Shapiro delay facts for kids
The Shapiro time delay is a cool physics experiment. It's one of the main ways scientists test Einstein's general relativity theory using our Solar System.
Imagine sending a radar signal past a huge object, like the Sun. This experiment shows that the signal takes a tiny bit longer to travel to its target and come back. It's like the massive object makes space a little "sticky" for the signal!
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How the Time Delay Was Discovered
The idea of this time delay was first thought of in 1964. A smart scientist named Irwin I. Shapiro predicted it. He suggested a way to test his idea.
Shapiro proposed bouncing radar beams off the surfaces of Venus and Mercury. Then, scientists would measure how long the round trip took.
Testing Shapiro's Prediction
When the Earth, Sun, and Venus line up just right, Shapiro calculated something amazing. He figured out that a radar signal traveling from Earth to Venus and back would be delayed. This delay would be about 200 microseconds.
A microsecond is a super tiny amount of time. It's one millionth of a second! Even back in the 1960s, technology was good enough to measure such small delays.
First Successful Tests
The first tests happened in 1966 and 1967. Scientists used a special radar antenna at the MIT Haystack Observatory. These tests were a big success!
The results perfectly matched the predicted time delay. Since then, these experiments have been done many more times. Each time, they get even more accurate, confirming Shapiro's idea.
Images for kids
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Left: Light rays traveling in empty space. Right: Light rays bending and slowing down near a massive object (click to see the animation).
See also
In Spanish: Efecto Shapiro para niños
