公转
我们为什么不会从地球上飘走？
Why don't we float off the Earth?
地球有一种看不见的力叫引力，一直轻轻把我们往下拉。所以我们能稳稳地站在地面上。
Earth pulls on us with an invisible force called gravity, holding us gently down. That is why we stay firmly on the ground.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#引力 #地球
为什么在月球上能跳得更高？
Why can you jump higher on the Moon?
月球比地球小得多，表面引力只有地球的六分之一左右。用同样的力气蹬地，人就能跳得更高，落下来也更慢。
The Moon is much smaller than Earth, so its surface gravity is only about one sixth as strong. With the same push off the ground, you rise higher and come down more slowly.
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
Carl Sagan,《Cosmos》Random House,1980;中译《宇宙》
C. Sagan, Cosmos, Random House, 1980; Chinese ed.
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9780394502946（按标识回读: Cosmos）
#月球 #引力