I have always wondered if time-lapse affects astronauts by the time they come back to the earth after spending considerable time in space. Do they grow older or younger than they are supposed to be or there is no difference? I know it's not likely that the rocket travels at a speed close to that of light.
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I suppose you mean astronauts, it actually depends on what they are doing in outer space. If they are not moving at all or moving around Earth at speeds lesser than that our planet (average orbital speed of earth is about 1670 km/hr), then they would grow older from our (we on Earth) perspective. But if they move at speeds greater than that of earth then we observe them to grow younger and this is generally due to "relative velocity time dilation". There's actually a space station (located outer space) called ISS (international space station) - it's main purpose is to carry out experimental researches not possible in our planet, it moves at a speed of about 27,600 km/hr (it moves relatively faster than Earth) so astronauts there if they get back to Earth, would look younger than they are supposed to be. But for the fact that the speed is still far lesser than the vacuum speed of light, we won't notice it.
Interesting