Speed of light 3x10

1)ACTUAL SPEED OF LIGHT:

In the vacuum of the universe, light travels at a speed of 299,792,458 meters (983,571,056 feet) per second. 186,282 miles per second - also called c, or the speed of light - is a universal constant in equations.

The majority of modern physics is based on Albert Einstein's theory of special relativity, which states that nothing can travel faster than light. As matter approaches the speed of light, the mass of that matter becomes infinite. As a result, the speed of light is the speed limit of the universe. 
The moon is about 1 light-second away from our eyes since light travels from the moon to our eyes in about 1 second. Considering that sunlight takes 8 minutes to reach our eyes, the sun is approximately 8 light-minutes away. Our nearest star system, Alpha Centauri, is 4.3 light-years away. Light from Alpha Centauri takes 4.3 years to reach us, so Alpha Centauri is 4.3 light-years away.


One light-year is a distance that can be covered by light in an entire year - about 6 trillion miles (10 trillion kilometers). Astronomers and physicists use this method to measure distances across the universe.

2) HISTORY OF MEASURING SPEED OF LIGHT:

In the 5th century B.C., Empedocles and Aristotle disagreed about light speed. Emeptocles believed that light, whatever it was, had to travel and, therefore, must have a rate of travel. Aristotle explained that light, unlike sound and smell, is instantaneous. There was no way to prove Aristotle wrong for hundreds of years, of course.

 In the middle of the 1600s, according to PBS NOVA, Galileo Galilei put two identical people on hills less than a mile apart. Both held lanterns. A lantern was uncovered by one person; once the other saw the flash, he too uncovered his. But Galileo's experimental distance wasn't far enough for his participants to record the speed of light. He could only conclude that light traveled at least 10 times faster than sound.  

Poland-born Albert A. Michelson was another scientist who investigated the speed of light mystery. Since Michelson's original measurement of 186,355 miles per second (299,910 km/s), the speed of light has been known to be the most accurate for 40 years until Michelson retraced his steps. The Space magazine reported that in his third attempt, just days before he died in 1931, he constructed a mile-long depressurized steel tube pipe. It simulated a near-vacuum that would eliminate any effect of air on speed, allowing an even finer measurement, slightly below the speed of light today. As a result, he became the only person in history to win a Nobel Prize for not discovering anything. In the end, the experiment was a complete failure, but the lessons we learned from it are far more valuable to humanity today and our understanding of the universe than any success!

3) EINSTEIN'S THEORY OF RELATIVITY:

The equation E = mc*2 combines energy, matter, and speed of light in Einstein's theory of special relativity. Small amounts of mass (m) contain inherently enormous amounts of energy (E) and thus constitute the relationship between the two. A nuclear bomb is so powerful because it is converting mass into blasts of energy. Since energy equals mass times the speed of light squared, the speed of light serves as a conversion factor, explaining how much energy must exist within matter. Moreover, since the speed of light is so great, even small masses must equal vast quantities of energy.
Taking the speed of light into account is critical for Einstein's elegant equation to accurately describe the universe. According to Einstein, light moves through a vacuum, and in such a manner that it moves the same speed regardless of the observer's speed. 
Regardless of how the universe evolves, Einstein's elegant equation requires the speed of light to remain a constant. As Einstein proposed, light moves through a vacuum, and in such a way that it moves at the same speed regardless of the observer's speed. 
As Einstein said, the speed of light doesn't fluctuate with time and place or with speed of movement.

The speed of light cannot be reached by objects with mass, according to this theory. The mass of an object would become infinite if it ever reached the speed of light. So the object's movement would require infinite energy as well. 
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