In order to determine how far your superhero would have to go to require a full second to travel, we need to consider the speed of light and the concept of time dilation.
The speed of light in a vacuum is approximately 299,792 kilometers per second. If your superhero is capable of moving at this speed, we can calculate the distance required for a full second of travel by multiplying the speed of light by one second:
299,792 kilometers/second * 1 second = 299,792 kilometers
So, your superhero would need to travel approximately 299,792 kilometers to require a full second of travel time.
Now, let's discuss the concept of time dilation. According to Einstein's theory of relativity, as an object approaches the speed of light, time appears to slow down for that object relative to a stationary observer. This effect is known as time dilation. As your superhero moves at speeds close to the speed of light, time dilation would come into play.
If your superhero is moving at the speed of light, time dilation would cause time to stand still from their perspective. This means that, for your superhero, there would be no subjective experience of time during their journey. However, from the perspective of an external observer, time would continue to pass normally.
It's important to note that reaching the speed of light is not currently considered possible for massive objects due to the energy requirements involved. Nevertheless, for the purposes of your superhero story, you can invoke fictional elements to allow for this power.
Remember that time dilation and the exact consequences of moving at the speed of light are still areas of active research and theoretical understanding. So, as an author, you have some creative freedom to shape the specifics of how time dilation affects your superhero's abilities in your novel.