Many people think that the theory of relativity is very far away from us, and the time and space curve is completely irrelevant to us, even if we do not believe that the space-time is curved, or there is no concept.
When Einstein published general relativity predicts that when the curvature of space-time, the British sent two fleet, until the total eclipses, rushed to the distant place two on earth, were measured the sun blocked starlight, finally prove time is curved.
Walk ten thousand miles long road, only in order to verify the stars by the sun bending 0.00046 degrees (1.65). But this is the most important part of human history, we have a fundamental change in the understanding of time, space, and the universe.
Over the past 100 years, now general relativity has been widely accepted by scientists, but many people still do not believe that space is curved, because even the space we have not seen the bending, and bending time? Time bending and what is it like? Is there anything we can do to prove that time is curved?
The evidence is in our hands, almost everyone will use the mobile phone GPS satellite navigation. The basic principle of GPS navigation is that the mobile phone receives at least four different positions of the earth's GPS satellite launch time and position signals, through the comparison of the calculation of their own position, marked on the map. So why does the GPS satellite navigation system prove that the time is curved? This principle has already been known to many people, here is a brief introduction.
The bending of time is measured by the time becomes slow. According to general relativity, the speed of motion of an object will cause its time to bend, and the faster the speed of the object, the slower it becomes. The GPS satellite orbits at a speed of about 14 thousand km / h, and it's time will be slowed by 7 s per day.
General relativity also believes that the mass of the object will lead to the time and space around the bend, the specific performance in the closer to the quality of the object, the time will become more slowly. GPS is running about twenty thousand kilometers from the earth's orbit, and its time is about 45 sec faster than the earth's surface.
Synthesis of two effects, the time on the GPS satellite is bent, the day will be approximately 38 s per day, after calculation, this will lead to the positioning accuracy of the ground accumulated deviation of about 11 km per day. When the United States launched the first GPS satellite, did not take into account the space-time bending effect of general relativity, resulting in a fundamental can not be used to locate. That is how to solve this problem? Very simple, engineers will be the atomic clock on the GPS satellite to move slowly around 10 billion minutes 4.465, GPS satellite will be able to send the correct time and position signal to the receiving device. Of course, I think the United States launched the first GPS satellite will find this issue is likely to be false, just to increase the dramatic events, because only a single satellite can not be positioned.
So, if you use the phone GPS navigation, you have to practice the Einstein's general theory of relativity.