- Attachments :
- Light travels at 657,633,500 miles per hour.
- Light travels at 186,237 miles per second.
- Light travels slower in other medium, or appears to. It really only travels at light speed but in other media it can be absorbed and re-emitted so it appears to be traversing the medium at a slower speed. Light only has 2 speeds. zero or light speed.
- If you see a bolt of lighting and you want to know how far away the lightning struck, you count, 1 second, 2 seconds, 3 seconds, 4 seconds and then the clap of thunder. You waited 4 seconds for the sound to reach you.
- Sound travels at 750 miles per hour.
- Sound travels at 0.208 miles per second.
- Sound travels 1100 feet per second.
- So the lighting strike is 8/10ths of a mile away.
- Meanwhile the lightning has traveled 745,000 miles.
- The Moon is 239,000 miles away so the light would have traveled to the Moon, reflected and traveled back to Earth, re-reflected and traveled back to the Moon while you were waiting to hear the thunder.
- If you were on the Moon you would see the lightning in 2 seconds, but you would wait 13 days for the thunder to arrive.
- Ok, I know, sound can not travel through outer space, so, in fact you would never hear the thunder. The Moon has no atmosphere so there is no sound on the Moon. We intrepret sound as what our ears can hear. Actually, sound is a density wave that our ears are sensitive to and it needs a medium like air to travel through. However, to destroy a myth, outer space is full of sound waves, called density waves.
- The density waves in space are very important to the evolution of our Universe. The sound waves detected in the Cosmic Microwave Background radiation allowed astronomers to calculated the age of the Universe, 13.75 billion years old. The harmonics in the sound wave allowed the calculation of the composition of the Universe to be 73% Dark Matter, 23% Dark Energy, 5% Ordinary Matter. All that we know and understand lies in that little 5%. Density waves are responsible for creating the structure of the galaxies throughout the Universe. Sound waves are responsible for the birth of stars.
- Back to that light that left the lighting bolt. It would take 4 hours of the light to reach Neptune. If we had a spacecraft there we would need to send the radio signal 4 hours early before it told the spacecraft what to do. The we would have to wait another 4 hours for the spacecraft to tell us that it did it.
------------- Neptune is 30 Astronomical Units from the Sun.
------------- We are 1 AU.
------------ 1 AU is 93 million miles.
------------ Light travels 11,200,000 mils per minute.
----------- It takes light 242 minutes to get there 29 AU away.
- To communicate to the nearest star we would have to send the message 4.3 years in advance.
- To get to the Andromeda Galaxy we would need to send it 2,500,000 years in advance, and then wait that long for a response.
-------------- Light travels vast but space has enormous distances. By the way Andromeda Galaxy is the farthest thing you can see with the naked eye. Check it out.
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707-536-3272, Thursday, January 26, 2012
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