十万个为什么·科学启蒙30篇（4）

18 / 30

已读 0 / 30 课

为什么卫星能绕地球运行不掉下来

Satellites stay in orbit because they move forward so fast that Earth’s gravity pulls them into a curved path instead of straight down.
This balance between forward velocity and gravitational pull creates continuous free-fall around the planet.
Low Earth orbit satellites travel about 17,500 miles per hour to maintain stable circular paths.
If they moved slower, gravity would dominate and bring them down; if faster, they’d drift away into space.
Orbital height matters too—higher orbits require less speed but take longer to circle Earth.
Engineers calculate precise launch angles and velocities using Newton’s laws and Einstein’s relativity corrections.
Atmospheric drag is minimal above 120 miles, allowing satellites to orbit for years without propulsion.
Solar radiation pressure and gravitational tugs from the Moon or Sun cause tiny orbital changes over time.
Ground stations track positions and occasionally fire small thrusters to adjust orbits as needed.
This delicate dance of motion and gravity lets satellites deliver GPS, weather data, and global communications reliably.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

This balance between forward velocity and gravitational pull creates continuous free-fall around the planet. 这种前向速度与引力之间的平衡，形成了围绕地球持续的自由落体运动。
Orbital height matters too—higher orbits require less speed but take longer to circle Earth. 轨道高度也很关键——高度越高，所需速度越低，但绕地球一圈耗时越长。
Engineers calculate precise launch angles and velocities using Newton’s laws and Einstein’s relativity corrections. 工程师依据牛顿定律并结合爱因斯坦相对论修正，精确计算发射角度和速度。

这篇中文题目最接近哪一句？为什么卫星能绕地球运行不掉下来一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？卫星能保持在轨道上，是因为其前进速度极快，使地球引力将其拉入一条弯曲路径，而非直线下坠。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why Satellites Orbit Earth Without Falling Down How to cook noodles A maths worksheet

This balance between forward velocity and gravitational pull creates continuous free-fall around the planet.

This balance between forward velocity and gravitational pull creates continuous free-fall around the planet.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：This balance between forward velocity and gravitational pull creates continuous free-fall around the planet.