Content tagged "light-years".
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The night sky looks packed with stars. But shrink the Sun to a ping-pong ball (4 cm across), and Earth becomes a grain of sand 4.3 meters away, while the nearest star is another ping-pong ball roughly 1,100 km off. Set it down in Tokyo, and that star lands south of Kagoshima. In between: almost total vacuum. With over 100 billion stars in our galaxy, the universe is mostly made of the gaps between them.
Sunlight takes about 8 minutes to reach Earth. Light from Proxima Centauri, the nearest star beyond the Sun, takes over four years. Every star you see at night is a snapshot of its past -- and no one can ever see what's happening there right now.
Sunlight left the Sun about eight minutes ago. Light from Proxima Centauri, our nearest star, is about 4.2 years old. The Andromeda Galaxy's light is roughly 2.5 million years old. Because light speed is finite, looking farther always means looking further back in time. SORABUMI translates this into everyday scale to explain why a single glance at the night sky holds hundreds of millions of years at once.