You Can't go Faster than Light?
Einstein says that no signal and certainly no physical object can travel faster than light. But why? What would happen if we could travel faster than light? Now the sped of light is just a number. 186,000 miles per second! A big number to be sure but still it’s just a number. Let’s see what would happen of you woke up one day and everything was just as it is except the speed of light had changed to 50 feet per second! That’s only about 35 miles per hour. Let’s see what would happen to a simple game of catch.
You stand in the park and your friend stands 200 feet away. He winds up and throws you a ball. Let’s say he can throw a ball at 100 ft/s. Double the speed of light. What would you see as the catcher?
First of all consider the delay in seeing things at all. Looking at your friend 200 feet away you are seeing his motions delayed by 4 seconds. That’s how long it takes light to travel 200 feet now. Of course you can’t notice this. You see things when you see them. Even now with the real speed of light, light from the sun takes eight minutes to get here so when you gaze at a sunset that actually happened eight minutes ago. In our new pretend universe it is much worse with our pokey speed of light.
Now you see your friend wind up to throw the ball. . . And SMACK! The ball is suddenly in your mitt! What the hell? You never saw it coming. Then you see a ball travel backward out of your mitt toward your friend while you still hold the real baseball. When it gets to the pitcher’s hand it disappears! What just happened? Let’s analyze bit by bit.
The physical ball outran ALL of it’s images. As it traveled from pitcher to catcher light was bouncing off the ball and heading to the catcher’s eyes but no matter where the ball is, it out runs the information about where it was. So, the FIRST thing that happens from the catcher’s point of view is that the ball hits his mitt. The image of the ball about to hit his mitt is only slightly delayed because the ball was close then. That would be what the catcher would see next. Then the image of the ball a little farther away as that is delayed even more. And so on. So while the catcher is holding the ball he would watch another ball - not a ghostly see-through ball but a real gosh darn baseball - travel backward to the pitcher! That ball has to disappear as the catcher is holding the real ball. It would disappear at the point in the pitchers delivery where the ball first broke the speed of light.
Let’s use a chart to analyze more closely. For now accept the idea of “Real Tiime” - “God’s wristwatch” as she gazes down at events. T= 0 is when the ball is released by the pitcher.
C= speed of light = 50 ft/s
V = ball speed = 100 ft/s
All distances in feet and time is in seconds.
The total time columns show that it takes some time for the ball to reach a point and then some additional time for the light from there to reach either the pitcher or the catcher. Baseball travel time + light travel time = total time.
Note: Events happen in the correct order for the pitcher but to him it looks like the ball is traveling at 50 ft/s even though he knows he can throw at 100 ft/s.
200 feet/4 sec = 50 ft/sec
Worse yet for the catcher. He’s watching his friend wind up when WHAM the ball is in his mitt. This is actually 2 seconds after the ball was thrown but all other information about the ball comes AFTER that as you can see in the last column. He would say that the speed of the ball was -100 ft/s. Right number. . . Wrong direction!
Now there is no “God’s wristwatch”. Everyone lives in the same universe and has to deal with making observations and measurements using light information. How could the pitcher or catcher every decide who was “right”? Einstein reasoned that we just don’t live in a universe where events could be seen out of order like our poor catcher is seeing. It would be a real mess if it were otherwise. People would drop dead and THEN the gun would go off! Puppies would be hit by cars and THEN they’d (well, their ghost) would see it coming! Or I should say NOT coming!
Let’s put the pitcher and catcher together as one person, namely, a guy standing by the side of the road ‘watching’ a car go by. A faster than light car that is. As the car approaches, the observer is in the catcher’s position so he sees nothing until, YIKES, a car appears right beside him. Then the car would split into two. One would travel backwards at the correct speed of the car while the real car would continue on at a speed slower than it is really going.
Watching a major league baseball game would also be a bit confusing to say the least. Say you’re siting in the bleachers. Sound is now WAY faster than light. So you see the pitcher just begin his wind up and CRACK. You know the batter is going to hit the ball! Since sound goes at about 1100 feet per second there is only a small delay there but you’re going to have to wait about 8 seconds if your 400 feet away to actually see the batter swing! Better hope the ball isn’t hit at you because you’ll never see it coming! Infielders have NO chance. (No Tinker nor Evers either!)
No, the universe doesn’t work that way. The speed of light cannot be exceeded by anything. That makes this a darn big universe. It probably means that, all the science fiction not withstanding, we ain’t going anywhere. For inter-stellar and galaxy size distances the speed of light is just too pokey. The Milky Way is 100,000 light years across. We’d never get a space ship up to any significant fraction of the speed of light by conventional means which means even the closest stars are years and years of travel time away from us. We could perhaps launch a small civilization on an expedition. The crew that takes off wouldn’t live to arrive at a new home but perhaps their great great great great grandchildren would.
