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NASA astronauts Sunita Williams and Butch Wilmore successfully returned to Earth on March 19 after spending months in space. Their journey ended with a dramatic splashdown in the SpaceX Dragon spacecraft off the coast of Florida at approximately 3:30 AM.
Assisting in their recovery were fellow astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov.
Their return marked the conclusion of the Crew-9 mission, which departed the International Space Station (ISS) on March 18, completing a journey of over 15 hours.
As the world eagerly awaited Williams’ return, online searches for her name surged. According to Google Trends, searches for Sunita Williams reached a staggering 2 million in the past two days.
With her latest mission drawing to a close, interest has also grown around her experiences aboard the Starliner and SpaceX missions.
Funny you should say that… astronauts actually age more slowly in orbit than on Earth (because of the Station’s speed and time dilation due to special relativity) BUT the effect is very small – after spending six months on the ISS, astronauts have aged about 0.005 seconds less…
— European Space Agency (@esa) February 24, 2024
Why Do Astronauts Age Slower in Space?
One of the most fascinating aspects of space travel is time dilation, a phenomenon where astronauts age slightly slower compared to people on Earth. This effect is rooted in Einstein’s Theory of Relativity, which states that time is not absolute—it is influenced by gravity and velocity.
Time moves slower in stronger gravitational fields. Since gravity is weaker in space compared to Earth, astronauts experience a minuscule slowdown in their aging process.
The faster an object moves, the slower time progresses for it. Since astronauts on the ISS travel at speeds of approximately 28,000 km/h, they experience a slight reduction in their aging rate.
These two effects occur simultaneously on the ISS, leading to astronauts aging approximately 0.005 seconds less after spending six months in space, as confirmed by the European Space Agency (ESA).
Scientific Proof of Time Dilation
The concept of time dilation has been experimentally verified using highly precise atomic clocks placed on:
Fast-moving aircraft
Satellites in orbit
Regions with strong gravitational fields
While the difference is almost imperceptible for short-duration space missions, the effect becomes more significant when traveling at extremely high speeds or being near intense gravitational forces for extended periods.
The Twin Paradox: A Mind-Boggling Thought Experiment
To illustrate time dilation, physicists often refer to the Twin Paradox:
One twin remains on Earth while the other travels at near-light speed.
Upon returning, the space-traveling twin would have aged significantly less than the one who stayed behind.
Although astronauts on the ISS do not travel at such extreme speeds, the combination of weaker gravity and high velocity still causes a small but measurable difference in aging.
If you’ve ever wished for a longer weekend, you technically can—by either moving extremely fast or spending time in lower gravity. While this won’t make your days feel longer, you might just gain a fraction of a second in the race against time!
