How does the speed of light limit what we can see of the universe?

The speed of light limits what we can see of the universe due to its finite speed.

The speed of light is the fastest speed at which anything can travel in the universe. It travels at a speed of approximately 299,792,458 metres per second in a vacuum. This means that light from distant objects takes time to reach us, and the further away an object is, the longer it takes for its light to reach us.

For example, the nearest star to us, Proxima Centauri, is approximately 4.24 light-years away. This means that the light we see from Proxima Centauri today actually left the star over four years ago. Therefore, we are seeing the star as it was four years ago, not as it is now.

The speed of light also limits the size of the observable universe. The universe is estimated to be around 13.8 billion years old, meaning that the light from the most distant objects we can observe has been travelling towards us for 13.8 billion years. Anything beyond this distance is simply too far away for its light to have reached us yet.

In summary, the speed of light limits what we can see of the universe by making distant objects appear as they were in the past and by restricting the size of the observable universe.