In the context of space travel, the concept of "aging faster" is often associated with time dilation, which is a consequence of Einstein's theory of relativity. Time dilation occurs when an object or person is moving relative to another reference frame or experiencing a stronger gravitational field.
In space, particularly during high-speed interstellar travel or near massive objects like black holes, time dilation can occur. Essentially, this means that time would appear to pass more slowly for the moving object or person compared to a stationary observer. This effect has been observed and verified experimentally through various experiments and measurements.
So, to clarify, it's not that individuals in space are physically decaying more quickly. Instead, their experience of time is different from those on Earth. From their perspective, they may perceive time passing more slowly relative to someone on Earth. This effect is often referred to as "time travel" in popular culture because an astronaut traveling at high speeds or in a strong gravitational field could potentially return to Earth and find that more time has passed for people on Earth than for the astronaut.
It's important to note that the time dilation effects experienced by astronauts in space are relatively small unless they are traveling at extremely high speeds or in close proximity to massive objects. For most space missions, the time dilation effects are negligible and do not significantly impact the aging process of astronauts.