Chapter 119 Question 1: Inertial Reference System
Einstein stood on the stage, with a crowded crowd below.
He adjusted his condition to the best and then turned on the projector. He had already practiced under the guidance of Li Qiwei before.
Suddenly, a huge light and shadow was projected on the wall behind.
The writing on the screen is clear and the colors are bright. Even those in the last row of the venue can see it clearly.
Now displayed on the homepage are the words "The First Symposium on Relativity".
That was written by Einstein on the spot.
Anything he writes on the projector's template will be displayed on the big screen in real time.
It looks completely the same as the PPT of later generations, and it is more convenient to modify.
The participants were attracted by this gadget on the spot. It was simply an instrument tailor-made for scientists to hold meetings.
But soon, they were shocked by the content of the speech.
With the blessing of the projector, Einstein was even more powerful.
As a young man in his twenties, he didn’t know what foreshadowing, turning point, warm-up, etc. were.
Tear up the formulas with your hands, click them, and directly deduce the core formulas of the theory of relativity on the spot.
“Everyone, the premise of the theory of relativity is two axioms.”
"The first is that in all inertial reference systems (reference systems at rest or linear motion), all physical laws are equivalent."
"The second is that in all inertial reference systems, light The speed c in a vacuum never changes. "
"The core of the theory of relativity is the relativity of space and time."
"Only by understanding that space and time are relative can we reasonably explain the speed of light. "
"And according to the formula, the speed of any material cannot reach the speed of light, and the speed of information transmission cannot exceed the speed of light."
“The faster an object travels, the slower the time it takes relative to a stationary observer.”
“The length of an object measured in the direction of motion also becomes shorter.”
"It should be noted that the shortening here is relative to a stationary observer."
"The observer on the object itself will not change when measuring the size of the object."
"The above is the core conclusion of the theory of relativity."
"According to Newton's absolute space-time point of view, time and space are independent of each other."
"And both are evenly distributed and have nothing to do with the motion state of the object."
"But the theory of relativity holds that , space-time is an indivisible whole, and they are related to the speed of movement of objects. "
"These are the explanations of the theory of relativity. Please feel free to ask questions."
Wait until Einstein finishes. , there was a moment of silence in the venue at first.
Everyone looked at the formula on the screen, thinking secretly, and making exclamations from time to time.
Einstein’s explanation on the spot was indeed more vivid and easier to understand than reading the paper himself.
Soon, some young people who were not afraid of tigers as newborn calves began to ask questions at Lorenz’s signal.
The first person to appear was Laue. In real history, Laue later became Einstein's lifelong best friend, and the two often exchanged academic ideas together.
“Hello, Einstein.”
"My question is, since the premise of the theory of relativity is that an object must be in an inertial reference frame to be valid."
"So, if an object is moving with acceleration, how should the theory of relativity deal with it."
< br>"It can't be just a theory that needs strict restrictions."
When the question came up, it did not cause the commotion as expected.
Obviously, this is a basic question, which is very suitable for a young Karami like Laue to raise.
Almost all the physicists and physicists present can think of it.
After Einstein listened carefully to the question, he smiled and said: "Thank you very much for your question, Laue, this is a very good question."
"Newton's laws of motion are established. The premise is also an inertial system. "
"But when dealing with accelerated objects, Newton's laws of motion still apply."
"Similarly, although the theory of relativity is based on an inertial system, it does not. This means that it cannot handle motion in non-inertial frames.”
“If an object moves at variable speeds in an inertial frame, we can use the idea of calculus to solve it.”
“That is to establish multiple instantaneous inertial frames, and then perform integral operations on all processes.” In this way, the theory of relativity can be used to describe the variable speed.”
Let’s talk, Einstein will do the math directly.
Immediately calculate the LQW transformation, in which the integral of the change in speed dazzled the people present.
Everyone admired in their hearts that the young man on the stage had a very strong foundation in mathematics.
Soon, a beautiful result was displayed in front of everyone.
The theory of relativity can completely handle the problem of non-inertial systems.
Laue was also impressed by the simple and beautiful proof process. He first applauded to express his approval.
Immediately afterwards, there was moderate applause in the venue.
Obviously, a small inertial system problem is not enough to impress the physics masters.
At this time, another young man asked a question. Li Qiwei looked at him and it turned out to be Born.
At the last exchange meeting for young scholars, this young man left a very deep impression on everyone.
He has sharp vision, tricky angles, and leaping thinking. He is an out-and-out genius.
Sure enough, Born raised a sharp question:
"Hello Einstein, my question requires a thought experiment."
"Suppose there are two identical trains A and B, moving at close to the speed of light."
"They On two parallel tracks, A is on top and B is on the bottom, running towards each other at the same speed. "
"We make a rule."
"Event 1 represents the front of train A. Meeting at the back of train B”
"Event 2 means that the front of train B and the rear of train A meet."
"If we stand on a stationary ground and look at it, events 1 and 2 should happen at the same time."
"However, according to the calculations of the theory of relativity, people on train A will observe that train B becomes shorter due to the movement of train B."
"This is caused by the shrinkage effect deduced by you."
“So, for the people on train A, event 1 happens first and event 2 happens after.”
"But in the same way, for the people on train B, it becomes that event 2 happens first, and event 1 happens after."
"Isn't this a contradiction? Obviously events 1 and 2 should It happens at the same time.”
“How does the theory of relativity explain this problem?”
Wow!
After Born’s question was raised, everyone present looked sideways at this naughty young man.
Many people don't even understand the question, what are 1 and 2, A and B, but they still don't understand the seriousness of it.
Even the physics masters couldn’t help but observe each other. The young people who asked questions were not simple!
This thought experiment is very interesting, and it is essentially a problem between reference systems.
But after thinking logically, you can find the contradictions between the theory of relativity and logic.
Awesome!
Everyone commented to Born in their hearts.
Today, besides studying physics, Born’s favorite thing is logic and mathematics.
That’s why he was able to find loopholes in the so-called theory of relativity with his extremely insightful ideas.
Einstein also admired Born very much, thinking that the heroes in the world are really like the prince crossing the river, so happy!
He quickly drew a diagram on the screen based on Born's question.
Sure enough, when the schematic diagram came out, everyone understood the problem.
Then I discovered that Born, you are really a fucking genius.
This question seems to be very contradictory indeed.
It is obviously the same thing, but how come different people observe it in different order?
As a result, everyone in the venue couldn't help but look at Einstein.
They wanted to know how the young man could explain this problem.
On the stage, Einstein smiled slightly, as if he had everything under control.
Does anyone know about Born’s problem?
(End of this chapter)