Posted by: Panamá Jeff | August 13, 2009

Speed Perspective

sunSound and Light

The speed of sound  is roughly 768 mph (1,236 kph), or about one mile in five seconds. Although “the speed of sound” is commonly used to refer specifically to the speed of sound waves in air, the speed of sound can be measured in virtually any substance. Sound travels faster in liquids and non-porous solids than it does in air, traveling about 4.4 times faster in water than in air. That’s pretty fast, comparatively.

Now, the speed of light travels 186,000 miles per second, 1 million times greater than the speed of sound. That’s right, 186,000 miles per second!  Light can travel around the entire Earth 7.4 times in one second. Our sun is 8 or so light minutes away. The distance of the Sun from the Earth is approximately 149.6 million kilometers , and its light travels this distance in 8 minutes and 19 seconds. If the sun were to suddenly explode right now, we wouldn’t know about it for eight minutes because that is how long it would take for the light of the explosion to get here. The closest star to Earth (besides the sun) is something like 24,000,000,000,000 miles (38,000,000,000,000 kilometers) away. That’s the closest star. There are other stars that are billions of times farther away than that!  Let’s say that a star is 1 million light years away. The light from that star has traveled at the speed of light to reach us. Therefore, it has taken the star’s light 1 million years to get here, and the light we are seeing today was created 1 million years ago. So the star we are seeing is really how the star looked a million years ago, not how it looks today. supermanNow I wonder why Superman was only faster than a bullet?

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