No, it is not true that one hour in space is equivalent to seven years on Earth. This statement is a common misconception or an exaggeration often found in science fiction.
The idea behind this misconception may stem from the concept of time dilation, which is a real phenomenon predicted by Albert Einstein's theory of relativity. According to the theory of relativity, time can be affected by gravity and relative motion. When an object is in motion or experiences intense gravitational forces, time can appear to pass differently for that object compared to a stationary observer.
In practical terms, this means that time would appear to pass slightly slower for an object in motion or under the influence of strong gravity compared to a stationary observer. However, the effect is relatively small and would require extreme conditions to become noticeable. For example, for an astronaut aboard the International Space Station (ISS), time dilation due to their motion and proximity to Earth's gravity is very small and negligible.
The notion that one hour in space is equivalent to seven years on Earth is an exaggeration and not supported by scientific evidence. The actual time dilation effects experienced by astronauts in space missions are far less significant.