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The Sun is one of billions of stars in the Milky Way galaxy. Yet to us here on Earth, it is everything. Without the Sun, we’d have no food, no flowers, no calendars, no weather—and no nasty sunburns. Our world would be just another frozen rock floating in space.
In earliest times, people thought that 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 in fact a flaming rock about 100 miles wide.
Since then, we’ve learned a great deal more about the Sun. For example, we now know that it’s actually 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 the closest to Earth. It provides the heat and light that power our planet, making all life here possible.
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▲ Where Is Our Sun?
Our Sun’s home is on Orion’s Arm, on the outskirts of the Milky Way galaxy. It also lies 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 travels about 150 miles per second around the center of the Milky Way galaxy. One round trip takes roughly 225 million years.
◀ The Milky Way, with about 200 billion stars, is one of around 100 billion galaxies in the universe. The hottest and brightest stars are blue. Those with medium heat are yellow. The coldest and dimmest ones are red. Big ones are called giants or supergiants. Smaller ones are called dwarfs. Although its size is in the middle range, our Sun is classified as a yellow dwarf. The temperature for the stars is rated on the Kelvin (K) scale. Scientists use this scale to measure extreme temperatures. About 90 percent of all known stars fall along the Main Sequence.
WARNING!
NEVER look directly at the Sun! Even a brief glance can hurt your vision, and a long stare can cause blindness. Using binoculars and telescopes is even more dangerous, because they concentrate the Sun’s damaging rays. Sunglasses and other devices will NOT protect your eyes. ▶
Sun Fact
Age
4.6 billion years
