general relativity and light
I woke up and read some more of "The Elegant Universe." I read about general relativity, some elements of special relativity, and the properties of light.
Regarding general relativity, quoted from book:
"When your companion throws the grenade, it will still fly toward you, but because you are running, the speed with which it approaches you will be less than 20 feet per second. In fact, common experience tells us that if you can run at, say, 12 feet per second then the hand grenade will approach you at (20-12=) 8 feet per second."
However, according to intensive years of research, no matter if you are running away from light, running after light, running towards light, or watching it pass you, it will always be measured going the same speed, which is 670 million miles per hour. In this way, you cannot theoretically "catch up" to the speed of light, as it does not slow down relative to another object's movement. And even if you are running away from a beam of light, it will not slow down relatively to you, and will still bypass you moving the same speed as though you were stationary.
To quote from the book:
"No matter how hard you chase after a light beam, it still retreats from you at light speed. You can't make the apparent speed with which light departs one iota less than 670 million miles per hour, let alone slow it down to the point of appearing stationary. Case closed."
My question after initially reading was this:
Though you cannot theoretically catch up to light, what if you depart at the same exact time a light beam is turned on in the same precise direction of the light beam, traveling at light speed? Won't light then appear stationary next to you?
I felt this question was not answered, but now I understand it. Even if I am moving at 670 million miles per hour, light is not going to slow down relatively. It will still pass me at 670 million miles per hour as though I was stationary. General relativity simply does not apply to light. Hence, special relativity. (At least I THINK I've got this right. It may deserve another re-read).
It still is baffling and seems impossible on an intuitive level, especially once you've accepted and understood the general gist of general relativity. But I understand it in theory, and I am intrigued.
I really love this book. ^___^;
Regarding general relativity, quoted from book:
"When your companion throws the grenade, it will still fly toward you, but because you are running, the speed with which it approaches you will be less than 20 feet per second. In fact, common experience tells us that if you can run at, say, 12 feet per second then the hand grenade will approach you at (20-12=) 8 feet per second."
However, according to intensive years of research, no matter if you are running away from light, running after light, running towards light, or watching it pass you, it will always be measured going the same speed, which is 670 million miles per hour. In this way, you cannot theoretically "catch up" to the speed of light, as it does not slow down relative to another object's movement. And even if you are running away from a beam of light, it will not slow down relatively to you, and will still bypass you moving the same speed as though you were stationary.
To quote from the book:
"No matter how hard you chase after a light beam, it still retreats from you at light speed. You can't make the apparent speed with which light departs one iota less than 670 million miles per hour, let alone slow it down to the point of appearing stationary. Case closed."
My question after initially reading was this:
Though you cannot theoretically catch up to light, what if you depart at the same exact time a light beam is turned on in the same precise direction of the light beam, traveling at light speed? Won't light then appear stationary next to you?
I felt this question was not answered, but now I understand it. Even if I am moving at 670 million miles per hour, light is not going to slow down relatively. It will still pass me at 670 million miles per hour as though I was stationary. General relativity simply does not apply to light. Hence, special relativity. (At least I THINK I've got this right. It may deserve another re-read).
It still is baffling and seems impossible on an intuitive level, especially once you've accepted and understood the general gist of general relativity. But I understand it in theory, and I am intrigued.
I really love this book. ^___^;