The Sun: what it is and how it turns
NASA Science Editorial Team · 2024
Learn how it is built, then write your own with it: for each sentence and paragraph, learn the example, see its structure, and write your own — with AI grading.
NASA names the Sun, places it, and then explains why a day there is not one length. Every sentence carries a single fact, and the hard idea arrives only after the plain ones have prepared it.
What you will practice
- 01Put one fact in one sentence
- 02Give a number a comparison the reader already holds
- 03Answer a hard question by first defining the thing it is about
Prepared source text
161 words · 11 sentencesOur Sun is a 4.5 billion-year-old yellow dwarf star – a hot glowing ball of hydrogen and helium – at the center of our solar system. It’s about 93 million miles (150 million kilometers) from Earth and it’s our solar system’s only star. Without the Sun’s energy, life as we know it could not exist on our home planet.
The Sun is the only star in our solar system. It is the center of our solar system, and its gravity holds the solar system together. Everything in our solar system revolves around it – the planets, asteroids, comets, and tiny bits of space debris.
Measuring a “day” on the Sun is complicated. The Sun is made of super-hot, electrically charged gas called plasma. This plasma rotates at different speeds on different parts of the Sun. At its equator, the Sun completes one rotation in 25 Earth days. At its poles, the Sun rotates once on its axis every 36 Earth days.
Source and rights
A work of the United States federal government, which carries no copyright in the United States under 17 U.S.C. §105. Scripta reproduces the wording as published and normalizes only typography.