## Jul 16 The Edge of The Universe.

Where is the edge of the universe? Most importantly, what happens if we try to get there? Let's state the obvious, surely there can be no edge to our universe if the universe is infinite. On the other hand, how can it be part of our universe if we can't interact with it? After all, the universe is all the space and time that exists.

General relativity tells us that the universe is flat and that galaxies go on forever. Although how flat? It is difficult to imagine that anyone can measure the curvature of the Universe to a definite accuracy.

The universe that we can see, the 93 billion light years in diameter, is the observable universe. An astronomically large distance. If you stand at one end and fire a laser pointer it would take 93 billion years to reach the other side. The radius of the universe is 46 billion light years in all directions from our point of observation outward.

This doesn't make us or our solar system/galaxy the centre of the universe. The distance of 46 billion light years away is only the maximum distance that we can currently see. The maximum distance that light is currently reaching us from.

The Universe is expanding and that expansion is accelerating. To recap, the universe is expanding at 71 km per second per 32,000,000 or so light years. If you see a galaxy 32,000,000 away through a telescope it is currently moving away at 71km/ per second. So how do we see it? Simply because when it emitted the light we can see now it was closer to us.

At the moment we would only be able to travel to that 46 billion light year point if the universe stopped expanding. At 46 billion light years away the universe is expanding faster than the speed of light! Even if we somehow built a space ship that can travel 186,282 miles per second in a vacuum, we still wouldn't reach the edge of the known universe as it will have expanded away from us faster than the spaceship could carry us.

Like black holes, the universe also has an event horizon. To recap again, beyond the event horizon nothing can escape or communicate with us. Not even light! The event horizon of our universe is around 16 billion light years away. There Galaxies can be observed that we will never be able to communicate with. At this point the galaxy is moving away from us faster than light and therefore faster than a radio signal message.

So let's assume we can build a warp drive capable of 5x faster than light travel to chase the edge of the universe. What will we find? Probably just more Universe. The "edge" of the universe at 46 billion light years away from us is the furthest point that we can see. Not necessarily the end of the universe itself.

You never know, maybe there is life beyond the edge of what we can see. The fact is we will simply never know. So what if we go further again past the edge of the known universe? That depends on the shape of the universe....

Jude Morrow