Does Flash age slower because of his ability to run at relativistic speed?

Question

Due to Time dilation, time is perceived differently at greater speed.

Time dilation is an actual difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses.

Time dilation explains why two working clocks will report different times after different accelerations. For example, ISS astronauts return from missions having aged slightly less than they would have been if they had remained on Earth.

And, we know the Flash can run even faster than light.

Is the effect on his aging ever mentioned anywhere?

Answer 1

The wikipedia entry you reference describes two opposing forms of time dilation, one that will make you age quicker and one that will make you age slower. Both have noticeable effect only on extremely extended or close to light speed movement. The ISS astronauts, for instance, said to have aged slower, by 0.007 seconds for every 6 months on the station.

Consider, however, that The Flash mostly runs around on Earth. The earth's circumference is about 40,000 kilometers. Even if the Flash runs at only 13% of light speed, he can go around the entire earth in one second. As I understand it, he spends 99% of his time in "normal speed", only gearing up for full speed when necessary. This means that to achieve a sizeable time dilation will take decades, probably. Maybe more.

(Disclaimer: I did not really run any numbers here, neither for time dilation or for aggregated time spent in near light speed. I'm going mostly by intuition here)

Answer 2

No, the Flash does not get any significant aging benefit because he is running at faster than light speeds. There are several limitations which need to be taken into account:

• He spends the bulk of his life moving at a normal pace and thus does not utilize his relativistic movement except in extreme emergencies. His average pace around the city is only around 180-200 miles per hour.

• Given the extremes of speed once you start reaching Mach 10 or more, the Flash, even with his speed aura is reluctant to approach relativistic speeds. More importantly, there are almost no reasons he would need to approach even ten percent of the speed of light while on Earth which would approach 6,706,166 miles per hour (circling the Earth 268 times in a hour).

• When he is moving at a percentage of light speed which varies from writer to writer, his speed is so great whatever feat he is performing happens and ends within a few seconds and rarely lasts for more than a few minutes tops.

The Flash empties an entire city in North Korea (2 people at a time in a few seconds).

• Relativistic aging benefits would only occur if he were maintaining a sustained top speed for a significant amount of time, say if he were moving from star to star. Depending on his top speed he might slow his aging considerable in comparison to the flow of time on Earth.

The Flash's powers are not clearly defined by the laws of physics, nor by the DC Comics franchise. We are left unfortunately to speculate as to how he defies or obeys the laws of physics as determined by the writer/editor team at the moment.

See also:

1. Can the Flash see the future?
2. How does the Flash perceive time?
3. Why isn't the Flash unstoppable?

Answer 3

For arguments sake, I would like to think that any time he does gain from the small amount of time dilation he might experience (as stated in more depth in the other answers) is lost due to his accelerated metabolism. It seems he uses a lot more energy and puts a lot more stress on his body when at full speed, so it would seem the two would likely cancel each other out.

Answer 4

My theory is (now it's not necessarily the case, but just a thought) if his body is being sped up meaning like in S1 of the CW's flash when Felicity asks if his newly gotten powers make him age faster which Dr. Wells doesn't answer but instead says "everything we're doing here is for Barry's own good". But to the point, if his speed powers were making him age faster, his accelerated healing should theoretically cancel it out.

Answer 5

Well consider this: the Flash's metabolism is faster than any human's and as a side effect he ages slower. When a human gets older their metabolism gets slower and their cells begin to die, so because of that the Flash's metabolism, which as many fans already know, moves faster so then he would age slower.

Answer 6

In the flash when felicity come to central city and Barry in on the treadmill that Cisco makes she asks if his body is sped up then won't he age faster and wells said no while his body is moving faster everything else is slowed down including how fast she ages that why reverse flash tell him they would be enemy's for centuries and reverse flash was from156 years in the future so there you have it the flash ages slower