STEM与日常科技·英语30篇（1）

1 / 30

韦布望远镜为何放在拉格朗日点

The James Webb Space Telescope orbits not around Earth, but near the Sun-Earth L2 point — one of five stable gravitational zones.
At L2, the telescope stays in constant alignment with Earth and the Sun, allowing its sunshield to block heat and light from both bodies.
This position keeps its infrared sensors extremely cold, which is essential for detecting faint heat signals from distant galaxies.
Unlike Hubble, which circles Earth every 95 minutes, Webb’s L2 orbit minimizes fuel use and avoids frequent eclipses.
Gravitational forces at L2 balance perfectly, so only tiny thruster adjustments are needed to maintain position over years.
Engineers chose L2 because it offers an unobstructed, thermally stable view of deep space — critical for observing cosmic origins.
Although L2 is 1.5 million kilometers away, communication remains reliable via NASA’s Deep Space Network antennas.
No human maintenance is possible there, so Webb was designed for full autonomy and redundancy before launch.