The speed of light is one of the fundamental constants in the universe (along with the Gravitational constant, permitivitty etc.). Changing any constant even slightly will have deadly consequences. But if we manage to survive (somehow), we would find ourselves in a very ‘interesting’ universe.
The constant for the speed of electromagnetic waves ‘c’ has a value of 300 million metres/second. Imagine that some one hacks the universe’s secure servers and changes ‘c’ to 1. The following is a roughly chronological list of things that would happen in a universal conspiracy to end the human race:
1. We would shrivel up and die
Literally. The speed of light is directly related to the strength of electromagnetic force. This is the same force that prevents you from falling out of your house when you lean against a wall, or from falling through a chair while you are sitting. It also helps you keep you in shape while gravity is doing its best to pull you to the ground. If the speed of light were to suddenly decrease by several orders of magnitude, all matter (or most of it) would start to collapse under its own gravity. The world would literally shrink out of existence.
2. The sun would go out
Again: literally. As matter collapses under its own gravity, its gravitational pull on the surface increases and stuff like rebellious atoms and people who can afford a rocket will need higher speeds to escape a body’s gravity. Eventually the ‘escape velocity would exceed the speed of light. And since classically one cannot productively travel faster than light, including light, all matter with high escape velocities would become black holes, including the sun and the earth and all the planets in the solar system.
3. Time will s l o w d o w n
If by any miracle we are still alive we will notice (that’s putting it subtly) that everything has shrunk. The gravitational field will be extremely strong. And since light is so slow, our every motion will be at relativistic speeds. That means that on a jolly morning when I decide to go out for a walk, I might as well come back to my house to find it in ruins from age. In other words we wouldn’t need to wait an entire week for new episodes of our favourite shows.
4. The world will look W13rD
Take a look at these pictures:
This is what light looks like if it is slowed down. On a post-hacked universe, you could stand behind something heavy and literally make copies of yourself (gravitational lensing, kage bunshin no jutsu! for Naruto fans). Since light will bend under extreme gravity, you will be able to see whats happening on the other side of the earth, or the back of your head for that matter. You could swipe your hand through the ‘air’ and turn your palm into a black hole and deflect bullets with a wave of your hand.
All in good time. In the real world we would just stop existing the moment a single constant was changed. If all universal constants were scaled down proportionally, we might have a chance, but alas we don’t even know all of them. So why did I conjure images of a Matrix/Naruto/Avengers/ Harry Potter universe? Simple. I just got carried away.