No, it is not true that one hour in outer space is equal to seven years on Earth. The idea that time passes differently in space is based on the concept of time dilation, which is a consequence of Einstein's theory of relativity.
Time dilation occurs due to differences in gravitational forces and relative motion. When an object is in a strong gravitational field or moving at very high speeds, time appears to pass more slowly for that object compared to a stationary observer or an object in a weaker gravitational field.
However, the time dilation effects experienced by astronauts in space are relatively small. For example, astronauts aboard the International Space Station (ISS), which orbits at a distance of about 400 kilometers (250 miles) from Earth's surface, experience a time dilation of about 0.01 seconds for every six months spent in space. This means that after spending one year on the ISS, they would have aged about 0.02 seconds less compared to someone on Earth.
So, while there is a slight time dilation effect, it is nowhere near the magnitude of one hour in space being equivalent to seven years on Earth.