The universe is an incredibly vast expanse, and its size is difficult to comprehend. The speed of light, which is approximately 299,792 kilometers per second (186,282 miles per second) in a vacuum, is the fastest known speed in the universe. However, even at this incredible speed, it still takes an enormous amount of time for light to traverse the vast distances across the universe.
The observable universe, which is the portion of the universe we can currently observe, has a diameter of about 93 billion light-years. This means that it would take light approximately 93 billion years to travel from one end of the observable universe to the other.
It's important to note that the concept of "across the universe" is a bit challenging since the universe is constantly expanding, and our current understanding of its size and structure is limited. Additionally, due to the expansion of the universe, some distant objects that are currently beyond our observable universe will eventually become visible to us in the future.
In summary, the time it takes for light to go across the universe depends on the size and structure of the universe, and it would take an incredibly long period of time for light to travel across its vast distances.