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The Sun is one of billions of stars in the Milky Way galaxy. But here on Earth, it’s everything. Without the Sun, we’d have no food, no flowers, and no calendars. We’d also have no weather—and no sunburns. Our world would be just a frozen rock floating in space.
In early times, people thought the Sun was a powerful god or goddess. But in 430 B.C., the Greek scientist Anaxagoras (an-aks-AG-oo-ras) put forward the idea that the Sun was a flaming rock about 100 miles wide.
Since then, we’ve learned much more about the Sun. Now we know it’s a ball of hot gas. It’s also so huge that more than a million Earths could fit inside it.
Of the billions of stars in our galaxy, the Sun is closest to Earth. It gives us the heat and light that power our planet and makes all life here possible.
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▲ Where Is Our Sun?
Our Sun’s home is on Orion’s Arm. That’s on the outskirts of the Milky Way galaxy. The Sun is also at the center of Earth’s solar system. But that’s not a fixed point in space. While Earth and seven other planets spin around the Sun, the Sun goes around the center of the Milky Way. It’s moving about 150 miles per second. One round trip takes about 225 million years.
◀ The Milky Way has about 200 billion stars. It’s one of about 100 billion galaxies in the universe. The hottest and brightest stars are blue. The medium hottest ones are yellow. The coldest and dimmest are red. Big stars are called giants or supergiants. Smaller ones are called dwarfs. Our Sun is medium size, but it ranks as a yellow dwarf. A star’s temperature is rated on the Kelvin (K) scale. Scientists use this scale to measure extreme heat and cold. About 90 percent of all known stars fall along the Main Sequence.
WARNING!
NEVER look directly at the Sun! Even a short glance can hurt your vision. A long stare could make you blind. Using binoculars and telescopes is even worse. That’s because they make the Sun’s damaging rays even stronger. Sunglasses and other devices will NOT protect your eyes. ▶
Sun Fact
Age
4.6 billion years