You stand in the park and your friend stands 200 feet away. He winds up and throws you a ball. Let’s say he can throw a ball at 100 ft/s. Double the speed of light. What would you see as the catcher?
First of all consider the delay in seeing things at all. Looking at your friend 200 feet away you are seeing his motions delayed by 4 seconds. That’s how long it takes light to travel 200 feet now. Of course you can’t notice this. You see things when you see them. Even now with the real speed of light, light from the sun takes eight minutes to get here so when you gaze at a sunset that actually happened eight minutes ago. In our new pretend universe it is much worse with our pokey speed of light.
Now you see your friend wind up to throw the ball. . . And SMACK! The ball is suddenly in your mitt! What the hell? You never saw it coming. Then you see a ball travel backward out of your mitt toward your friend while you still hold the real baseball. When it gets to the pitcher’s hand it disappears! What just happened? Let’s analyze bit by bit.
The physical ball outran ALL of it’s images. As it traveled from pitcher to catcher light was bouncing off the ball and heading to the catcher’s eyes but no matter where the ball is, it out runs the information about where it was. So, the FIRST thing that happens from the catcher’s point of view is that the ball hits his mitt. The image of the ball about to hit his mitt is only slightly delayed because the ball was close then. That would be what the catcher would see next. Then the image of the ball a little farther away as that is delayed even more. And so on. So while the catcher is holding the ball he would watch another ball - not a ghostly see-through ball but a real gosh darn baseball - travel backward to the pitcher! That ball has to disappear as the catcher is holding the real ball. It would disappear at the point in the pitchers delivery where the ball first broke the speed of light.
Let’s use a chart to analyze more closely. For now accept the idea of “Real Tiime” - “God’s wristwatch” as she gazes down at events. T= 0 is when the ball is released by the pitcher.
C= speed of light = 50 ft/s
V = ball speed = 100 ft/s
All distances in feet and time is in seconds.
The total time columns show that it takes some time for the ball to reach a point and then some additional time for the light from there to reach either the pitcher or the catcher. Baseball travel time + light travel time = total time.
Note: Events happen in the correct order for the pitcher but to him it looks like the ball is traveling at 50 ft/s even though he knows he can throw at 100 ft/s.
200 feet/4 sec = 50 ft/sec
Worse yet for the catcher. He’s watching his friend wind up when WHAM the ball is in his mitt. This is actually 2 seconds after the ball was thrown but all other information about the ball comes AFTER that as you can see in the last column. He would say that the speed of the ball was -100 ft/s. Right number. . . Wrong direction!
Now there is no “God’s wristwatch”. Everyone lives in the same universe and has to deal with making observations and measurements using light information. How could the pitcher or catcher every decide who was “right”? Einstein reasoned that we just don’t live in a universe where events could be seen out of order like our poor catcher is seeing. It would be a real mess if it were otherwise. People would drop dead and THEN the gun would go off! Puppies would be hit by cars and THEN they’d (well, their ghost) would see it coming! Or I should say NOT coming!
Let’s put the pitcher and catcher together as one person, namely, a guy standing by the side of the road ‘watching’ a car go by. A faster than light car that is. As the car approaches, the observer is in the catcher’s position so he sees nothing until, YIKES, a car appears right beside him. Then the car would split into two. One would travel backwards at the correct speed of the car while the real car would continue on at a speed slower than it is really going.
Watching a major league baseball game would also be a bit confusing to say the least. Say you’re siting in the bleachers. Sound is now WAY faster than light. So you see the pitcher just begin his wind up and CRACK. You know the batter is going to hit the ball! Since sound goes at about 1100 feet per second there is only a small delay there but you’re going to have to wait about 8 seconds if your 400 feet away to actually see the batter swing! Better hope the ball isn’t hit at you because you’ll never see it coming! Infielders have NO chance. (No Tinker nor Evers either!)
No, the universe doesn’t work that way. The speed of light cannot be exceeded by anything. That makes this a darn big universe. It probably means that, all the science fiction not withstanding, we ain’t going anywhere. For inter-stellar and galaxy size distances the speed of light is just too pokey. The Milky Way is 100,000 light years across. We’d never get a space ship up to any significant fraction of the speed of light by conventional means which means even the closest stars are years and years of travel time away from us. We could perhaps launch a small civilization on an expedition. The crew that takes off wouldn’t live to arrive at a new home but perhaps their great great great great grandchildren would.
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